The nitration of some substituted 4-methylphenols; X-ray crystal structure of (Z)-3-Bromo-5-(bromonitromethylene)furan-2(5H)-one

Abstract

The nitrations of 2-substituted 4-methyl-6-nitrophenols (1a),(l1b) and (1c) give 6-substituted 3-methyl-2-nitro-1,4-benzoquinones (2a), (2b) and (2c). Similar reaction of 2,3-dibromo-4-methyl- 6-nitrophenol (5) gives 2,3-dibromo-5-methyl-6-nitro-1,4-benzoquinone (7) and the 4-nitratocyclo- hexa-2,5-dienone (12). In contrast, 2,3,6-tribromo-(4a) and 2,6-dibromo-(4b) 4-methylphenols give 1,4-benzoquinones with loss of the methyl group. Lactone (18) was formed in the nitration of the 2,6-dibromophenol (4b) and its structure was determined by single-crystal X-ray analysis.