Thiolane ring

One of the more interesting reactions involving the reduction of a sulphone was recently described in a paper87 that reported on a synthetic approach to biotin. The molecule in question contains a sulphone as part of a thiolane ring that is fused to a cyclic urea. As outlined in equation (33), either functionality can be reduced depending on the selection of... 

An interesting reaction related to the ring expansions of penicillin S-oxides (208) was observed in the thermal rearrangement of 2,2,4A-tetramethyl-thiethan-3-one 1-oxide to the five-membered thiolane ring 209. Oxidation attempts of these thermally unstable thietanone oxides led via ring opening to the more stable heterocycle. The reaction mechanism (Scheme 11) was... 

Oxathiane 2-oxides aie fonned by the oxidative ring expansion of 2-alkylthio-2-benzylthiolane 1-oxides brought about by [bis(trifluoroacetoxy)iodo]benzene. That the reaction is only successful with the (lR )-diastereoisomeis is attributed to chelation between the nucleophilic S and O atoms and the hypervalent iodine <99EJ0943>. A diazo-mediated thiolane ring expansion is the key step in a synthesis of the acenaphtho-[U-b][l,4]oxathiine system <99JCS(P2)755>. 

The intensity of the thiolanes-thiols C28-C30 on the FPD trace is exagerated because of the two sulfur atoms carried by thiolane-thiols and because of the quadratic response of the FPD detector. The mass-spectra of the C30 thiolane-thiol, displays the fragments m/z 55 (100%), m/z 87 (62%) the typical thiolane ring, a fragment m/z 451 (17%) which corresponds to the C30 thiolane, and a molecular ion M+ 484 (60%) which could be result of the adjonction of a thiol (S-H) to the C30 thiolane. The molecules eluting in doublets with the thiolane-thiols are not identified. The C20 thiophenic isoprenoids are also present, with the compound I dominating. 

The n-alkyl thianes and thiolanes are thermally interconvertible, with the equilibrium shifted toward the thiolane side. Also, the thiolane ring can move along the n-alkyl side chain hopping by three carbon atoms until it reaches a terminal position (11). For this reason the original thiane/thiolane distribution in the asphaltene molecule before its thermal breakup could have been somewhat different from that in the pyrolysis oil. 

To determine the three-dimensional structure of iV-phenylthiolano[3,4-rf]thiazolidine-2-thione 5,5-dioxide (13), an X-ray diffraction study was carried out. The thiazolidine ring is planar, while the thiolane ring has an envelope configuration, presumably the result of the effect of the thiazolidine ring portion (82CHE668). 

Sodium or ammonium salts of 1,1-dithiols have been used as 1,3-S,S-dinucleophiles for the annelation to the thiolane ring (Scheme 19) to quinoxaline (78USP4075209). 

Biotin 3 (vitamin H) occurs in egg yolk and in yeast. It promotes the growth of microorganisms. In biotin, an imidazolidine ring is condensed with a thiolane ring. Several syntheses have been elaborated [125]. Some start from the proteinogenic amino acid (jR)-cysteine ... 

The presence of excess tetrafluoroethylene promotes reaction of the fluorocarbon radical end of 1 with another molecule of tetrafluoroethylene to form a new diradical, 2. Stabilization of 2 occurs by intramolecular attack of the carbon radical end on sulfur with formation of a favored thiolane ring, 3, and displacement of the sulfur chain. Yields of 20% of 3 have been attained. 

In sulfides with more than one sulfur center, more ns bands are observed (Fig. 9). In the propellanes 1-5 two thiolane rings are sterically fixed. The distance between the sulfur atoms varies slightly, from 4.6 A in 5 to J to 4.9 A in i. The PE data for / to 3 are summarized in Fig. 11... 

Late degradation of thiolane-ring frogments to yield CH3SH, H2S. S and SOf... 

The structures of several natural products containing a thiolan ring have been determined. Among these are breynolide (30), which is a degradation product of a bio-active sulphur-containing glycoside, and several related alkaloids, e.g. thiobinupharidine (31), isolated from Nuphar plant material. ... 

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