One-Pot Synthesis of 2,3,4,4a,10,10a-Hexahydro-1H-phenoxazines

Abstract

A procedure has been proposed for the synthesis of 2,3,4,4a,10,10a-hexahydro-1H-phenoxazines by reductive cyclization of 2-(2-nitrophenoxy)cyclohexan-1-ones over palladium catalysts under mild conditions (ethanol, 318 K, p_{H 2} = 0.1 MPa). The product structure and ratio were determined by ¹H and ¹³C NMR spectra, X-ray analysis, and GC/MS data. The reductive cyclization of 2-(2-nitrophenoxy)cyclohexan-1-one and 2-(4-methyl-2-nitrophenoxy)cyclohexan-1-one has been shown to produce 2,3,4,4a,10,10a-hexahydro-1H-phenoxazine and its 8-methyl analog as mixtures of stereoisomers with trans and cis-junction of the cyclo-hexane and morpholine rings at ratios of 1:3 and 3:1, respectively.