NEW FACILE ALKOXYCARBONYLATING AGENT, ALKYL PYRAZOLE-1-CARBOXYLATES -THE PREPARATION AND THE UTILITIES

Alkyl pyrazole-1-carboxylates (2), which were readily prepared from al kyl chloroformate or carbazate in good yields, were provided as the ne w facile alkoxycarbonylating agents toward the Grignard reagents for t he synthesis of one carbon higher carboxylic esters. Also amines were alkoxycarbonylated by 2 to produce the corresponding urethanes even in an aqueous medium. Benzyl 3,5-dimethylpyrazole-1-carboxylate (2d) cou ld be utilized for the Cbz-protection of amino acids and esters in goo d yield without any racemization. (C) 1998 Elsevier Science Ltd. All r ights reserved.