Abstract
The reactions of salts of a group of related carbon acids with nucleophiles have been investigated. These acids were tricyanomethane, dicyanoacetamide and N-substituted dicyanoacetamides, and esters of dicyanoacetic acid and dicyanothiolacetic acid. Amines added to one of the cyano groups to give N-substituted derivatives of 1,1-diaminoethylenes. Hydrogen chloride gave 1-amino-1-chloro-ethylenes, which reacted with alcohols to give 1-alkoxy-1-aminoethylenes. Hydrazines added to two cyano groups to give 3,5-diaminopyrazoles, except with hydroxyiminomalononitrile, which decomposed. The initial products of reaction with o-phenylenediamines generally cyclised, with loss of ammonia, to give benzimidazolines. The products of reactions with anthranilic acid cyclised, with loss of water, to give 4-(1H)-quinazolinones. For comparison, 1-alkylamino-1-arylaminoethylenes were prepared by a two-step synthesis from bis-(methylthio)-methylene derivatives of malono-nitrile, cyanoacetamide and cyanoacetic esters. 5-Amino-1-methyl-3-methylthio, and 3-amino-1-methyl-5-methylthio, pyrazole-4-carbonitriles were prepared from methyl hydrazine and bis-(methylthio)-methylenemalononitrile, which was also used to prepare 1-alkyl-3-amino-5-alkylaminopyrazole-4-carbonitriles by a three-step synthesis. These pyrazoles reacted with acid chlorides, followed by aqueous alkali, to give 3-methylthio-, and 3-alkylamino-, 5H-pyrazolo-(3,4-d)-pyrimidin-4-ones. The 3,5-diaminopyrazole-4-carbonitriles, prepared from hydrazines and tricyanomethane, reacted with carboxylic acids, or acid chlorides followed by aqueous alkali, to give 3-amino-5H-pyrazolo-(3,4-d)-pyrimidin-4-ones. The 3,5-diaminopyrazole-4-carboxamides, prepared from hydrazines and dicyanoacetamide, reacted similarly with carboxylic acids. Usually, if 1-alkylpyrazoles were used, 2-alkylpyrazolopyrimidinones were formed, rather than the 1-alkyl isomers. The structure of one such product, 3-amino-6-(1,1-dimethylethyl)-2-methyl-5H-pyrazolo-(3,4-d)-pyrimidin- 4-one, was proved by X-ray crystallography. The structures of other pyrazolopyrimidinones were established by analogy and comparison with this one.