E. B. Tsupak

5-Diazouracils in azo coupling reactions

Abstract6-Hydroxy-5-diazo-6H-uracil and 6-hydroxy-5-diazo-1,3-dimethyl-6H-uracil enter into azo coupling reaction with CH-acids, active phenols, arylamines, and heterocycles. The conditions of reaction depend on the substrate character.

Pyrrolopyrimidines. 1. Electrophilic substitution reactions of 1,3-dimethylpyrrolo[3,2-d]pyrimidine-2,4-dione

The reactions of halogenation, aminomethylation, acylation, and azo coupling in 1,3-dimethylpyrrolo[3,2-d]pyrimidine-2,4 dione proced at position 7, whereas nitration in acetic acid is directed primarily to position 6. In a num of cases, products of substitution of both hydrogen atoms in the pyrrole ring have been synthesized.

Pyrrolopyrimidines. 4. A convenient method for the production of 6-(2-aminovinyl)-5-nitropyrimidines and their transformation into pyrrolo[3,2-d]pyrimidines

A convenient method is proposed for the production of 6-(2-aminovinyl)pyrimidine-2,4-diones, involving the reaction of 6-methyluracils with triethyl orthoformiate and secondary amines.

Pyrano[4,3-d]pyrimidinium salts: 1. Reactions with N-nucleophiles

Abstract5-Aroyl-1,3,6-trimethyluracils were converted to pyrano[4,3-d]pyrimidinium salts. Reactions of the salts obtained with ammonia, primary amines, and hydrazine were studied.

Structure and Reactivity of Uracil Derivatives. 2. Ambident Nucleophilic Reactivity of 5-Diazouracil

On the basis of 3-21G type ab initio calculations we have studied all the possible complexes of 5-diazouracil with boron trifluoride. The most stable of these are the systems with the BF3 coordinated at the 3, 9, and 10 positions of the heterocyclic molecule.

Pyrrolopyrimidines. 3. 5-Amino-1,3-dimethylpyrrolo-[3,2-d]pyrimidine-2,4-dione

Reaction of 5-amino-1,3-dimethylpyrrolo[3,2-d]pyrimidine-2,4-(1H,3H)-diones with β-diketones produces enaminoketones. Some of these are converted by Lewis acids into pyrrolopyridazines.

Organolithium and organosodium compounds of n-substituted 2-alkylbenzimidazoles

Organolithium and organosodium compounds of 1,2-dimethyl-, 1-methyl-2-ethyl-, 1-methyl-2-propyl-, and 1-phenyl-2-methylbenzimidazole, containing the metal in the alkyl group at position C(2), were obtained by metallation. It was found that metallation can be complicated by the addition of the metalling reagent at the C=N bond of the heterocycle. It was shown that the obtained organometallic compounds can be used for the synthesis of various derivatives of benzimidazole.

Pyrrolopyrimidines. 2.* Synthesis and oxidative conversions of 5-amino-1,3-Dimethylpyrrolo[3, 2-d]pyrimidine-2, 4-diones

By the action of hydroxylamine-O-sulfonic acid in an alkaline medium on 1,3-dimethyl- and 1,3-dimethyl-7-bromopyrrolo[3,2-d]pyrimidine-2,4-diones, their 5-amino derivatives have been obtained. It has been shown that the oxidation of these derivatives leads to the formation of the corresponding tetrazenes and products of deamination, the ratio of which is determined by the type of oxidizing agent and by the reaction conditions. I-Aminoindole behaves analogously.

Research on benzimidazole derivatives. XXXVII. 2-Benzazolonitrile oxides

It was shown by IR spectroscopy that 2-benzazolonitrile oxides, which are formed by the action of triethylamine on 2-benzazolylmethylhydroxamoyl chlorides, are extremely labile; the presence and nature of a substituent near the fulmide group and the basicity of the heterocyclic fragment of the molecule have a great effect on their stabilities.

Investigation of benzimidazole derivatives

Under the influence of nitrosylsulfuric acid, 5- and 6-bromo-substituted 2-amino-1-methylbenzimidazoles are converted, as a result of self-coupling, to, respectively, 2′,5- and 2′,6-azobenzimidazoles, which are resistant to reductive cleavage. 5,6-Dibromo-2-amino-1-methylbenzimidazole forms similarly constructed azo compounds by splitting out of one of the bromine atoms. The behavior of bromo-substituted 2-aminobenzimidazoles toward nitrosylsulfuric acid in the presence of arenes was studied.