Some reactions with 3-Methyl-1H-naphtho[2,1-b]pyran-1-one

3-Methyl-1H-naphtho[2,1-b]pyran-1-one 1 has been shown to react with various aldehydes to give the styryl derivatives 2. Reaction of 1 with P₂S₅ gave the thio-derivative 3 which reacted with aldehydes giving the thiostyryl-derivatives 4. Hydroxylamine reacted with 1 giving the isoxazole derivative 5. Hydrazine reacted with 2 giving the pyrazole derivative 6. Compounds 2 have been shown to undergo DIELS-ALDER reaction to give the adducts 7, 8 and 9. When 1 was allowed to react with different dicarboxylic acid anhydrides, the phthalide derivatives 10 were obtained, which on reaction with phenol, gave the dihydroxyphthalophenones 11.