Dichloromethane → Hydrochloric Acid

Participants

Reaction Steps

A mixture of 500 mg of 3,4-dihydro-5-methoxy-2H-[1]-benzothiopyran-3-amine and 361 mg of acetic anhydride in 10 mL of methylene chloride is kept at room temperature for 15 min. The solvent is removed in vacuo and the resulting 3,4-dihydro-N-acetyl-5-methoxy-2H-[1]-benzopyran-3-amine is dissolved in 10 mL of 1M diborane in tetrahydrofuran. After 3 hr reflux, the reaction mixture is poured into 6N hydrochloric acid, washed with ether, basified with 45% potassium hydroxide and reextracted with ether. After drying over magnesium sulfate, the solvent is removed in vacuo. Acidification with ethanolic hydrochloric acid affords 3,4-dihydro-N-ethyl-5-methoxy-2H-[1]-benzothio-pyran-3-amine hydrochloride melting at 222°-224°.

Provenance & Evidence