A series of novel pyridine-based type I photoinitiators were synthesized. UV spectroscopy revealed absorption characteristics very similar to those of a commercially available hydroxyalkylphenone [2-hydroxy-2-methyl-1-phenyl propan-1-one (1b)]. Photo-differential scanning calorimetry was used to study the polymerization kinetics of lauryl acrylate photoinitiated by the new pyridines. Under a nitrogen atmosphere, a 3-substituted derivative [2-hydroxy-2-methyl-1-pyridin-3-yl-propan-1-one (3b)] gave results comparable to those obtained with 1b. Measurements under air indicated decreased sensitivity toward oxygen quenching reactions. Additionally, pyridine derivatives showed good water solubility (4.9 g/100 mL). Preliminary steady-state photolysis experiments with 2,2,6,6-tetramethyl-1-piperidinyloxy as a radical scavenger were carried out, and the a-cleavage mechanism was found to be the main reaction pathway. The quantum yields of a-cleavage were approximately 0.30 +/- 0.04 for 3b and 0.18 +/- 0.03 for 1b. (C) 2003 Wiley Periodicals, Inc.