Thionyl Chloride → HCID 178436086, compound

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Reaction Steps

N'-Tosyl-2-[2-(2-hydroxyethyl)phenylimino]imidazolidine from Example 17, Step B (1.8 g) is dissolved in pyridine (25 ml) containing thionyl chloride (3 ml). The mixture is heated at reflux until thin layer chromatography shows starting material to be gone [silica gel=dichloromethane:methanol (19:1)], about three hours. The volatiles are evaporated in vacuo and the residue is partitioned between water and ether. The aqueous layer is extracted (3×50 ml) with ether and the combined extracts are washed with brine, dried over sodium sulfate and evaporated to off white crystals which can be purified by recrystallization from ethyl acetate (1.23 g, 72%). Ammonia (50 ml) is condensed in a cooled flask fitted with a dry ice condenser. The N-tosyl derivative (0.5 g) is added and when solution occurs, small pieces of freshly cut metallic sodium are added one at a time until a blue color persists. Solid ammonium chloride is added to remove the blue color and the ammonia is evaporated in a stream of nitrogen. The solid residue is partitioned between water and ether. The aqueous layer is basified to pH 14 and reextracted with dichloromethane (2×50 ml). The organic extracts are pooled, extracted with 2 N acetic acid (3×50 ml) and these extracts are combined, back-extracted with dichloromethane, and neutralized with dilute hydrochloric acid.

Provenance & Evidence