Synthesis of novel acetal thia-cage compounds

The synthesis of novel acetal this-cage compounds has been accomplished by the direct substitution for the oxygen atom by the sulfur atom in the react ion of the acetal groups of era-cages with Lawesson reagent (LR). Reaction of the tetraoxa-cage compound 2 with LR in dichloromethane at 25 degreesC s equentially gave the monothia-, dithia-, trithia-, and tetrathia-cage compo unds 3, 6, 7, and 9. The reaction mechanism for the conversion from era-cag es into thia-cages was proposed. The diacetal trioxa-cages 18-20 and 24-26 were also transformed into the thia-cages 21-23 and 27-29, respectively. Re action of the trioxa-cages 34 and 35 with LR under the same reaction condit ions gave the thia-cages 36 and 37 with the carbonyl group intact. Treatmen t of the pentaoxa[5]-peristylane 40 with LR in chloroform under supersonic shaking at refluxing temperature gave the monothia[5]peristylane 41 and the dithia-[5] peristylane 42. Attempts to synthesize the thia[5]-peristylanes from the tetraoxa-cage 51 and the transformation from the parent (unsubsti tuted) pentaoxa[5]peristylane 46 to the thia-cages have been made. Reaction of the pentaoxa[5]-peristylane 40 with P2S5 in refluxing toluene gave 41, 42, and a rearrangement product 47. The synthesis of new heterocyclic cage compounds 59 and 60, which contain oxygen, nitrogen, and sulfur atoms in th e same molecule, was also accomplished.