Alkylation of phenol with 1-phenyl-3,5-dimethyl-4-chloromethylpyrazole under phase transfer catalysis

Abstract

In order to determine whether C-alkylated phenol is a precursor of pyrazolylmethyl ether [3], in the present work we report the results of phenol I alkylation with 1-phenyl-3,5-dimethyl-4-chloromethylpyrazole II under phase transfer catalysis. At the phenol alkylation the formation of ambident ions is not excluded [4]. In this case both Oand Calkyl derivatives can be formed. Thus, at the alkylation of phenol I with 1-phenyl-3,5-dimethyl-4-chloromethylpyrazole II we isolated and characterized the O(V) and C-alkylated products (III, IV) (1:1) in a total yield of 63%. According to the H NMR data, the C-alkylated products (III, IV) are a mixture of orthoand para-isomers in a ratio of 9:1. The proton signal of the hydroxy group of the isomer III appears downfield (8.99 ppm) in comparison with the corresponding signal of the isomer IV (8.21 ppm). Isomer III was isolated in pure form by crystallization. DOI: 10.1134/S1070363211080330