OLiterat~ re~~ mp 147-148" C. bLiterature3a mp 263-265" C.'I= activity> 10 wM. With ClCH, COCH, CO, Et. eliteraturea mp 84-85" C. dihydroimidazo [1, 2-a] quinoxaline-2-carboxylate (la)? was found to have an ICbo value of 175 nM compared with 6 nM for that of nitrazepam. This prompted us to screen a large number of heterocyclic esters which we had previously prepared2* J'during the course of the antiallergy program for which la had been ...