Fused Tetracyclic Heterocycles by Thermally Initiated Intramolecular Criss-Cross Cycloaddition of 3-Substituted Homoallenylaldazines

✍ Scribed by Hana Zachová; Stanislav Man; Marek Nečas; Milan Potáček

• Book ID: 102170377
• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 172 KB
• Volume: 2005
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200400814

✦ Synopsis

Abstract

The thermally initiated intramolecular criss‐cross cycloaddition of 3‐substituted homoallenylaldazines 5 has been explored. Their cyclization led to interesting new fused heterocyclic systems 6 consisting of four five‐membered rings with two nitrogen heteroatoms. The azines were prepared by the reaction of homoallenyl aldehydes 4 with hydrazine. The homoallenyl aldehydes 4 were synthesized by the Claisen rearrangement of new N,N‐disubstituted 4‐[(2‐methylprop‐1‐en‐1‐yl)oxy]but‐2‐yn‐1‐amines 3a–f prepared by Mannich reaction of 2‐methylprop‐1‐en‐1‐yl prop‐2‐yn‐1‐yl ether (2). The success of the reaction was based on the improved solvent‐free synthesis of 1‐chloro‐2‐methylpropyl prop‐2‐yn‐1‐yl ether (1) and its conversion to isolable 2‐methylprop‐1‐en‐1‐yl prop‐2‐yn‐1‐yl ether (2) in high yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)