Furosemide → 2,2,2-Trichloroethyl 5-(aminosulfonyl)-4-chloro-2-[(2-furanylmethyl)amino]benzoate

Participants

Reaction Steps

Benzene (30 mL) (or toluene) and 2,2,2-trichloroethanol (0.024 mole) are added to a round-bottomed flask. Furosemide (10) (5-(aminosulfonyl)-4-chloro-2-[(2-furanylmethyl)amino]benzoic acid, Aldrich) (0.025 mole), benzene (30 mL), and p-toluenesulfonic acid (0.001 mole) catalyst are added to the flask. A Dean-Stark trap is filled with benzene, and the contents of the flask are refluxed with stirring for several hours or until no additional water is collected in the trap. The reaction is cooled, extracted with sodium bicarbonate solution, washed with water, and then with a saturated sodium chloride solution. The organic layer may be dried over sodium sulfate, filtered and concentrated in vacuo to give 2,2,2-trichloroethyl 5-(aminosulfonyl)-4-chloro-2-[(2-furanylmethyl)amino]benzoate. See Sandler et al., Organic Functional Group Preparations, (1968) p. 249.

Provenance & Evidence