1,3,3-Trimethyl-2-methyleneindoline → HCID 22336199, compound

Participants

Reaction Conditions

Reaction Steps

A solution is prepared of 2.17 g. (0.0295 mole) of 2-hydroxy-6-nitro-1-naphthaldehyde in 80 cm3 of hot ethanol, to this is added 1.73 g. (0.0295 mole) of 1,3,3-trimethyl-2-methyleneindoline and the mixture is heated for two hours at boiling temperature under reflux. The mixture is then cooled to 0° C. and a precipitate of indolinespiropyran is obtained. This is filtered and dried. The composition has a melting point of 234° C. The product is recrystallized twice from benzene and the melting point is increased to 240°-241° C. The purified product weight is 1.34 g. which represents a recovery of 36%.

Provenance & Evidence