

AN AgOAc-CATALYZED REACTION OF 3-NITRO-2H-CHROMENES WITH ETHYL DIAZOACETATE: AN EFFICIENT ONE-POT SYNTHESIS OF ETHYL 3,4-DIHYDROCHROMENO[3,4-c]PYRAZOLE-1-CARBOXYLATES

Abstract
A regioselective method for the synthesis of ethyl 3,4-dihydrochromeno[3,4-c]pyrazole-1-carboxylates from 2-substituted 3-nitro-2H-chromenes and ethyl diazoacetate in 68–87% yields was developed. This approach involves an AgOAc-catalyzed 1,3-dipolar cycloaddition of ethyl diazoacetate to nitrochromenes followed by elimination of HNO2 by the action of DBU.
Authors: Lyudmila S. Bykova, Ivan А. Kochnev*, Alexey Yu. Barkov, Nikolay S. Zimnitskiy, Vladislav Yu. Korotaev*, Vyacheslav Ya. Sosnovskikh
Keywords
chromeno[3,4-c]pyrazoles; ethyl diazoacetate; 3-nitro-2H-chromenes; 1,3-dipolar cycloaddition
Latvian Institute of Organic Synthesis - Aizkraukles iela, 21, Riga, LV-1006, Latvia - hgs@osi.lv