Hydrochloric Acid → 1-Chloro-4-(4-isothiocyanatophenoxy)benzene

Participants

Reaction Steps

Unless otherwise indicated, all thioureas, isothiocyanates, thioamides and amines were purchased from Maybridge Chemical Co. Ltd.(Cornwall, U.K.), Transworld Chemical Co. (Rockville, Md.), or Aldrich Chemical Co., (Milwaukee, Wis.). (a) 4-Amino-4′-chlorodiphenylether (TCI America, Portland Oreg., 520 mg, 2.03 mmol) was slurried in 10 mL of ether and treated with ca. 1 mL of ether saturated with HCl gas. After 5 min. the solvent was removed in vacuo. To a stirring biphasic solution amine-HCl salt in 20 mL CHCl3-sat'd NaHCO3 (1:1, v/v) at ambient temperature was added thiophosgene (1.2 equiv, 2.4 mmol) in 5 mL of CHCl3 dropwise via an addition funnel. The reaction was vigorously stirred for 1 h (TLC, 50% ethyl acetate-hexanes indicates clean conversion to a higher Rf spot), at which time the layers were separated, the aqueous layer extracted with CHCl3 (1×20 mL), and the combined organic layers washed with brine (1×20 mL) and dried (Na2SO4). Concentration of the solvent in vacuo yielded the crude 4-(4-chlorophenoxy)-phenylisothiocyanate (414 mg). (b) The 4-(4-chlorophenoxy)-phenylisothiocyanate was transferred to an Ace Glass pressure tube equipped with a Teflon coated stir bar and treated with a 2.0 M solution of NH3 in 5 ml methanol (Aldrich Chemical Co., Milwaukee, Wis.)). The tube was sealed and immersed in a 80° C. oil bath. After 2 h, the reaction was cooled to 0° C. in an ice bath. The precipitates were filtered and dried under vacuum to yield amino{[4-(4-chlorophenoxy)phenyl]amino}methane-1-thione (328 mg, 79%). 1H NMR (DMSO-d6, 300 MHz) 7.02 (m, 4H), 7.41 (m, 4H), 9.65 (s, 1H); Mass Spectrum (ESI) m/z calcd. for C13H11ClN2OS, 278.8 (M+H), found 279.4.

Provenance & Evidence