Unexpected one pot C (aryl)–N bond cleavage and Questiomycin A formation from the reduction reaction of 2-amino-6-nitrophenol derivatives
摘要:
2-Amino-6-nitrophenol derivatives 5A and 5B have been prepared from the bromonitro phenol derivative 4 using the Buchwald conditions. While attempting one pot reduction of nitro group and deprotection of phenolic benzyl group of the compounds 5A and 5B separately using Pd/C in methanol under H-2 atmosphere, an unexpected C(aryl)-N bond cleavage reaction had occurred which was followed by formation of a known compound Questiomycin A (2-amino-3H-phenoxazin-3-one) 1 from both the compounds. In the present study, the danger of deamination of Buchwald products 5A and 5B under the conditions of catalytic hydrogenation and the simultaneous formation of phenoxazine I is disclosed. (C) 2015 Elsevier Ltd. All rights reserved.
Unexpected one pot C (aryl)–N bond cleavage and Questiomycin A formation from the reduction reaction of 2-amino-6-nitrophenol derivatives
摘要:
2-Amino-6-nitrophenol derivatives 5A and 5B have been prepared from the bromonitro phenol derivative 4 using the Buchwald conditions. While attempting one pot reduction of nitro group and deprotection of phenolic benzyl group of the compounds 5A and 5B separately using Pd/C in methanol under H-2 atmosphere, an unexpected C(aryl)-N bond cleavage reaction had occurred which was followed by formation of a known compound Questiomycin A (2-amino-3H-phenoxazin-3-one) 1 from both the compounds. In the present study, the danger of deamination of Buchwald products 5A and 5B under the conditions of catalytic hydrogenation and the simultaneous formation of phenoxazine I is disclosed. (C) 2015 Elsevier Ltd. All rights reserved.