DERIVATIVES 2-(BENZO[B]THIOPEN-5-YL)-2-HYDROXYETHANOL, ITS OPTICALLY ACTIVE FORM AND ITS SALT

摘要

Prodn.of an optically active benzo(b)thiophen-5-yl dialkylamino-ethoxy-ethanol deriv., of formula (VIA), (VIB) or their salts, comprising: (a) inoculating a supersatd. soln. of a dioxolo of formula (I) with seed crystals of the optically active dioxolo (IIA) or (IIB), depending on whether (VIA) or (VIB) is the objective, in the presence of a racemisation catalyst, to crystallise optically active (IIA) or (IIB) preferentially; (b) subjecting to alcoholysis or hydrolysis in presence of an acid catalyst; (c) protecting the free OH gp. to give (IIIA) or (IIIB); (d) reducing to diol deriv. (IVA) or (IVB); (e) reacting with a dialkylaminoethyl halide of formula (V); and (f) removal of the OH protecting gp., if desired, is new. In the formulae, R2 = H or a protecting gp.; R4,R5 = 1-6C alkyl; R2a = a protecting gp.; R3 = H or a protecting gp.; and BT = benzo(b)thiophen-5-yl; and X = a removable gp.. Specifically claimed are cpds. (-)-1-(Benzo(b)thiophenyl -5-yl)-2-(2- (N,N-diethylamino) ethoxy)ethanol; and (-) or (+) 2,2-dimethyl-(benzo(b)thiophen-5-yl)- 1,3-dioxolan-4-one.