Formaldehyde → HCID 19823878, compound

Participants

Reaction Steps

A solution of 2-[1-(4-chlorophenyl)cyclobutyl]-2-dimethylaminoacetonitrile (4.7 g prepared as described in Example A) in dry tetrahydrofuran (20 ml) was added at -20° C. to lithium diisopropylamide [prepared by adding a solution of diisopropylamine (2.02 g) in dry tetrahydrofuran (30 ml) to a 2.7M solution of butyllithium in hexane (7.5 ml) at -10° C⟧ Formaldehyde vapour produced by heating paraformaldehyde to 180° C. was passed into the resulting solution at -50° C. until the colour changed from red-brown to pale yellow. Methanol (50 ml) was added and sodium borohydride (6 g) added portionwise with stirring. Stirring was continued for 3 days and then water (50 ml) and excess dilute hydrochloric acid were added. Methanol was removed by evaporation in vacuo to leave a solution which was basified and extracted with ether. Removal of the ether after drying yielded an oil which was dissolved in 5N hydrochloric acid (8 ml) and water (50 ml). The solution was evaporated and the residue dried by azeotropic distillation with propan-2-ol. The residue was crystallised from acetone to give 2-[1-(4-chlorophenyl)cyclobutyl]-2-dimethylaminoethanol hydrochloride (m.p. 230°-231° C.). A solution of this compound in the form of its free base (1.01 g) in dry tetrahydrofuran (10 ml) was added dropwise to a stirred mixture of sodium hydride (0.35 g, 50% suspension in mineral oil) and dry tetrahydrofuran (10 ml) under nitrogen. Stirring was continued until hydrogen evolution had ceased and the mixture was heated at 40°-45° C. for 20 minutes. After cooling to 20° C. a solution of iodomethane (0.6 g) in dry tetrahydrofuran (5 ml) was added and the mixture heated under reflux for two hours. Water (20 ml) was added dropwise to the cooled reaction mixture which was then extracted with ether and the extract washed with water. The ether extract was dried and evaporated and the residue was dissolved in propan-2-ol (15 ml). Concentrated hydrochloric acid (2 ml) was added and the mixture evaporated to dryness to give a solid which was recrystallised from ethyl acetate to give N,N-dimethyl-1-[1-(4-chlorophenyl)cyclobutyl]-2-methoxyethylamine hydrochloride (m.p. 180°-185° C.).

Provenance & Evidence