Facile Syntheses of 2H-1,2,4-Benzothiadiazine 1,1-Dioxides and 4-Oxo-3,4-dihydroquinazolines from 2-Aminobenzenesulfonamide or 2-Aminobenzamide and Aldehydes in the Presence of Sodium Hydrogen Sulfite

Synthesis and biological activity of novel 3-heteroaryl-2H-pyrido[4,3-e][1,2,4]thiadiazine and 3-heteroaryl-2H-benzo[e][1,2,4]thiadiazine 1,1-dioxides

“…The most common method is the reaction of 2-aminobenzenesulfonamides with carboxylic acids, their halides, or anhydrides [ 14 , 15 ]. Synthesis via the reaction of 2-aminosulfonamides with aldehydes is another method that has been used [ 16 ]. Other authors have reported the reaction of 2-halobenzenesulfonyl chlorides with amidines and aminopyridines in the presence of potassium carbonate [ 17 ].…”

Synthesis and Preliminary Cytotoxic Evaluation of Novel 3,4-Dihydro-2h-1,2,4-Benzotiadiazine-1,1-Dioxide Derivatives

“…Despite this methodology has been used successfully with non substituted 2-aminobenzenesulfonamides (16), and in the preparation of their isostere counterparts 4(3//)-quinazolinones (16,17), it failed for all our cases (Table 1) to generate the 3,4-double bond of desired 2H-1,2,4-benzothiadiazines 3, even at higher temperatures (up to 180°C) or longer heating times (12 h 12, No. 5, 2006 Synthesis and preliminary cytotoxic evaluation of novel 3,4-dihydro-2H-1,2,4-benzotiadiazine-1, 1-dioxide Somehow, the halogen located at C-5 of the sulfonamide affects the double bond generation, cause only a 5% of the unsaturated compound was detected by 'HNMR -typically characterized by a broad singlet NH signal at around 12 ppm-at longer reaction times.…”

“…Initial reports from Ekbom (12) and Freeman (13) consisted in their preparation by condensation of a 2-amino-benzenesulfonamide with an alkyl-orthoformate. Other reported procedures includes acylation of the above with reactive carboxylic acid derivatives followed by a cyclodehydration promoted by heating with base (13,14), direct cyclocondensation with amidines at elevated temperatures (15), and cyclodehydrogenation with aldehydes in the presence of sodium hydrogen sulfite (16). During our research program, directed toward the preparation of novel compounds of the 4(3//)-quinazolinone (17) and l,8-naphthyridine-4-one (18) type with potential cytotoxic-antitumoral activity, we decided to explore the synthesis and biological testing of new 3-aryl-substituted 1,2,4-benzothiadiazine 1,1-dioxides as their isostere analogs.…”

Ionic Liquids: A Class of Versatile Green Reaction Media for the Syntheses of Nitrogen Heterocycles

“…In addition, quinazolinones were also synthesized through reaction of isatoic anhydride with benzamide [198], by intra-molecular aza-Wittig reaction [199], by thermolysis of anil at 300 o C [200] and two-step reaction from benzoyl chloride and 2-aminobenzamide [201]. Furthermore, quinazolinones have also been prepared from 2-aminobenzamide and sodium hydroxide [202], through the solid phase synthesis using variety of Lewis acids [203,204], by microwave [205] and by using various transition metals such as Cu, Ru, Pt, and Pd complexes [206,207]. In recent years, ionic liquids have received much attention for the synthesis of these compounds and many researchers have directed their efforts to the syntheses of these compounds using variety of ionic liquids.…”