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Tin reduction of 3,4,4,5-tetrachloro-4H-1,2,6-thiadiazine afforded perchloro-9-thia-1,5,8,10-tetraazaspiro[5.5]undeca-1,4,7,10-tetraene (10%) and 3,5-dichloro-4H-1,2,6-thiadiazine-4-thione (27%), the structures of which were supported by single crystal X-ray crystallography. Treating the tetrachlorothiadiazine with Ph3P (1 equiv.) afforded the corresponding spirocycle in a useful 66% yield, the degradation of which with BnEt3NCl (0.5 equiv.) afforded densely functionalized 4,5,6-trichloropyrimidine-2-carbonitrile in 81% yield. Rational mechanisms for the formation of products are proposed. © 2017 Elsevier Ltd 58 26 2618 2621

The reactivity of 3,5-dichloro-4H-1,2,6-thiadiazine 4,4-ketals towards nucleophilic substitution or palladium-catalyzed C–C coupling at the C-3/5 positions led to seven new 3,5-disubstituted 4H-1,2,6-thiadiazine ethylene glycol 4,4-ketals and seven 3,5-disubstituted 4H-1,2,6-thiadiazine catechol 4,4-ketals in 83–98% yields. Furthermore, 3,5-diphenyl-4H-1,2,6-thiadiazine ethylene glycol and catechol 4,4-ketals were successfully hydrolysed in conc. H2SO4at 20 °C to afford 3,5-diphenyl-4H-1,2,6-thiadiazin-4-one in 74% and 89% yields. © 2016 Elsevier Ltd 57 30 3307 3310 Cited By :2

Palladium catalyzed direct C-H arylation of 3-bromoisothiazole-5-carbonitrile with aryl/hetaryl iodides in the presence of AgF gave 13 4-aryl/hetaryl-3-bromoisothiazole-5-carbonitriles. The scope of this arylation was investigated and explanations for the limitations proposed. 3-Bromoisothiazole-5-carboxamide was isolated as a side-product, and its formation was attributed to Ag+-catalyzed hydration of the C-5 nitrile. The analogous phenylation of 3-chloroisothiazole-5-carbonitrile and 3-bromoisothiazole-4-carboxamide gave 3-chloro-4-phenylisothiazole-5-carbonitrile and 3-bromo-5-phenylisothiazole-4-carboxamide in 83 and 64% yields, respectively. © 2014 Elsevier B.V. All rights reserved. 38 6796 6802 Cited By :1

[3,5-Bis(dialkylamino)-4H-1,2,6-thiadiazin-4-ylidene]propanedinitriles 6a-c, react with sodium methoxide or ethoxide to give the corresponding 6-alkoxy-4-dialkylamino substituted pyrrolo[2,3-c][1,2,6]thiadiazine-5-carbonitriles 7a-f in variable yields. These new compounds are fully characterised and two rational mechanisms are proposed for their formation. © 2010 Elsevier Ltd. All rights reserved. 66 10 1817 1820 Cited By :9

Treatment of 1,2-bis(4-chloro-5H-1,2,3-dithiazol-5-ylidene)hydrazine 4 with benzyltriethylammonium iodide (1 equiv) affords dicyano-1,3,4-thiadiazole 3 and 5-cyano-1,3,4-thiadiazole-2-carboxamide 5 in 79 and 21% yields, respectively. By using polymer bound triphenylphosphine instead of benzyltriethylammonium iodide the dicyano-1,3,4-thiadiazole 3 can be isolated in 70% yield without chromatography. The reaction of DAMN with Appel salt 8 gave 2-(4-chloro-5H-1,2,3-dithiazol-5-ylideneamino)-2-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)acetonitrile 7 (14%), 2,3-bis-(4-chloro-5H-1,2,3-dithiazol-5-ylideneamino)fumaronitrile 10 (14%), and 2,3-bis(4-chloro-5H-1,2,3-dithiazol-5-ylideneamino)maleonitrile 11 (24%) together with other products. The maleonitrile 11 isomerizes into the fumaronitrile 10 on irradiation at 365 nm. Reaction of aminoacetonitrile with Appel salt 8 gives the (dithiazolylidene)acetonitrile 7 in 33% yield. Treatment of (dithiazolylidene)acetonitrile 7 with polymer bound triphenylphosphine gives tricyanothiazole 6 in 76% yield. A rational general mechanism for the transformation of bisdithiazoles to percyanoheteroles is proposed. © 2009 Elsevier Ltd. All rights reserved. 65 48 9967 9972 Cited By :18

4,5-Dichloro-1,2,3-dithiazolium chloride 1 (Appel salt) reacts in wet DCM, THF or MeCN to give elemental sulfur, dithiazole-5-thione 4, dithiazol-5-one 5 and thiazol-5-one 6. Furthermore the reaction of 2-phenylthiazol-5(4H)-one 12 with Appel salt 1 at ca. 20 °C gives 4-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)-2-phenylthiazol-5(4H)-one 13 (26%) while at ca. 82 °C a new product 2,2′-diphenyl-4,4′-bithiazol-ylidene-5,5′-dione 14 (36%) is additionally isolated. Finally, 4,4′-bithiazolylidene-5,5′-dione 14 is prepared directly by treating 2-phenylthiazol-5(4H)-one 12 with N-chlorosuccinimide. All new compounds are fully characterised and rational mechanisms are proposed for the formation of all key compounds. © 2009 Elsevier Ltd. All rights reserved. 65 34 6859 6862 Cited By :3