Preparation method of copolymerizable photoinitiators

An intermediate for preparing (meth)acrylated photoinitiators according to Formula (I):

• wherein:
• R1 is selected from the group consisting of hydrogen and a methyl group;
• A represents a group including at least one photoinitiating moiety selected from the group consisting of benzil ketals, α,α-dialkoxyacetophenones, α-hydroxyalkylphenones, α-aminoalkylphenones, acylphosphine oxides, bis-acylphosphine oxides, acylphosphine sulfides, α-haloketones, α-halosulfones, phenylglyoxalates, benzophenones, thioxanthones, and 1,2-diketones;
• L represents a n+o-valent linking group including at least one carbon atom, but containing not more than 20 carbon atoms;
• n and o each independently represent an integer from 1 to 4;
• p is equal to 1;
• X represents a group selected from the group consisting of Cl, Br, I, and R2SO3;
• and
• R2 represents an optionally substituted group selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkaryl group, an aralkyl group, an aryl group, and a heteroaryl group.

A method for the preparation of an intermediate according to Formula (I) by reacting a starting material according to Formula (II) with an acid chloride according to Formula (III) in an aprotic solvent using an inorganic base or a salt of a carboxylic acid:

• wherein:
• R1 is selected from the group consisting of hydrogen and a methyl group;
• A represents a group including at least one photoinitiating moiety selected from the group consisting of benzil ketals, α,α-dialkoxyacetophenones, α-hydroxyalkylphenones, α-aminoalkylphenones, acylphosphine oxides, bis-acylphosphine oxides, acylphosphine sulfides, α-haloketones, α-halosulfones, phenylglyoxalates, benzophenones, thioxanthones, and 1,2-diketones;
• L represents a n+o-valent linking group including at least one carbon atom;
• n and o each independently represent an integer from 1 to 4;
• p is equal to 0 or 1;
• X represents a group selected from the group consisting of Cl, Br, I, and R2SO3;
• and
• R2 represents an optionally substituted group selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkaryl group, an aralkyl group, an aryl group, and a heteroaryl group.