Research on arylhydrazones of substituted glyoxylic acids

Reaction of the hydrazides and acetylhydrazides of cyanoacetic acid with aryldiazonium chlorides gives arylhydrazones of the hydrazide and acetylhydrazide of cyanoglyoxylic acid. 2-Acetyl-3-imino-4-arylpyrazol-5-ones and 3-imino-4-arylazopyrazol-5-ones are obtained by cyclizing the arylhydrazones.For Part IX see [1].     

Research on arylhydrazones of substituted glyoxylic acids

Substituted 2-benzalhydrazono-3-phenyl-4-(arylhydrazonochloroformyl)-4-thiazo-lines and 2,2′-azinobis[3-aryl-4-(arylhydrazonochloroformyl)-4-thiazolines], respectively, are formed in the condensation of arylhydrazones of chloromethylgly-oxyloyl chloride with 4-phenylthiosemicarbazones and 1, 6-diarylhydrazodithiocar-bonamides.     

Investigations on arylhydrazones of substituted glyoxylic acids

The reaction of arylhydrazones of ethyl cyanoglyoxylate with hydroxylamine hydrochloride in aqueous ethanolic solution in the presence of sodium acetate at the boil has given 3-amino-4-arylazoisoxazol-5-ones. The reaction of arylhydrazones of ethy cyanoglyoxylate with hydroxylamine in the presence of sodium ethoxide in the cold has given arylhydrazones of the amide-oxime of ethyl mesoxalate. The action of acetic anhydride or aryl isothiocyanates on arylhydrazones of the amide oxime of ethyl mesoxalate has given arylhydrazones of the ethyl esters of 5-substituted 1,2,4-oxadiazolyl- or 1,2, 4-thiadiazolylglyoxylic acids.For part XI, see [11].     

Synthesis of substituted 2,3,4,5-tetrahydro-1,2,4-triazines from nitroformaldehyde arylhydrazones

2,3,4,5-Tetrahydro-1,2,4-triazines were obtained by condensation of nitroformaldehyde arylhydrazones with aldehydes and ammonia or primary amines.     

Research on a number of substituted arylamides of dithiocarboxylic acids

Dithiomalonic acid diarylamldes are cyclized to 3,5-diarylamino-1,2-dithiolium halides by oxidation with an equivalent amount of bromine (iodine) in chloroform solution; the same amides are cyclized to 4-bromo-3,5-diarylamino-1,2-dithiolium bromides with excess bromine and to 3-arylamino-5-arylimino-1,2-dithiols in alkaline media with potassium ferricyanide. The behavior of the synthesized substituted 1,2-dithiols with respect to various reagents was studied.     

Synthesis of amino substituted 4-oxo-1,2,3,4-tetrahydropyridines from arylhydrazones and methyl acrylate

Arylhydrazones react with methyl acrylate in the presence of aluminium chloride to afford amino substituted 4-oxo-1,2,3,4-tetrahydropyridines.     

Kinetics of the chromic acid oxidation of glyoxylic and pyruvic acids

The reactions of glyoxylic and pyruvic acids by chromium (VI) have been studied in the presence of perchloric acid. Each reaction is first order with respect to chromium (VI), α-keto acid and hydrogen ion concentrations. The addition of sodium perchlorate to the reaction mixture had no effect on the rates but sodium chloride and sodium dihydrogen phosphate have retarding influences. Manganous ions increase the rate of reaction. The activation parameters are evaluated and tentative mechanisms for the oxidation reactions are discussed.     

Studies on arylhydrazones of ethyl arylsulfonylglyoxylates

The reaction of arylhydrazones of 4-arylthiosemicarbazides of arylsulfonylglyoxylic acid with ω-bromoacetophenone has given arylhydrazones of N-(3-aryl-4-phenyl-2-thiazolinylidene)hydrazides of arylsulfonylglyoxylic acids. The reaction of ethyl p-toluenesulfonate with o-aminothiophenol and o-phenylenediamine in polyphosphoric acid has given 2-(p-tolylsulfonyl)methylbenzothiazole and 2-(p-tolylsulfonyl)methylbenzimidazole. From 2-(p-tolylsulfonyl)methylbenzothiazole, a styryl and the corresponding carbocyanine with a substituted indoline have been obtained. The considerable hypsochromic shift of the absorption maxima of the latter is explained by the influence of the voluminous electronegative group SO₂R in the position α to the heterocyclic nuclei.     

Researches on substituted arylamides of dithiocarboxylic acids

Reaction of N-aryl cyanoacetamides with hydrazine hydrate, or its monoaryl-substitution products, gives 3-arylamino-5-aminopyrazoles and 1-aryl-3-arylamino-5-aminopyrazoles. Treatment of aminopyrazoles with aryldiazonium chlorides leads to isolation of the arylazo derivatives. A hypothesis that the pyrazole derivatives synthesized have an amine structure is put forward on the basis of their chemical properties and IR spectra.     

Researches on substituted arylamides of dithiocarboxylic acids

The following compounds hitherto undescribed in the literature, are prepared: ethyl esters of arylamides of cyanomonothiomalonic acid, with electronegative substituents in the phenyl groups, aryl amides of cyanoacetic acid, and nitriles of substituted anilides of arylazothiomalonic acid. Heating arylamides of cyanoacetic acid with -bromoacetophenone in absolute alcohol gives quaternary salts of 2-cyanomethyl-3-aryl-4-phenylthiazoles and their methylene bases. Reaction of the quarternary salts of 2-cyanomethyl-3-aryl-4-phenylthiazoles with substituted phenyldiazonium salts gives a number of 2-cyanoarylazomethylene-3-aryl-4-phenylthiazoles.     

Researches on substituted arylamides of thiocarboxylic acids

Heating monothio- and dithiomalonic acids with-bromoacetophenone in dry ethanol gives 2,3,4-substituted thiazole derivatives.For Part VI see [1].     

Synthesis of substituted benzylphosphonic acids

Russian Chemical Bulletin -     

Preparation of substituted gem-dimethylcyclopropanecarboxylic acids

Conclusions A method, based on the addition of Grignard reagent to cyclopropene hydrocarbons, was proposed for the synthesis of alkyl-, phenyl-, and alkenylcyclopropanecarboxylic acids that bear a geminal dimethyl grouping in the ring.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 669–671, March, 1979.     

Arylamides of substituted thioacetic acids

The reaction of arylamides of monoacetylthioacetic acid with arylhydrazines and hydrazine hydrate has given, respectively, 1-aryl-5-arylamino-3-methylpyrazoles and 5-arylamino-3-methylpyrazoles, the structures of which have been confirmed by independent synthesis and by their IR and UV spectra. It has been shown that, on reacting with arylamides of monoacetylthioacetic acid, nitrogen bases attack first the carbonyl and then the thiocarbonyl group of these compounds, forming substituted pyrazoles.For part III, see [3].     

Arylamides of substituted thiocarboxylic acids

Cyclization of arylamides of acetylthioacetic acid with-bromoacetophenone gives mixtures containing hydrobromides of 2-(acetylmethylene)-3, 4-diarylthiazolines and 2-(acetylmethylene)-3, 4-diarylthiazolines, and from these mixtures hitherto undescribed substituted 4-thiazoline derivatives were isolated by chromatography. 2-(Acetylmethylene)-3-aryl-4-thiazolidones were obtained for the first time by reacting arylamides with acetylthioacetic acid with monochloroacetic acid in the presence of fused sodium acetate in glacial acetic acid.     

Asymmetric synthesis of alpha-amino acids based on carbon radical addition to glyoxylic oxime ether

The first asymmetric synthesis of alpha-amino acids based on diastereoselective carbon radical addition to glyoxylic imine derivatives is reported. The addition of an isopropyl radical, generated from i-PrI, Bu(3)SnH, and Et(3)B in CH(2)Cl(2) at 25 degrees C, to achiral glyoxylic oxime ether 1 proceeded regioselectively at the imino carbon atom of the oxime ether group to give an excellent yield of the C-isopropylated product 2. The competitive reaction using glyoxylic oxime ether 1 and aldoxime ether 4 showed that the reactivity of the glyoxylic oxime ether toward nucleophilic carbon radicals was enhanced by the presence of a neighboring electron-withdrawing substituent. Thus, the alkyl radical addition to glyoxylic oxime ether 1 proceeded smoothly even at -78 degrees C, in contrast to the unactivated aldoxime ether 4. A high degree of stereocontrol in the carbon radical addition to the glyoxylic oxime ether was achieved by using Oppolzer's camphorsultam as a chiral auxiliary. The stannyl radical-mediated reaction of the camphorsultam derivative 6 with an isopropyl radical at -78 degrees C afforded a 96:4 diastereomeric mixture, 7a, of the C-isopropylated product. The reductive removal of the benzyloxy group of the major diastereomer (R)-7a, by treatment with Mo(CO)(6) and the subsequent removal of the sultam auxiliary by standard hydrolysis, afforded the enantiomerically pure D-valine (R)-12 without any loss of stereochemical purity. To evaluate the new methodology, a variety of alkyl radicals were employed in the addition reaction which gave the alkylated products 7 with excellent diastereoselectivity, allowing access to a wide range of enantiomerically pure natural and unnatural alpha-amino acids. Even in the absence of Bu(3)SnH, treatment of 6 with alkyl iodide and Et(3)B at 20 degrees C gave the C-alkylated products 7 with moderate diastereoselectivities. The use of Et(2)Zn as a radical initiator, instead of Et(3)B, was also effective for the radical reaction. The enantioselective isopropyl radical addition to 1 using (R)-(+)-2, 2'-isopropylidenebis(4-phenyl-2-oxazoline) and MgBr(2) gave excellent chemical yield of the valine derivative 2 in 52% ee.     

Studies on arylhydrazones of ethyl arylsulfonylglyoxylates

The reaction of arylhydrazones of 4-arylthiosemicarbazides of arylsulfonylglyoxylic acid with -bromoacetophenone has given arylhydrazones of N-(3-aryl-4-phenyl-2-thiazolinylidene)hydrazides of arylsulfonylglyoxylic acids. The reaction of ethyl p-toluenesulfonate with o-aminothiophenol and o-phenylenediamine in polyphosphoric acid has given 2-(p-tolylsulfonyl)methylbenzothiazole and 2-(p-tolylsulfonyl)methylbenzimidazole. From 2-(p-tolylsulfonyl)methylbenzothiazole, a styryl and the corresponding carbocyanine with a substituted indoline have been obtained. The considerable hypsochromic shift of the absorption maxima of the latter is explained by the influence of the voluminous electronegative group SO₂R in the position to the heterocyclic nuclei.