Monomers with a high refraction index based on acryloyl derivatives of spirocyclic piperidin-4-one thioacetals

Dithioazaspiroheterocyclic derivatives are synthesized by condensing dithiols with piperidin-4-one in the presence of catalytic amounts of Lewis acids. Acrylic dithioazaspiroheterocyclic derivatives are obtained by the reaction with acryloyl chloride. The polymerization of monomers yields transparent polymer films of optical quality. The refractive indices for the synthesized monomers and polymers are in the range of $n$ = 1.59–1.64.