The synthesis of the first examples of two new classes of glyoxal bis-dithioacetals: trans-1, 4, 5, 8-tetrathiadecalin and trans-2, 3-bis (methylthio) 1, 4-dithiane, has been performed. The conformation of 2, 2'-bis-1, 3-dithiolane and trans-2, 3-bis (methylthio)-1, 4-dithiane in CDCl3 solution has been studied using 1H NMR techniques. In the first case an antiperiplanar conformation has essentially been found whereas a 83/17 mixture of diaxial ...