Hydrochloric Acid → Isotiquimide

Participants

Reaction Steps

A stirred solution of di-isopropylamine (12.2 ml, 0.085 mol) in benzene (100 ml) at 0° C was treated dropwise with a 9% w/v solution of butyl lithium in hexane (62 ml, 0.085 mol). After 1 hour at 0° C, 4-methyl-5,6,7,8-tetrahydroquinoline (12.8 g, 0.085 mol) was added dropwise and then after a further hour the anion was treated dropwise with trimethylsilyl isothiocyanate (12.2 ml, 0.095 mol). After 0.5 hours at 0° C and 0.5 hours at room temperature the reaction mixture was diluted with water (50 ml) and the pH adjusted to 2.0 with conc. HCl. The aqueous layer was separated and adjusted to pH 10.0 with solid sodium carbonate and extracted with chloroform (3 × 50 ml) and the combined extracts were dried over MgSO4, filtered and the solvent was removed in vacuo. The residual oil was triturated with n-hexane to give 4-methyl-5,6,7,8-tetrahydroquinoline-8-thiocarboxamide (3.4g, 19%). The hydrochloride was prepared by dissolving in hot iso-propyl alcohol adding excess ethereal HCl solution and allowing to crystallise to give 4-methyl-5,6,7,8-tetrahydroquinoline-8-thiocarboxamide, hydrochloride m.p. 212-3° C. (Found: C, 54.9; H, 6.4; N, 11.5. C11H14N2S. HCl requires C, 54.4; H, 6.2; N, 11.5%).

Provenance & Evidence