Synthesis of purine‐like ring systems derived from 1,2,6‐thiadiazine 1,1‐dioxide

Abstract

7‐Amino‐1H,4H‐imidazo[2,3‐c][1,2,6]thiadiazine 5,5‐dioxide was prepared by a multi‐step reaction sequence form 3,5‐diamino‐4H‐1,2,6‐thiadiazine 1,1‐dioxide. 7‐Amino‐4H‐furazano‐[3,4‐c][1,2,6]thiadiazine 5,5‐dioxide was obtained by lead tetraacetate oxidation of 3,5‐diamino‐4‐hydroxyimino‐4H‐1,2,6‐thiadiazine 1,1‐dioxide.

Synthesis of fused [1,2,6]thiadiazine 1,1-dioxides as potential transition-state analog inhibitors of xanthine oxidase and guanase

“…(C3H3N302S) C, , N. 4-Amino-l,7-dihydropyrazolo[3,4-c][l,2,6]thiadiazine 2,2-Dioxide (7). A mixture of 2.0 g (18.5 mmol) of 3-aminopyrazole-4-carbonitrile (13),20 50 mL of hexamethyldisilazane, and 0.1 g of (NH4)2S04 was refluxed under N2 overnight. After the addition of 100 mL of toluene, the filtered solution was evaporated to dryness and 50 mL of toluene was added.…”

“…Thus, 12 was trimethylsilylated with refluxing hexa- initially formed was converted to 3 by treatment with aqueous NaOH. The method was extended to the synthesis of the aminothiadiazine derivatives, as exemplified by the synthesis of 7 from 3-aminopyrazole-4-carbonitrile20 (13) by the same three-step process. Compound 7 is another example of this new heterocyclic ring system, pyrazolo [3,4-c][l,2,6]thiadiazine.…”

Novel Arylpyrazino[2,3-c][1,2,6]thiadiazine 2,2-Dioxides as Inhibitors of Platelet Aggregation. 1. Synthesis and Pharmacological Evaluation

“…Thus, the first step is the condensation between 3,4,5-triamino-2 H -1,2,6-thiadiazine 1,1-dioxide ( 1 ) and adequately functionalized dicarbonyl compounds. So, reaction of 1 with symmetric 1,2-dicarbonyl compounds such as benzil, 2,2‘-thenil, 2,2‘-furil, and 2,2‘-pyridil afforded the corresponding 6,7-diphenyl, 6,7-di(2-thienyl), 6,7-di(2-furyl), and 6,7-di(2-pyridyl) compounds 2 , 3 , 4 , and 5 , respectively (Scheme ).…”

Novel Arylpyrazino[2,3-c][1,2,6]thiadiazine 2,2-Dioxides as Platelet Aggregation Inhibitors. 2. Optimization by Quantitative Structure−Activity Relationships

“…The synthesis of N (1) H -pyrazinothiadiazines was carried out from 46 with 1,2-dicarbonyl compounds, α-keto aldehydes, and α-hydroxyimino ketones (Table ). Reaction of 46 with 4,4‘-dimethoxybenzil, 3,3‘-dimethoxybenzil, 4,4‘-dichlorobenzil, 2,2‘-dichlorobenzil, 4,4‘-difluorobenzil, and 4,4‘-dibromobenzil ( 47a − f ) afforded the corresponding 6,7-bisarylpyrazinothiadiazines 48 − 53 (Scheme ).…”