A method for preparing a compound of formula I ##STR1## in which X is O or S; both groups R together with the two carbon atoms to which they are attached form a fused aromatic group; R.sub.1 is an organic radical; and n is 0, 1, 2 or 3 comprising reacting a compound of formula II ##STR2## where R, R.sub.1 and n are defined above and where each R.sub.3, independently, is C.sub.1-12 alkoxy or one R.sub.3 is C.sub.1-12 alkoxy and the other R.sub.3 is halogen, with elemental sulphur in an alkaline medium, a metal sulphide or a metal hydrosulphide. Compounds of formula I and formula II are useful as photoinitiators.
一种制备式I的化合物的方法 ##STR1## 其中X为O或S; 两个R基与它们附着的两个碳原子形成融合的芳香基团; R.sub.1为有机基团; n为0、1、2或3,包括将式II的化合物 ##STR2## 其中R、R.sub.1和n如上所定义,每个独立的R.sub.3是C.sub.1-12烷氧基或一个R.sub.3是C.sub.1-12烷氧基,另一个R.sub.3是卤素,与元素
硫在碱性介质中、
金属
硫化物或
金属氢
硫化物反应。式I和式II的化合物可用作光
引发剂。