One-Pot Synthesis of Photochromic 6′-Amino-Substituted Spirooxazines from 1-Nitroso-2-naphthol Zinc Chelate and Indoline Base

Abstract

A series of spirooxazine derivatives containing nitrogen heterocycles were synthesized through the condensation of 2-methylene-1,3,3-trimethylindoline derivatives with the zinc salt of 1-nitroso-2-naphthol using ethanol as solvent. The method is simple, starts from readily accessible and inexpensive reagents, and leads to the synthesis of 6′-substituted spirooxazines in moderate to good yields. We simplified the workup and found that, for some target compounds, recrystallization can effectively improve efficiency of the separation and purification.

Key words

spirooxazines - heterocycles - condensation - photochromism - one-pot synthesis

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