A process for the preparation of uv absorbers

A process for preparing a compound of formula (A)

• wherein Ar1 and Ar2 are independently a moiety of the formula (B),
• wherein
• R1, R2, R3, R4 and R5 are independently selected from the group consisting of hydrogen, halogen, substituted or unsubstituted, linear or branched C1-C24 alkyl, substituted or unsubstituted, linear or branched C2-C24 alkenyl, substituted or unsubstituted C5-C24 cycloalkyl, substituted or unsubstituted C5-C24 cycloalkenyl, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C7-C24 arylalkyl, C(═O)R, OR, NRR′, C(═O)NRR′, CN, SR, S(═O)2R, S(═O)2OH and S(═O)2OM;
• wherein M is an alkali metal;
• or
• R1 and R2 together with the carbon atoms to which they are bonded or
• R2 and R3 together with the carbon atoms to which they are bonded or
• R3 and R4 together with the carbon atoms to which they are bonded or
• R4 and R5 together with the carbon atoms to which they are bonded form an unsaturated or aromatic 5- to 20-membered carbocyclic ring that optionally contains 1, 2 or 3 heteroatom(s) selected from O, N or S as ring member(s);
• Q is selected from hydrogen and OH;
• R1 is selected from the group consisting of hydrogen, substituted or unsubstituted, linear or branched C1-C24 alkyl, substituted or unsubstituted, linear or branched C2-C24 alkenyl, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C7-C24 arylalkyl, substituted or unsubstituted C5-C24 cycloalkyl and substituted or unsubstituted C5-C24 cycloalkenyl, and C(═O)R;
• R7, R8 and R9 are independently selected from the group consisting of hydrogen, halogen, substituted or unsubstituted, linear or branched C1-C24 alkyl, substituted or unsubstituted, linear or branched C2-C24 alkenyl, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C7-C24 arylalkyl, substituted or unsubstituted C5-C24 cycloalkyl, substituted or unsubstituted C5-C24 cycloalkenyl, C(═O)R, OR, NRR′, C(═O)NRR′, OC(═O)R, CN, SR, S(═O)2R, S(═O)2OH and S(═O)2OM, wherein M is an alkali metal, or
• R7 and R8 together with the carbon atoms to which they are bonded form an unsaturated or aromatic 5- to 20-membered carbocyclic ring that optionally contains 1, 2 or 3 heteroatom(s) selected from O, N or S as ring member(s);
• Y is selected from the group consisting of hydrogen, halogen, O, —NR″, or S, wherein R″ is selected from the group consisting of hydrogen, substituted or unsubstituted, linear or branched C1-C24 alkyl, substituted or unsubstituted, linear or branched C2-C24 alkenyl, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C7-C24 arylalkyl, substituted or unsubstituted C5-C24 cycloalkyl and substituted or unsubstituted C5-C24 cycloalkenyl;
• with the proviso that in case Y is hydrogen or halogen, then R is not present;
• and
• R and R′ are independently selected from the group consisting of hydrogen, substituted or unsubstituted, linear or branched C1-C24 alkyl, substituted or unsubstituted, linear or branched C2-C24 alkenyl, substituted or unsubstituted C5-C24 cycloalkyl, substituted or unsubstituted C5-C24 cycloalkenyl, substituted or unsubstituted C6-C24 aryl and substituted or unsubstituted C7-C24 arylalkyl;
• comprising at least the steps of:
• i) reacting at least one compound of formula (C)
• wherein LG is halogen, O—S(═O)2CF3 or O—S(═O)2CH3;
• with at least one compound of formula (B1)
• wherein R1, R2, R3, R4 and R5 are defined as above;
• in the presence of at least one acid to obtain a compound of formula (D)
• wherein Ar1 and Ar2 are defined as above;
• ii) reacting the compound of formula (D) obtained according to step i) with at least one metal hydroxide to obtain a compound of formula (E)
• wherein Ar1 and Ar2 are defined as above;
• iii) reacting the compound of formula (E) obtained according to step ii) with at least one halogenating reagent to obtain a compound of formula (F)
• wherein Ar1 and Ar2 are defined as above, and
• W is selected from the group consisting of F, Cl, and Br;
• and
• iv) reacting at least one compound of formula (F) obtained according to step iii) and at least one compound of formula (G),
• wherein Y, Q, R6, R7, R8 and R9 are defined as above,
• in the presence of an at least one acid to obtain a compound of formula (A).