According to the present invention there is provided process for preparing a compound of formula (I): ##STR1## or a salt, acylate or sulphonate derivative thereof; wherein R.sup.1 is an optionally substituted aryl group, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are selected from hydrogen, C.sub.1-4 alkyl, C.sub.1-4 alkanoyl or --CO.sub.2 R.sup.a wherein R.sup.a is C.sub.1-4 alkyl or R.sup.2 and R.sup.3 or R.sup.4 and R.sup.5 together with the carbon atom to which they are attached form a C.sub.3-6 cycloalkyl ring, provided that at least R.sub.2 and R.sup.3 or R.sup.4 and R.sup.5 are not both hydrogen and that not more than two of R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are C.sub.1-4 alkanoyl or --CO.sub.2 R.sup.a ; which process comprises reacting a compound of formula (II): ##STR2## wherein R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are as defined in relation to formula (I) with a compound of formula (III): R.sup.1 COCN (III) wherein R.sup.1 is as defined in relation to formula (I) in the presence of a base and a Lewis acid.
根据本发明提供了制备化合物的方法,其
化学式为(I):或其盐、酰化物或
磺酸酯衍
生物;其中R^1是可选择的取代芳基,R^2、R^3、R^4和R^5选择自氢、C1-4烷基、C1-4醇酰基或--CO2R^a,其中R^a是C1-4烷基或R^2和R^3或R^4和R^5与它们连接的碳原子一起形成一个C3-6环烷基环,前提是至少R^2和R^3或R^4和R^5不同时为氢,且R^2、R^3、R^4和R^5中不超过两个为C1-4醇酰基或--CO2R^a;该方法包括将化合物(II):其中R^2、R^3、R^4和R^5如
化学式(I)所定义,与化合物(III):R^1COCN (III)在碱和Lewis酸存在下反应。