Synthesis and some reactions of ethyl 2-[2-(substituted methyleneamino)anilino]cyclohepta[b]pyrrole-3-carboxylates

Synthesis and some reactions of ethyl 2-[2-(substituted methyleneamino)anilino]cyclohepta[b]pyrrole-3-carboxylates

Creators Abe Noritaka

Creators Kakehi Akikazu

We synthesized Schiff bases, ethyl 2-[2-(benzilideneamino)anilino]cyclohepta[b]pyrrole-3-carboxylate (2a) and ethyl 2-[2-(2-butenylideneamino)anilino]cyclohepta[b]pyrrole-3-carboxylate (2b), from ethyl 2-(2-aminoanilino)cyclohepta[b]pyrrole-3-carboxylate (1) in excellent yields by treating 1 with benzaldehyde or 2-butenal in the presence of molecular sieves 4A, respectively. Further, the cyclization and cycloaddition reactions of the Schiff bases were investigated. Treatment of 2a with iron(III) chloride or Pd-C gave ethyl 2-(2-phenylbenzimidazol-1-yl)cyclohepta[b]pyrrole-3-carboxylate and 12H-5,13-dihydrocyclohepta[1',2' : 4,5]pyrrolo[2,3-b][1,5]benzodiazepin-12-one (4). A similar treatment of 2b, however, gave ethyl 2-(4-methylqinolin-8-yl)aminocyclohepta[b]pyrrole-3-carboxylate and 4. The reaction of 2a with dimethyl acetylenedicarboxylate (DMAD) gave 15a-ethyl 5,6,7,15-tetramethyl 15,15a-dihydro-14H-pyrrolo[2',1' : 1,2]isoquino[3,4-b][1,5]benzodiazepine-5,6,7,15,15a-pentacarboxylate (6) and methyl 4-(3-ethoxycarbonylcyclohepta[b]pyrrol-2-yl)-3-oxo-1,2,3,4-tetrahydroquinoxalin-2-ylideneacetate (7). The reaction of 2b with DMAD, however, gave the 1,4-dihydropyridine derivative as a Diels-Alder adduct, along with 7. The structures of 6 and 7 were confirmed by single-crystal X-ray analyses.

[ISSN]0009-2673

[NCID]AA00580132

info:doi/10.1246/bcsj.65.1538

[isVersionOf] [URI]http://www.jstage.jst.go.jp/browse/bcsj/-char/en