Thiabenzenes. IV. 1- and 2-Thianaphthalenes and 10-Thiaanthracenes. Evidence for Cyclic Conjugation

Ylide character and stability of heterocyclic benzenes

“…Among the ylides, thiabenzene reported by Price and Suld [19] is of interest to chemists owing to in situ generation and Stevens's rearrangement to thiopyrans [20][21][22][23][24]. This ylide has partly aromatic and ylide character.…”

New method for the preparation of dibenzo[b, f][1,4]thiazepines

“…9H-Thioxanthen-9-ol (2a) was prepared according to the reported literature method [5]. 9-Substituted 9H-thioxanthen-9-ols 2b-e were prepared by the reaction of thioxanthen-9-one (1) with alkyl and phenyl Grignard reagents in ether under reflux conditions [5][6][7].…”

“…9H-Thioxanthen-9-ol (2a) was prepared according to the reported literature method [5]. 9-Substituted 9H-thioxanthen-9-ols 2b-e were prepared by the reaction of thioxanthen-9-one (1) with alkyl and phenyl Grignard reagents in ether under reflux conditions [5][6][7]. It is known that the isolation of 9-substituted SCHEME 1 alcohols is generally unsuccessful [7,8], but 9-methyl and 9-isopropyl-thioxanthen-9-ols 2b and 2d could be obtained in 84% and 95% purity, respectively, and 9-ethyl-and 9-phenyl-thioxanthen-9-ols 2c and 2e could be isolated in 88% and 65% yields, respectively, by recrystallization from the reaction mixtures.…”

“…The driving force for such migration may be responsible for the formation of imino thioxanthylium cations 4. It is well known that thioxanthene-9-ols react with sulfuric acid or perchloric acid to produce the corresponding thioxanthylium cations [5,6,11]. Tamura et al have reported that thioxanthene N-( p-toluenesulfonyl)sulfimide and 9-substituted thioxanthene N-( p-toluenesulfonyl)sulfimide undergo rearrangement to 9-N-( ptoluenesulfonamido)thioxanthene [12].…”

“…The compounds 2b-e could not be isolated by silica-gel column chromatography. But the compounds 2c and 2e could be isolated by recrystallization from the reaction mixtures [5][6][7].…”