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16 alpha, 17alpha-methoxy-methylene-di:oxy pregnene derivs. prepn. - by reacting a 16alpha-formyl:oxy-17alpha-hydroxy-pregnene deriv. with acetal in the presence of phosphorus pent:oxide
16 alpha, 17alpha-methoxy-methylene-di:oxy pregnene derivs. prepn. - by reacting a 16alpha-formyl:oxy-17alpha-hydroxy-pregnene deriv. with acetal in the presence of phosphorus pent:oxide
The prepn. of steroids of formula (I), comprises reacting a steroid of formula (II) with an acetal of formula R3C(OR2)2 (III) in the presence of phosphorus pentoxide. In the formulae dotted line is a single or double bond; X is H, F or Me; Y and Z are each H or together form a C-C bond, or Y is H, F, Cl or Br and Z is OH; R1 is lower alkyl; R2 is H or lower acyl; R3 is lower alkyl. Corticoids (Ia) of formula (I), where X and Y are H and Z is OH are new. (I) are pharmaceuticals. Previous processes were costly and gave only low yields. The process gives high yields.
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机译:的准备。式(I)的类固醇的“合成”包括在五氧化二磷存在下使式(II)的类固醇与式R 3 C(OR 2)2(III)的乙缩醛反应。在公式中,虚线是单键或双键; X是H,F或Me; Y和Z各自为H或一起形成C-C键,或Y为H,F,Cl或Br且Z为OH; R1是低级烷基; R 2为H或低级酰基; R 3是低级烷基。其中X和Y为H且Z为OH的式(I)的皮质类固醇(Ia)是新的。 (一)是药品。先前的工艺成本高昂,并且收率低。该方法产生高产率。
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