Method for the preparation of symmetrical monoacetals of aromatic 1,2-diketones starting from the corresponding alphahydroxyketones

摘要

The invention relates to a process for the production of symmetrical monoacetals of aromatic 1,2-diketones starting from the corresponding alphahydroxyketones and to their use as photoinitiators of polymerisation by ultraviolet radiations.;According to the process of the invention, protection of the carbonyl group is not operated, and the aromatic alphahydroxyketones react, in the first step of the reaction, with an halogenating agent in presence of N-substituted aliphatic amide or an aliphatic alcohol from 1 to 5 atoms and, in the second step, with an alkaline metal alcoholate or an alcohol. If the carbonylic group is protected, the alphahydroxyketones are first converted into acetals or hydrazones and then into the products of the invention by means of oxidation or acetalisation.