3-Cyanopyridine-2 -thiones

A Thorpe-Ziegler intramolecular cyclization starting with 3-cyanopyridine-2-thione derivatives leads to the formation of 3-amino-2-(organylsulfinyl)thieno[2,3- ]pyridines in high yields <2006RCB529>. 

Thiophen Analogues of Quinoline. - Pyrolysis of 3-(2-thienyl)propenal O-methyloxime at 650°C in a silica tube gave a 33% yield of thieno[3,2-h]-pyridine.New methods for the synthesis of 3-cyanopyridine-2-thiones... 

Isothia2olo[5,4-6]pyridme.—The synthesis of 2-aminoisothiazoles from n-mer-captonitriles and hydroxylamine-O-sulphonic acid in basic media has been successfully extended to the production of 3-aminoisothiazolo[5,4-6]pyridines (83) from 3-cyanopyridine-2-thiones. ... 

Among these methods, Thorpe isomerization of substituted 2-alkylthio-3-cyanopyridines is of considerable interest. The advantages of this approach are that the starting 3-cyanopyridine-2(l //)-thiones (7) are readily accessible, diverse 3-cyanopyridine-2(l //)-thiones can be used, one-pot procedures can be employed, and the final products are prepared in high yields. The mechanism of this transformation can be represented by the Scheme (1985MI1, 1989MI2) ... 

Examples of the synthesis of thieno[2,3-Z>]pyridines according to method C are scarce. In this case, the synthesis of the starting 3-cyanopyridine-2(l //)-thione, its -alkylation, and cyclization of an intermediate occur as a multicomponent one-pot process. For example, the reaction of thioamides 28 with l-(4-morpho-lino)cyclohexene (29) in anhydrous ethanol followed by treatment with a twofold excess of KOH and then with a-bromo ketones produced thienoquinolines 30 (1997KGS1384). 

In a basic medium pyridines 89 are involved in cascade heterocyclization giving rise to fused pyrimidines 90. The starting compounds 89 can be generated in situ from 3-cyanopyridine-2(l //j-thiones 7 (1997KGS837). 

Litvinov VP, Rodinovskaya LA, Sharanin YA, Shestopalov AM, Senning A (1992) Advances in the chemistry of 3-cyanopyridin-2(lH)-ones, -thiones, and selenones. Sulfur Rep... 

Rodinovskaya LA, Shestopalov AM, Gromova AV, Shestopalov AA (2008) One-Pot synthesis of diverse 4-Di(tri)fluoromethyl-3-cyanopyridine-2(lH)-thiones and their utilities in the cascade synthesis of annulated heterocycles. J Comb Chem 10(2) 313-322 Suzuki H, Sakai N, Jwahara R, Fujiwa T, Satoh M, Kakehi A, Konakahara T (2007) Novel synthesis of 7-fluoro-8-(trifluoromethyl)-lH-l,6-naphthyridin-4-one derivatives intermo-lecular cyclization of an N-silyl-l-azaallyl anion with perfluoroalkene and subsequent intramolecular skeletal transformation of the resulting pentasubstituted pyridines. J Org Chem 72(15) 5878-5881... 

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