STILBENE DERIVATIVES

摘要

Stilbene derivatives of the formula wherein X is chlorine or bromine, R1 is hydrogen, carboxyl, cyano, C1-C6-alkyl or a non-chromophorically esterified carboxyl group, and R2 and R3 independently of one another are each hydrogen, unsubstituted or non-chromophorically substituted C1-C6-alkyl or C3-C4-alkenyl, or a non-chromophoric substituent of the 2nd order. They are valuable intermediates for producing optical brighteners of the 4,4'-disubstituted stilbene series.