HCID 14547436, compound → HCID 22165626, compound

Participants

Reaction Steps

A 1.6M solution of n-butyllithium in hexane (36 ml) was added dropwise over 40 minutes to a stirred, cooled (acetone/cardice bath) solution of 1-{[4-(2,3-dichlorophenyl)-3-ethoxycarbonyl-5-methoxycarbonyl-6-methyl-1,4-dihydropyrid-2-yl]methoxy}prop-2-yne (11.0 g) in tetrahydrofuran (110 ml) and the mixture allowed to warm to -40° over one hour. The mixture was then cooled to -60° and carbon dioxide bubbled through the stirred solution at that temperature for one hour. Carbon dioxide was then bubbled through the mixture for a further one hour whilst it was allowed to warm up to 0°. The mixture was then diluted with water (100 ml) and the layers separated. The aqueous layer was washed with diethyl ether, acidified to pH 1.0 with concentrated hydrochloric acid and extracted into dichloromethane. The combined dichloromethane extracts were dried over MgSO4 and evaporated and the residue triturated with methanol. The resulting solid was collected, washed with methanol and dried to give the title compound (8.87 g) as a hemihydrate containing half a mole of methanol of crystallisation, m.p. 100°.

Provenance & Evidence