Allergenic alpha-methylene-gamma-butyrolactones. Study of the capacity of beta-acetoxy- and beta-hydroxy-alpha-methylene-gamma-butyrolactones to induce allergic contact dermatitis in guinea pigs.

(+/-)-Tulipalin B was prepared in six steps from phenyl sulfide and ethyl 2-bromopropionate. The sensitizing power in the skin of (+/-)-tulipalin A (1a) and B (1b) and of the beta-acetoxy derivatives (1c) was studied. All are able to induce allergic contact dermatitis (ACD) and give cross-reactions. gamma,gamma-Disubstituted analogues (with a -(CH2)5- chain in the gamma-position) were synthesized and used to induce ACD in guinea pigs: they all were sensitizers and cross-reacted. However no cross-reaction was demonstrated between gamma,gamma-unsubstituted and gamma,gamma-substituted compounds showing a great specificity of ACD.