| Abstract: | N-Amidino-3,5-diamino-6-chloropyrazinecarboxamide ( 1 ) has been shown to be an effective potassium sparing diuretic. Various carboxyl activating agents have been employed with 3-amino-pyrazinecarboxylic acids in an effort to synthesize analogs of 1. Stable enol esters were isolated from a number of such acids and N-t-butyl-5-methylisoxazolium perchlorate ( 12 ). Although strong bases in DMF or DMSO catalyze a competing destruction of the enol ester system, these esters are useful acylating agents for a variety of nucleophilic substrates in less polar media. Amides, esters, and thiol esters are produced in good yields under mild conditions from these activated esters. |
