The electrocatalytic cascade assembling of isatins, malononitrile and N-alkyl barbiturates:: An efficient multicomponent approach to the spiro[indole-3,5′-pyrano[2,3-d]pyrimidine] framework

Electrochemically induced catalytic multicomponent transformation of isatins, barbituric acid or N-alkyl barbiturates and malononitrile in alcohols in an undivided cell results in the formation of substituted 7'-amino-2,2'.4'-trioxo-1,1',2,2',3'.4'-hexahydrospirolindole-3.5'-pyrano[2.3-d]pyrimidine]-6'-carbonitriles in 80-95% yields. The developed efficient electrocaralytic approach to corresponding spiro[indole-3,5'-pyratio[2,3-d]pyrimidine] system is beneficial from the viewpoint of diversity-oriented large-scale processes and represents a new example of the ecologically pure synthetic concept for electrocatalytic multicomponent reactions strategy. (c) 2008 Elsevier Ltd. All rights reserved.