Dihydrobenzo b thiophene

In contrast, the thiophenone (204) undergoes a stereospecific conrotatory photocyclization via the enol (205) to give cis fused dihydrobenzo[b] thiophen (206).165 Initial nitrogen-sulfur bond homolysis is believed to be responsible for the photoisomerization of isothiazol-3(2//)-ones to thiazol-2(3//)-ones.166... 

The catalytic hydrogenation of benzo[b]thiophene to 2,3-dihydrobenzo[b]thiophene using both a PdS catalyst and a rhodium catalyst have been reported (equation 116). Fish and coworkers have also accomplished this reduction using a ruthenium catalyst. ... 

Dihydrobenzo[b]thiophene 1,1-dioxide undergoes electrochemical cleavage of the aryl-sulfur bond,21 to give the sulfinate anion,... 

In previous reviews, thiooxindole (benzo[b]thiophen-2(3//)-one) and thioindoxyl (benzo[f>]thiophen-3(2/f)-one) have been discussed in the sections dealing with hydroxybenzo[f>]thiophenes.1,2 Because they are now known to exist mainly as the oxo tautomers, tradition has been broken, and they are here discussed as oxo derivatives of 2,3-dihydrobenzo[b]thiophene. To prevent confusion, a few 2-substituted thioindoxyls, which are known to be predominantly enolic, are referred to as derivatives of the oxo... 

Dihydrobenzo[b]thiophene may be obtained by reduction of ben-zo[b]thiophene (Section III,A,1) by treating 2-o-(benzylthio)phenyIethanol with SOCl2-pyridine (91%),208 and by cyclization of o-(methylthio)phenyl-carbene at 250°C (45%) the last procedure is mainly of academic interest.304 Substituted phenyl vinyl sulfides undergo photocyclization to the expected... 

Ruthenium clusters were evaluated for catalytic activity for hydrodesulfurization (HDS) of benzo[b]thiophene. At 423 43 K and 100 atm, hydrogen benzo[b]thiophene was converted to 2,3-dihydrobenzo[b]thiophene and 2-ethylthiophenol. The best catalyst precursor was H4Ru4(CO)g(PPh3)4, which gave 81% conversion to 2,3-dihydro-benzo[b]thiophene after 384 h at 443 K about 5% ethylbenzene was also formed, showing some HDS activity. The clusters were more active than the monometallic precursor Ru(CO)3(PPh3)2. However, the reaction conditions are rather severe and the involvement of decomposition products is very possible. ... 

C-Dihydrobenzo[b]thiophen-4(50)-one 2,3-Dihydro-4C-1-benzothiopyran-4-one 4,5-Dihydro-2-benzyl-1C-imidazole... 

The principal mechanisms proposed for the heterogeneous HDS of a prototypical thiophenic molecule, namely benzo[b]thiophene (BT), are illustrated in Scheme 1. The hydrogenation of C-C double bonds occurs in step a, involving the regioselective reduction of BT to dihydrobenzo[b]thiophene (DHBT), as well as in step e, where styrene is reduced to ethylbenzene [1]. 

Allenmark and coworkers also studied the asymmetric sulfoxidation catalyzed by vanadiumcarboxy)phenyl methyl sulfide and 2-(carboxy)vinyl methyl sulfides [74, 79]. 

Dihydrobenzo[b]thiophene-2-oxide is heated in a sublimation apparatus with aluminum oxide in vacuum, resulting in the sublimation of benzo[c]thiophene. The compound is isolated as colorless crystals of mp 53-55 °C. It is thermally unstable and decomposes, even at — 30°C under nitrogen, within a few days. Its stability is increased by substituents in the 1,3-positions as in the case of benzo[c]furan. 

Under the reducing conditirms, thiophene and benzo[f>]thiophene are readily and smoothly converted into tetrahydrothiophene and 2,3-dihydrobenzo[b]thiophene with cOTiversion rates of 85% and 86%, respectively. However, for the 2-methylthiophene, the reaction went more slowly, and the conversion rate was only 11% under the same conditions (Table 6). Possible reasons for this are that substituents at C-2 or C-3 reduce the jt-acceptor character of the olefin and sterically hinder the f/ -(C,C)-coordinati(Mi mode as well. In addition, electron-donating alkyl groups enhance the dmior ability of the sulfur atom, thereby favoring S-coordination. 

Dihydrobenzo[b]thiophene-l-oxide, Z 7.13 2-Mercapto-2-phenylacetic acid, A 19.6... 

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