DERIVATIVES OF THIACYCLOBUTENE (THIETE) .4. THERMAL DECOMPOSITION OF A NAPHTHOTHIETE SULFONE . AN OXIDATION - REDUCTION REACTION AND FORMATION OF A CYCLIC SULFINATE ESTER (SULTINE)2-4

Pyrolysis of 3,8-diphenyl-2H-naphtho[2,3-b] thiete 1,1-dioxide, 1, at 360-400° for 5 min in a nitrogen atmosphere gives two principal organic products* which'are thiophene derivatives: 14H-benzo[b]benzo[3,4]fluoreno-[2,1-d]thiophen-14-one (2) and 14H-benzo[&]benzo[3,4]fluoreno[2,1-d]thiophene (3). Sulfur dioxide is not evolved in any significant amounts and no evidence for formation of a naphthocyclopropene was observed. When the pyrolysis is done in the presence of 9,10-dihydroanthracene, the reaction took a completely different course yielding 78-81% cyclic sulfinate ester or sultine, 4,9-diphenyl-3H-naphth[2,3-c]-2,1-oxathiole 1-oxide (6). The cyclic sulfinate by itself decomposes on pyrolysis to the two thiophene derivatives obtained from the naphthothiete sulfone. © 1969, American Chemical Society. All rights reserved.