| abstract |
Compounds of formula (I), wherein A is S or O; x is 0 or 1; a is SR<SUB>10 </SUB>or N(R<SUB>11</SUB>)(R<SUB>12</SUB>); R<SUB>1 </SUB>and R<SUB>2 </SUB>are C<SUB>1</SUB>-C<SUB>24</SUB>alkyl, OR<SUB>10</SUB>, CF<SUB>3 </SUB>or halogen; R<SUB>3</SUB>, R<SUB>4 </SUB>and R<SUB>5 </SUB>are hydrogen, C<SUB>1</SUB>-C<SUB>24</SUB>alkyl, OR<SUB>10 </SUB>or halogen; or two of the radicals R<SUB>11 </SUB>R<SUB>21 </SUB>R<SUB>31 </SUB>R<SUB>4 </SUB>and/or R<SUB>9 </SUB>together form C<SUB>1</SUB>-C<SUB>2</SUB>oalkylene uninterrupted or interrupted by O, S or NR<SUB>13</SUB>; R<SUB>6</SUB>, R<SUB>11 </SUB>R<SUB>8 </SUB>and R<SUB>9 </SUB>are hydrogen, C<SUB>1</SUB>-C<SUB>24</SUB>alkyl; C<SUB>2</SUB>-C<SUB>24</SUB>alkyl which is interrupted one or more times by non-consecutive O atoms and unsubstituted or substituted by OH and/or SH, or R<SUB>6</SUB>, R<SUB>7</SUB>, R<SUB>8 </SUB>and Rg are OR<SUB>10</SUB>; halogen; or phenyl unsubstituted or substituted one or more times by C-Calkyl; R<SUB>10</SUB>, R<SUB>11 </SUB>and R<SUB>12 </SUB>are e.g. hydrogen; X is e.g. (II), and R<SUB>2</SUB>; have one of the meanings given for R<SUB>1 </SUB>and R<SUB>2</SUB>; and R<SUB>3</SUB>', R<SUB>4</SUB>' and Rs' have one of the meanings given for R<SUB>3</SUB>, R<SUB>4 </SUB>and R<SUB>5</SUB>; are suitable as photoinitiators, especially for irradiation with light of relatively long wavelengths |