4H-l,3-Thiazin-4-ones

Chemical Name 2-(4-Chlorophenyl)tetrahydro-3-methyl-4H-l,3-thiazin-4-one-1,1-dioxide... 

Stirring a chloroform solution of 9a-amino-2-fm-butyl-4,6,7,8,9,9a-hexahy-dropyrido[2,l-b][l,3]thiazin-4-one at 35°C for 64 h afforded 2-tert-butyl-6,7,8,9-tetrahydro-4H-pyrido[l,2-fl]pyrimidin-4-one in 95% yield [89JCS(P1)1231]. 

There have been reports of various 3-cyano-l-p-D-glucopyranosyl- and -1-P-D-galactopyranosyl-pyridin-2-ones and pyridin-2-thiones, along with o-l-arabinopyranosyl- and P-D-xylopyranosyl-3-cyano-2-pyridinethiones. 5-Amino-6-aryl-3-(P-D-gluco-or -galacto-pyranosyl)tetrahydro-2-thioxo-4H-1,3-thiazin-4-ones have been made by elaboration of the appropriate tetra-O-acetyl-P-D-hexopyranosyliso thiocyanates, and l-(2-acetamido-2-deoxy-P-D-glucopyra-... 

H-Benzo-3,l-thiazines, 1,3-thiazin-4-ones, and related compounds. ... 

Several thioureas have been synthesized by ring-opening reactions of heterocyclic compounds such as l,3-dithiolan-2-thiones, 5-arylimino-l,2,4-dithiazolidine-3-thiones, benzoxazole-2-thiones, and 3,1-benzo-thiazine-4-thione derivatives. Similarly, the action of triphenylphosphine on 5-amino-l,2,4-dithiazolo-3-thiones gave thiocarbamoyl isothiocyanates (304). Other thioureas have been obtained by thermolytic decarbonylation of 2-amino-5(4H)-thiazolones and by treatment of 4,5,6,7-tetrahydro-cyclopenta-l,3-dioxin-4-one" and 3-nitrophthalic anhydride with thiourea. ... 

The majority of syntheses of 1,4-thiazines involve the elimination of HL from species of type 11. Precursors of type 11a are not usually isolable compounds but are generated as intermediates. Two methods for the formation of such intermediates have been described one utilizes tetrahydro-1,4-thiazine-3,5-diones as starting materials, and the other requires diacyl sulfides and ammonia. Thus the synthesis of 2/f-l,4-thiazine (6), reported in 1948, was achieved by heating compound 16 at 450°C in the presence of powdered aluminum. Potentially, the procedure may be applied to the preparation of thiazines variously substituted at positions 2 and 6 however, the low yield (13%) achieved for the parent compound is a detraction. It was initially claimed that the reaction of diphenacyl sulfide with ammonia gave 3,5-diphenyl-4H-l,4-thiazine subsequent studies, however, revealed that the product was the 2//-tautomer 3,5-Diaryl-2/f-l,4-thiazines and... 

Dicyanomethylenediphenylcyclopropene and an equimolar amount of mesoionic 3-methyl-2,4-diphenylthiazol-5-one refluxed 8 hrs. in xylene -> product. Y 74%. F. e. s. H. Matsukubo and H. Kato, Soc. Perkin I 1975, 632 4H-l,4-thiazine 1,1-dioxides by cycloaddition-extrusion-ring expansion s. Chem. Lett. 1975, 1153. 

A soln. of 6-phenyl-2,3,4,7-tetrahydro-l,4,5-thiadiazepin-3-one 1,1-dioxide in acetic anhydride refluxed 6 hr. 4-(diacetylamino)-2,3-dihydro-5-phenyl-4H-l,4-thiazin-3-one 1,1-dioxide. Y 50%. I. Sataty, Tetrahedron 28, 2307 (1972). 

H. Mofakham, Z. Hezarkhani, A. Shaabani, J. Mol. Cat. 2012, 360, 26-34. CeUulose-SOjH as a biodegradable solid acid catalyzed one-pot three-component Ugi reaction synthesis of a-amino amide, 3,4-dihydroquinoxalin-2-amine, 4H-benzo [f>][l,4]thiazin-2-amine and l,6-dihydropyrazine-2,3-dicarbo-nitrile derivatives. 

Benzo-l,4-thiazines and Related Compounds.— The chemical behaviour of the Vilsmeier product (111), derived from l,4-benzothiazin-3(4H)-one, has been the subject of detailed studies. Hydrolysis under different conditions affords the acid (112), the aldehyde (114), or the chloro-aldehyde (113), depending on the method of hydrolysis. Treatment of the perchlorate of (111) with DMSO leads to the displacement of the chlorine atom to give the dimethylsulphoxonium derivative (115), while reaction with pyridine proceeds with selective attack at the aminomethylene function, yielding the pyridinium salt (116). This latter reacts readily with aniline in acetic acid medium to give, along with 2-formyl-3-anilino-l,4-benzothiazine (117), the anilinomethylene derivative (120), whose formation probably involves an intramolecular rearrangement of the intermediate pyridinium salt (118), as depicted. 

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