Recent Advances in the Chemistry of Benzisothiazoles and Other Polycyclic Isothiazoles

New 5-Substituted Derivatives of Ethyl 2,3-Dihydro-3-oxoisothiazolo[5,4-b]pyridine-2-acetate

“…5-Phenyl derivative (7) was obtained by condensation of 3-dimethylamino-2-phenylacrolein with cyanothioacetamide in refluxing methanol-sodium methoxide for 8 h to give 3-cyano-5-phenylpyridine-2(1H)-thione which was refluxed in 37 % HCI for 8 h to give 7 (52% overall yield). Compound('l)was also prepared in 51% overall yield by treating I,2-dihydro-2-oxo-5-phenyl-3-pyridinecarboxylic acid with phosphorus oxychloride/DMF to give 2-chloro-5-phenyl-3-pyridinecarboxylic acid (10) which was treated with thiourea (5 M) in diethylene glycol for 10 h at 1500C followed by hydrolysis of the isothioureido intermediate with concentrated HCI. While the reaction of 10 with thiourea in boiling water or in diluted HCI at 150 psi gave 7 in very poor yields (<lo%), treatment of 2-bromo-5-methyl-3-pyridinecarboxylic acid with thiourea in boiling water for 3 h gave the 5-methyl derivative (8) …”

Synthesis of novel 2,3‐dihydro‐3‐hydroperoxy‐2‐aryl‐4,5‐diphenylisothiazole 1,1‐dioxides and their epoxidation ability

“…They show biological activities such as antibacterial [5,6], anticonvulsant [7,8], sedative-hypnotic [9], and peptidomimetic [10,11]. Sultams have found application as chiral auxiliaries in several asymmetric processes such as Diels-Alder reactions [12,13], alkylation [14], and dihydroxylation [15] and are used in enantioselective catalysis [16].…”

Sultam and Sultim Structures, Part 5 [1]. Weak Hydrogen Bonds in Molecular Networks of 2-Hetaryl-3-oxosultams in Comparison with 2-Aryl-3-oxosultams

“…Isothiazol-3-(2H)-ones and their 1,1-dioxides are known to exhibit a broad range of biological activities [2 -5], especially the class of N-substituted 1,2-benzisothiazole-3-(2H)-one 1,1-dioxides are pharmaceutically active compounds [4]. Monocyclic 2,4,5-triarylsubstituted isothiazol-3-(2H)-one 1,1-dioxides, which are synthesized by oxidation of the corresponding isothiazolium salts [6], cause inhibition of the human leukocyte elastase (HLE) [7,8].…”