反应详情

Paraformaldehyde (1.5 g) and dimethylamine hydrochloride (3.75 g) were added to a solution of the product of Stage (iii) (10 g) in acetic acid (70 ml) and then heated to reflux for 8 h. On cooling to ambient temperature the reaction mixture was poured into water (400 ml). The oil which separated out was triturated with ether (500 ml) to give a solid (9 g) which was partitioned between ethyl acetate (2×30 ml) and saturated aqueous sodium carbonate (100 ml). The organic phase was evaporated and the residue purified by flash chromatography (G) to give the pure free base as a solid (0.40 g). A sample (0.4 g) was dissolved in ethanol (10 ml), filtered, and ethereal HCl (6 ml) was added. On addition of dry ether (20 ml), the title compound crystallized as a solid (0.38 g) m.p. 219°-220°.

1. temperatureheated
2. temperatureto reflux for 8 h
3. customThe oil which separated out
4. customwas triturated with ether (500 ml)