SYNTHESIS OF 3-ALKYLCOUMARINS AND 3-ALKYL-ALPHA,BETA-UNSATURATED DELTA-LACTONES FROM 3-DIETHYLPHOSPHONOCOUMARINS, 3-DIETHYLPHOSPHONOLACTONES AND ALDEHYDES

The treatment of salicylaldehyde 1 and derivatives 2-4 with triethyl p hosphonoacetate 5 in refluxing toluene using piperidine acetate and be ta-alanine affords 3-diethyl phosphonocoumarins 6-9. By hydrogenation of the compounds 6-9, 3-diethylphosphono-3,4-dihydro-=coumarins 10-13 have been obtained. The compounds 10-13 react with the aromatic aldehy des 14-18, under Wittig-Horner conditions, to give 3-alkyl-coumarins 1 9 - 24 in satisfactory yields. The reaction of 3-diethyl-phosphonolact ones 25,26 with isatin 27 and 5-bromoisatin 28, under similar reaction conditions, leads to 3-alkyl-alpha,beta-unsaturated delta-lactones 29 -31.