Reaction of 4,6-dimethylpyrimidine with chlorides of aromatic carboxylic acids

The reaction of methyl groups with acyl chlorides is described for the first time in the pyrimidine series. The corresponding ketones — 6-methyl-4-phenacylpyrimidines — have been obtained from 4,6-dimethylpyrimidine and chlorides or aromatic carboxylic acids. A possible mechanism of the reaction is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp, 1132–1135, August, 1973.     

s-Triazine derivatives. 3. Investigation of the reaction of chloromethoxy-s-triazines with CH acids

The condensation of 2-chloro-4,6-dimethoxy- and 2,4-dichloro-6-methoxy-s-triazines with sodium derivatives of ethyl esters of acetoacetic and cyanoacetic acids and malonodinitrile was investigated. 2-Dicyanomethylene-4,6-dimethoxy-1,2-dihydro-, 2-carbethoxycyanomethylene-4,6-dimethoxy-1,2-dihydro-, and 2,4-bis(carbethoxy-methylene)-6-methoxy-1,2,3,4-tetrahydro-s-triazines were obtained in high yields.See [1] for Communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 264–267, February, 1981.     

Pyrimidines. 72. Synthesis and some properties of 5-amino-2-r-4,6-diphenylpyrimidines and the products of their transformations

The corresponding 5-aminopyrimidines were obtained by reduction of 2-substituted 5-nitro-4,6-diphenylpyrimidines, and reactions involving the amino group were studied. A Schiff base was obtained, and acetylation and diazotization reactions were carried out. The corresponding diazonium salts were converted to 2-dimethylamino-5-hydroxy-4,6-diphenylpyrimidine and 5-azido-2-methoxy-4,6-diphenylpyrimidine. 2-Methoxy-4-phenyl-5H-pyrimido[5,4-b]indole was obtained by photocyclization of the latter.See [1] for Communication 71.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1278–1282, September, 1980.     

Synthesis and properties of 1-aryl-2,5,7-trimethyl-4-oxo-1,4-dihydropyrido[2,3-d]pyrimidines

1-Aryl-2,5,7-trimethyl-4-oxo-1,4-dihydropyrido[2,3-d]pyrimidines are formed from the cyclization of N-acetyl-2-arylamino-4,6-dimethylnicotinonitriles by perchloric acid in a mixture of acetic acid and acetic anhydride. 1-Aryl-2-acetonyl-5,7-dimethyl-4-oxo-1,4-dihydropyrido[2,3-d]pyrimidines areformedonheating2-arylamino-4,6-dimethylnicotinamides with acetic anhydride. These and analogous compounds were obtained by acylation of 1-aryl-2,5,7-trimethyl-4-oxo-1,4-dihydropyrido[2,3-d]pyrimidines with acetic anhydride or benzoyl chloride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1234–1236, September, 1992.     

Sigma-complexes in the pyrimidine series. 11. 5-arylazo-5-nitro-2,5- and -4,5-dihydro-pyrimidines from anionic sigma complexes of 5-nitropyrimidine

We have studied the reaction of acetonyl anionic sigma complexes of 5-nitropyrimidines with aryldiazonium salts. We have established that, independently of the position of the geminal unit in the sigma complex, electrophilic attack by the diazonium ion occurs at the C₍₅₎ atom with formation of 5-arylazo-5-nitro-2,5- and 4,5-dihydropyrimidines. The latter are unstable and upon isolation are converted to N-methoxycarbonyl-N-(1-acetonyl-2-nitro-2-arylhydrazono)ethyl-O-methylisourea. The structure of one of these compounds has been proven by x-ray diffraction. Under alkaline conditions, aromatization of 2,5-dihydropyrimidines to 5-arylazo-2-acetonylpyrimidines occurs.For Communication 10, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 215–223, February, 1993.     

Methanolysis and hydrolysis of derivatives of methyl 2,5- and 4,5-dihydrofuran-2-carboxylates

Methyl 2,5-dimethoxy-2,5-dihydrofuran-2-carboxylate is formed in the reaction of HCl-CH₃OH with methyl 5-nitro-2-acetoxy-2,5-, 5-nitro-4-acetoxy-4,5-, and 2,5-diacetoxy-2,5-dihydrofuran-2-carboxylates, whereas methyl 2,5-dioxo-3-pentenoate bis(2,4-dinitrophenylhydrazone) and 4-oxo-2-penten-1,5-dioic acid 2,4-dinitrophenylhydrazone are isolated in the presence of 2,4-dinitrophenylhydrazine. Methyl 5-nitrofuran-2-carboxylate is formed by treatment of methyl 5-nitro-2-acetoxy-2,5-dihydrofuran-2-carboxylate with aqueous solutions of acetic or phosphoric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1600–1603, December, 1977.     

Synthesis of new condensed heterocyclic systems

Two new diamines — [1,3-bis(5-phenyl-1,2,4-triazol-3-yl)-4,6-diamino]benzene and [1,3-di-(2-benzimldazolyl)-4,6-diamino]benzene — were synthesized from 4,6-dinitroisophthalic acid. Newheterocyclic systems — 3,5,9,11-tetraphenyl[benzo[1,2-a; 4,5-a]bis(1,2,4-triazolo[4,3-c]pyrimidine)] and 2,16-diphenyl[benzo[1,2-a;4,5-a']bis(pyrimido[1,6-a]benzimidazole)]—were obtained by reaction of the diamines with benzoyl chloride and subsequent cyclization.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1274–1277, September, 1977.     

Synthesis of two naphthoquinone antibiotics, dehydroherbarin and 6-deoxybostrycoidin

The synthesis of two naphthoquinone antibiotics, dehydroherbarin (7) and 6-deoxybostrycoidin (5), was accomplished by reaction of 3-acetonyl-2-bromomethyl-6,8-dimethoxy-1,4-naphthoquinone (23) with either triethylamine or ammonia, respectively. This is the first report on their synthesis.     

2,2-Dimethyl-5-(5-R-furfurylidene)-1,3-dioxane-4,6-diones. 3. Selective hydrogenation of the exocyclic double bond and three-dimensional structures of the reaction products

The reaction of 2,2-dimethyl-5-(5-R-furfurylidene)-1,3-dioxane-4,6-diones with sodium borohydride in alcohol leads exclusively to products of hydrogenation of the exocyclic double bond. The three-dimensional structure of one of them — 2,2-dimethyl-5-(5-methyl-furfuryl)-1,3-dioxane-4,6-dioxane — was investigated by x-ray diffraction analysis (XDA).See [1] for Communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1201–1207, September, 1989.     

Synthesis of 2-Amino- and 2-Hydrazino-substituted 5-Nitro-4,6-diphenylpyrimidines

Nitrogen-containing derivatives of 5-nitro-4,6-diphenylpyrimidine have been synthesized by the reaction of 2-chloro-5-nitro-4,6-diphenylpyrimidine with amines or of 2-hydrazino-5-nitro-4,6-diphenylpyrimidine with carbonyl or -dicarbonyl compounds. Their structures were confirmed by data of IR spectroscopy and mass spectrometry.     

Nitro azines. 21. Reactivities and electron structures of 6-nitroazolo[1,5-a]pyrimidines

6-Nitroazolopyrimidines react with the acetonyl anion to give 6-nitro-7-acetonyl-4,7-dihydroazolo[1,5-a]pyrimidines. The reactivity of this class of compounds with respect to charged and uncharged nucleophiles is determined by their aromatic character and the deficit of electron density in the pyrimidine ring, while the direction of attack is determined by the overall charge on fragments of the valence-bonded atoms.For Communication 20 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 807–813, June, 1993.     

Nucleophilic substitution reactions of 2,4,6-tris(trinitromethyl)-1,3,5-triazine. 2. interaction of 2,4,6-tris(trinitromethyl)-1,3,5-triazine with primary amines and hexamethyldisilazane

2-R-amino-4,6-bis (trinitromethyl)-1,3,5-triazines have been synthesized, and their structures have been established. Dynamic¹³C NMR spectroscopy has been used to measure the rotational barriers of the tertbutylamino group around the C₍₂₎-NHBu-t bond in 2-(tert-butylamino)-4,6-dichloro-1, 3, 5-triazine and 2-(tertbutylamino)-4,6-dimethoxy-1,3,5-triazine. X-ray diffraction was used to investigate the structure of 2-(tertbutylamino)-4,6-bis (trinitromethyl)-1,3,5-triazine. From the results obtained in this work it has been concluded that the bond between the NHBu-t group and the triazine ring has a partial double-bond character.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from ] Khimiya Geterotsikiicheskikh Soedinenii, No. 5, pp. 679–688 May, 1995. Original article submitted March 7, 1995.     

Recyclization of 1-amino-3.5-diaryl-2.6,6-tricyanocyclohexa-1,3,-dienes to pyridine derivatives

The base-catalyzed recyclization of 1-amino-3,5-diaryl-2,6, 6-tricyanocyclohexa-1,3-dienes to 2,4-diaryl-5-cyano-6-dicyanomethylene-1,2,3,6-tetrahydropyridines, 4,6-diaryl-3-cyano-2-dicyanomethylene-1,2-dihydropyridines, and 4,6-diaryl-3-cyano-2-dicyanomethylpyridines has been investigated. The intermediate products of this reaction — cis, trans-2-amino,4,6-diaryl-1,1,3-tricyanohexa-1,3,5-trienes —have been isolated; on heating these are transformed reversibly into the initial cyclohexadienes or they isomerize irreversibly into trans, trans-hexatrienes, while in the presence of a base (piperidine, diethylamine, triethylamine, KOH), they cyclize to form the above-mentioned' pyridine derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, PP. 621–625, May, 1986.     

Indirect Electrochemical N-Dimethoxyphenylation of 3-Nitro-1,2,4-triazole and Tetrazole

Using the obtaining of 1,4-dimethoxy-2-(3-nitro-1,2,4-triazole-1-yl)benzene (I) and 1,4-dimethoxy-2-(tetrazolyl-1+-2)benzene (II) as an example, a method for indirect electrosynthesis of these substances is developed. In the first stage of this process, electrosynthesis of 1,1,4,4-tetramethoxycyclohexane-2,5-diene is realized by means of oxidation of 1,4-dimethoxybenezene on a platinum anode in an environment of MeOH in a diaphragmless cell. In the second, chemical interaction of this diene with 3-nitro-1,2,4-triazole and tetrazole is performed when heating a mixture of these substances for a long time at 110°C in the presence of additives of collidine. As a result, target products I and II were obtained with a good (60–90%) yield. Realization of this process opens new possibilities for producing N-arylazoles.__________Translated from Elektrokhimiya, Vol. 41, No. 8, 2005, pp. 1014–1019.Original Russian Text Copyright © 2005 by Burasov, Vakhotina, Petrosyan.     

2,5-Dimethoxy-2,5-dihydrofurans in 1,3-dipolar cycloaddition reactions

Itis shown that 2,5-dimethoxy-2,5-dihydrofurans enter into 1,3-dipolar cycloaddition with benzonitrile N-oxides and with diphenylnitrilimines to form derivatives of 1,3-dimethoxy-6-phenyl-1,3,3a,6a-tetrahydrofuro[3,4-d]isoxazole and 1,3-dimethoxy-4,6-diphenyl-1,3,3a,-6a-tetrahydrofuro[3,4-d]pyrazole, respectively.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 150–151, February, 1971.     

Isoquinoline derivatives

6,7-Dimethoxy-1,2,3,4-tetrahydroisoquinoline-4-spirocyclopentane was obtained by condensation of 3,4-dimethoxyphenyl-1-(aminomethyl)cyclopentane with formalin. The corresponding amides, which were reduced to tertiary amines, were synthesized by reaction of the latter with the acid chlorides of substituted benzoic and phenylacetic acids. Substituted dibenzo[a,-g]quinolizines, isoindolo[1,2-a]isoquinolines, and 1-(3,4-dimethoxyphenyl)-1-[(6,7-dimethoxy-1, 2,3,4-tetrahydro-2-isoquinolinyl)methyl]cyclopentane were synthesized, respectively, by condensation of 1-aryl (or aralkyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline-4-spirocyclopentanes and their open analog -1-(3,4-dimethoxyphenyl)-1-(3,4-dimethoxyphenylethylaminomethyl)cyclopentane — with formalin.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 679–682, May, 1973.     

Sigma complexes in the pyrimidine series. 2. σ Complexes of 5-nitropyrimidine and methoxy-substituted 5-nitropyrimidines with the acetone anion

The corresponding σ complexes of the Meisenheimer type, viz., anions of the potassium salts of 6H-5-nitro-6-acetonylpyrimidines, were obtained and isolated in the reaction of 5-nitro-, 5-nitro-4-methoxy-, 5-nitro-2-methoxy-, and 5-nitro-2,4-dimethoxypyrimidines with acetone in the presence of potassium hydroxide. The structures of the complexes were proved by means of the PMR, IR, and UV spectra. It is shown that the acetone anion in all cases adds to the methoxy-unsubstituted position of the pyrimidine ring, whereas nucleophilic attack takes place at the C₄ atom when the 2 and 4 positions are free. See [1] for communication 1. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 239–242, February, 1980.     

Condensed imidazo-1,2,4-azines. 4. Synthesis of 1,4-Dihydroimidazo[1,5-c]-1,2,4-triazine derivatives

The reaction of 2-methyl-4(5)-nitro- and 2-methyl-4(5)-nitro-5(4)-bromoimidazoles with -halo ketones was investigated, during which a number of 1-acylmethyl-substituted 2-methyl-4-nitro- and 2-methyl-4-nitro-5-bromoimidazoles were obtained. 1,4-Dihydro derivatives of imidazo[1,5-c]-1,2,4-triazine were synthesized by reaction of the latter with hydrazine and its monosubstituted derivatives. The structures of the 1-acylmethyl-substituted 2-methyl-4-nitro-5-bromoimidazoles and 1,4-dihydro derivatives of imidazo[1,5-c]-1,2,4-triazine were confirmed by their IR, PMR, and mass spectra.See [1–3] for Communications 1–3, respectively.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 833–837, June, 1981.     

A facile synthesis of 4,6-dimethoxy-[2-<Superscript>14</Superscript>C]-2-methylsulphonylpyrimidine

Summary 4,6-dimethoxy-2-methylsulphonylpyrimidine is a key intermediate for the synthesis of pyrithiobac-sodium, a selective herbicide for cotton plant. ¹⁴C labeled pyrithiobac-sodium is required for studying the translocation and metabolism in cotton plants. It was prepared by oxidation of 4,6-dimethoxy-[2-¹⁴C]-2-methylmercaptopyrimidine with H₅IO₆/CrO₃ in ethyl acetate at room temperature to give 4,6-dimethoxy-[2-¹⁴C]-2-methylsulphonylpyrimidine in high yields.     

Synthesis of 2,2′-bipyrimidine derivatives

A new total synthesis of 2,2′ -bipyrimidine derivatives by the direct condensation of 2-amidinopyrimidinebenzenesulfonate with dicarbonyl compounds is described. The following 2,2′-bipyrimidines have been prepared: 5-ethyl-4,6-dihydroxy-2,2′-bipyrimidine; 5-ethyl-4,6-dichloro-2,2 -bipyrimidine; 4,6-dihydroxy-2,2′ -bipyrimidine; 5-ethyl-4,6-dimethoxy-2,2′ -bipyrimidine.