Synthesis of 4-arylthio and alkylthio-thiochromans.

Ring-closure reactions of 3-phenyltiopropionaldehyde (1 a) and its methyl derivatives which were formed by the additions of benzenethiols to acrylaldehydes using acetonitrile as a solvent have been investigated. The reactions of ( 1 a) and its methyl derivatives with a variety of thiols in acetonitrile at room temperature provided 3-plienylthiopropionaldehyde hemithioacetals (2). The reaction of (2) in the presence of sulfuric acid in acetonitrile afforded the corresponding 4-arylthioand alkylthiothiochromans (3 a-i) in good yields.