3-Thiolcoumarin (I) and 3,3'-dithiobis(coumarin) were prepared When I was reacted with various Michael acceptors, some of the intermol. primary addition products reacted further through a sequential intramol. Michael addition with ring closure forming a series of tetrahydrothienobenzopyranone derivatives (e.g. II). The stereochem. of the tricyclic compounds was determine and discussed. The allyl thioethers of I were prepared and subjected to Claisen rearrangement in N,N-dimethylaniline, the expected rearranged products III and IV being obtained. However 3-cinnamylcoumarin thioether under the same condition gives 3-(p-N,N-dimethylamino)thiobenzylcoumarin and other products. Ph cinnamyl thioether reacts similarly giving p-(N,N-dimethylamino)benzyl Ph thioether.

Key words: MERCAPTAN, MOLECULAR STRUCTURE, BROMOHYDROCARBON, BENZOPYRAN P, COUMARIN P, DISULFIDE, STEREOCHEMISTRY, ADDITION REACTION, THIOPHENE P, PROPENE P