One-Step Synthesis of Substituted 6-Amino-5-cyanospiro-4-(piperidine-4‘)- 2<i>H</i>,4<i>H</i>-dihydropyrazolo[3,4-<i>b</i>]pyrans

Abstract

Three-component condensation of 4-piperidinones (7), 5-pyrazolones (8), and malononitrile (4) proceeds chemically and electrochemically and is a convenient one-step means of synthesis of substituted 6-amino-5-cyanospiro-4-(piperidine-4')-2H,4H-dihydropyrazolo[3,4-b]pyrans (12). The electrochemical reactions proceed under milder conditions and with yields 12-15% greater than those of the reactions catalyzed by chemical bases.