Synthesis of benzodiaza[14]annulenes from 4,6-dibromomethyl-5,2,8-ethanylylidene-5H-1,9-benzodiazacycloundecine

Abstract

The reaction of 4,6-dibromomethyl-5,2,8-ethanylylidene-5H-1,9-benzodiazacycloundecine with dimethyl malonate under basic conditions gives dimethyl 6,7-dihydro-2,10,4,8-propane-1,3-diylidene-5H-1,11-benzodiazacyclotridecine-6,6-dicarboxylate. Demethoxycarbonylation of this diester with lithium chloride in dimethylformamide-water affords epimeric monoesters. The reaction of dimethyl 5-bromo-6,7-dihydro-2,10,4,8-propane-1,3-diylidene-5H-1,11 -benzodiazacyclotridecine-6,6-dicarb-oxylate with lithium chloride in dimethylformamide–water affords methyl 2,10,4,8-propane-1,3-diylidene-5H-benzodiazacyclotridecine-6-carboxylate. The reaction of 4,6-dibromomethyl-5,2,8-ethanylylidene-5H-1,9-benzodiazacycloundecine with tetramethylethane-1,1,2,2-tetracarboxylate under basic conditions gives tetramethyl 5,6,7,8-tetrahydro-2,11,4,9-propane-1,3-diylidene-1,2-benzodiazacyclotetradecine-6,6,7,7-tetracarboxylate. Demethoxycarbonylation of this tetraester affords epimeric diesters. Elaboration of both the tetraester and these diesters afforded the [14]annulene, dimethyl 2,11,4,9-propane-1,3-diylidene-1,12-benzodiazacyclotetradecine-6,7-dicarboxylate.