-
HARUO OGURA, KAZUYOSHI TAKEDA, HIROSHI TAKAHASHI
1975 Volume 23 Issue 11 Pages
2469-2473
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Nucleophilic reaction of penicillin lactam with various lithiated compounds was discussed. Phenacyl benzylpenicillanate was reacted with phenylethynyllithium in tetrahydrofuran at -75°to yield a phenylethynyl derivative (2). When methyllithium or phenyllithium was used as the reagent in ether at -75°, only a ring-opened compound (4) was obtained. On the other hand, use of butyllithium or phenyllithium in tetrahydrofuran at -75° afforded an unexpected butoxycarbonyl derivative (5). The butoxyl group was derived from tetrahydrofuran, and which was confirmed by the formation of butanol from the reaction of tetrahydrofuran and phenyllithium at -75°.
View full abstract
-
HARUO OGURA, KIMIO FURUHATA, KATSUKO FURUHATA
1975 Volume 23 Issue 11 Pages
2474-2477
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
L-Prolyl-L-valine anhydride (I) was obtained from the cultured broth of Streptomyces No. K-73 as a by-product of an antibiotic No. 13-1. The structural elucidation of I were done by the determination of infrared, nuclear magnetic resonance (NMR),
13C-NMR, and mass spectra. Conformation of 2, 5-diketopiperazine group compounds was discussed from the NMR spectra.
View full abstract
-
MIYOJI HANAOKA, HIRONORI SASSA, CHIEKO SHIMEZAWA, YOSHIO ARATA
1975 Volume 23 Issue 11 Pages
2478-2484
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
The total synthesis of (±)-methyldecinine, the methyl ether of decinine, was described. The Ullmann reaction of 6-bromoveratraldehyde (IV) with the ester (V) gave the biphenyl (VI) along with the dimeric dialdehyde (VII) and the fluorenones (VIII and IX). The Mannich condensation of isopelletierine with VI afforded stereoselectively the transquinolizidin-2-one (XI), which, on treatment with the Henbest catalyst, furnished the axial alcohol (XII) together with the equatorial alcohol (XIII). Each of the alcohols was shown to be a mixture of two atropisomers from the dynamic nuclear magnetic resonance spectra. Hydrolysis of XII and lactonization of the resulting hydroxy-acid (XIV) provided (±)-methyldecinine (II) in an excellent yield.
View full abstract
-
FUMIHIKO YOSHIZAKI, YOSHIKAZU KONDO, TSUNEMATSU TAKEMOTO
1975 Volume 23 Issue 11 Pages
2485-2491
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Triethyloxonium fluoroborate (TEOF), which is one of the ethylating agents, was substantially inactive to adenosine 5'-monophosphate (AMP) at various pHs. TEOF reacted on cytidine 2'(3')-monophosphate (CMP), uridine 2'(3')-monophosphate (UMP) and guanosine 5'-monophosphate (GMP) in pH 7-11 buffer solutions having a moderate ionic strength (μ≃0.6) to give the corresponding ethylated nucleotides. The extent of ethylation was influenced by the pH and especially the ionic strength of the buffer employed. At lower ionic strength (μ<0.2) TEOF was much less reactive toward CMP and UMP. When ribonucleic acid (RNA) was treated with TEOF in a buffer solution at pH 8.9 and μ=0.1 and hydrolyzed with hydrochloric acid, the resulting hydrolysate contained approximately 50% of the ethylated guanine residue by base analysis. Deoxyribonucleic acid (DNA) was ethylated to a similar extent under the same conditions. In both cases, the chromatographic analysis revealed that uracil (thymine), cytosine, and adenine residues were left practically intact. The ethylated DNA contained a small amount of dialyzable material which was identical with 7-ethylguanine. The physical properties showed that DNA on ethylation underwent partial loss of tertiary structure although the molecule retained considerable double strandedness.
View full abstract
-
HIROSHI MORIMOTO, TAKEO KAWAKAMI, NOBUYOSHI HAYASHI
1975 Volume 23 Issue 11 Pages
2492-2495
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Es wurde Reaktionsmechanismus, nach welchem sich der Aktivester aus der Acylaminosaure und N-Hydroxysuccinimid mit Dicyclohexylcarbodiimid bildet, mit der
18O markierten Aminosaure untersucht.
18O befindet sich in der Carboxylgruppe des Aktivesters und in dem Dicyclohexylharnstoff. Durch Abspaltung des Hydroxyls der Carboxylgruppe mit Dicyclohexylcarbodiimid wird der Carboxyl-Kohlenstoff aktiviert und bildet mit N-Hydroxysuccinimid den Aktivester.
View full abstract
-
EIICHI YOSHII, TORU KOIZUMI, HIROKAZU IKESHIMA, KYUICHI OZAKI, ICHIHIR ...
1975 Volume 23 Issue 11 Pages
2496-2506
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Practical synthetic methods of natural cardenolides are illustrated in the syntheses of xysmalogenin and digitoxigenin. The new routes employ pregn-14-en-20-one as key intermediate which was prepared by partial reduction of 14, 16-dien-20-one with triphenylstannane or triethylsilane. A general and efficient method was devised for obtaining cardenolides consisting of (1) 21-methylsulfenylation of pregnen-20-one, (2) the reaction of the resulting 21-methylthio derivative with bromoacetate and zinc, (3) alumina chromatography of epoxy ester obtained from the S-methylated Reformatsky product.
View full abstract
-
AKIRA YOSHIDA, SADAO OIDA, EIJI OHKI
1975 Volume 23 Issue 11 Pages
2507-2517
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Methylthiolation reactions of 7-benzamido-3-methyl-3-cephem-4-carboxylic ester (3) via its carbanion gave 4-substituted derivatives, whereas its oxide (7) gave 2-substituted derivatives exclusively. In the presence of excess base, 7-substituted compounds were also obtained. In addition, some alkylation reactions and zinc reductions of 2-methylthio compounds thereby obtained were investigated.
View full abstract
-
AKIRA YOSHIDA, SADAO OIDA, EIJI OHKI
1975 Volume 23 Issue 11 Pages
2518-2522
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
A new rearrangement reaction of some 2-methylthiocephem derivatives to an oxazolone compound (2) is described.
View full abstract
-
HIROYUKI INOUYE, SHINICHI UEDA, KENICHIRO INOUE, TOSHIMITSU HAYASHI, T ...
1975 Volume 23 Issue 11 Pages
2523-2533
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Durch Applikation der 1-(
14C-Carboxy)-o-succinylbenzoesaure (OSB) bzw. 1-(
14C-Carboxy)-(2'-
3H
2)-OSB an die Catalpa ovata-Pflanze wurde die Einbauart von OSB in den Catalpalacton (1) und Catalponol (4) untersucht. Somit wurde bewiesen, dass es sich bei den beiden Stoffen (1) and (4) um Prenylnaphthochinonabkommlinge handelt, die uber OSB gebildet werden, und daruber hinaus, dass die Prenylierung dabei an der der Stellung 3' von OSB entsprechenden Position erfolgt, ohne dass die beiden Stoffe bei ihrer Bildung ein Intermediat mit aromatischem B-Ring durchlaufen.
View full abstract
-
MORIO IKEHARA, YUKO OGISO
1975 Volume 23 Issue 11 Pages
2534-2538
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
N
1-Oxides of 8, 2'-, 8, 3'- and 8, 5'-S-cycloadenosine were synthesized by the oxidation using monoperphthalic acid. The structure of these N-oxides was confirmed by unambiguous synthesis from 2'- or 3'-O-triisopropylbenzenesulfonyl-8-bromoadenosine, which were oxidized at N
1-atom and cyclized with NaSH to give 2'- or 3'-S-cyclonucleoside N-oxide. For 5'-isomer, 2', 3'-ethoxymethylidene-5'-tosyl-8-bromoadenosine was converted to 8-mercapto N
1-oxide by the successive treatment with monoperphthalic acid and NaSH. Cyclization with sodium acetate in dimethylformamide and removal of ethoxymethylidene group with acetic acid gave 8, 5'-S-cycloadenosine N
1-oxide. Ultraviolet and nuclear magnetic resonance spectral properties of these N-oxides were investigated.
View full abstract
-
SHUNICHI YAMADA, NORIO TAKAMURA, TOMISHIGE MIZOGUCHI
1975 Volume 23 Issue 11 Pages
2539-2549
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
For a total synthesis of the optically active carene congeners from optically active α-amino acids, several attempts were made on intramolecular cyclization of 2-cyclohexenyl esters of α-substituted α-diazoacetic acid (III) which were derived from the corresponding amino acid esters. One of the optically active diastereoisomers (X) which was obtained by separation of 2-cyclohexenyl L-alaninate was diazotized with isoamylnitrite and then cyclized using Cu powder as a catalyst to afford the optically active lactone (XIX). XIX was then converted into the key intermediate (XXI) having the bicyclo[4, 1, 0]heptane ring system, from which (+)-2-carene was synthesized.
View full abstract
-
KAZUMOTO MIYAHARA, ETSUKO KANEZAKI, TOSHIO KAWASAKI
1975 Volume 23 Issue 11 Pages
2550-2555
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
A new spirostanol (I), mp 249-250°, [α] D-15.5°, was isolated from a crude sapogenin mixture obtained by acid hydrolysis of the methanol extracts of the aerial parts of Dioscorea tokoro MAKINO. The structure of I was established as (25R)-5β-spirostane-2β, 3α, 19-triol, that is 19-hydroxy-yonogenin. This is the first spirostane derivative having an oxygen function at C
19, and an additional example of the unusual spirostanol carrying the α-hydroxyl group at C
3.
View full abstract
-
MAKOTO TAKAI, YUKIO OGIHARA, YOICHI IITAKA, SHOJI SHIBATA
1975 Volume 23 Issue 11 Pages
2556-2559
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Frangulanine is a peptide alkaloid, with a 14 membered macrocyclic ring, from Hovenia dulcis THUNB. The X-ray analysis of frangulanine derivative and the synthetic study revealed the conformation of frangulanine as shown in Fig. 1 and Fig. 2. The tetrapeptide, Ile-Hyleu-Leu-Tyr, a hypothetical intermediate of frangulanine biosynthesis, was also synthesized.
View full abstract
-
AKIRA UENO, KUNIO MORINAGA, SEIGO FUKUSHIMA, YOICHI IITAKA, YUKIKO KOI ...
1975 Volume 23 Issue 11 Pages
2560-2566
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
A new stereoisomer of matrine was isolated from "Ku-Shen, " dry roots of Sophora flavescens, and named (+)-isomatrine. Epimerization of this compound into (+)-matrine (I) demostrated its flamework. X-Ray analysis of (+)-isomatrine hydrobromide was performed and its structure, [5R, 6R, 7S, 11R]-17-oxomatridine (VI), was elucidated. The conformations of A, B, C and D ring in VI are chair, boat, boat and half-chair, respectively.
View full abstract
-
MITSUTAKA NATSUME, MORITAKA WADA
1975 Volume 23 Issue 11 Pages
2567-2572
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
1-O-Methyl-N-benzoyl-dl-nojirimycin was synthesized from dihydropyridine derivative by stereoselective introduction of the hydroxyl function.
View full abstract
-
TOKURO OHISHI, IKUO IIJIMA, NOBUO ITOH, SHIGEHIKO SUGASAWA
1975 Volume 23 Issue 11 Pages
2573-2577
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Hydrolytic cyclization of 2-acyl-(2-cyanoethyl) succinates (Ib, c) was found to give 2, 3, 3a, 4, 5, 6-hexahydroindole-2, 6-diones (IIb, c), which readily yielded 6-hydroxyoxindoles (III) by dehydrogenation. Four-step synthesis of the erythrinane skeleton from methyl acetoacetate via IIb is also described.
View full abstract
-
OSAMU HOSHINO, HIROSHI HARA, MASASHI OGAWA, BUNSUKE UMEZAWA
1975 Volume 23 Issue 11 Pages
2578-2583
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
A diastereomeric mixture (IV) obtained previously was separated chromatographically into (±)-4α- and (±)-4β-acetoxy-O-acetylthaliporphine (IVa and IVb). Furthermore, the lead tetraacetate oxidation of (±)-thaliporphine (VII) in acetic acid was found to afford stereospecifically in quantitative yield amorphous (±)-4β-acetoxythaliporphine (XI), whose hydrolysis and successive methylation produced (±)-cataline (IX) in overall 86.5% yield.
View full abstract
-
YOHMEI OKUNO, MASATOSHI KAWAMORI, KENICHI HIRAO, OSAMU YONEMITSU
1975 Volume 23 Issue 11 Pages
2584-2590
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
On irradiation in an aqueous solution, N-chloroacetyl-2, 5-dimethoxyphenethylamine (1) gave 6, 9-dimethoxy-1, 2, 4, 5-tetrahydro-3H-3-benzazepin-2-one (2), 7-hydroxy-1, 2, 4, 5-tetrahydro-3H-3-benzazepin-2-one (4), 4-methoxy-1-azatricyclo[6, 2, 1, 0
4, 11]undeca-5-ene-2, 7-dione (7) and 11-methoxy-1-azatricyclo[6, 2, 1, 0
4, 11]undeca-7-ene-2, 6-dione (8). The structure of 2, 4 and 8 were determined by their spectral data. Compound 7 has also nicely assignable spectra except the ultraviolet spectrum in which no π-π band of the enone group appears above 200 nm. However, the structure of 7 has been confirmed through the conversion to pyrroloindole derivatives (11, 13, 14) and the deuterium exchange reaction. Compound 8 also gave other pyrroloindole derivatives (16, 17). The mechanism of these rather unusual photocyclizations were finally discussed.
View full abstract
-
HIROSHI YAMANAKA, SETSUKO NIITSUMA, YUMI BANNAI, TAKAO SAKAMOTO
1975 Volume 23 Issue 11 Pages
2591-2597
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Reactions of 4, 6-disubstituted pyrimidine N-oxides (Ia-f) with some enamines in the presence of benzoyl chloride were investigated. When Ia-f were treated with 1-morpholino-1-isobutene (II) in a similar manner given for the reaction of quinoline 1-oxide with II, α, α-dimethyl-(4, 6-disubstituted 2-pyrimidine) acetaldehyde (IIIa-f) were obtained in moderate yields. Similarly, the reaction of Ia-f with 1-morpholino-1-cyclohexene (IV) and 1-morpholino-1-cycloheptene (VI) afforded 2-(4, 6-disubstituted 2-pyrimidinyl)-cyclohexanones (V) and-cycloheptanones (VII), respectively. However, the reaction of 4-ethoxy-6-methylpyrimidine 1-oxide with 1-piperidino-1-styrene under the same condition resulted in the formation of 2-phenacylpyrimidine (IX) in a poor yield. Pyrimidine N-oxides used in this investigation were as follows : 4-methoxy-6-methyl-(Ia), 4-ethoxy-6-methyl-(Ib), 4-isopropoxy-6-methyl-(Ic), 4-benzyloxy-6-methyl-(Id), 4-methyl-6-phenyl-(Ie), and 4, 6-dimethyl-pyrimidine 1-oxide (If).
View full abstract
-
MITSUAKI WATANABE, MAKOTO KODERA, TOSHIO KINOSHITA, SUNAO FURUKAWA
1975 Volume 23 Issue 11 Pages
2598-2604
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Dimethylsulfonium acetylmethoxycarbonylmethylide (Ia) was found to react with quinoline 1-oxide (II) in the presence of benzoyl chloride to give three compounds : 1-methoxycarbonyl-2-oxo-3-(2-quinolyl)-1, 2-dihydropyrrolo[1, 2-α]quinoline (III), 1-methoxycarbonyl-2-oxo-1, 3-di (2-quinolyl)-1, 2-dihydropyrrolo[1, 2-α]quinoline (IV), and 2-benzoyloxy-1-methoxycarbonyl-3-(2-quinolyl) pyrrolo[1, 2-α]quinoline (V). Similarly, the reaction of dimethylsulfonium diacetylmethylide (Ib) with II gave 4-benzoyl-1-methyl-2-methylthio-3-oxo-3H-pyrido[1, 2-α]quinoline (XII).
View full abstract
-
YOSHIO BAN, MASAHIKO SETO, TAKESHI OISHI
1975 Volume 23 Issue 11 Pages
2605-2613
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
The total synthesis of (±)-rhynchophylline (Ia) and (±)-isorhynchophylline (Ib) which are oxindole alkaloids of Uncaria rhynchophylla MIQ (Ourouparia rhynchophylla MATSUM), has been completed through eight stages starting from the condensation of 2-hydroxytryptamine hydrochloride (III) with ethyl sodium formyl acetate (IV). The success in the first-stage condensation is significant since ethyl sodium formyl acetate (IV) is rather unstable and has not been existent as the liberated ester. The sterostructures of the intermediates are discussed and mostly assigned.
View full abstract
-
HIDEO INOUE, SETSUKO TOMITA, TOHRU UEDA
1975 Volume 23 Issue 11 Pages
2614-2619
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Treatment of 5'-O-acetyl-2', 3'-O-isopropylidene-5-bromouridine with benzyl mercaptan yielded both 5-benzylthio and 6-benzylthio derivatives, (IIa) and (IIIa). Deprotection of those derivatives gave 5-benzylthiouridine (IIc) and 6-benzylthiouridine (IIIc). Treatment of IIIa with methoxide followed by H
2S afforded 2', 3'-O-isopropylidene-6-thiouridine (IV). Methylation of IV gave 6-methylthiouridine (VI) after deblocking. Oxidation of IV with hydrogen peroxide afforded uridine-6-sulfonic acid (VII), an orotidine analog. Nuclear magnetic resonance and circular dichroism data were given and conformations of these nucleosides were discussed.
View full abstract
-
JOSEPH F. BUNNETT, JOHN E. SUNDBERG
1975 Volume 23 Issue 11 Pages
2620-2628
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Numerous aryl bromides and iodides react with acetone enolate ion in liquid ammonia under irradiation to form arylacetones in high yield. This synthesis is successful with bromo-or iodobenzene derivatives carrying alkoxy, alkyl, phenyl, halogen, and carboxylate substituents, and with halogen derivatives of polynuclear aromatic hydrocarbons. The method is remarkably insensitive to steric hindrance ; for example, 2, 4, 6-triethylbromobenzene reacts quite well. With greater steric hindrance, as in 2, 4, 6-triisopropyliodobenzene, reactivity falls and a side reaction of dehalogenation becomes appreciable, for reasons which are suggested. The synthesis was unsuccessful with the diethylamino, nitro and ionized hydroxy (-O
-) substituents. Potassium metal-stimulated reactions of a few aryl diethyl phosphates with acetone enolate ion give generally lower yields of arylation and larger yields of dephosphation (hydrocarbon) products, compared even to potassium-stimulated reactions with aryl bromides. It is postulated that the lesser formation of hydrocarbon products from the aryl bromides is related to transport effects and solution inhomogeneity.
View full abstract
-
TETSUZO KATO, TAKAO SAKAMOTO
1975 Volume 23 Issue 11 Pages
2629-2633
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Reaction of diketene with ethyl N-benzylacetimidate (Ia) in acetic acid gave 3-acetyl-1, 6-dibenzyl-4, 7-dimethyl-1H, 6H-1, 6-naphthyridine-2, 5-dione (IIa) in 51% yield. Similarly lactim ethers such as 2-methoxy-1-pyrroline (Ib), 2-methoxy-3, 4, 5, 6-tetrahydropyridine (Ic), and 2-methoxy-3, 4, 5, 6-tetrahydro-7H-azepine (Id) gave the corresponding 5-acetyl-6-methyl-4, 7-dioxo-1, 2, 10, 11-tetrahydro-4H, 7H, 9H-dipyrrolo[1, 2-g : 3', 2', 1'-tj]-1, 6-naphthyridine (IIb) (35%), 6-acetyl-7-methyl-5, 8-dioxo-2, 3, 10, 11, 12, 13-hexahydro-1H, 5H, 8H-quinolizino[1, 9-ab]quinolizine (IIc) (66%), and 7-acetyl-8-methyl-6, 9-dioxo-1, 2, 3, 4, 12, 13, 14, 15-octahydro-6H, 9H, 11H-bisazepino[1, 2-g : 3', 2', 1'-tj]-1, 6-naphthyridine (IId) (40%). Treatment of IIa-d with KOH in EtOH resulted in the formation of the deacetylated derivatives IIIa-d.
View full abstract
-
TETSUJI KAMETANI, YOSHIRO HIRAI, MASAHIRO KAJIWARA, TAMIKO TAKAHASHI, ...
1975 Volume 23 Issue 11 Pages
2634-2642
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
A total synthesis of (±)-yohimbine (I) has been achieved from 1, 2, 3, 4, 5, 6, 7, 12b-octahydroindolo[2, 3-a]quinolizin-2-one (XXXIV) via 15, 16-dehydroyohimbinone (XXXVII) and yohimbinone (XXXVIII). Moreover, hexadehydroyohimbine (XXIX) was synthesized from 2-bromo-5-methoxybenzaldehyde (VIII). α-Cyanophenylpropionic acid (X), prepared from VIII through the α-cyanocinnamic acid (IX), was cyclized to the indanone (XI), which was converted into 6-bromo-3-methoxy-2-methoxycarbonylphenylpropionic acid (XIV) via the corresponding dicarboxylic acid (XII) and diester (XIII). Debromination of XIV, followed by cyclization, gave the indanone (XXIII), which was transformed into the indan-1, 2-dione (XXV) through the α-hydroxyimino ketone (XXIV). Pictet-Spengler reaction of XXV with tryptamine afforded the spirobenzyl-β-carboline (XXVI), whose photolysis yielded the decadehydroyohimbane (XXVII) and the decadehydroyohimban-21-one (XXVIII). Reduction of both products gave O-methylhexadehydroyohimbine (XXIX).
View full abstract
-
TAISUKE ITAYA, TOHRU SAITO, SATOSHI KAWAKATSU, TOZO FUJII
1975 Volume 23 Issue 11 Pages
2643-2653
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Rates of the Dimroth rearrangements of 1-benzyloxyadenosine (Id) and 1-alkoxy-9-methyladenines (Ia-c), which give the rearranged products (IIIa-d) and the deformylated compounds (IVa-d) competitively through the isolable monocyclic intermediates (IIa-d), have been measured at different pH's and ionic strength 1.0 at 40°. It has been shown that all reactions obey good pseudo-first-order kinetics. The ring-opening (I→II) follows the rate law given by k
(0)II. obsd[I]
total=k
(0)II. lonie[I·H
+][OH
-]+k
(0)II. neit[I][OH
-] where k
(0)II. obsd is the observed limiting rate constant for zero buffer concentration ; [I·H
+] is the concentration of the protonated base ; [I], the concentration of the free base ; [I]
total, the sum of [I·H
+] and [I]. Comparison of the individual second-order rate constants thus obtained (Table III) has revealed that attack of hydroxide ion on the protonated species is faster than on the neutral species by a factor of 560-1200 and that both reaction modes are promoted by the β-D-ribofuranosyl substituent at the 9-position. Both the ring-closure (II→III) and the deformylation (II→IV) in 0.1M buffer solutions are enhanced by the β-D-ribofuranosyl group at the 1-position of II, whereas the benzyl group on the O-atom of the amidoxime moiety of II exerts the stabilizing effect on II. The unusually low pK
a's of 9.9 to 10.6 at 40°observed for II have been assigned to the acidic ones of the formamido group of II. Probable mechanisms for the ring-closure and the deformylation of II are also described.
View full abstract
-
TANEZO TAGUCHI, SHIRO MORITA, YUICHI KAWAZOE
1975 Volume 23 Issue 11 Pages
2654-2659
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Analogously to the Strecker degradation method, α-amino acids were converted to carbonyl derivatives by treatment with N-sulfinylaniline below 100° in dimethylsulfoxide (or benzene). The sodium salts prefer to the free acids as substrates (35-75% yield). In contrast with other α-amino acids, glycine was further oxidized to formic acid derivative. Also, α-amino acid ethyl esters were submitted to the same treatment and usually converted to keto acid esters as expected. However, the reaction of ethyl glycinate proceeded unordinarily to afford diethyl 1, 2, 5-thiadiazole-3, 4-dicarboxylate. The degradation reaction pathway of α-amino acids was discussed with some evidences and speculations.
View full abstract
-
HIROYUKI AKITA, AKIRA TAHARA
1975 Volume 23 Issue 11 Pages
2660-2668
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
The phenacylidene ester 2, methyl 13-isopropyl-7-oxo-podocarpa-5, 8, 11, 13-tetraen-15-oate, underwent novel rearrangements on refluxing with an excess of aluminum chloride to afford 13-isopropyl-1α-methyl-1β-methoxycarbonyl-7-oxo-15, 16-bisnor-10α-podocarpa-5, 8, 11, 13-tetraene (7) and 10α-hydroxy-13-isopropyl-7-oxo-1, 10-seco-spiro(1.5)-podocarpa-8, 11, 13-trien-15-oic acid 15→10 lactone (8) in 57 and 5% yields, respectively. Their structures were unequivocally established by chemical conversions and spectral examinations. The reaction courses (a) and (b) through 6 were proposed for the mechanisms of these rearrangements which somewhat differ from the rearrangement of 2 by means of protonic acid. It was further found that boron trifluoride etherate promoted also these rearrangement, but was less effective as catalyst, and treatment of 7 with aluminum chloride under the same condition led to the formation of 2 and 8 though in respective small yields.
View full abstract
-
SHIGEHARU INOUYE, TAKASHI SHOMURA, TAKASHI TSURUOKA, YASUAKI OGAWA, HI ...
1975 Volume 23 Issue 11 Pages
2669-2677
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
In the course of the chemical screening study on the metabolites from actinomycetes, two unusual amino acids were isolated : L-β-(5-Hydroxy-2-pyridyl)-alanine (1) and L-β-(3-hydroxyureido)-alanine (9). The structures of 1 and 9 were elucidated from the physico-chemical properties of these amino acids and derivatives, and supported by synthesis. Antibacterial activities of 1 and its methylester (2) were antagonized by L-tyrosine, and those of 9 and its derivative (17) by L-glutamine.
View full abstract
-
A. NAGEL, H.C. vander PLAS
1975 Volume 23 Issue 11 Pages
2678-2681
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
2-Methylthio-4, 6, 7-triphenylpteridine (1) is slowly converted by potassium amide in liquid ammonia at -33°into 2-amino-4, 6, 7-triphenylpteridine (2) as the main product and into a ring contraction product which is proved to be 6, 8-diphenyl-2-methylthiopurine (3). The latter is found to be the major product when 4, 6-diphenyl-2-methylthiopteridine (4) and 4, 7-diphenyl-2-methylthiopteridine (5) are treated likewise. The mechanism of the ring contraction is discussed.
View full abstract
-
H.C.van der PLAS, D.J. BUURMAN
1975 Volume 23 Issue 11 Pages
2682-2685
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Based on experiments with 8-nitro-[2, 4-
14C]-quinoline and 8-nitro-[4-
14C]-quinoline, it has been found that during the ring transformation of 8-nitroquinoline into 7-nitrooxindole by action of hydrogen peroxide in acetic acid, the C
2-atom of the quinoline ring is expelled. A mechanism for the ring transformation is proposed.
View full abstract
-
ISAO KITAGAWA, HIDEKAZU TAKENO, HIROTAKA SHIBUYA, ITIRO YOSIOKA
1975 Volume 23 Issue 11 Pages
2686-2695
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
As a continuative study to clarify the structure requirement for the ready conversion of 5α, 6α-epoxy-eudesman-8β, 12-olide (1) to eremophilane-type compounds via the biogenetic-type 1, 2-shift of 10-Me, acid treatment under a variety of acid conditions of 4α, 5α-epoxy-eudesman-8β, 12-olide (2) has been examined. It has been found that acid treatment of 2 with HCOOH-acetone, BF
3-etheratebenzene, CF
3COOH-CHCl
3, or p·TsOH·H
2O-EtOH furnish no eremophilane-type compound, but yield four products such as AT-1 (10), AT-2 (11), AT-3 (12), and AT-4 (13) with different compositions depending upon the reaction conditions. The reaction pathways are also discussed.
View full abstract
-
KEISUKE SHIGEZANE, SUSUMU HATSUNO, NORIO TAKAMURA, TOMISHIGE MIZOGUCHI ...
1975 Volume 23 Issue 11 Pages
2696-2700
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Pyroglutamylhistidyltryptophyl-(O-Bzl) seryl-(O-Bzl) tyrosylglycylleucyl-(N
G-nitro)-arginylprolylglycinamide was synthesized by successive fragment condensations of three peptide derivatives, pGlu-His-NHNH
2, Boc-Trp-(O-Bzl) Ser-(O-Bzl) Tyr-Gly-NHNH
2 and Boc-Leu-(N
G-nitro) Arg-Pro-Gly-NH
2 ; the latter two were prepared by the modified solid phase method using bromoacetylpolystyrene resin as carrier. Removal of all the protecting groups from the decapeptide derivative was easily effected by hydrogenolysis over a new type of catalyst, colloidal palladium on PVP. Thus the present reduction method made the large scale production of the peptide quite easy.
View full abstract
-
SHIRO IKEGAMI, JUNICHI OHISHI, SANYA AKABOSHI
1975 Volume 23 Issue 11 Pages
2701-2710
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
In connection with our studies on the roles of heteroatoms (N, S, O) in solvolytic reactions, the effects of the heteroatoms in ring openings of epoxides, methylenecyclohexane epoxide (4), 3-methylene epoxides of tetrahydropyran (5), N-methylpiperidine (6) and tetrahydrothiopyran (7), were examined. All epoxides were synthesized according to Corey's procedure from the corresponding cyclanones. Ring-opening reactions of epoxides were carried out as follows : a) Reduction with lithium aluminum hydride, b) reduction with lithium metal in ethylenediamine, c) reduction with borane-lithium borohydride, d) acetic acid-catalyzed opening, e) hydrochloric acidcatalyzed opening, and f) reaction of 7 with Lewis acid (boron trichloride). No appreciable effects of heteroatoms were observed in the reactions a and b for 4, 5, and 6. The reactions c, d, and f for 7 resulted in the predominant formation of ring-contracted 5-membered ring derivatives. These results strongly suggest that an enormous amount of participation, particularly by the sulfur atom, is also involved in the ring-opening reactions of epoxides as well as that observed in solvolysis.
View full abstract
-
KENICHI TAKEDA, HIROSHI TANIDA, KUSUO HORIKI
1975 Volume 23 Issue 11 Pages
2711-2727
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
25D-Spirosta-1, 4, 11-trien-3-one (5a) and androsta-1, 4, 11-trien-17β-ol-3-one acetate (16b) were prepared from hecogenin and 5β-androstane-3α, 12α, 17β-triol, respectively. The dienone-phenol rearrangements of these compounds were carried out and the structures of all reaction products were clarified. Rates of the rearrangement of 16b were determined in a 95 : 5 (w/w) mixture of acetic acid and acetic anhydride containing p-toluenesulfonic acid at 20° and varying acidity function H
0. Comparison with a reference compound, androsta-1, 4-dien-17β-ol-3-one acetate (36), indicated for 16b a reactivity enhanced by a factor of 180 at 20°and H
0=0. Products were found to be four kinds of the A-aromatic B-seco allyl acetates (at 20°and H
0=-0.80 ; Δ
9(11)-12α-OAc (25c) 75%, Δ
9(11)-12β-OAc (25d) 2%, and Δ
11(12)-9 (α and β)-OAc (26c) 23%) with the A-aromatic B/C cis Δ
11(12)-steroid (27c) (3%). The results suggest important participation of the C-11 (12) double bond in the rearrangement of 16b. Treatment of the B-seco Δ
9(11)-12α-allyl alcohol (25b) with the acid of H
0=-1.86 at 80° led to the B/C cis steroid (27c) with a concurrent isomerization to an intermediate, B-seco Δ
9(11)-12β-allyl acetate (25d), which is interpreted as a result of electrophilic aromatic substitution of an allyl cation formed from the B-seco Δ
9(11)-12α-allyl alcohol.
View full abstract
-
MASATO TANABE, BARBARA BIGLEYSOCKOLOV, DAVID F. CROWE
1975 Volume 23 Issue 11 Pages
2728-2734
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
By the reaction of prednisolone and dexamethasone with 2, 2-dimethoxypropane, the synthesis of the 17α, 21-acetonides of these corticosteroids was examined. The utility of the 17α, 21-acetonide function as a protecting group for the labile cortical dihydroxyacetone function is demonstrated. It is particularly valuable for the direct introduction into intact corticoids of C-21 substituents. The synthesis of 21α-methyl and 21-trifluoroacetyl analogs of prednisolone and dexamethasone are described. Condensation of the 17α, 21-acetonides with formaldehyde yields the 21-methylene derivatives 13 and 14, which serve as intermediates for the synthesis of the 21β-nitroethyl derivative 17 and the γ-lactone 19.
View full abstract
-
ROLF HUISGEN, AKIHIRO OHTA, JOCHEN GEITTNER
1975 Volume 23 Issue 11 Pages
2735-2743
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
1-Substituted butadienes (R=CH
2, CH
3, O, C
3H
5, CO
2CH
3, CN) and 2-phenylbutadiene accept diazomethane at the 3, 4-bond yielding 3-vinylpyrazoline derivatives. Tautomerization of the 1-to 2-pyrazolines takes place either at room temperature (R=CO
2CH
3, CN), on heating (R=C
6H
5) or on acid catalysis (R=H, CH
3, OCH
3) ; the 2-pyrazolines are characterized as 1-carbamoyl and 1-nitroso derivatives. 1-Substituted butadienes follow in their rate constants of diazomethane cycloaddition a linear free energy relationship with Hammett's σp values, ρ=+4.2. The rates and orientations are discussed in the light of the recent MO perturbation treatment.
View full abstract
-
SHOZO KAMIYA
1975 Volume 23 Issue 11 Pages
2744-2748
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
3-Pyridylmethyl analogs of 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), 1-methyl-1-nitrosourea (MNU) and N-methyl-N-nitrosourethan (MNUT) were synthesized by nitrosation of the corresponding N-acyl-N-(3-pyridyl)methylamines. 3-Alkyl(aryl)-3-nitroso-1-(3-pyridyl)methylureas were also synthesized by nitrosation of 3-alkyl(aryl)-1-(3-pyridyl)methylureas. The reaction of some of these N-nitroso compounds with alkali, was examined. Among hese N-nitroso compounds the mutagenic activity of 3-nitro-1-nitroso-1-(3-pyridyl)methylguanidine was as potent as the ethyl analog of MNNG in the mutation assay using streptomycin-dependent E. coli Sd-4.
View full abstract
-
GORO KOBAYASHI, YOSHIRO MATSUDA, YOSHINORI TOMINAGA, KAZUMICHI MIZUYAM ...
1975 Volume 23 Issue 11 Pages
2749-2758
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
The reaction of enaminodithiocarboxylates, which have a conjugated thiocarbonyldiene system, with dimethyl acetylenedicarboxylate as a dienophile resulted in a 1, 4-cycloaddition to afford various thiapyrane derivatives and spiro (benzothiazoline) and thiazolinecyclopentadiene derivatives by the monodesulfurization. The reaction of thioamide derivatives of lepidine and 4-picoline gave benzoazocine and azocine derivatives.
View full abstract
-
GORO KOBAYASHI, YOSHIRO MATSUDA, YOSHINORI TOMINAGA, CHIKATOSHI MASEDA ...
1975 Volume 23 Issue 11 Pages
2759-2766
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
From the reaction of 4-imino-6-methyl-4H-quinolizine derivatives (I) with acid anhydrides (glutaric anhydride and crotonic anhydride), the corresponding 1-azacycl-[3, 3, 3]azine derivatives (V, VI) were obtained. 1-Aza-5-oxo-2, 3, 4, 5-tetrahydrobenzo[b]cycl[3, 3, 3]azine (X) was yielded, as a stable free base, by the decarboxylation of VI. On the other hand, 2-methyl and 2, 5-dimethyl-1-azacycl[3, 3, 3]azine (XVIa, b), which were very unstable free bases, were prepared by the degradation of II and IV. These nuclear magnetic resonance spectral data of XVIa and XVIb may be interpreted in term of a paramagnetic ring current.
View full abstract
-
SHOKO SUEYOSHI, IKUO SUZUKI
1975 Volume 23 Issue 11 Pages
2767-2772
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Catalytic reduction of 4-nitro-3, 6-dimethylpyridazine 1, 2-dioxide (II) over palladiumcharcoal in ethanol, the reaction being stopped after absorption of four moles of hydrogen, afforded 4-amino-3, 6-dimethylpyridazine 1-oxide (III) and 5-amino-3, 6-dimethylpyridazine 1-oxide (IV), while after absorption of three moles of hydrogen, II gave 5-hydroxylamino-3, 6-dimethylpyridazine 1-oxide (V) in 38% yield. Heating of II with hydrochloric acid or with hydrobromic acid formed 4-chloro-3, 6-dimethylpyridazine 1, 2-dioxide (IXa) or 4-bromo-3, 6-dimethylpyridazine 1, 2-dioxide (IXb), respectively. When II was treated with acetyl chloride at room temperature for 7 days, 3, 6-dimethyl-4, 5-dichloropyridazine 1-oxide (X), 3-chloromethyl-4-nitro-6-methylpyridazine 1-oxide (XI) and 3-methyl-4, 5-dichloro-6-cyanopyridazine 1-oxide (XII) were obtained besides IXa. In addition to above-mentioned new pyridazine dioxide derivatives (IXa and IXb), 4-methoxy-3, 6-dimethylpyridazine 1, 2-dioxide (XIIIa) and 4-benzyloxy-3, 6-dimethylpyridazine 1, 2-dioxide (XIIIb) were synthesized.
View full abstract
-
YOSHIRO KOBAYASHI, ITSUMARO KUMADAKI, AKIO OHSAWA, YASUO SEKINE, HIROY ...
1975 Volume 23 Issue 11 Pages
2773-2778
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
The structure of photo isomer of 2, 3, 4, 5-tetrakis (trifluoromethyl) thiophene (I) was determined as "Dewar" type (II) by
13C-NMR (nuclear magnetic resonance) and other physical and chemical data. Diels-Alder reaction of II with furans gave exo-exo type products, 10-oxa-4-thiatetracyclo[5.2.1.0
2, 6.0
3, 5]dec-8-ene derivatives (VI), which was derived to substituted oxahomocubanes, 9-oxapentacyclo[4.2.1.0
2, 5.0
3, 8.0
4, 7]nonanes (VIII) by successive desulfurization and photochemical reactions.
View full abstract
-
TOSHIRO IBUKA, NORIO MASAKI, IKUTARO SAJI, KIYOSHI TANAKA, YASUO INUBU ...
1975 Volume 23 Issue 11 Pages
2779-2790
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Racemate of pumiliotoxin C which is a toxic constituent of skin extracts of Neotropical frogs, Dendrobates pumilio and Dendrobates auratus, was synthesized. The epoxy-lactam (8) was synthesized from octahydroquinolone (4) via the N-benzyl-cis-octahydroquinolone (7). The bromohydrin (9) from 8 was successively subject to Jones' oxidation, dehydrobromination, and the conjugated addition to give the methyl-ketone (14). The thio-lactam (40) was obtained from the methyl-ketone (14) via the decahydroquinolone (39). Using the Eschenmoser's procedure, the thio-lactam (40) was transformed to the vinylogous amide (42). Catalytic hydrogenation of 42, followed by Jones' oxidation, gave the aminoketone (44). Reductive desulfurization of the thioacetal (45) gave dl-pumiliotoxin C (46), the stereochemistry of which was confirmed by a single crystal X-ray analysis. Three stereoisomers, (17), (19), and (36), of the methyl-ketone (14) were also prepared.
View full abstract
-
HIROSHI IGETA, HEIHACHIRO ARAI, HIROSHI HASEGAWA, TAKASHI TSUCHIYA
1975 Volume 23 Issue 11 Pages
2791-2797
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
The reaction of pyridazine N-oxide (1) with benzyne produced 1-benzoxepine (5) in moderate yield, via the 1, 3-cycloadduct (4). By the similar reaction, N-acetyliminopyridazinium ylide (2) and pyridazinium dicyanomethylide (3) yielded the 1, 3-cycloadducts (9 and 21). The adduct (9) was transformed into the 3-vinylindazole (10) and 3-(2-acetoanilino)-pyridazine (11) by heating or treatment with sodium methoxide. Irradiation of the adduct (9) resulted in the aromatization to form indazolo[2, 3-b]pyridazine (12) and in the ring contraction to form indole derivatives (13 and 14) via 1-benzazepine (19). The formation mechanism of these compounds is also discussed.
View full abstract
-
HIROSHI IGETA, CHISATO KANEKO, TAKASHI TSUCHIYA
1975 Volume 23 Issue 11 Pages
2798-2804
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
The reaction of 1-methoxypyridazinium methosulfate (1) with cyanide ion resulted in the ring fission and subsequent elimination of N
2 to give the cyano substituted vinyl acetylenes (2 and 3) and 1, 3-butadienes (4). On the other hand, reactions of the salt (1) with hydroxide and dicyanomethyl anion resulted in the similar ring-opening, followed by elimination of the methoxyl group, to give vinyl diazomethanes (6 and 9), which were easily converted into the corresponding pyrazole derivatives (7 and 10) by an intramolecular 1, 3-dipolar cycloaddition. The reaction mechanism is also discussed.
View full abstract
-
SHINICHIRO SAKAI, NORIO AIMI, AKINORI KUBO, MASAYUKI KITAGAWA, MASAKO ...
1975 Volume 23 Issue 11 Pages
2805-2817
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Gardneramine, the main alkaloid of Gardneria spp. (Loganiaceae), was found to have the structure I. At the same time a minor base, alkaloid G, was elucidated to be 18-demethylgardneramine (XVIII). Both alkaloids have an iminoether ring as the masked oxindole, some novel reactivities of which are described. Three trimethoxy oxindoles (XXXII a, b, c) were synthesized as the model compounds for locating the aromatic substituents of I.
View full abstract
-
SACHIKO YAMADA, MASAYUKI ISHIKAWA, CHIKARA KANEKO
1975 Volume 23 Issue 11 Pages
2818-2834
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Photolysis of a series of acridine 10-oxides (Ia-Ig) in various solvents is reported. The structures of photo-products were determined by syntheses, chemical transformation to the known compounds, or by direct examination of their spectroscopic data. Based on the structures of photo-products and the solvent effect on the product distribution in these photolyses, a mechanistic rationalization of these photo-reactions is presented. The characteristic features of the photo-rearrangement reactions of acridine 10-oxides are discussed and compared with those of bicyclic and monocyclic azine N-oxides, e, g., quinoline 1-oxides and pyridine 1-oxides.
View full abstract
-
MASATO AIURA, YUICHI KANAOKA
1975 Volume 23 Issue 11 Pages
2835-2841
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Benzoyl peroxide converts pyrroles into 2-hydroxy-and 2, 5-dihydroxy O-benzoates. The mono-and di-O-benzoates of N-substituted pyrroles were prepared by this convenient one-step procedure. The mechanism was discussed in terms of both homolytic and heterolytic factors, and general aspects of homolytic substitution of the pyrrole ring were also discussed in comparison with other five-membered heterocycles. On treatment with benzoyl peroxide N-substituted pyrrole-2-methanols undergo novel C-C cleavage to give the O-benzoates.
View full abstract
-
HIROAKI SAWAI, TAKEO TAKIZAWA
1975 Volume 23 Issue 11 Pages
2842-2849
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
Isocyanide-mercuric chloride complexes, which were obtained from isocyanides and mercuric chloride, react readily with active methylene compounds in the presence of triethylamine giving 2 : 1 adducts. The adducts were formed through a redox decomposition reaction of the complexes accompanying with the formation of metallic mercury. The reaction of the adducts was also investigated.
View full abstract
-
SHOJI HARA, KUNIO MIBE
1975 Volume 23 Issue 11 Pages
2850-2859
Published: November 25, 1975
Released on J-STAGE: March 31, 2008
JOURNAL
FREE ACCESS
For the investigation of the solvent selectivity in liquid solid chromatography, the mobilities of various steroidal pharmaceuticals were systematically measured using silica gel and alumina thin-layer chromatography (TLC). The parameters (ΔR
M values) for the contribution of individual functional groups on the mobility were calculated by applying eleven solvent systems. The solvent selectivity was discussed on the basis of these values in relation to the structure of the steroids. For scaling the chromatographic systems examined by TLC to high performance liquid column chromatography (HPLC), their correlation in terms of mobility was extensively investigated. It was shown that the optimum system selected by TLC is applicable to HPLC with some minor modifications.
View full abstract