反应详情

180.5 g (0.4 mol) of finely divided compound from Example I are intensively stirred under reflux for 5 h in 2.6 l of 2N HCl using a mechanical stirrer. The mixture is then neutralised with NaHCO3 and extracted several times with ethyl acetate, and the extracts are dried. 37.6 g of the title compound are obtained by crystallisation. Chromatography of the mother liquor (silica gel, toluene→toluene/ethyl acetate 2:1) yields a further 23.14 g of the title compound. Total yield: 60% M.p.: 136° C.

1. extractionextracted several times with ethyl acetate
2. customthe extracts are dried