Iodine → HCID 19377149, compound

Participants

Reaction Steps

Magnesium turnings (2.04 g) and a crystal of iodine were stirred in dry diethyl ether (24 ml) as a solution of 1,2-dichloro-4-iodobenzene (23.17 g) in dry diethyl ether (60 ml) was added over 15 minutes. The mixture was stirred for 15 minutes and refluxed for a further 15 minutes to complete formation of the Grignard reagent. The mixture was cooled to room temperature and a solution of N-(1,2,3,4-tetrahydro-4-keto-1-naphthyl)-N-methylacetamide (12.3 g) in dry tetrahydrofuran (134 ml ) was added over 5 mutes. The mixture was stirred for 4 hours at room temperature, heated under reflux for 30 minutes, cooled and treated with 4N aqueous sulphuric acid (30 ml). The lower aqueous phase was separated and discarded, dichloromethane was added, and the solution was washed with water (2×25 ml). The organic layer was evaporated under vacuum to give a mixture of racemic cis-(1R*, 4S*)- and trans-(1R*, 4R*)-isomers (ratio 87:13 respectively by nmr spectroscopy techniques) as a light brown gum (24.5 g) which was stirred with diethyl ether (150 ml) for 1 hour, then filtered, to give the title compound as cream crystals (10.2 g, 49.5%), m.p. 146°-148° C.; Rf 0.41 (silica; chloroform, methanol; 95:5). Found: C,62.96; H,5.24; N,4.00 C19H19Cl2NO2 requires C,62.65; H,5.26; N 3.85%. GLC assay on a 2.1 m×4 mm 3% OV-17 column, temperature programmed from 100° to 275° C. at 10° C./minute, showed the product to be 96% pure (retention time 41.5 minutes) containing 3% recovered ketone.

Provenance & Evidence