羟基处于醛基邻位和对位的苯甲醛与几种苯乙酮衍生物的缩合，多数没有得到预期的产物，或收率极低；苯乙酮环上的羟基对缩合反应影响很大，羟基越多，缩合越困难。

The groups in ring of benzaldehydes, no matter they are electron withdrowing or electron donating except of hydroxy, do not seem to have much effect on the yield.

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羟基处于醛基邻位和对位的苯甲醛与几种苯乙酮衍生物的缩合，多数没有得到预期的产物，或收率极低；苯乙酮环上的羟基对缩合反应影响很大，羟基越多，缩合越困难。

The groups in ring of benzaldehydes, no matter they are electron withdrowing or electron donating except of hydroxy, do not seem to have much effect on the yield.

youdao