Phenyl Isothiocyanate → N-(3-(Dimethylamino)propyl)-N'-phenylthiourea

Participants

Reaction Steps

Phenyl isothiocyanate (5.283 g, 39.1 mmole) in 30 mL t-butyl methyl ether was added to a solution of 3-(dimethylamino)propylamine (3.993 g, 39.1 mmole) in 10 mL isopropanol. After stirring 2 hr at room temp., the solid which separated was filtered out and washed with t-butyl methyl ether to afford 6.51 g of 1-[3-(dimethylamino)propyl]-3-phenylthiourea (mp 112-114° C.), part of which (2.374 g, 10 mmole) was dissolved in ethanol (20 mL) containing conc. HCl (1.67 mL, 20 mmole) and added to 2-methylnaphthoquinone dissolved in warm ethanol (35 mL). After 4 days in a stoppered flask at room temp., the mixture was concentrated, and dissolved in ethyl acetate. The solid which separated after 16 hr was filtered out, but became sticky on the filter and was discarded. The filtrate was stored another 12 days at room temp. The powder which separated was filtered out to give 600 mg of pinkish-buff powder. Of this, 325 mg was recrystallized from 10 mL methanol+60 mL ethyl acetate containing a few drops of water to give 260 mg of the title compound, mp 238-240° C.

Provenance & Evidence