Microwave-Assisted Fluorous Synthesis of 2-Aryl-Substituted 4-Thiazolidinone and 4-Thiazinanone Libraries

Chemistry of Substituted Thiazinanes and Their Derivatives

Thiazinanes and its isomeric forms represent one of the most important heterocyclic compounds, and their derivatives represented a highly potent drug in disease treatment such as, 1,1-dioxido-1,2-thiazinan-1,6-naphthyridine, which has been shown to have anti-HIV activity by a mechanism that should work as anti-AIDS treatment, while (Z)-methyl 3-(naphthalen-1-ylimino)- 2-thia-4-azaspiro[5 5]undecane-4-carbodithioate showed analgesic activity, cephradine was used as antibiotic and chlormezanone was utilized as anticoagulants. All publications were interested in the chemistry of thiazine (partially or fully unsaturated heterocyclic six-membered ring containing nitrogen and sulfur), but no one was dealing with thiazinane itself which encouraged us to shed new light on these interesting heterocycles. This review was focused on the synthetic approaches of thiazinane derivatives and their chemical reactivity.

2,3-Diphenyl-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one

In the title compound, C₂₀H₁₅NOS, the dihedral angle between the phenyl rings is 74.25 (6)°. The six-membered 1,3-thia­zine ring has an envelope conformation with the C atom at the 2-position forming the flap. The crystal structure features weak C—H⋯O inter­actions, which lead to the formation of a tape motif along [110].

Facile method for the combinatorial synthesis of 2,2-disubstituted quinazolin-4(1H)-one derivatives catalyzed by iodine in ionic liquids

A mild and facile method for the combinatorial synthesis of quinazolin-4-(1H)-one derivatives, containing simple 2,2-disubstituted quinazolin-4-(1H)-ones, spirocyclic quinazolin-4-(1H)-ones, spiro-heterocyclic quinazolin-4-(1H)-ones, and dispirocyclic quinazolin-4-(1H)-ones, is described, which results in high yields by using ionic liquids as green media. The method involves the reaction of 2-aminobenzamides with various ketones catalyzed by iodine and provides new quinazolin-4-(1H)-one library for biomedical screening.

Use of cyclohexylisocyanide and methyl 2-isocyanoacetate as convertible isocyanides for microwave-assisted fluorous synthesis of 1,4-benzodiazepine-2,5-dione library

A new protocol in which cyclohexylisocyanide and methyl 2-isocyanoacetate are used as convertible isocyanides for Ugi/de-Boc/cyclization/Suzuki synthesis of biaryl-substituted 1,4-benzodiazepine-2,5-diones has been developed. Ugi reactions of Boc-protected anthranilic acids, fluorous benzaldehydes, amines, and cyclohexylisocyanide or methyl 2-isocyanoacetate were carried out at room temperature. Microwave-promoted de-Boc/cyclization reactions afforded 1,4-benzodiazepine-2,5-diones (BZDs). Suzuki coupling reactions further derivatized the BZD ring by removing the fluorous tag and introducing the biaryl group. A thirty three-member biaryl-substituted BZD library containing four points of diversity was prepared by microwave-assisted solution-phase fluorous parallel synthesis.

Green method for the synthesis of highly substituted cyclohexa-1,3-diene, polyhydroindene, polyhydronaphthalene, isochromene, isothiochromene, and isoquinoline derivatives in ionic liquids

An efficient and green method for the synthesis of highly substituted cyclohexa-1,3-diene, polyhydroindene, polyhydronaphthalene, isochromene, isothiochromene, and isoquinoline derivatives has been developed. The synthesis was achieved by using a multicomponent procedure in ionic liquid media. The features of this procedure are characterized by the following: mild reaction conditions, high yields, one-pot procedures, operational simplicity, and environmentally benign conditions.

Microwave-assisted fluorous synthesis of a 1,4-benzodiazepine-2,5-dione library

Fluorous displaceable linker-facilitated synthesis of 1,4-benzodiazepine-2,5-dione library has been developed. Perfluorooctanesulfonyl protected 4-hydroxy benzaldehydes were used as the limiting agent for Ugi four-component reactions to form condensed products. Postcondensation reactions of the Ugi products generated 1,4-benzodiazepine-2,5-dione ring skeleton. Microwave-assisted Suzuki coupling reactions removed the fluorous tag and introduced biaryl functionality to the benzodiazepine ring. The library scaffold has four points of substitution diversities. The fluorous tag facilitated the intermediate purifications using fluorous solid-phase extraction (F-SPE) and had no negative impact on the reactivity of the Ugi reactions and postcondensation reactions.

Ionic liquid mediated and promoted eco-friendly preparation of thiazolidinone and pyrimidine nucleoside-thiazolidinone hybrids and their antiparasitic activities

Without any catalyst, 2,3-disubstituted-1,3-thiazolidin-4-one derivatives were synthesized efficiently via the three-component reaction of aldehyde, amine and mercaptoacetic acid in [bmim][PF(6)]. The whole procedure is simple and straightforward and no aqueous work-up is needed. By employing this protocol, a series of novel pyrimidine nucleoside-thiazolidin-4-one hybrids were prepared and their preliminary antiparasitic activities were also studied and reported.