Alpha-hydroxyketones

Compounds of the formula I′

• wherein
• x is an integer from 1-4;
• Ar is phenyl, naphthyl, anthryl or phenanthryl each of which optionally is substituted by one or more CN, OR5, C3-C5alkenyl or C1-C6alkyl which optionally is substituted by one or more OR6, COOR6 or halogen;
• R1 when x is 1, is OR7, O−X+, NR8R9, C1-C20alkyl optionally substituted by one or more COOR10, or is C2-C5alkenyl or phenyl-C1-C4alkyl;
• R1 when x is 2, is C1-C20alkylene, C2-C20alkylene which optionally is interrupted by one or more O, or is O-A-O, O-A-NR15, NR15-A-O, NR′15-A-NR15, NR15a-A1-NR15b or NR′15—(CH2)x′-A-(CH2)x′—NR15 or is O−X2+O−;
• x′ is an integer from 1-4;
• R1 when x is 3, is N(R30O)3—;
• C3-C20alkanetriyltrioxy which optionally is substituted by OH;
• C3-C20alkanetriyltriamino;
• a trivalent siloxane, or O3−X3+;
• R1 when x is 4, is C4-C20alkanetetrayltetraoxy optionally substituted by OH;
• C4-C20alkanetetrayltetraamino;
• a tetravalent siloxane;
• or O4−X4+;
• R5 is hydrogen, C1-C4alkyl, phenyl which optionally is substituted by one or more C1-C4alkyl, C1-C4alkoxy or halogen;
• or is (C2-C6alkyleneO)n—R6;
• n is an integer from 1-20;
• R6 is hydrogen, C1-C4alkyl, C2-C5alkenyl or C2-C6alkanoyl;
• R7 is hydrogen, C2-C5alkenyl, C2-C20alkyl which is substituted by one or more OH, NR11R12 or Si(R14)y(OR13)z;
• or is C2-C20alkyl which is interrupted by one or more O or NR15 and optionally is substituted by one or more OH, NR11R12 or Si(R14)y(OR13)z;
• or is C1-C20haloalkyl which optionally is substituted by one or more OH, NR11R12 or Si(R14)y(OR13)z;
• or is C2-C20haloalkyl which is interrupted by one or more O or NR15;
• R8 and R9 independently of one another are hydrogen, C1-C20alkyl;
• C1-C8alkyl substituted by CN, COOR11 or Si(R14)y(OR13)z;
• C2-C8alkyl substituted by one or more NR11R12 or OR11;
• or are C3-C8cycloalkyl, C3-C5alkenyl, phenyl-C1-C4alkyl or phenyl which optionally is substituted by C1-C4alkyl, OR11 or halogen;
• or R8 and R9 together are C3-C7alkylene which optionally is interrupted by one or more O or NR15 and which C3-C7alkylene or interrupted C3-C7alkylene optionally is substituted by one or more C1-C4alkyl or COOR11;
• z is an integer from 0-3;
• y is an integer from 0-3, wherein the sum of y+z is 3;
• R10 is hydrogen or C1-C4alkyl;
• R11 and R12 independently of one another are hydrogen or C1-C4alkyl which optionally is substituted by OH;
• R13 is hydrogen, C1-C4alkyl or Si(R14)(R′14)(R″14);
• R14, R′14 and R″14 independently of each other are hydrogen or C1-C4alkyl;
• R15 and R′15 independently of one another are hydrogen;
• C1-C20alkyl which optionally is substituted by OH, COOR11 or CN;
• or is C2-C20alkyl which optionally is interrupted by one or more O;
• or is C3-C5alkenyl, phenyl-C1-C4alkyl, C1-C5alkanoyl or benzoyl;
• R15a and R15b independently of one another form an aliphatic ring with a carbon atom of A1 or R15a and R15b together are C1-C3alkylene;
• R30 is C2-C8-alkylene optionally interrupted by one or more O;
• A is C2-C20alkylene which optionally is interrupted by one or more O or NR15;
• C2-C20haloalkylene which optionally is interrupted by one or more O or NR15;
• C5-C20cycloalkylene;
• or A is a divalent siloxane
• A1 is C2-C20alkylene which optionally is interrupted by one or more O or NR15;
• and
• X is a x-valent cationic counter ion.