Metal-Free and Regioselective Synthesis of Substituted and Fused Chromenopyrrole Scaffolds the Divergent Reactivity of α-Azido Ketones in Water.

A green and simple approach was developed for the regioselective synthesis of structurally diverse chromenopyrrole frameworks from 3-formylchromones, active methylenes, and α-azido ketones using piperidine as a catalyst in the aqueous medium through a tandem one-pot multicomponent reaction. Further, the synthesized pyrrole framework was successfully converted into biologically significant 6-azaindole derivatives in a simple synthetic transformation. An exciting feature of this synthetic protocol is that the reaction mechanism and formation of the products depend on the nature of the active methylene used.

Spectrophotometric and fluorimetric determination of hexamine in pure form and its pharmaceutical formulation.

Ethyl acetoacetate and methyl acetoacetate have been tested for the determination of hiprex (methenamine hippurate). Both the esters react with hexamine and hiprex forming fluorescent yellow Hantzsch esters. The products show absorption maximum at 370 nm and a fluorescence emission maximum at 465 nm in aqueous n-propanol.