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1,2,4,6-Thiatriazine 1,1-dioxides, tautomers

The 1,2,4,6-thiatriazine system is the most common in all the oxa- and thi-atriazine series, and some investigations of the tautomeric behavior of 1,2,4,6-thiatriazine 1,1-dioxides 135, which can exist as N[2(6)]H 135a and N(4)H 135b tautomers (Scheme 39), have been performed. [Pg.292]

The existence of tautomers B and C rather than A for 3,5-diamino-l,2,4,6-thiatriazine 1,1-dioxide (145) (7OCRV593) has been claimed without conclusive evidence. However, the existence of tautomer A is more likely on the basis that it occurs in thiatriazine 64a and in related thiadiazine Ila (Section II,A,5). In any case, an NMR study is necessary. [Pg.159]

Some investigations of the tautomeric behavior of 1,2,4,6-thiatriazine-l,1-dioxides 71, which can exist as N[2(6)]H 71a and N(4)H 71b, have been performed. The parent compound (R = H) exists predominantly in the 4//-form (71b), according to NMR data (and comparison with the 4-Me derivative). The symmetrical structure was also established for the 3,5-di(trifluoromethyl) derivative 71b (R= CF3) on the basis of a unique signal in the F NMR spectrum. Ad initio calculations also indicated the 4//-tautomer 71b to be more stable than 71a by S.SkcalmoP (STO-3G ) or 2.8kcalmor (3-21G ) <2001AHC(81)253>. [Pg.748]


See other pages where 1,2,4,6-Thiatriazine 1,1-dioxides, tautomers is mentioned: [Pg.155]    [Pg.158]   
See also in sourсe #XX -- [ Pg.81 , Pg.292 ]

See also in sourсe #XX -- [ Pg.81 , Pg.292 ]

See also in sourсe #XX -- [ Pg.81 , Pg.292 ]

See also in sourсe #XX -- [ Pg.81 , Pg.292 ]




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1,2,4,6-Thiatriazines

Tautomer

Tautomers

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