Studies in azole chemistry. Part 2. Nitration of 1,4,5-trimethylimidazole 3-oxide and 1-methylpyrazole 2-oxide, and some reactions of the products
Abstract
In sulphuric acid, 1,4,5-trimethylimidazole 3-oxide and 1-methylpyrazole 2-oxide are nitrated as the free bases at C-2 and C-5, respectively. At high acidities the pyrazole gives 1-methyl-3,5-dinitropyrazole 1-oxide. With phosphorus trichloride the pyrazole oxides were deoxygenated, and with phosphoryl chloride, 1-methylpyrazole 2-oxide gave 5-chloro-1-methylpyrazole. 1-Methyl-5-nitropyrazole 2-oxide with acetyl chloride gave 5-chloro-1-methyl-4-nitropyrazole.