Synthesis of photochromic spiroindolinopyrans with extended conjugation

Article abstract of DOI:10.1016/0040-4020(96)00416-4

Unsaturated side chains have been introduced in benzopyran site of parent indolinospiropyran moiety using Wittig reaction under conditions of Phase Transfer Catalysis in a one pot synthesis. The resultant unsaturated photochromic indolinospirobenzopyrans show significant bathochromic shift in the uv region of absorption spectra.