Nitric Acid → (R)-3-methyl-4-nitroxy-2-(2-propynyl)-2-cyclopenten-1-one

Participants

Reaction Steps

Into a mixed solution of 8 g of fuming nitric acid and 24 g of acetic anhydride, kept at a temperature of -5° to 10° C., was added dropwise 6 g of (R)-4-hydroxy-3-methyl-2-(2-propynyl)-2-cyclopenten-1-one ([α]D23 ; -19.5° (C=1.36, in chloroform), (R)-isomer/(S)-isomer=96.7/3.3). Then, the mixture was stirred for 30 minutes at the same temperature. Thereafter, the reaction mixture was poured into 200 ml of ice water, and then subjected to a toluene extraction. The toluene layer was separated and washed with an aqueous 5% sodium hydrogencarbonate solution and then with water. The extract was dried over anhydrous magnesium sulfate and, then, concentrated to give 7.56 g of crude (R)-3-methyl-4-nitroxy-2-(2-propynyl)-2-cyclopenten-1-one.

Provenance & Evidence