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佐藤 良博, 小田 泰子, 斉藤 肇
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Recent development of the proton-decoupled pulsed Fourier transform nmr method have opened the way to employ ^2H nmr to various types of chemical and biological problems. In the elucidation of the biosynthetic pathways of griseofulvin (1) by Penicillium urticae, we demonstrate that ^2H nmr is very powerful nondestructive method to study biosynthetic pathways involving hydrogen. Earlier studies from our laboratories have demonstrated the incorporation of [2-^3H, 2-^<14>C]acetate using the shaking culture of P. urticae. In order to investigate the behavior of hydrogens in detail, sodium [2-^2H_3]acetate was added to the seven-days-old mycelia of the microorganism in the synthetic medium, giving ^2H-enriched griseofulvin for ^2H nmr analysis. In order to perform unambiguous assignment of ^2H signals, a series of selectively deuterated griseofulvin samples were prepared. Figure 1 shows ^2H nmr spectra of deuterated griseofulvin samples, indicating the incorporation of deuterium atoms at 5, 3', 5'α, 6'-methyl, and methoxyls. Those assignments were confirmed from measurements of T_1s and comparison of the peak intensities with those of proton-coupled spectra. The extent of deuterium incorporation was unequivocally obtained from the measurement of peak areas. In addition, seven-days-old mycelia of P. urticae were fermented in the media containing 50% D_2O and cold sodium acetate. ^2H nmr studies show that the deuterium atoms from D_2O were incorporated in the positions anticipated from the results of [2-^2H_3]acetate tracer experiment (Figure 2). As an another application of ^2H nmr, we have investigated the microbial transformation of dehydrogriseofulvin (3) by Streptomyces cinereocrocatus, proving the stereochemistry of the reduction of 3 to griseofulvin and the hydroxylation of the latter to 5'α-hydroxygriseofulvin (4) (Figure 3 and Scheme 1).
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大村 智, 田中 晴雄, 小山 泰昭, 長井 敏明, 丸茂 博大
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In the course of our research for new antibiotics produced by actinomycetes, new antibiotics, nanaomycins A, B, C and D, effective against mycoplasma, fungi and Gram-positive bacteria were obtained from the cultured broth of a strain which had been isolated from a soil sample collected at Nanao-shi, Ishikawa prefecture and designated Streptomyces rosa var. notoensis. Evidence is put forward which describes the structure and stereochemistry of nanaomycins A, B, C and D, as I, V, IV and VI, respectively. In order to study biosynthesis and to determine the position of the hydroxyl group in the naphthoquinone moiety, a feeding experiment with [1-^<13>C] acetate was effectively carried out. Nanaomycins are synthesized from 8 acetate units via a "polyketide" in S. rosa var. notoensis. Since the carbon atom adjacent to the phenolic hydroxyl group was enriched with [1-^<13>C] acetate, the hydroxyl group is not at C-6 position but must be at C-9 position. The absolute configuration was determined by ORD comparisons. The results indicated that nanaomycin D is an enantiomer of kalafungin produced by S. tanashiensis. The production of each enantiomer by two different species belonging to the genus Streptomyces is of interest in the biosynthesis of a series of these antibiotics.
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小倉 治夫, 古畑 公夫, 原田 義則, 飯高 洋一
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Structures of p-bromobenzoylpikromycin (11), 8,9-anhydropikromycin hydrobromide (10) and bis-p-bromobenzoyloleandomycin (20) were fully confirmed by X-ray crystallographic analyses. The conformation of the 14-membered macrolide antibiotics is discussed on the "diamond lattice" conformation models (A, B, C, D, and E). In conclusion, the most favorable "diamond lattice" conformation model A, C, D, and E are applied to the compounds 2, 9, 12, 13, 18; 5, 6, 7, 14; 8, 11; 3, 4, 20, erythronolide B, triacetyloleandomycin, respectively. New "diamond lattice" conformation models C, D, and E are proposed as shown in Figures 7, 8, and 9, respectively.
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通 和夫, 十倉 一也, 岡部 啓, 江幡 光雄, 大塚 英夫, 松下 和弘, G. Lukacs
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Sulfur-containing peptide antibiotics, siomycins (SIM) A, B, and C isolated from Streptomyces sioyaensis are known to have structures quite similar to that of thiostrepton (TST) isolated from S. azureus. The 25-MHz ^<13>C FT NMR and 220-MHz ^1H NMR spectra of TST and SIM's were determined in CDCl_3-CD_3OD (8: 2) at various temperatures to obtain structural relationships between these antibiotics. ^<13>C signals were tentatively assigned by ^1H noise decoupling, single-frequency and noise off-resonance decouplings, and partially-relaxed FT techniques and using known chemical-shift rules, the chemical shifts of amino acids reported, and those observed for thiostreptine and a quinaldic acid derivative. Their ^<13>C spectra quite similar to each other revealed the numbers of carbon atoms and dehydroalanine (Deala) residues. It was found that (1) the signals of the Val-Deala residues in SIM's are changed to those of the Ile-Ala residue in TST, that (2) SIM-B lacks of the terminal Deala-Deala residue in the long side-chain, and that (3) SIM-C has an unknown amino-acid residue instead of the terminal Deala. On the basis of the above spectral and other chemical studies, and a tentative structure (Ia) proposed for TST by an X-ray crystallographic analysis, the structures Ib, II, and III were concluded to be assigned to TST, and SIM-A and -B, respectively.
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野本 信也, 豊島 正, 若宮 建昭, 芝 哲夫
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The antituberculous peptide capreomycin (Cpm), isolated from Streptomyces capreolus, is composed of four congeners, Cpm IA,IB, IIA, and IIB. The structure of Cpm was first proposed by Bycroft et al. in 1971. However, since we could not agree with it on the analogy of the structure of the similar antibiotics tuberactinomycin (Tum) group, we investigated the structure of Cpm by means of NMR analysis and chemical degradacions. From the results of the comparative study on the NMR spectra of Cpm and Tum, the structures in the cyclic peptide moieties of Cpm IA and IB were newly proposed. The β-Lys residue as a branched part was determined to be linked at β-amino group of Dpr^3 residue from the results of Edman degradation and detection of β-DNP-Dpr in the hydrolyzates of DNP derivatives. Since this conclusion was further supported by the exact analysis of NMR, the total structure of Cpm was correctly determined. In order to confirm the proposed structure, we performed the total sytheses of Cpm IA and IB. The synthetic products were identical with the natural Cpm IA and IB respectively in all aspects. Consequently, the structure of Cpm was first clearly established.
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宮本 正志, 近藤 信一, 長縄 博, 前田 謙二, 大野 雅二, 梅沢 浜夫
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Neothramycin is a new antitumor antibiotic isolated from a culture filtrate of Streptomyces No. MC916-C4, and exhibits a marked prolongation-effect in the survival period of mice implanted with leukemia L-1210 cells. We report here the structure established on the basis of spectral data, chemical degradations and total synthesis. In an aqueous solution, neothramycin exists as a mixture of two isomers, neothramycins A and B (1a and 1b, C_<13>H_<14>N_2O_4). A mixture of the corresponding O-alkylneothramycins A and B are easily obtained either from neothramycin A or B by simple treatment with anhydrous alcohols. Alkaline hydrolysis of butylneothramycin A (3a) with Ba(OH)_2-saturated aqueous solution afforded 4-hydroxy-5-methoxyanthranilic acid identical with synthetic one. Treatment of 3a with phenyldiazomethane followed by mild hydrolysis with 0.01N HCl-dioxane (1: 1 in volume) gave a mixture of O-benzylneothramycins A and B. It was oxidized with KMnO_4 in acetone to afford a compound (5). Acid hydrolysis of 5 with HCl at 105℃ gave a slightly racemized mixture of L-glutamic acid hydrochloride From the results of the chemical degradations and the PMR data (Table 1), the absolute structures of 1a and 1b were elucidated as (3S,11aS)- and (3R,11aS)-2,3,5,11a-tetrahydro-3,8-dihydroxy-7-methoxy-5-oxo-1H-pyrrolo[2,1-c][1,4]benzodiazepine, respectively. A total synthesis of neothramycin was designed to approach by a new route different from that of anthramycin. Thus, neothramycin has been synthesized starting from vanillic acid (6) through 7-step procedure (Fig. 2), in which the key stage involves ring formation of the 1,4-benzodiazepine with retention of the absolute configuration.
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高久 洋, 加藤 正篤, 畑 辻明
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8-Quinolyl group has been used as a protecting group of phosphates of the internucleotidic bonds. A triester, 2-cyanoethyl 8-quinolyl 5'-O-monomethoxytritylnucleoside 3'-phosphate is a key intermediate in the synthesis of deoxyribooligonucleotide. The utility of this protecting function, and the triester method, is indicated by the synthesis of a several di-,tri-, and tetra- nucleotides. The tetranucleotides were prepared by fragment condensation from two dinucleotide unites.
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土田 清美, 池田 一芳, 水野 義久
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The present report deals with the synthesis of isowillardiine (II) and the polyoxin skeleton which have the α-aminouracil structure in common, by the four-component (aldehyde, isocyanide, amine, and organic oxyacid) condensation (Ugi reaction). This reaction permited us to synthesize the above structure (in their protected forms) in one step starting from the corresponding aldehyde. Removal of the protecting group in VIII under conditions of 9N HCl-48 hr afforded isowillardiine, whereas many attempts at complete removal of the protection to XVI is not rewarding, yet.
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後藤 俊夫, 星野 力, 高瀬 茂弘
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Commelinin is a blue pigment which was reported to be composed of 2 molecules each of awobanin (A) (an anthocyanin) and flavocommelin (F) (a flavone) and 1 atom each of Mg and K. Its extraordinary stability and blue color were explained in terms of complex formation of Mg^<++> with A and F. We found, however, that commelinin is constructed from A and F in the absence of Mg^<++>. Molecular weight of commelinin was determined in 3M NaCl by centrifugation method to be 1400-5600, mainly 4100±400. A proposed structure of commelinin is shown in Fig. 2 and 3, in which A and F are associated to form a tight molecular complex. The driving force for the formation of the complex would be hydrophobic interactions between the aromatic rings of A and F, and covering the hydrophobic parts with glucose residues. The AF complexes further associate each other to form (AF)_2, (AF)_3, etc. Addition of F strongly retards the decomposition of commelinin in water, whereas Mg^<++> and A pseudobase have no effect. A mechanism is proposed for this phenomenon.
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伊藤 祥輔, Giovanna Nardi, Giuseppe Prota
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Adenochrome, the iron (III)-containing pigment from the branchial heart of Octopus vulgaris, has been isolated as colorless des ferri-adenochrome (DFA) and shown to consist of a mixture of closely related peptides formed from glycine and two novel amino acids, adenochromines A (1a) and B (1b), the ratio of glycine to adenochro mines being 2: 1. On acid hydrolysis with 6M-HCl-4% thioglycolic acid DFA gave glycine and adenochromines (1), along with some secoadenochromines (2) and the thiol (3) which proved to be derived from (1) by an unusual cleavage of thioether bonds (Scheme 1). Hydrolysis of DFA with 57% HI-red phosphorous yielded glycine, L-dopa (5), and 5-thiol-L-histidine (3; N^1 being partially methylated) in a molar ratio of 2: 1: 2. Further information on the structure of (1) was provided by hydrolysis of (1a) or (1b) with 48% HBr-4% thioglycolic acid which gave, besides (3) and (5), secoadenochromine A (2a). Moreover, on air oxidation of the two isomers only (1a) is converted to an amino chrome-like pigment (Fig.2), suggesting that position 6 is unsubstitute. Adenochromines (1) may be formed in vivo by addition of 5-thiohistidine (3) to dopaquinone arising from tyrosine by tyrosinase oxidation (Scheme 2), as in model experiments the same reaction gave (1) and (2). Of particular biological significance are the findings that the same adenochrome occurs in various parts of Octopus and that a possible biosynthetic precursor is found in the white body which might be the site of biosynthesis.
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岩田 正彰, 葛原 弘美, 江本 栄
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A chiral pyridoxal analogue (5) was prepared from pyridoxine (vitamine B_6, 3). The synthesis consists of three stages. In the first stage, 3 was converted into a dichloride 11 via several modified reactions. The next stage included synthesis of ansa-compounds such as 13 and 14 and subsequent oxidation of 14 to pyridoxal derivatives (4). In the last stage, one of 4 (n=5) was optically resolved to 5 via Schiff's base formation with an amino sugar derivative (17) and subsequent hydrolysis. Compound 5 catalyzed the racemization of L-and D-glutamic acids in different rates.
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大類 洋, 江本 栄
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(+)-Biotin(I) was synthesized from D-mannose(1). (+)-Avenaciolide(IIa) and (-)-Avenaciolide(IIb) were synthesized from D-glucose(17) and the absolute configuration of natural Avenaciolide was determined as IIb. (S)-(-)-Frontalin(III) was also synthesized stereoselectively from D-glucose(17) and the absolute configuration of natural Frontalin was determined unequivocally as III. Thus, carbohydrates have been shown to be very useful starting materials for the synthesis of optically active natural products other than sugar derivatives.
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小川 智也, 松井 正直
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Recently silylated organic molecules have been extensively employed in organic reactions in order to modify the reactivity of original molecules in the field of carbohydrates and nucleoside chemistry. In this report we described both mild and specific transformations of carbohydrates based on the reactivity of trialkylstannylated compounds. [I] O-Glycoside Synthesis: a) Lewis Acid Catalysed Method; Reaction of acetobromoglucose 1 with tri-n-butylstannyl alkoxides in the presence of equivalent amount of Lewis acid gave corresponding O-glycosides in good to fair yields. (see Table 1) b) Modified Koenigs-Knorr Method; Reaction of 1 with tri-n-butylstannyl alkoxides inthe presence of silver salts such as AgBF_4 gave corresponding β-glycosides in good yields. c) 1,2-cis Glycoside Synthesis; Reaction of 2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl chloride with tri-n-butylstannyl alkoxides in the presence of halide anion gave α-glycosides such as 3 or 4 in reasonable yields. d) Orthoester Method; Reaction of acetohalogenoses such as 1, 11,13 with stannylated alkoxides in the presence of bromide anion gave good yields of orthoesters. (see Table 2) e) O-Glycosyl Ester Synthesis; Reaction of 1 with trialkylstannyl carboxylic esters in the presence of bromide anion gave corresponding O-glycosyl esters in good yields. [II] S-Glycoside Synthesis: The reaction of readily available tri-n-butylstannyl alkylsulfides with acetbromoglucose 1 in the presence of Lewis acid gave good yields of the mixture of α and β-thioglycosides. By employing peracylated mono- and di-saccharides in stead of halosugar high yields of thioglycosides could be obtained in a stereo-specific manner. (see Table 3 and 4)
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市原 耿民, 白石 久二雄, 佐藤 博二, 坂村 貞雄, 西山 幸司, 酒井 隆太郎, 古崎 昭雄, 松本 毅
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Coronatine (1), produced by Ps. coronafacience var. atropurpurea, is chlorosis-inducing toxin on the leaf of italian rye grass and also has an activity to expand potato cells in the concentration of 1×10^<-7>mole/1. Coronatine consists of two parts, coronamic acid (4) and coronafacic acid (16a), which are bonded each other by an amide linkage. The former, confirmed by the synthesis, is an unique amino acid having cyclopropane ring (NH_2/CH_2CH_3, trans). The latter exists as two stereoisomers, (16a) and/or (16b) depending on the conditions of crystallization. The erroneous structure (15, R=H) assumed firstly for coronafacic acid was proved to be incorrect by the synthesis, and another possible structure for coronafacic acid was deduced from the spectroscopic data of the derivatives, and conclusive structure was obtained by X-ray crystallographic analysis of (16b), which has not been encountered in nature. Coronatine, resulted by partial synthesis from natural (16a) and synthetic (4), shows the same phsiological activity as natural specimen.
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井上 博之, 上田 伸一, 井上 謙一郎, 塩原 義則, 和田 稲美
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Systematic examination by methods including GC-MS of the constituents in the benzene extract of Catalpa ovata cultured cells demonstrated the presence of menaquinone-1, dehydro-iso-α-lapachones, 1-hydroxy-2-methylanthraquinone etc. along with the known constituents of the wood of this plant such as catalpalactone and α-lapachones. Administration of 1-(^<14>C-carboxy)-o-succinylbenzoic acid (OSB) to the callus tissues followed by dilution analysis enabled us to confirm the incorporation of OSB into each of the callus constituents and to trap various biosynthetic intermediates. These results revealed the presence of the main biosynthetic pathway (COT→prenyl-COT→catalponone) and a subsidiary one (CHT→prenyl-CHT→catalponol) and also revealed the stereochemistry of prenylation. It was also clarified from the results of the administration of (1'-^3H, 1-(^<14>C-carboxy))-OSB to the intact Catalpa plant that OSB is directly cyclized to COT, which is then reduced to CHT.
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野村 太郎, 深井 俊夫, 山田 サチ子, 平野 陽司, 片柳 眞佐
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The structures of five new flavone derivatives, morusin, cyclo-morusin, compound A, kuwanone A, and kuwanone B, which had been isolated from the root bark of the cultivated mulberry tree (a kind of Morus alba L.), were shown to be I, II, III, IV, and V, respectively. During the course of the study, we had encountered an unusual photooxidation of morusin (I), When a solution of I in CHCl_3 was exposed to bright sunshine, hydroperoxide (IX) was obtained in very high yield. The structure (IX) of this hydroperoxide was determined from chemical and spectral analysis. The mechanism of this reaction was discussed and the phenoxy radical (XV) was suggested to be the intermediate of this photooxidation.
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宮下 正昭, 八浪 哲二, 加藤 紀元, 吉越 昭
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Aliphatic nitroolefins (1-3), which were readily available from the corresponding nitroalcohols (G), react with trimethylsilyl enol ethers (H) in the presence of Lewis acids to give 1,4-diones directly. Several silyl enol ethers examined showed high regio-specificity and good yields in the formation of the 1,4-diones, which were then converted to conjugated cyclopentenones in high yields on alkali treatment (Table 2). Similarly, nitroolefins react with 1,3-dicarbonyl compounds in the presence of KF in hot xylene. In general, 2-alkyl-1,3-di-carbonyl compounds gave mixtures of nitroketones and triketones (Table 3), although 2-methylcyclohexane-1,3-dione (9) and 2-nitropropene (1) yielded an acetonylation product (11) quantitatively. On the other hand, 2-methylfurans were obtained in good yields on the reaction of 2-unsubstituted-1,3-dicarbonyl compounds and 1 (Table 4). The reaction mechanism of acetonylation of 9 with 1 was elucidated by means of the ^<18>o-labeled dione (22). As an application of the cyclopentenone annulation using nitroolefins, the synthesis of barbatane sesquiterpenoids (27-29) has been attempted.
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安東 政義, 高瀬 嘉平
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Eudesmane type sesquiterpenes possessing functional groups at C_1 and C_4 positions were synthesized from α-santonin in the following manner. I) Vulgarin were synthesized according to Scheme 1. Allyl rearrangement of 2a, followed by oxidation with Collins reagent gave 4. Ketalization of 4 and successive isomerization of double bond gave 6. Oxidation of 6 with OsO_4 gave ketal (7), (9) and ketone (8). Treatment of 7 and 8 with boiling 50% aq AcOH gave vulgarin. II) Arglanine was synthesized according to Scheme 2. Phenyl-selenylation of 7 and successive oxidative syn-elimination gave 11. Deketalization and spontaneous dehydration of 11 gave arglanine. III) Reynosin was synthesized according to Scheme 3. Bromination of 6 gave 12 by spontaneous dehydrobromination and deketalization. Reduction of 12 with zinc and acetic acid gave 13. Reduction of 13 with LiAlH(tBuO)_3 gave 14. Phenylselenylation of 14 followed by oxidative syn-elimination gave reynosin. IV) Epoxysantamarine was synthesized according to Scheme 4. Reductive dehydration of vulgarin and its C_4-epimer gave 16, which was reduced with LiAlH(tBuO)_3 to give 17. Epoxidation of 17 followed by phenylselenylation and syn-elimination gave epoxy-santamarine. V) 1β-Hydroxyarbusclin A was synthesized according to Scheme 5. Catalytic hydrogenation of vulgarin followed by reduction with NaBH_4 gave 21, which was converted to 1β-hydroxyarbusclin A.
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山川 浩司, 坂口 礼司, 佐藤 毅
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Syntheses of (±)-liguralone (2) and some eremophilanes by the Diels-Alder reaction of 3-ethoxy-1,3-pentadiene (5) and furanoquinone (6) or 3-carendione (20), respectively, were investigated. 1) Total Synthesis of (±)-Liguralone (2) The Diels-Alder reaction of the diene (5) and quinone (6) gave an adduct (7) regioselectively, which was easily epimerized to epimer (8). Reduction of (8) with NaBH_4 gave epimeric alcohol (9) and (10), whose dehydration afforded cis-dimethyl compound (12) in low yield. Catalytic reduction of (12) afforded diketone (16) which was identified with authentic (16). Conversion of (16) into (+)-liguralone (2) had been completed by Naya et al. The adduct (7) and (8) were converted into triketone (19), which was identified with Bohlmann's compound. 2) Synthesis of Eremophilanes by the Diels-Alder Reaction of Diene (5) and Carendione (20) The Diels-Alder reaction of diene (5) and carendione (20) afforded the adduct (20) and (22) in a ratio of 1: 3. (22) was easily epimerized to triketone (23) with acid. Reduction of ketal (24) with NaBH_4 gave 9α-OH (25) and 9β-OH (26) in a ratio of 7: 3. Treatment of (25) and (26) with TsCl in pyridine yielded eremophilane skeletal compound (29). Moreover, conversion of diol (30) and (31) into eremophilane type diene (32) was carried out. The base-induced transannular hydride shift was found between ketol (25) and (34). A novel hydride rearrangement was confirmed by deuterated compound (35) and (36).
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飯尾 英夫, 河合 龍彦, 磯部 稔, 後藤 俊夫
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発行日: 1976/09/20
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Novel cyclopropyl intermediate, type 3, has been selected in the synthetic studies directed toward vernolepin 1, a sesquiterpene bismethylene lactone having antitumor and cytotoxic properties. Construction of A/B cis configuration of vernolepin ring system was achieved by thermodynamic control-base catalized intramolecular cyclization of the malonyl ester, 7-to afford a sole product, 9, whose bromination and subsequent cyclization gave the key intermediate 10. This compound plays remarkable roles not only for the introduction of two hydroxy groups in regio- and stereo-specific manners owing to its rigid ring system but also for protection of the active methine atom. This intermediate has further been converted to compound 19 carrying all of the necessary carbon atoms and to compound 26 possessing the α-cis dihydroxyl groups, respectively. Further studies for the total synthesis of 1 and 2 are now in progress.
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Samuel Danishefsky, 北原 武, Paul F. Schuda, Sarah J. Etheredge
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セッションID: 21
発行日: 1976/09/20
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The total synthesis of dl-vernolepin and vernomenin, tumor inhibiting sesqueterpene lactone, was achieved by the following route. Novel highly active diene 4 was prepared and it was proved that Diels-Alder reaction of 4 with some proper dienophiles involved new sythetic route to Δ^1-octalin-3-one systems. This procedure was applied to the stereospecific synthesis of the key intermediate, protected epoxide 53. Diels-Alder adduct 20 was converted to the epoxydilactone 29, which on unusual orthoesterification gave orthoester 40. DIBAH reduction of 40, followed by Wittig reaction yielded 53. The remarkable epoxide opening by the action of dilithioacetate on 53 with inversion at C_7 position, followed by cyclization afforded precursors 57, 58, which were transformed to vernolepin and vernomenin by novel method of bis-α-methylenation. The synthesis was achieved in 18 steps and 1.6% overall yield.
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益岡 典芳, 神川 忠雄, 久保田 尚志
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発行日: 1976/09/20
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12,13-Epoxytrichothec-9-ene (2) is a metabolite isolated from Trichothecium roseum by Nozoe et al. and its structure was synthetically confirmed by Tatsuno et al. In this paper we wish to report the first biomimetic synthesis of (2) modelled on the proposed biogenetic scheme. The key intermediate (4) was synthesised by photocyclo-addition followed by acid cleavage. This was transformed into the diene diol (33) which was stereoselectively cyclised to (34) by acid. Epoxydation of (34) gave the title compound.
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藤本 康雄, 清水 猛, 辰野 高司
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セッションID: 23
発行日: 1976/09/20
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We describe a novel method for the preparation of cyclodecanone intermediate(29, 30, 31, 33) which is useful for the synthesis of not only germacrene-type sesquiterpenoids but guaiane-type sesquiterpenoids, and also describe the synthesis of dihydrocostunolide(42) isolated from cotus root oil. α-Santonin was treated with m-chloroperbenzoic acid to give the α-epoxide(2), β-epoxide(3) and diepoxide(4). Selective reduction of the carbonyl group of 2 with LiAlH_4 afforded a mixture of 5 and 6. Similar reduction of 3 gave a mixture of 7 and 8. The allyl alcohols(5, 6, 7, 8) were stereospecifically chlorinated to the corresponding 3-chloro derivatives(9, 10, 11, 12) having the inverted configuration of C_3-H by the action of MsCl(or TsCl)-pyridine. A diastereomeric mixture of the chloride(9, 10) was treated with NaI-Zn to give a dienol (23), while treatment of a mixture of 11 and 12 gave a dienol(24). The irradiation of 23 (7W low- pressure mercury lamp, MeOH, 15℃) provided a diastereomeric mixture of dienones(29, 30, 31). Treatment of 29 with refluxing benzene or SiO_2 gave a guaianolide-type derivative(32) in quantitative yield. Hydrogenation of 29 over Pd-C, followed by treatment of the resulting dihydro derivative(37) with NaBH_4 afforded an alcohol(40). 40 was converted into a mesylate(41) which was then treated with tetra-n-butylammonium oxalate to give the dihydrocostunolide. The synthetic dihydrocostunolide was identical with an authentic specimen in tlc, glpc, ms, it and nmr spectra.
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森 謙治, 滝川 哲夫, 織田 雅次, 松井 正直
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発行日: 1976/09/20
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Chiral epoxides are known among natural products as important biosynthetic intermediates or biologically active compounds. We undertook the studies on chiral epoxides with a special emphasis on their roles as intermediates in natural products syntheses. A) Chiral epoxides as targets. (+)-Disparlure (1) and its antipode (2), the pheromone of gypsy moth, was synthesized stereoselectively starting from L-(+)-tartaric acid (6). B) Chiral epoxides as precursors of lactones. The (S)-(+)-isomer (3) of massoilactone, a defense substance of formicine ants, was synthesized from D-(+)-glyceraldehyde acetonide (25). The same starting material was converted into the antipode (4) of (-)-pestalotin, the gibberellin synergist. C) Epoxides as precursors of alcohols. The stereochemistry of (-)-4-methylheptan-3-ol (43), a component of the pheromone complex of smaller European elm bark beetle, was established as (3S: 4S)-threo (68) by synthetic works including the preparation of its enantiomer (5) from (R)-(+)-citronellic acid (58).
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奥田 拓男, 吉田 隆志, 延原 順子, 藤井 夏子
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発行日: 1976/09/20
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Three new piscicidal sesquiterpenes, buddledin A (C_<17>H_<24>O_3), B (C_<15>H_<22>O_2) and C (C_<15>H_<22>O) and two new related sesquiterpenes, buddledin D (C_<15>H_<22>O) and E (C_<15>H_<24>O), have been isolated from the root bark of Buddleja davidii Franch. (Buddlejaceae). The structure 1 of buddledin A has been deduced on the basis of spectroscopic and chemical evidences, and finally confirmed by X-ray analysis of bromohydrin (8). The absolute configuration of 1 was determined by the application of dibenzoate chirality rule and benzoate rule. Structures of buddledin B, C and D have been determined to be deacetylbuddledin A (2), deacetoxybuddledin A (3) and cis isomer of 3, respectively, by chemical transformations, and comparisons of their spectra with those of 1 and its cis isomer (20), which was obtained by the photorearrangement of 1. Structure of buddledin E has been presumed to be 5 by its spectral data and deuteration experiments.
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内尾 康人, 松尾 昭彦, 中山 充, 林 修一
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From the steam-volatile oil of the title plant, two novel sesquiterpene ketones, named vulgarone A and B, were isolated to be respectively determined as an β,γ-unsaturated ketone(1) with new carbon skelton and an α,β-unsaturated ketone(7) with (+)-α-longipinene carbon skelton based on the spectral data and chemical treatments. Vulgarone B was prepared by allylic methylene oxidation of (+)-α-longipinene (12), with CrO_3-(pyridine)_2 complex in CH_2Cl_2, and A was obtained as a main product (41%) in photochemical reaction of vulgarone B. The structures of by-products, (13, 9%), (14, 6%), (15, 15%), (16, 8%) and (17, 6%) were also discussed.
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上村 大輔, 中山 豊, 信原 一敬, 片山 忠二, 平田 義正
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発行日: 1976/09/20
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Our previous reports described the isolation and structures of toxic principle and abietane-type diterpenes from the title plant. Further investigation from biogenetic interests of ingenol and high-oxygenated diterpnes gave four new diterpenes, which were named jolkinols A (1), B (2), C (3), and D (4). The structures of these new diterpenes on the basis of the chemical interrelation of jolkinols, the chemical transformation of jolkinol B (2) to lathyrol (20) whose structure has been determined by E. Hecker, NOE experiments with jolkinol C (3), and epoxidation of the isolated carbon-carbon double bond in jolkinol D (4). Furthermore, the pattern of the cleavage of the epoxide in jolkinols A and B, and the stereospecific epoxidation of jolkinol D indicate that some lathyrane-type diterpenes may be oxidatively derived from jolkinols in their biosynthetic process, as shown in Fig.2. Moreover, the atructure of jolkinolide B possessing the novel oxidolactone was determined by X-ray analysis.
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藤田 栄一, 落合 正仁
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Applying a powerful oxidation ability and the "soft" character of Tl^<3+>, we carried out the following reactions and obtained some interesting results. 1) Allylic nitration: ent-16-Kaurene (1) on treatment with thallium (III) nitrate (TTN) in glyme gave allylic nitrates (2) and (3), while ent-15-kaurene (4) gave compound (5) as the major product, besides (2) and (3). Comparison of the reactivity of (1) with that of (4) and their reaction mechanism are discussed. A [3,3]-sigmatropic rearrangement between (2) and (3) is also described. 2) Oxidative rearrangement of a ketone: ent-17-Norkauran-16-one (18) on treatment with TTN in acetic acid afforded oxidative rearrangement products (19), (20a), (20b), and (21b). The structure determination of these products and the synthesis of their basic hydrocarbon skeleton (35) from the main product (19) have been carried out. 3) Selenoxide formation and Pummerer rearrangement: Diphenyl selenide (36) and phenyl benzyl selenide (38) were treated with TTN in THF to give the corresponding selenoxides in high yields. Applying these results, Pummererlike reaction was carried out. Thus, compound (43) derived from (18) on treatment with 3 mol. equivalents of TTN in THF gave diketone (44). The same reaction in methanol yielded compound (45).
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北原 喜男, 加藤 忠弘, 高柳 久男, 一の瀬 功, 小林 東洋彦, 細貝 武郎, 鈴木 政信, 顔 晋璋
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In connection with the biogenetic type synthesis of natural products presented at 19th symposium of natural products(1975), further studies concerning the following topics were continued. I. Brominative cyclization of polyenes We have already found that TBCO(2,4,4,6-tetrabromocyclohexadienone) is suitable for the introduction of bromine atom at the terminal double bond of polyenes. Reactivity of TBCO was found to be divided into three types 1, 2, and 3. Snyderols (5a,b) was synthesized from nerolidol (22). II. Acylation of polyenes From chloroketone (23), cembrene type natural products (26), (34), (35), (36), and (37) were synthesized. d- and 1-neocembrene showed the same pheromone activities toward the termite. Acylation of (42), (44), and (46) were also tried to give (43), (45), and (48), respectively.
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児玉 三明, 松木 安生, 島田 和明, 横尾 俊一, 伊東 椒
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Macrocyclic terpenes, such as diterpenic nephthenol 1 and cembrene-A 2, and sesquiterpenic hedycaryol 3, were synthesized by anion-induced cyclization of suitably functionalized acyclic terpenes. Thus, the diterpenic epoxy thioether 6 derived from E, E-geranyllinalool yielded 7 by the action of n-BuLi in the presence of DABCO. Desulfurization of 7 afforded 1 and its isomer 8. Treatment of 1 with SOCl_2 gave 2 which is known to be termite trail pheromone of Nasutitermes sp. Geometry of all double bonds in 1 and 2 were established. Interestingly, 2 has pheromonal activity also to Coptotermes formosanus and Reticulitermes speratus. Cyclization of the E,E-farnesyl derivative 11 on the contrary afforded 12 and 13, while 16 was obtained as the major product from the Z,E-derivative 15 under the same condition. Desulfurization of 12 afforded inseparable mixture of 3 and 17. Thermolysis of the mixture converted 3 to elemol 18, and left 17. Similarly 13 gave 19 which was converted to cis-elemol 20 by Cope rearrangement. Desulfurization of 16 yielded a mixture of 22 and 23. Treatment of 19 with acid afforded 24 and 25. Stereochemistry of these three products from 19 revealed the conformation of 10-membered ring in each transition state.
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嶋垣 正之, 中田 忠, 小原 伸介, 田原 昭
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発行日: 1976/09/20
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d-Kaurene (17) and d-phyllocladene (18) were synthesized from 1-abietic acid (1) by using a carbon unit of its isopropyl group, via a Li-liq. NH_3 reduction of a dicarboxylic acid (6), an intramolecular carbenoid reaction of diazoketones (9) and subsequent cleavage of the resulting cyclopropyl ring of (10) and (11) with Li-liq. NH_3. d-Phyllocladene (18) was also synthesized from (1) by using two carbon units of its 13-side chain, via a stereo-selective hydrogenation (RuO_2) of an oxo diester (19) and a PPA-AcOH cyclization of a half ester (21), followed by a monothio-ketalization of a dioxo ester (25). Synthesis of 1-hibaene (48) from (1) was achieved by using a whole of the carbon units of its side chain, via a catalytic hydrogenation (RuO_2) of an oxoxy ester (29) and a methyl migration of a magnesium salt of a bromohydrin (41).
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針谷 義弘, 伊藤 正善, 恩田 政行, 嶋垣 正之, 田原 昭
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発行日: 1976/09/20
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Synthesis of the steroid skeleton was planned from dehydro-abietic acid (2), a representative resin acid of pine tree. 1. Synthesis of Antipodal Steroids The ketone compounds (4 and 5), important intermediates in synthesis of the skeleton of antipodal steroids, were synthesized via the γ-lactone (7) derived from dehydroabietic acid (2). 2. Synthesis of Steroid A-Ring i) The 3-keto compound (36) having a steroid type A-ring was synthesized by the use of the 4-methyl group in (2) via the keto esters (34 and 35), important intermediates, from the phenacyliden (32) and 1-en ester (33). ii) The phenacyliden (60), obtained via the 4-keto compound (37) derived from dehydroabietic acid (2), was also converted into 3-keto compound (36) 3. Synthesis of Steroid D-Ring i) The C-aromatized steroids (65 and 66) were synthesized by the use of a part or whole of the carbon units of the isopropyl group in dehydroabietic acid (2). ii) The 14-keto compound (69) considered to be an important intermediate in synthesis of steroid skeleton having the 13-methyl group was synthesized via the 14-nitro compound (85) from dehydroabietic acid (2). Synthesis of steroid type D-ring from the 14-keto compound already been completed in the total steroid synthesis.
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亀谷 哲治, 根本 英雄, 石川 尚子, 白山 恵子, 福本 圭一郎
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発行日: 1976/09/20
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A potential intermediate, 8,13-ethano-6,7,8,9,11,12,13,14-octahydro-3-methoxy-13-methylphenanthren-14-one (25), for tetracyclic diterpenoids has been stereospecifically synthesised by an intramolecular cycloaddition of the o-quinodimethane derivative which was derived thermally from 5-n-butylthiomethylene-2-[2-(4-methoxybenzocyclobutenyl)-ethyl]-2-methylcyclopentanone (4), followed by desulphurisation. Secondly a stereo-and regioselective synthesis of O-methyl-D-homoestrone (33) has been achieved by an intramolecular cycloaddition of the o-quinodimethane (32), derived from thermolysis of the benzocyclobutene derivative (31), which was obtained by a condensation of β-(4-methoxy-benzocyclobutenyl)ethyl iodide (19) with 6-n-butylthiomethylene-2-methyl-3-vinylcyclohexanone (29) followed by removal of n-butylthiomethylene group of the resulting product (30). Since O-methyl-D-homoestrone (33) had previously been correlated to estrone (35), this work constitutes a total synthesis of estrone (35).
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宇根山 健治, 白神 裕成, 鳥居 滋
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The discovery of a simple and practical method for the preparation of functionalized cyclocitryl derivatives promising versatile applications for the synthesis of naturally occurring biologically active terpenoids such as vitamin A, abscisic acid and so on has long been recieved much interests. In the last communications we demonstrated that cyclocitryl phenyl sulfone 2 was effectively prepared by acid-catalyzed cyclization of geranyl phenyl sulfone 1 and, furthermore, the sulfone 2 and its derivatives 3 and 5 could be used as key intermediates for the terpenoid syntheses. Here, we show a novel synthesis of vitamin A_1 and A_2 acids involving C_<10>-C_<10> coupling reaction between 2 or 5, and the corresponding bromo compounds 29, 30, and 33. The compounds 29, 30, and 33 were prepared in reasonable yields by the coupling of C_5 unit as shown in scheme 3. The reaction of 2 with 29 was performed in 92% yield by lithiation of 2 with (i-Pr)_2NLi followed by the action of 29 in THE at -78℃. Similarly, 19 and 20 were obtained in 67 and 68%, respectively. Finally, the base-catalyzed desulfination of 18, 19, and 20 was effected with t-BuOK in t-BuOH-THF (2: 1), yielding vitamin A acid as a mixture of trans and cis isomers on C_2 carbon.
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大橋 尚仁, 阿知波 一雄, 山田 俊一
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We developed new general synthetic routes for optically active epoxyterpenes from an optically active α-amino acid without a resolution step. The keto acetonide(8), a key intermediate for these syntheses, was synthesized from L-glutamic acid and converted to R-(+)-epoxygeraniol(14), R-(+)-, S-(-)-marmin(17) and R-(+)-epoxyaurapten(18). Naturally occurring (+)-marmin and (+)-epoxyaurapten were shown to possess R-configuration. Further, optically pure R-(+)-epoxyfarnesol(19) and R-(+)-, S-(-)-squalene-2,3-oxide(45) were synthesized.
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平田 敏文, 村井 京子, 井手尾 玲子, 菅 隆幸
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From the male flower of Alnus serrulatoides Call., we isolated three new triterpenes, named alnuserol (I), alnuselide (II) and alnuserrudiolone (III), respectively, together with β-amyrenone (IV), taraxerone (V), alnincanone (VI) and hederagenin (VII). The structure of I was determined by spectroscopic and X-ray crystallographic analyses. The structures of II and III were proposed on the bases of chemical and spectral evidences. Biogenetically, it is fascinating to note that the compounds, I and VI, having a tetrahydrofuran ring might have originated by the cyclization of the side chain of III, and that the lactone II might have been produced from VI via the C-3/C-4 seco-dammarane derivative.
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笠井 良次, 鈴尾 瑞恵, 松浦 清子, 浅川 順一, 山崎 和男, 田中 治, 矢原 正治
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The assignments of ^<13>C NMR signals of Ginseng sapogenins, (I, II) and their related dammarane type triterpenes were substantiated with the aid of the shift derivative and deuterated compounds (Table I). It was demonstrated that the intramolecular hydrogen bonding between the 12β- and the 20-tert-hydroxyl groups has remarkable effect on the chemical shifts of 17C, 20C, 21C, and 22C signals and ^<13>C NMR is highly useful in differentiation between the C-20 epimeric pair of the triterpenes of such a type (Table II). Several aliphatic β-glucosides including β-D- and β-L-glucosides of cholestanol and dammarenediol-I were prepared. The shifts of ^<13>C resonances around the glucosyl linkage from the corresponding positions in the spectra of methyl β-D-glucoside and the aglycone-alcohols were investigated. It was found that the magnitudes of the signal-shifts of the anomeric carbon (1'C) of the sugar and α- and β-carbons of aglycone-alcohols depend significantly upon the stereo-structures of the hydroxyl group of the aglycones as shown in Table III. On the basis of the present results, the structures of the glycosides of roots, leaves, and buds-flowers of Panax spp. were elucidated mainly by ^<13>C NMR spectroscopy.
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竹本 常松, 在原 重信, 中島 正, 奥平 恵, 浜田 厚子
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A colorless amorphous, mp 197-201°(decomp),[α]^<20>_D -9.4°(H_2O), C_<60>H_<102>O_<29>・2H_2O, was isolated as sweet principle from Fructus Momordicae (fruit of Momordica grosvenori Swingle, Cucurbitaceae), a crude drug of Kwangsi, China. The compound was considered to be an unknown triterpene glycoside. So it was named "S-5", temporary. The aglycone of S-5, mp 118-119°,[α]^<17>_D+70.0°(MeOH), C_<30>H_<52>O_4, was obtained by enzymatic hydrolysis. The structure of aglycone(S-O_1) has been elucidated to be 13 on the basis of chemical and physicochemical evidence. Final evidence for the chemical structure of S-5(1) was obtained by methanolysis of permethylates, NMR spectroscopy and molecular optical rotation of S-5 and its parcial hydrolysates.
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通 元夫, 橘 和夫, 鳥居 功博, 森山 祥彦, 露木 孝彦, 高橋 武美, 山田 修三
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セッションID: 39
発行日: 1976/09/20
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Boron rifluoride etherate-catalyzed backbone rearrangement of 3α,4α-epoxyshionane (7), 3β,4β-epoxyfriedelane (32), and 3β,4β-epoxyshionane (8) was investigated. Rearrangement of D-homo-steroidal epoxide (25) and bicyclic epoxybenzoate (30) was also accomplished. 3α,4α-Epoxyfriedelane (18) or 7 gave 5(10)-en-3α-ol (19 or 14) of D: B-friedo-type and 12-en-3α-ol (21 or 12) in which backbone rearrangement was highly effected, while 25 yielded only 27. The formation of rearranged products (19-23) from 18 has already been reported. Bicyclic epoxybenzoate (30), as a model of A/B ring part of friedelane and shionane type triterpenes, gave cyclic etherbenzoate (31) upon treatment with boron trifluoride etherate. Two epoxides (32 and 8) reacted with boron trifluoride etherate in ether at low temperature to afford dendropanoxide (33) and dihydrobaccharis oxide (2), respectively. Each of these epoxides (32 or 8) also produced 4α-fluoro-3β-ol (34 or 38), 5-en-3β-ol (36 or 39), 5(10)-en-3β-ol (35 or 15), 12-en-3β-ol (37 from 32), and 7-en-3β-ol (40 from 8). The epoxide (8) was found to rearrange into 39, 15, 42, 40, and 10 in benzene at room temperature. The relative yields of the products afforded by the rearrangement in various solvents are shown in the Table.
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瀬戸 秀夫, 林 紘司, 三橋 博
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The structures of twelve ester-type polyoxypregnane derivatives, isolated from Marsdenia tomentosa DECNE (Asclepiadaceae), were determined with some interesting information for their properties on the bases of chemical and physico-chemical evidences. The configuration at C-20 of tomentogenin (I) and utendin (II) was determined as S by means of the circular dichroism (CD) experiment of 20-O-O-nitrobenzoyl-derivatives to define their absolute configurations. A hypothetical biogenetic pathway of polyoxypregnanes in M. tomentosa is proposed on the bases of the position of ester linkages and the nature of oxygen functions of ester-type derivatives.
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森崎 益雄, 坂内 清, 佐藤 晋, 池川 信夫, 色田 幹雄
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Biosynthesis of steroid hormones starts with the side chain cleavage of cholesterol to give pregnenolone. This reaction is catalyzed with cytochrome P-450_<scc> (cholesterol C-20,22 lyase) and requires 3 moles of O_2 and 3 moles of NADPH. The potential intermediates of this reaction were chemically synthesized and incubated with cytochrome P-450_<scc>. Pregnenolone formed was quantitatively analyzed by mass fragmentography. None of the four stereoisomers of 20,22-epoxycholesterol nor (E)-20(22)-dehydrocholesterol were significantly converted to pregnenolone. Among the stereoisomers of hydroxycholesterols, (20S)-20-, (22R)-22-, (22S)-22-hydroxycholesterols and (20R,22R)-20,22- and (20R,22S)-20,22-dihydroxycholesterols were efficiently converted to pregnenolone. Relative yields to pregnenolone from these hydroxycholesterols, together with their successful identification in the incubation medium of cholesterol suggests the major pathway: cholesterol→(20S)-20- and/or (22R)-22-hydroxycholesterols →(20R,22R)-20,22-dihydroxycholesterol→Pregnenolone.
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村井 章夫, 笹森 浩之, 岩佐 徳昭, 竹田 雅美, 正宗 直
原稿種別: 本文
セッションID: 42
発行日: 1976/09/20
公開日: 2017/08/18
会議録・要旨集
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In connection with studies aimed at the synthesis of biologically active normal steroids from etiojervanes, we prepared several 12,13-epoxyetiojervanes and examined acid and/or base epoxy cleavage reactions as well as photochemical transformations of the epoxy compounds. The epoxides, 11-oxygenated 17α-acetyl-12,13-epoxy- (20〜26) and 17-oxygenated 12,13-epoxy-etiojervanes (37〜42), were prepared according to the processes described in Charts 1〜3. The configuration of each epoxide was defined on the basis of the chemical and spectral evidence. Treatment of 17α-acetyl-12α,13α-epoxides (20, 20a, 21 and 26) with acid (BF_3) produced mixtures of several compounds, respectively, including interesting rearranged products, e.g., compounds (49 and 50) with bicyclo[3.3.1]nonane-2,9-dione and hydrooxepin moieties (Chart 4), while the 12α,13α-epoxides (20 and 23) on treatment with base (KOH) gave a 13α-pregnane derivative (52), but 11-unsubstituted 12α,13α-epoxide (26) and 12β,13β-epoxides (22 and 24) afforded no such rearranged products (Charts 5 and 6). Although no desirable rearranged products were obtained by acid treatment of 17-oxygenated 12α,13α-epoxides (37, 37a, 39 and 40), irradiation of epoxy-ketone (39) proceeded as expected to give an androstane derivative (67) (Charts 7 and 8).
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毛利 公則, 曳野 靖子, 在原 重信, 竹本 常松, ヒキノ ヒロシ, 森 弘, 柴田 健雄, 小川 俊太郎, 西本 喜重, 吉田 昭義
原稿種別: 本文
セッションID: 43
発行日: 1976/09/20
公開日: 2017/08/18
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Inokosterone, a phytoecdysone isolated from Achyranthes fauriei (Amaranthaceae), has been partially acetylated to give the 2,26-diacetate (2) which has been converted into methyl 5-acetoxy-4-methylpentanoate (9) and 2β-acetoxy-3β,14α-dihydroxy-5β-pregn-7-ene-6,20-dione (3). Chemical and physico-chemical studies have shown the configurations at C-20 and C-22 to be R. Inokosterone has thus been concluded to be a mixture of C-25 epimers of (20R,-22R)-2β,3β,14α,20,22,26-hexahydroxy-5β-cholest-7-en-6-one (1). After the synthesis of the model compound, a C-25 epimeric mixture of (20R,22R)-3β,20,22,26-tetrahydroxy-5α-cholestane (16), inokosterone has been synthesized via (20R)-2β,3β,14α,20-tetrahydroxy-20-formyl-5β-pregn-7-en-6-one (18) by Grignard reaction with 4-(tetrahydropyran-2-yloxy)-3-methylbutynylmagnesium bromide (12) followed by hydrogenation and hydrolysis. The use of an NMR shift reagent with the inokosterone acetates (4, 21) and the optical activity measurement of α-methylglutaric acid (6) derived from inokosterone have established that inokosterone is a 1: 2 mixture of the C-25 R and S epimers. Inokosterone was then submitted to high speed liquid chromatography using a Permaphase ODS column to separate the two epimers, inokosterone A and B, which were very similar in the physico-chemical and biological properties to each other. The proportion of both epimers was found to vary depending upon the plant materials.
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釜野 徳明, 道下 一彦, 館 安英, 中神 淨二, 五井 正美, 沢田 二郎, 田中 一郎
原稿種別: 本文
セッションID: 44
発行日: 1976/09/20
公開日: 2017/08/18
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Recently, as the topical anti-inflammatory agents, the 17-esters, 17,21-diesters or 17-ester-21-halides of corticosteroids are used successfully. The mostly favorable and new method on syntheses of these compounds were found on reexamination of several known synthetic methods. It was known that the 17,21-cyclic orthoesters of corticosteroids, which were prepared from the 17,21-dihydroxy compounds by reaction with the orthoester reagent, were converted easily by the weak acid to the 17-monoester compounds. This method was much better than other several direct 17-esterifications, although the 21-ester compound was obtained as by-product. Direct 17-esterifications by known methods did not Rive the desired 17-ester compounds in the satisfactory yield. Also, all direct esterifications of the 16α-methyl corticosteroid, dexamethasone were unsuccessful. Ring opening-reaction of the 17,21-cyclic orthoesters of corticosteroids by employing Ph_3CCl as reagent and DMF as solvent provided the 17-monoester compounds in good yield. Similar reaction of the 17,21-cyclic orthoester compounds by using (CH_3)_3SiCl as reagent and DMF or DMSO as solvent provided directly the 17-ester-21-chloride compounds in good yield. Also, by the use of suitable halide reagents, the corresponding 17-ester-21-halides were obtained. The new route to the 17-ester-21-halides was much industrially better than the known three step method.
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