Newman-Kwart rearrangement

Transformation of phenol to the corresponding thiophenol, a variant of the Smiles reactiom 

Name Reactions A Collection of Detailed Mechanisms and Synthetic Applications, DOI 10.1007/978-3-319-03979-4 192, Springer International Publishing Switzerland 2014 

Ponaras, A. A. Zain, O. In Encyclopedia of Reagents for Organic Synthesis, Paquette, L. A., Ed Wiley New York, 1995,2174—2176. (Review). 

Albrow, V. Biswas, K. Crane, A. Chaphn, N. Easun, T. Gladiah, S. Lygo, B. Woodward, S. Tetrahedron Asymmetry 2Wi3,14,2813-2819. 

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Zonta C, De Lucchi O, Volpicelli R, Cotarca L (2007) Thione-Thiol Rearrangement Miyazaki-Newman-Kwart Rearrangement and Others. 275 131-161... 

Scheme 33. DoM of aryl O-thiocarbamate. Link to the Newman-Kwart rearrangement and consequent S-thiocarbamate cross-coupling.

A Newman-Kwart rearrangement features in a synthesis of 3,8-diiododibenzo-l,2-dithiin which possesses a screw-boat conformation. The substituents allow elaboration of the molecule, though preferably prior to formation of the thiin ring <06TL9135>. 

A Newman-Kwart rearrangement of the O-thiocarbamoy I derivative of a thiacalix[4]arene results in the synthesis of thiacalix[2]thianthrenes 69. The two thianthrene units are linked by two sulfur bridges producing a basket-shaped molecule <07TL5401>. Treatment with... 

Abstract Thione-to-thiol rearrangements represent a general route for the synthesis of sulfur compounds from hydroxyl functionalities. In particular, the Miyazaki-Newman-Kwart rearrangement has been widely used for the synthesis of aromatic thiols from the corresponding phenols. 

Keywords Thermal rearrangement Newman-Kwart rearrangement Aromatic thiols... 

Another description of large scale analysis come from AstraZeneca in a study directed towards the synthesis of a neurokinin inhibitor of the central nervous system [100]. The synthesis inherited from the research stage already contained a Newman-Kwart rearrangement for the introduction of the sulfur atom (Scheme 40). This step was maintained in the reaction scale-up [101,102]. 

Thiacalix[4]arenes can undergo, in principle, all reactions described for calixarenes , including, for instance, the de- or transbutylation or the Newman-Kwart rearrangement ". However, some qualitative differences were found. 

Newman-Kwart rearrangement 1401, 1415 Nickel compounds, as oxidants 1287, 1302, 1304... 

This ring is formed in high yield from a mercapto-amine and either phosgene or disuccinimido carbonate (see Section 1.3). Ethyl potassium xanthate is also effective [3038]. An aminophenol in which the hydroxy group is masked as its dimethyl aminothiocarbamate cyclizes under conditions which generate the amine from the nitro group. The product is the result of a Newman-Kwart rearrangement [B-40, Vol. 3, p. II). 

Methylphenol has been converted by way of the diethylaminothionecarbamate to thediethylaminothiol carbamate, (through the Newman-Kwart rearrangement), which in 80% acetic acid with excess chlorine gave 2-methylbenzene sulphonyi chloride in 95% yield, (characterised in 94% yield as the dimethylamide by reaction with 40% aqueous dimethyiamine) (ref.48). 

Two recent studies have reported a range of reactions performed in all the commercial reactors discussed above. The first of these deals with the high-temperature Newman-Kwart rearrangement (NKR) (Scheme 5.2) performed in all the microwave units, thus giving a direct comparison between them. The second covers a suite of reactions performed using different microwave units, several of which will be discussed further below. In both cases, scale-up to 1 mol or beyond was accomplished with commercially available equipment. Earlier, partial comparisons between several scale-up microwave reactors had also been reported. ... 

This reaction is related to the Newman-Kwart Rearrangement. 

Other references related to the Newman-Kwart rearrangement are cited in the literature. ... 

Scheme 14.14 DoM of O-a lthiocarbamates, their Newman-Kwart rearrangement to S-a lthiocarbamate and their Kumada-Corriu cross coupling [79].

The Newman—Kwart rearrangement has been used for the synthesis of the thiahehcene 40. Heating the bis O-thiocarbamoyl derivative 41, at 285 °C for 45 min affords the thiahehcene 40 in 36% isolated yield (Scheme 17) (2005SYN1109). Although the yield of this rearrangement is modest, this route represents a facile path to substituted thiahelicenes using BINOL derivatives as precursors. 

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