Disclosed are merocyanine derivatives of formula (1), wherein R1 and R2 independently from each other are branched C4-C22alkyl or branched C4-C12 alkenyl R3 and R4 independently from each other are cyano COR7, COOR7 CONR7R8 SO2(C6-C12)aryl C2-C12alk-1-enyl C3-C12cycloalk-1-enyl C2-C12alk-1-inyl C2-C12heteroalkyl C3-C5heterocycloalkyl C6-C10aryl or C1-C9heteroaryl wherein at least one of R3 and R4 is cyano R5 and R6 independently from each other are hydrogen C1-C6alkyl C5-C8cycloalkyl which may be substituted by one or more than one C1-C4alkyl and R7 and R8 independently from each other are hydrogen C1-C22alkyl C2-C12alkenyl C2-C12alkinyl C3-C12cycloalkyl C3-C12cycloalkenyl &mdash(CH2)tCOOH C7-C12aralkyl C1-C12heteroalkyl C2-C11heteroaralkyl C6-C10aryl C1-C9heteroaryl. The compounds are useful as UV absorbers for protecting human hair and skin against the damaging effect of UV radiation.
