Synthesis and structural studies of a new class of heterocyclic compounds: 1,2,4-Pyridothiadiazine 1,1-dioxides, pyridyl analogues of 1,2,4-benzothiadiazine 1,1-dioxides

3-Alkylamino-pyrido[4,3-<I>e</I>]-1,2,4-thiadiazine 1,1-dioxides as Potent K<SUB>ATP</SUB>-Channel Activators: Structural Study and Influence of Stereochemistry

“…We collected and compared UV, 13 C NMR and X-ray data for these selected compounds. The study demonstrates that, as described for 3-alkyl-1,2,4-pyridothiadiazine 1,1-dioxides and for diazoxide (Bandoli & Nicolini 1977;de Tullio et al 1995), 3-alkylamino-pyrido[4,3-e]-1,2,4-thiadiazine 1,1-dioxides without an alkyl group in the 2 or 4 position appear to exist preferentially under the tautomeric form I (Figure 4). Thus, the hydrogen atom of the thiadiazine ring is located on the nitrogen atom in the 4 position and these compounds are de®ned as 4H tautomers (Form I, Figure 4).…”

4H-1,2,4-Pyridothiadiazine 1,1-Dioxides and 2,3-Dihydro-4H-1,2,4-pyridothiadiazine 1,1-Dioxides Chemically Related to Diazoxide and Cyclothiazide as Powerful Positive Allosteric Modulators of (R/S)-2-Amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic Acid Receptors: Design, Synthesis, Pharmacology, and Structure−Activity Relationships

“…The synthesis of 4 H -pyrido[3,2- e ]-1,2,4-thiadiazine 1,1-dioxides ( 29 , 30 ) and 2,3-dihydro-4 H -pyrido[3,2- e ]-1,2,4-thiadiazine 1,1-dioxides ( 31 − 34 ) is illustrated in Scheme . 3-Aminopyridine-2-sulfonamide ( 28 ) was reacted with orthoesters to give the unsaturated compounds ( 29 ) . 4 H -Pyrido[3,2- e ]-1,2,4-thiadiazine 1,1-dioxide ( 29a ) was converted by alkylation to the 4-substituted derivatives ( 30 ).…”

“…The synthesis of 4H-pyrido[2,3-e]-1,2,4-thiadiazine 1,1-dioxides (12) has been previously described. 37 2,3-Dihydro-4H-pyrido[2,3-e]-1,2,4-thiadiazine 1,1-dioxides (13) were obtained from ring closure of the appropriate 2-aminopyridine-3-sulfonamide (11) with paraformaldehyde or acetaldehyde in the presence of hydrochloric acid as the catalyst (Scheme 1).…”

Crystal structure of 2-dimethylamino-1-methyl-1H-quino[4,3-e]-1,2,4-thiadiazine 4,4-dioxide, C13H14N4O2S

“…Significant biological activity of benzo-and pyrido-1,2,4-thiadiazine S,S-dioxides as potassium channel openers [2][3][4][5][6][7] has turned the medicinal chemists' attention to other areno-and heteroareno-fused1,2,4-thiadiazine S,S-dioxides as possible candidatesfor therapeuticapplication.The pharmacologicalactivity of this class of compounds maybeaffected by the shape of the molecule. The thiadiazine ring of 2-dimethylamino-1-methyl-1H-quino [4,3- (2) 4e 0.6329(2) 0.43974 (7) 0.7206 (2) 0.0141 (7) 0.0102 (7) 0.0120 (7) 0.0025 (5) 0.0015 (5) 0.0015(5) C(4A) 4e 0.4771(2) 0.31371 (7) 0.6805 (2) 0.0117 (7) 0.0132 (7) 0.0121 (7) 0.0007 (5) 0.0021 (5) -0.0008(5) C (5) 4e 0.4299(2) 0.24840 (7) 0.7068 (2) 0.0126 (7) 0.0142 (7) 0.0156 (7) -0.0016(5) 0.0035 (5) 0.0005(6) C(6A) 4e 0.6703(2) 0.20997 (7) 0.6113 (2) 0.0142 (7) 0.0134 (7) 0.0108(6) 0.0005(5) -0.0005(5) 0.0002(5) C (7) 4e 0.7651(2) 0.15474 (7) 0.5709(2) 0.0219 (7) 0.0106 (7) 0.0147 (7) 0.0011(6) 0.0010(6) -0.0005(6) C (8) 4e 0.9192(2) 0.16237 (7) 0.5143(2) 0.0206(8) 0.0154 (7) 0.0155 (7) 0.0069(6) 0.0020(6) -0.0022(6) C (9) 4e 0.9893(2) 0.22553(8) 0.5002(2) 0.0143 (7) 0.0206(8) 0.0170 (7) 0.0026(6) 0.0036(6) -0.0015(6) C (10)…”