Sodium Hydroxide → p-Aminobenzamidine

Participants

Reaction Steps

Addition of 50% sodium hydroxide (4.0 g., 0.05 mole) to a solution of 4-aminobenzamidine hydrochloride (0.5 mole) in 10 ml. of water affords 4-aminobenzamidine free base. Acetone (50 ml.) is added to the liberated free base and the mixture cooled to 5° C. 4-Nitrostyrylsulfonyl chloride is added to the mixture in a period of 5 min. while maintaining a temperature below 15° C. The mixture is stirred for 10 min., the reaction mixture concentrated under reduced pressure provides a residue which diluted with 100 ml. of water and neutralized with 3N hyrochloric acid affords a pale yellow solid precipitate. The precipitate is collected, washed thoroughly with water and then triturated first with isopropanol and then with ether to yield 7.3 g. (84%) of N-(4-NITROSTYRYLSULFONYL)-4-AMINOBENZAMIDINE, m.p. 188°-189° C. (b) A mixture of acetamidine hydrochloride (28.8 g., 0.15 mole) and 50% sodium hydroxide (12.0 g., 0.15 mole) in 150 ml. of acetone is stirred for a period of 10 min. to liberate the free base. A solution of styrylsulfonyl chloride (10.1 g., 0.05 mole) in 50 ml. of acetone is added dropwise to the mixture at a temperature of 20°-25° C. with stirring. After further stirring for 10 min., the mixture is concentrated under reduced pressure to remove acetone, the concentrate diluted with 200 ml. of water and acidified with 3N hydrochloric acid to provide a precipitate. The precipitate is collected, dissolved in chloroform and the chloroform extract dried. Evaporation of the chloroform solvent under reduced pressure provides a white solid, m.p. 130°-134° C. which is crystallized from isopropyl acetate affording 8.5 g. (76% yield) of N-(STYRYLSULFONYL)ACETAMIDINE, m.p. 134.5°-137.0° C. (corr.).

Provenance & Evidence