The 4.4′-benzidine rearrangement of 4-alkyl substituted hydrazobenzenes. Issue 23 (9th June 2016)

• Record Type: Journal Article
• Authors: Bouillon, Marc E.; Meyer, Hartmut H.
• Is Part Of: Tetrahedron. Volume 72:Issue 23(2016)
• Page Start: 3151
• Page End: 3161
• Publication Date: 2016-06-09
• Subjects: Benzidine rearrangement -- Hydrazobenzenes -- ipso-Benzidines -- ipso-Diphenylines -- Cyclohexa-2, 5-dienimines -- meta-Benzidines; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2016.03.103
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: When treated with dilute inorganic acids N, N ′-diarylhydrazines (hydrazobenzenes) with an alkyl substituent in the 4-position undergo [5, 5]-sigmatropic rearrangement reactions to furnish 4-(4′-aminophenyl)-4-alkylcyclohexa-2, 5-dienimines ( ipso -benzidines) in moderate to excellent yields. Steric bulk of the 4-alkyl substituent in the starting material decreases the yield of the respective ipso -benzidine. Additional electron-donating alkyl substituents in the ortho - and/or meta -positions on both rings generally promote the reaction and consequently increase the yield of the 4.4′-benzidine rearrangement product. Described herein are our findings regarding the scope and limits of this unusual benzidine rearrangement. Graphical abstract: