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Attempts to prepare ethyl 5-cyano-1-(1,1-dimethylethyl)-1H-pyrazole-4-carboxylate (7) by the reaction of the corresponding 5-chloro derivative 1b with cyanide ion were unsuccessful. The chloro ester was synthesized from the corresponding amino ester la utilizing nonaqueous diazotization with nitrosyl chloride. An alternate process was developed which allowed the preparation of 7 from the corresponding 5-methyl ester 3 in four steps. The structure of the N-methylamide 8 synthesized from 7 was confirmed by X-ray diffraction analysis.

Alkylation of 1-aryl-1H-1,2,4-triazol-3-ols with ethyl 2-bromopropionate under basic conditions resulted in the formation of 2-[(1-aryl-1H-1,2,4-triazol-3-yl)oxy]propionic acid, ethyl esters. No N-alkylated products were detected. Similar alkylation of 2-oxo-5-phenyl-1,3,4-thiazole and the corresponding 1,3,4-oxadiazole gave only N-alkylated derivatives. With 4-hydroxy-6-phenylpyrimidine and 2-oxo-4-phenylthiazole, both O- and N-alkylation occurred. Structure assignments were based on ir and 13C nmr spectral data.

The synthesis of 1-aryl-5-cyano-1H-pyrazole-4-carboxylic acid, ethyl esters 1 is described. Subsequent chemistry led to relatively simple and unique pyrazole derivatives. Most important of these are 1-aryl-5-(aminocarbonyl)-1H-pyrazole-4-carboxylic acids 2, which are chemical hybridizing agents in wheat and barley. The regioselective hydrolysis of 1-(3-chlorophenyl)-1H-pyrazole-4,5-dicarboxylic acid, dimethyl ester (7b) and subsequent chemistry is also described.