Synthesis of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines

5-Diazoimidazole-4-carboxazide was isolated in the diazotization of 5(4)-aminoimidazole-4(5)-carboxhydrazide. The diazotization of N-substituted hydrazides of 5(4)-aminoimidazole-4(5)-carboxylic acis was studied. It is shown that the resulting diazo derivatives undergo cyclization to 3-arylideneaminoimidazo[4,5-d]-1,2,3-triazin-4-ones.See [1] for communication 7.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 984–985, July, 1979.     

Synthesis of analogs of 5(4)-aminoimidazole-4(5)-carboxamide

In order to obtain 5(4)-aminoimidazole-4(5)carboxamide antagonists, the.hydrazides of 5(4)-aminoimidazole-4(5)-carboxylic acid and 5(4)-aminoimidazole-4(5)hydroxamic acid were synthesized, and the reaction of 5(4)-bromo-4(5)sulfamoylimidazole with amines was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1421–1422, October, 1971.     

Synthesis of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines

The corresponding 5(4)-mercaptoimidazoles, from which various 5(4)-mercaptoimidazole-4(5)-carboxylic acid derivatives were synthesized, were obtained from the amide and ethyl ester of 5-diazoimidazole-4-carboxylic acid by substitution of the diazo group. 5-Diazo-imidazole-4-hydroxamic acid does not undergo substitution with sodium disulfide but does undergo cyclization to 3-N-hydroxyimidazo[4,5-d]-1,2,3-triazin-4-one under these conditions. The kinetics of the cyclization of diazoimidazoles were studied, and the interrelationship between the structure and reactivity of the latter was examined.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1550–1554, November, 1975.     

Synthesis of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines

4-Chloroimidazo[4,5-d]-1,2,3-triazine was obtained by oxidative chlorinatlon from imidazo[4,5-d]-1,2,3-triazine-4-thione, and its reaction with nucleophilic agents and cleavage of the triazine ring to give 5-diazoimidazole-4-carbonitrile were studied. The newly synthesized diazoimidazole was subjected to C- and N-diazo coupling. It was established that 3-methylimidazo[4,5-d]-1,2,3-triazine-4-imine, formed by reaction of the diazo compound with methylamine, is capable of recyclization to 4-methylaminoimidazo[4,5-d]-1,2,3-triazine.See [1] for communication IV.Translated from Khimiya Getereotsiklicheskikh Soedinenii, No. 4, pp. 556–559, April, 1976.     

Synthesis of analogs of 5(4)-aminoimidazole-4(5)-caeboxamide and purines

4(5)-Sulfonyl chlorides, which were converted to the corresponding sulfamoyl derivatives, were obtained from the amide and ethyl ester of 4(5)-mercaptoimidazole-5(4)-carboxylic acid by oxidative chlorination. The azide of 4(5)-sulfamoylimidazole-5(4)carboxylic acid was synthesized through 4(5)-sulfamoylimidazole-5(4)-carboxylhydrazide, and its conversion in various media to 5(4)-aminoimidazole-4(5)-sulfonamide derivatives and to 3,4-dihydro-3-oxoimidazo[4,5-e]-1,2,4-thiadiazine 1,1-dioxide was studied.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1119–1122, August, 1976.     

The reaction of 5-aminoimidazole-4-carbohydrazides with orthoesters

The reaction of 5-aminoimidazole-4-carbohydrazides with orthoesters is shown to yield 1-amino-9-alkyl-hypoxanthines. Similar reaction of anthranilic acid hydrazide is shown to yield 3-amino-4-quinazolone, and not 1,4-dihydro-5H-1,3,4-benzotriazepin-5-one as previously reported.     

Synthesis and properties of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines. 14. Acylation of 5(4)-aminoimidazole derivatives

The acylation of 5(4)-aminoimidazole derivatives was studied. It is shown that acylation by means of carboxylic acid anhydrides and chlorides takes place at the amino group, whereas acylation by means of chlorocarbonic acid esters takes place at the nitrogen atoms of the imidazole ring. Methods for the selective introduction of a carbomethoxy group in the 1, 3, and 5 positions of the 5(4)-aminoimidazole-4(5)-carboxamide molecule were developed.See [1] for communication 13.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 247–252, February, 1984.     

The decomposition mechanism of new solid-state 4(5)-aminoimidazole-5(4)-carboxamide coordination compounds

Imidazole ring coordination compounds are very useful models to better understand the coordination properties and the reaction mechanisms of biologically important systems. On the basis of previous work, new Co(II)-, Ni(II)- and Cu(II)-4(5)-aminoimidazole-5(4)-carboxamide coordination compounds have been synthesized and characterized by elemental analysis, UV-Vis and IR spectroscopies. Their thermal stability was determined by differential scanning calorimetry and by thermogravimetry, and the decomposition mechanisms were investigated by evolved gas analysis (EGA).     

Synthesis and properties of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines. 15. Ring opening in imidazo[4,5-d]-1,2,3-triazines

It has been shown that 4-methylthio-, ethoxy-, and methoxyimidazotriazines and imidazotriazin-4-ones, unlike benzo-1,2,3-triazines, do not display cryptodiazonium behavior. A novel type of fission of the triazine ring to give esters and thioesters of 5-aminoimidazole-4-carboxylic acid is described.For Communication 14, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1248–1250, September, 1989.     

Synthesis and properties of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines. 11. Investigation of the structure and reactivity of imidazolethioamides

The IR, UV, and PMR spectra of 5(4)-mercaptoimidazole-4(5)-carboxamide, 5(4)-hydroxyimldazole-4(5)-thiocarboxyamide, 5(4)-mercaptoimidazole-4(5)-thiocarboxamide, and the corresponding methyl derivatives were studied. It is shown that the mercaptoimidazoles obtained exist in the form of zwitterions in solution. The methylation of the mercapto- and hydroxyimidazoles with various methylating agents in solvents was investigated, and the reaction of the thioamides with hydrazine was carried out.See [1] for Communication 10.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 957–962, July, 1982.     

Synthesis and properties of analogs of 5(4)-aminoimidazole-4(5)-carboxamide (AICA)

A new analog of AICA — 5(4)-hydrazinoimidazole-4(5)-carboxamide — forms the corresponding hydrazones with carbonyl-containing compounds and reacts with sodium nitrite to give 5(4)-azidoimidazole-4(5)-carboxamide, the structure of which was proved on the basis of IR spectroscopic data.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 94–95, January, 1973.     

Synthesis and properties of analogs of 5 (or 4)-aminoimidazole-4 (or 5)-carboxamide (AICA) and purines. 13. Synthesis of 5 (or 4)-hydrazinoimidazqles and their derivatives

A method for the synthesis of derivatives of 5 (or 4)-hydrazinoimidazole-4 (or 5)-carboxylic acid by reducing the corresponding diazoimidazoles with stannous chloride has been developed, and a number of hydrazones and semicarbazides have been synthesized. It has been shown that under the reduction conditions selected imidazo[4,5-d]-1, 2, 3-triazinone does not have cryptodiazonium properties.For Report 12, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1552–1555, November, 1983.     

Reactions of diazo derivatives of 5-membered heterocycles with hydrazines

Interaction of hydrazine or dimethylhydrazine with 5-diazoimidazole-4-carboxamide produced, presumably via tetrazenes, high yields of 5-azidoimidazole-4-carboxamide. In contrast, when semicarbazide reacted with either the diazoimidazole or the analogous diazo-1,2,3-triazole, the yield of the azidoheterocycle was low, and the yield of biurea, and presumably the aminoheterocycle, was high. 3-Azidopyrazole-4-carboxamide was obtained from a reaction of hydrazine with the diazopyrazole. Both azido and amino derivatives were formed from reactions of diazo-imidazole esters with hydrazine or thiosemicarbazide.     

Reactions of 3-hydrazino-5,6-diphenyl-1,2,4-triazine with 4-arylidene-2-phenyl-5(4H)-oxazolones and 4-benzylidene-3-methyl-5(4H)-isoxazolone

3-Hydrazino-5,6-diphenyl-1,2,4-triazine reacts with 4-arylidene-2-phenyl-5(4H)-oxazolones in toluene to give substituted acrylic acid hydrazides, and in glacial acetic acid to give substituted imidazolones. On the other hand the hydrazinotriazine reacts with 4-benzylidene-3-methyl-5(4H)-isoxazolone, probably via a 1,4 addition reaction followed by an elimination reaction, to give benzaldehyde 5,6-diphenyl-1,2,4-triazin-3-ylhydrazone and 3-methyl-5(4H)-isoxazolone.     

4-氧代-3（4H）-喹唑啉-5-羧酸的合成

以2-氨基-6-甲基苯甲酸为起始原料,通过合环反应生成两种4-氧代-3(4H)-喹唑啉-5-羧酸衍生物(1a, 1b), 1a, 1b分别经高锰酸钾氧化合成了4-氧代-3(4H)-喹唑啉-5-羧酸（2a, 2b）,其结构经¹H NMR, ¹³C NMR和MS表征。研究了投料比｛r［n(高锰酸钾) :n(5-甲基-3(4H)-喹唑啉-4-酮)］｝和反应温度等对收率的影响。结果表明：在最佳反应条件（r=7:1,中性高锰酸钾氧化,于90 ℃反应）下合成2总收率可达66%。     

Cyclization of 5-diazoimidazole-4-thioamide

Cyclization of 5-diazoimidazole-4-thioamide and -4-methylthioamide gives derivatives of a new heterocyclic system — imidazo[4,5-e]-2,3,4-thiadiazine — which are readily recyclized to 2-azapurines. 4-Methylthioimidazo[4,5-d]-1,2,3-triazine was synthesized, and its reactions with amines and hydrazines were studied.     

Synthesis of 4(5)-hydroxymethylimidazoles by hydroxymethylation and decarboxylation of imidazole-4(5)-carboxylic acids

4(5)-Hydroxymethylimidazoles were prepared by hydroxymethylation and decarboxylation of imidazole-4(5)-carboxylic acid esters. The reaction was simply carried out with aqueous formaldehyde solution in the presence of base.     

Substituted 4(5H)-oxazolones and their salts. 3. Synthesis of 4(5H)-oxazolonium salts from amides of 2,4-dihydroxy-3,3-dimethylbutanoic acid

2-Alkyl-substituted 4(5H)-oxazolonium salts were synthesized by the reaction of amides of 2,4-dihydroxy-3,3-dimethylbutanoic (pantoic) acid with aliphatic carboxylic acid anhydrides in the presence of an equimolar amount of perchloric acid. The hydrolysis of these salts was realized. Various acyl derivatives of pantoic acid amides were obtained, and the possibility of their cyclization to give 4(5H)-oxazolonium salts under the influence of condensing reagents was demonstrated. The mechanism of the heterocyclization of pantoic acid amides is discussed on the basis of these results.See [1] for communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 894–900, July, 1981.     

Diels-alder versus heterodiene in the reaction between 4-arylidene-5-pyrazolones and 2,3-dimethylbutadiene: the effect of acid catalysis(1)

The thermal reaction between (E) or (Z)-pyrazolones (1) and 2,3-dimethylbutadiene (2) gave 1,2-dimethyl-5-arylcyclohexen-4-spiro-4' (1'-phenyl-3'-substituted-5'-pyrazolones) (3, 4), from a Diels-Alder reaction, and 4-aryl-2-isopropenyl-2-methyl-5-substituted-7-phenyldihydropyran [3,2-d] pyrazoles (5, 6), from a heterodiene reaction. The effect of the configuration of the starting pyrazolone, as well as that of substituents, on isomer distribution is here discussed.The reaction can be conveniently catalyzed by different acids. The nature of the pyrazolone- acid complex was investigated by NMR.The acid influences, dramatically, both the chemoselectivity and the stereoselectivity of the reaction. The effect of the catalyst was rationalized by taking into account both the change of the MJs induced by complexation and steric hindrance of the acid.     

Ring closure reaction of 4-(2-hydroxyanilino)-2-phenyl-5-pyrimidinecarboxylic acid with acetic anhydride. Synthesis of pyrimido[5,4-c] [1,5]benzoxazepin-5(11H)ones

Syntheses of 11-acety1-2-phenylpyrimido[5,4-c][1,5]benzoxazepin-5(11H)one ( 16a ) and analogs ( 16b,c, 22 ) were described. The reaction of 4-chloro-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester ( 7 ) with 2-aminophenol afforded 4-(2-hydroxyanilino)-2-phenyl-5-pyrimidine-carboxylic acid ethyl ester ( 8a ). The latter was also prepared by catalytic reduction of 4-(2-nitrophenoxy)-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester ( 9 ), which was obtained from 7 and 2-nitrophenol. Involvement of 4-(2-aminophenoxy)-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester ( 12a ) in this reduction as an intermediate was demonstrated by an independent synthesis of 12a and its subsequent rearrangement to 8a. Hydrolysis of 8a or 12a gave 4-(2-hydroxyanilino)-2-phenyl-5-pyrimidinecarboxylic acid ( 15a ). Reaction of 15a with acetic anhydride afforded 16a , the first member of a novel ring system, the pyrimido[5,4- c ][1,5]-benzoxazepin. Additional examples ( 16b,c ) were prepared similarly. The corresponding 11-ethyl derivative ( 22 ) was prepared in similar fashion, starting with 7 and 2-ethylaminophenol. A possible reaction mechanism for the formation of 16a-c from 15a-c and acetic anhydride was discussed.