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Synthesis of 1‐(1,1‐dimethylethyl)‐1 H ‐pyrazole‐4‐carboxylate ester derivatives
Author(s) -
Beck James R.,
Lynch Michael P.
Publication year - 1987
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570240329
Subject(s) - chemistry , carboxylate , pyrazole , cyanide ion , cyanide , derivative (finance) , chloride , medicinal chemistry , organic chemistry , financial economics , economics
Attempts to prepare ethyl 5‐cyano‐1‐(1,1‐dimethylethyl)‐1 H ‐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.