Formation of an unexpected 3,3-diphenyl-3H-indazole through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate.

ABSTRACT: The one-pot reaction of 2,6-bis(diphenylmethyl)-4-methoxyaniline with tert-butylnitrite, BTEAC and DABSO in the presence of CuCl₂ provided an unexpected 3H-indazole product 8. The structure of the compound was determined by HRMS, IR, NMR and further confirmed by single crystal X-ray crystallography. The compound crystallises in the triclinic P-1 space group, with unit cell parameters a = 9.2107 (4), b = 10.0413 (5), c = 14.4363 (6) Å, ? = 78.183 (2), ? = 87.625 (2), ? = 71.975 (2)°. The formation of 8 proceeded through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate 9. The molecules of 8 are organised by edge-face Ar-H···?, face-face ?···?, and bifurcated OCH₂-H···N interactions. In addition to these, there are Ar-H···H-Ar close contacts, (edge-edge and surrounding inversion centres) arranged as infinite tapes along the a direction.

SUBMITTER: King AT 

PROVIDER: S-EPMC6604747 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature