Double-head haptens. Synthesis of and experimentally induced contact sensitivity to substances containing two unrelated haptens, pyrocatechol and alpha-methylene-gamma-butyrolactone, in the same molecule.

A "double-head" hapten containing a pyrocatechol and an alpha-methylene-gamma-butyrolactone moiety (3) and "monofunctional haptens" with either one of these moieties (18 and 19) connected by a six-carbon chain have been synthesized, and their sensitizing capacity was tested on guinea pigs. In the "double-head" hapten, only the pyrocatechol end is "recognized". A possible interpretation of the biological results is offered.