Various Mannich bases with dialkylaminomethyl group in the 5-position were prepared by reacting 2-acetamido-4-methyl- and 2-acetamidothiazoles with formaldehyde and various secondary amines. The Mannich reaction of 2-acetamido-4-methylthiazole is completed in a short time by mixing the reactants, without the use of a solvent, but that of 2-acetamidothiazole requires heating of 1-2 hours in a water bath. Alkylation of triethoxycarbonylmethane with 2-acetamido-4-methyl-5-morpholinomethylthiazole thereby obtained afforded 2-acetamido-4-methyl-5-(2-triethoxycarbonylethyl) thiazole of m.p. 107°, whose hydrolysis gave 2-amino-4-methyl-5-thiazolepropionic acid, m.p. 257°, in a good yield. The latter was identified by admixture with the substance of m.p. 257° obtained by the condensation of ethyl 4-acetylbutyrate and thiourea.
The tertiary Mannich bases of 2-acetamidothiazoles are not capable of direct C-alkylation but their methiodides undergo facile reaction with the sodium salts of ethyl acetoacetate, diethyl malonate, triethoxycarbonylmethane, and diethyl acetamidomalonate. It is considered that the alkylation by the methiodide of Mannich bases is due to the formation of a C-alkylation ability through substitution mechanism by the resonance stability of thiazolyl carbonium cation (XI), assumed to be the intermediate of this reaction. Two kinds of 5-thiazolylalanine (XIV and XV) were obtained by the alkylation of diethyl acetamidomalonate (XI) followed by hydrolysis.
Corresponding carboxamides and hydrazides were synthesized from 1, 2, 3-triazole-4-carboxylic acid and -4, 5-dicarboxylic acid via their esters. 4-Amino-1, 2, 3-triazole was obtained from the hydrazide compound by the Curtius reaction.
By the reaction of malonamamidine or ethyl cyanoacetamide and phenyl or benzyl azide, 1-phenyl- and 1-benzyl-5-amino-1, 2, 3-triazole-4-carboxamide was obtained. Debenzylation afforded 4-amino-1, 2, 3-triazole-5-carboxamide.
1) By the condensation of carbonyl sulfide with aminoacetonitrile, and arylaldehydes (o-, m-, and p-nitrobenzaldehyde, veratraldehyde, piperonal, 2, 4-dichlorobenzaldehyde, 1-naphthaldehyde, furfural, and 3-pyridinecarboxaldehyde), corresponding 5-arylideneamino-2-thiazolols (I to IX) were obtained. Treatment of these with alkyl iodides in the presence of sodium ethoxide afforded several kinds of 2-alkoxy-5-arylideneaminothiazoles (X to XVIII). 2) By the application of p-dimethylaminobenzaldehyde, furfural, p-anisaldehyde, vanillin, or piperonal to 4-phenyl-5-amino-2-thiazolethiol, corresponding 4-phenyl-5-arylideneamino-2-thiazolethiols (XIX to XXIII) were obtained. Sodium salts of these compounds were condensed with alkyl iodides, allyl bromide, benzyl chloride, 2-iodoethanol, 2-bromoethyl alkyl ethers, ethyl bromoacetate, bromoacetamide, or ethyl chloroformate to obtain the corresponding thioethers (XXIV to LX).
Many reports have been published regarding suppressive agent for melanin formation but they do not agree in various points and experimental conditions vary with each worker that their results cannot be compared. In order to make comparative examinations on the known suppression agents as well as some compounds thought to be of interest in this direction under the same experimental conditions, present series of experiments were undertaken. Effect of 14 kinds of copper-combining agents, chiefly chelation agents, on potato tyrosinase was measured by the Warburg manometric technique and results are given in Figs. 1 to 14 and in Table I.
Separatory determination of nicotinic acid and nicotinamide-like factors in 56 kinds of crude drugs was made by microbiological assay using Lactobacillus arabinosus 17-5 and Lact. fructosus 353. With the exception of a few, these crude drugs contain both vitamins and in 18 of them (32%), the amount of nicotinamide is larger than or equal to that of nicotinic acid. In general, the content of nicotinic acid is larger in crude drugs using subterranean portions (roots and rhizomes) than those using terranean portions (wood and bark), the content being 200 γ/g. in anemarrhena. The content is also larger in crude drugs used as tonics, such as ginseng, bupleurum, dioscorea, nuphar, and anemarrhena, than other drugs, the content being over 40 γ/g. The content is generally higher in animal drugs, such as Agkistrodon halys and larva of Protohermes grandis, but below that in anemarrhena. The amount of nicotinic acid found in bupleurum stored from few to scores of years was not greatly different from that in the fresh bupleurum immediately after collection. The presence of nicotinic acid and nicotinamide in the extracts of anemarrhena was examined by paper chromatography and the results of Separatory determination by microörganisms were confirmed.
Determination of pantothenic acid-like factor in 56 kinds of crude drugs was made by microbiological assay. With the exception of a few, these drugs contain this factor, 77% of the drugs (42 kinds) containing 0-9γ/g. and 23% of them 10-33γ/g. As in the case of nicotinic acid, the content of pantothenic acid-like factor was greater in the crude drugs used as tonics such as ginseng, anemarrhena, Japanese aconite, bupleurum, and cassia seed, and especially in glycyrrhiza, there being 33γ/g. Examination of this factor in glycyrrhiza and ginseng by paper chromatography suggested that this growth factor is identical with pantothenic acid. The amount of nicotinic acid and pantothenic acid contained in 25 kinds of preparations contained these 56 kinds of crude drugs showed that those used for ailments requir-ing these kind of vitamins contain a large amount, some of them containing 800-1000γ/day of nicotinic acid and up to 260γ/day of pantothenic acid. Such an amount of vitamins is not negligible from modern medicine and it is thought that it plays an important role in the concerted effect of these drugs and preparations.
The presence of nicotinic acid and pantothenic acid in 56 kinds of crude drugs was examined by microbiological assay. Since vitamin content in these crude drugs varies under various conditions, examinations were made on the individual difference of the content, relationship between duration of cultivation and content in the same variety, difference in the content due to cultivated area, and variation of content in pollens and honey according to difference in the original plant, and the following results were obtained. 1) There was no individual difference in vitamin content in ligusticum cultivated under identical conditions and no great difference in vitamin content was observed even under varying periods of cultivation and cultivated area. 2) There was no individual difference in liquorice, cnidium, and alisma, procured at the same time, except for a few examples. However, a fairly great individual difference was observed in anemarrhena, even with those cut into 3-4cm. pieces. 3) There was a fairly great individual difference in vitamin content of honey. This difference is thought to be due more to the kind and content of pollens mixed in the honey and the amount of Royal jelly, rather than to the kind of plants as source of honey.
Several new compounds were prepared by the Bischler-Napieralski reaction, i.e. 6, 7-ethylenedioxy-1, 2, 3, 4-tetrahydroisoquinoline (VII) and its N-methyl derivative, and 1-(4-methoxybenzyl)-6, 7-ethylenedioxy-1, 2, 3, 4-tetrahydroisoquinoline (XII) and its N-methyl derivatives.
Stability of the thiazine ring in pyrido-1, 4-thiazine derivatives was examined with 6-methoxy-1H-pyrido[2, 3-b]-1, 4-thiazine derivatives as the sample. The methylene in 3-position of 2-phenylpyrido[2, 3-b]-1, 4-thiazine derivatives is sensitive to oxidation irrespective of the kind of substituent in the 6-position and the compounds were found to be oxidized stepwise to 3, 3′-bis (2-phenyl-3H-pyrido[2, 3-b]-1, 4-thiazinylidene) via the 3, 3′-bis (2-phenyl-1H-pyrido[2, 3-b]-1, 4-thiazinyl).
Arylthio compounds from 3-amino-6-chloro-2-pyridinethiol were prepared and conditions for the Smiles rearrangement in pyridine derivatives were examined. It was found that the reaction was more easily effected than in benzene derivatives and this was assumed to be the additive effect of ring nitrogen and chlorine in 6-position of the pyridine ring. Azaphenothiazine derivatives were synthesized by the application of this Smiles rearrangement and the possibility of this ring formation was found to be easily understood by the hypothesis of a chelate ring forwarded by Brady and others in connection with phenoxazine-ring formation.
Aromatic acyl derivatives of 5-aminopentanoic acid, obtained by the Beckmann rearrangement of cyclopentanone oxime, when dry-distilled with soda lime, barium oxide, sodium amide, or zinc dust, afford a mixture of partially hydrogenated 2-arylpyridines, together with water vapor, ammonia, and inflammable gas. Dehydrogenation of this mixture easily affords 2-arylpyridine. Soda lime is the most effective condensation agent for 5-benzoylaminopentanoic acid (I) and the effect decreases in the order of zinc dust, sodium amide, and barium oxide. The yield also decreases in the respective order of 50%, 30%, 12%, and 3%, calculated as 2-phenyl-3, 4, 5, 6-tetrahydropyridine (II). Dehydrogenation of (II) could best be effected by heating with palladium black, in the presence of safrole, at 170-180° for 4-5 hours, from which 2-phenylpyridine (III) is obtained in 90-95% yield. The picrates of (II) and (III) do not show any depression of the melting point on admixture. Dry-distillation of (I) affords a non-basic substance, in 7-8% of the starting material, and this consists of biphenyl, acetophenone, and benzonitrile. Dry-distillation of 5-o- and -p-toluamidopentanoic acid with soda lime affords 2-tolyl-hydropyridine in 40% yield, whose dehydrogenation easily gives the corresponding 2-tolylpyridine.
Several kinds of thiourea derivatives were condensed with 2-methyl-4-amino-5-chioromethylpyrimidine hydrochloride (I) to form isothiuronium salts (II) and their properties were compared. Compounds of the formula (II), where R is phenyl, benzyl, methyl, or amino, change to bis (2-methyl-4-amino-5-pyrimidylmethyl) sulfide (XI) (cf. Table I) when aqueous solution of (II) obtained on neutralization with sodium hydrogen carbonate is heated. Hydrogen peroxide oxidation of alkaline solution of (II) affords his (2-methyl-4-amino-5-pyrimidylmethyl) disulfide (XII). On heating hydrochloric acid solution of (II), compounds with phenyl or methyl undergo cyclization to form 7-methyl-4H-pyrimido [4, 5-d]-m-thiazin-2 (1H)-one (XIII) while those with benzyl and amino do not form the thiazine ring but undergo hydrolysis of the imino group to the carbonyl to form the compounds (XIV) and (XV).
The aqueous solution of atropine sulfate does not indicate lowering of mydriatic action even if its action on isolated intestines is lowered. This fact was reexamined by mydriatic action in mice and the fact was confirmed. A mixed solution of atropine, tropine, and tropic acid shows only the mydriatic action of atropine present. Therefore, if aqueous solution of atropine sulfate has undergone partial hydrolysis, the mydriatic action of such a solution should be lowered by that much. On the other hand, the absence of tropine in the aqueous solution, whose antiacetylcholine action on isolated intestines is thought to have lowered already, was found by paper chromatography, i.e. hydrolysis had hardly taken place.
Solvent effect on the C-H out-of-plane vibration absorpiton of benzene, phenol, and anisole was examined and it was found that there was a marked effect, showing similar properties in all three. The shift of the absorption band was independent of εD but dependent on ε, the greater the value of ε of a solvent, the more likely was the shift of the absorption band to the higher frequency region. The infrared spectra of chlorobenzene and nitrobenzene exhibit an absorption, assumed to be due to factors other than C-H out-of-plane vibration, in the region of 650-900cm-1. The transition of absorption bands due to solvent effect differs with each band and it was clarified that difference in this nature may be utilized in discriminating the different origin of characteristic absorption bands.
Effect of hydrogen bond on the C-H out-of-plane vibration absorption in phenol was examined. It was found that such absorption transits to a higher frequency region when a proton acceptor is added to the carbon disulfide solution of phenol to form hydrogen bond between the two. The degree of such a shift was assumed to approximately correspond to the strength of hydrogen bonding between the two components. It was clarified that this effect of hydrogen bond should be considered apart from the solvent effect.
A new reaction of hydroxylamine was found from a reaction between quinazoline and hydroxylamine and the structure of this reaction product, quinazoline 3-oxide (III) was determined in a following manner. (1) Reduction of (III) with palladiumcarbon affords tetrahydropyrimidoquinazoline and this reduction indicates the presence of an easily reducible oxygen which is not in the hydroxyl group of the hydroxy compound of quinazoline. This points to the fact that (III) is an N-oxide of quinazoline. (2) Oxidation of (III) with hydrogen peroxide affords 4-quinazoline 3-oxide (IV). (3) The position of the N-oxide group was determined from the fact that the alkaline hydrolysis of ethiodide, obtained from (III) and ethyl iodide, affords o-ethylarinobenzaldehyde oxime. (4) Quinazoline 3-oxide was prepared by the reacion of o-aminobenzaldehyde oxime and ethyl orthoformate. Derivation of quinazoline to its N-oxide by the usual method failed to form the objective and 4-quinazolone was obtained in a quantitative yield.
1) Reaction of quinazoline and hydroxylamine at 125° results in concurrent specific reaction of hydroxylamine and amination, and 2-aminoquinazoline 3-oxide is formed from quinazoline. 2) Reaction of 4-methoxy- or 4-phenoxyquinazoline and hydroxylamine is expected to afford their N-oxides but the product obtained was 4-aminoquinazoline 3-oxide, a compound formed by further amination by ammonia or hydroxylamine of 4-methoxy- and 4-phenoxyquinazoline 3-oxide once formed by the specific reaction with hydroxylamine.
1) Reaction of hydroxylamine with quinazoline derivatives was further extended in order to examine its range of application and its reaction with 4-methylquinazoline afforded its 3-oxide as anticipated. 2) The structure of products obtained by these specific reaction of hydroxylamine was studied further and the present reaction product was identified as 4-methylquinazoline 3-oxide. 3) 4-Methylquinazoline 3-oxide can also be obtained by the reaction of 2-aminoacetophenone oxime and ethyl orthoformate. 4) An addition product was obtained from the reaction of 4-methylquinazoline and p-nitrobenzaldehyde and was assumed to be 4-(β-hydroxy-4-nitrophenethyl) quinazoline.
Hydroxylamine sulfate on silica gel carrier was used as an agent for removing nitrogen oxides in the determination of carbon and hydrogen but this substance was found not to remove nitrogen monoxide. Therefore, measures were taken to change this monoxide to nitrogen dioxide by utilizing the adsorptive power and oxygenoccluding power of silica gel itself and satisfactory results were obtained. The ability of this reagent in reducing and removing nitrogen dioxide was examined by the use of nitrogen monoxide generator and collector especially devised for this purpose and the ability was presumed in a short time from the amount of nitrogen monoxide consumed in the oxidation of the monoxide to the dioxide. It was concluded that the tube filled with this reagent may be used for about 250 analyses. This reagent is stable and the manner of its filling is simplified, as well as giving satisfactory results.
The sulfur analysis started by Stragand is made by heating sulfur-containing sample in an oxygen atmosphere, with platinum as a catalyst, the sulfur oxide is adsorbed on heated silver net, and this net is weighed. It was found in the present series of experiments that this platinum could be substituted with copper oxide without any trouble in the analytical values of sulfur. Concurrent determination of carbon, hydrogen, and sulfur by filling this copper oxide and silver net in the combustion tube was carried out and good results were obtained. This could be applied with air stream in case of a series of substances whose sulfur is easily oxidized.
Catalytic reduction of α-naphthocoumarin (Ia) and its 4-methyl derivative (Ib) with the Adams platinum in glacial acetic acid afforded their tetrahydro, hexahydro, and dodecahydro compounds and reduction route to the final product was clarified. The main route of reduction is the formation of 3, 4, 7, 8, 9, 10-hexahydro-2H-naphtho[1, 2b]pyran-2-one (Va) and its 4-methyl derivative (Vb) through their tetrahydro compounds (IIIa and IIIb), while 3, 4, 4a, 5, 6, 10b-hexahydro compound (VIa and b) is formed as a by-product in a small amount. (IIIa and b) were obtained by the Pechmann reaction of 5, 6, 7, 8-tetrahydro-1-naphthol (II) and (Va and b) were obtained through their reduction with sodium amalgam to 3-(1-hydroxy-5, 6, 7, 8-tetrahydro-2-naphthyl) propionic acid (IVa) or -butyric acid (IVb). The main route of reduction to the dodecahydro compound is in the order of (I)→(III)→(V)→ dodecahydro compound. High-pressure reduction of (Ia and b) with Raney nickel catalyst affords (Va and b) as the main product.
Partial catalytic reduction of β-naphthocoumarin (Ia) and its 1-methyl derivative (Ib) with Adams platinum affords 1, 2, 7, 8, 9, 10-hexahydro-3H-naphtho [2, 1-b]pyran-3-one (IIa) and its 1-methyl derivative (IIb). The high-pressure reduction of (Ia) using Raney nickel affords 3-(5, 6, 7, 8-tetrahydro-1-naphthyl) propionic acid, (IIa), and ethyl 3-(2-hydroxy-5, 6, 7, 8-tetrahydro-1-naphthyl) propionate in a ratio of 14:83: minute amount, while only (IIb) is formed from (Ib). Attempts to prepare (IIa) and (IIb) from 5, 6, 7, 8-tetrahydro-2-naphthol by the Pechmann reaction failed and 3, 4, 6, 7, 8, 9-hexahydro-2H-naphtho[2, 3-b]pyran-2-one and its 4-methyl derivative were obtained. The velocity of acid catalyzed lactone cleavage of the hexahydro compounds thereby obtained was measured and relationship between the structure and reactivity was discussed.
Velocity of alkaline hydrolysis of various coumarin derivatives were measured with an apparatus of Elhiney, Whitemore, and Lynch. It was proved that the cleavage of the lactone ring is a BAC 2 type and relationship between the structure and reaction velocity was discussed. Coumarin derivatives with a substituent in the 7-position agree with the Hammett Law but those with the substituent in the 6-position do not, although the application of para-substitute constants to the latter results in the variation of the observed and calculated values of reaction velocity due to the difference in the kind of substituents with a similar tendency, though they do not agree completely.
Introduction of an aldehyde group into 5, 6, 7, 8-tetrahydro-2-naphthol by the Gatter-mann, Reimer-Tiemann, and Duff reactions is effected at 1-positions, as would be expected from the Mills-Nixon effect, but is contrary to that effect by the Pechmann reaction, condensation taking place at 3-position to afford 6, 7, 8, 9-tetrahydro-2H-naphtho[2, 3-b]pyran-2-one and its 4-methyl derivative. Dehydrogenation of these compounds afforded naphthocoumarin and its 4-methyl derivative possessing anthracene-like structure which are the position isomers of β-naphthocoumarin, with known phenanthrene-like structure. The compound was therefore named iso-β-naphthocoumarin. The structures of β-naphthocoumarin and its 1-methyl derivative and iso-β-naphthocoumarin and its 4-methyl derivative were discussed together with their ultraviolet absorption spectra and velocity of alkaline hydrolysis.
The structure of the product obtained by the condensation of orcinol and 2-substituted acetoacetic ester is either 7- or 5-hydroxycoumarin derivative. The literatures published to date claim that it is a 5-hydroxycoumarin derivative with the exception of the condensate from 2-benzylacetoacetic ester. However, such conclusions were based on the fact that the solutions of the condensate in conc. sulfuric acid and sodium hydroxide do not show any fluorescence and direct proof of their structures has not been made. By the comparison of ultraviolet absorption spectra of 7- and 5-hydroxycoumarin with those of the condensate of orcinol and 2-substituted acetoacetic esters, it was proved that all the condensates are 5-hydroxycoumarin derivatives. Moreover, it was proved that the condensate of orcinol and 2-benzylacetoacetic ester was 3-benzyl-4, 7-dimethyl-5-hydroxycoumarin and not the 7-hydroxy compound as reported in past literature.
In vitro anthelmintic tests were carried out on naphthocoumarins, its pyrone-ring 4-methyl derivatives, and their reduction products (I to IX), in order to find relationship between chemical structure and anthelmintic effect. Of these, (IVb), (Va and b), and (VIIIa and b) were found to effect revolving motion and curling-up of ascaris, as with santonin, the action especially marked in (IVb).
An improved method in the microanalysis of carbon and hydrogen is given. The improvement consists of saving time necessary for the analysis especially in the combustion stage, applying a larger velocity and volume of air given in the combustion tube.
A condensation agent prepared by heating polyphosphoric acid (30g. of phosphorus pentoxide in 85% phosphoric acid) with 1/3 to 1/4 its amount of phosphoryl chloride on a water bath for 2 hours was used in heating the ethyl ester of N-acetyl-, -benzoyl-, -phenylacetyl-, and -formyl-L-cystelne at 150-160° (bath tem.) for 2 hours and 2-methyl-, -phenyl-, and -benzyl-thiazoles and thiazole were obtained in a respective yield of 4%, 20%, 10%, and 1%. Similar treatment of the diethyl ester of diacetyi-L-cystine the presence of stannous chloride afforded 2-methylthiazole, though in a small amount. As for the reaction mechanism for this formation of thiazole, it was assumed that it is the same as the formation of the isoquinoline ring from phenylalanine, reported in the preceding paper, since the reaction is accompanied with generation of carbon monoxide.
A mixture of the condensation agent prepared from polyphosphoric acid with the ethyl ester of acetyl- and phenylacetyl-L-tryptophan at 140-150° (bath temp.) for 1 hour results in generation of carbon monoxide and 1-methyl- and 1-benzyl-9H-pyrid[3, 4 b]indole are obtained in 20% and 9% yield, respectively. The base was not obtained from the reaction with benzoyl derivative. This reaction mechanism was also considered to be the same as that in the formation of isoquinoline from phenylalanine and of thiazole ring from cysteine.
Lead dioxide is usually used for removing nitrogen oxides in the determination of carbon and hydrogen but this substance has so various defects that many kinds of absorption agents are now being used. Of these, ammonium sulf amate was examined by absorption in silica gel to the content of 30% and 1.5g. of this substance was placed between water and carbon dioxide absorption tubes. Satisfactory results were obtained with 60 samples analyzed, all containing nitrogen. It was found by further examination of the absorber that silica gel itself absorbed nitrogen dioxide and the amount of this oxide generated during the decomposition of various nitrogenous compounds was determined by the use of silica gel.
Phenacetin (p-acetophenetidine) was determined colorimetrically by effecting hydrolysis by boiling with hydrobrornic acid to form p-aminophenol, adding 1% o-cresol solution to its solution in a concentration of 4-10γ/cc., and in alkalinity (pH 11.0-11.8) rendered by 0.1N sodium hydroxide and submitting the blue indophenol thereby formed to colorimetry at 605mμ. This method of determination is not interfered by the presence of acetanilide, acetylsalicylic acid, caffeine, aminopyrine, or diphenhydramine hydrochloride. The amount of phenacetin in various preparations was determined in 98-102% of the theoretical amount by this method. When the preparation contains phenyl salicylate, aqueous 1% phenol solution is added and similarly submitted to colorimetry at 620mμ. The coloration will slacken if the amount of light is small in this reaction, so that the reaction should be carried out in a well-lighted place.