Efficient palladium(II)-catalyzed homocoupling of thiazole-4-carboxylic or oxazole-4-carboxylic derivatives

An Overview of the Synthesis and Antimicrobial, Antiprotozoal, and Antitumor Activity of Thiazole and Bisthiazole Derivatives

Thiazole, a five-membered heteroaromatic ring, is an important scaffold of a large number of synthetic compounds. Its diverse pharmacological activity is reflected in many clinically approved thiazole-containing molecules, with an extensive range of biological activities, such as antibacterial, antifungal, antiviral, antihelmintic, antitumor, and anti-inflammatory effects. Due to its significance in the field of medicinal chemistry, numerous biologically active thiazole and bisthiazole derivatives have been reported in the scientific literature. The current review provides an overview of different methods for the synthesis of thiazole and bisthiazole derivatives and describes various compounds bearing a thiazole and bisthiazole moiety possessing antibacterial, antifungal, antiprotozoal, and antitumor activity, encouraging further research on the discovery of thiazole-containing drugs.

Metal-free C–H amination of arene with N-fluorobenzenesulfonimide catalysed by nitroxyl radicals at room temperature

The first C–H amination of arene with NFSI via organocatalysis is disclosed, which can be achieved at room temperature with a broad substrate scope.

NFSI-participated intermolecular aminoazidation of alkene through iron catalysis

An iron-catalysed intermolecular vicinal aminoazidation of alkene with NFSI is reported, with broader alkene scope comparing to previously reported aminoazidation.

Cobalt-Catalyzed Cross-Dehydrogenative C(sp2 )-C(sp3 ) Coupling of Oxazole/Thiazole with Ether or Cycloalkane

Direct C5-alkylation of oxazole/thiazole with ether or cycloalkane has been achieved through a cobalt-catalyzed cross-dehydrogenative coupling (CDC) process in moderate to good yields. This transformation represents the first C(sp² )-C(sp³ ) cross-coupling at the C5-position of the oxazole/thiazole via double C-H bond cleavages. Various functional groups on oxazole/thiazole substrates, as well as water and air, are well-tolerated with this concise and practical protocol, constituting straightforward access to heterocycles with great medicinal significance. A preliminary mechanism involving a radical process has also been proposed.

DDQ-promoted direct C5-alkylation of oxazoles with alkylboronic acids via palladium-catalysed C–H bond activation

The first protocol for the direct C5-alkylation of oxazoles through transition-metal-catalysed C(5)–H bond activation.

Oxidative Direct Arylation Polymerization Using Oxygen as the Sole Oxidant: Facile, Green Access to Bithiazole-Based Polymers

The most appealing oxidant, molecular oxygen, is employed for the first time as the sole oxidant in the transition metal-catalyzed oxidative direct arylation polymerization (C-H/C-H-type DArP), which eliminates by-product formation of stoichiometric metal salts except for water . Compared to conventional approaches, other than the avoidance of an end-capping procedure, the current protocol is remarkably advanced in the aspect of eco-friendliness, step- and cost-economy, and, of special significance, the purity of polymer products. As illustrative examples, six 5,5'-bithiazole-based polymers are synthesized using this new method, demonstrating higher number-average molecular weight (M_n up to 33 700) in better yields (up to 93 %) through only one step. The evolution of C-H/C-H-type DArP from heavy metal salts to O₂ alone as the oxidant could solve the problem of metal residues in polymers, which is considered harmful to the performance of devices.

Diversified syntheses of multifunctionalized thiazole derivatives via regioselective and programmed C-H activation

The sequential construction of diversified multifunctionalized thiazole derivatives through Pd-catalyzed regioselective C-H alkenylation has been accomplished. This versatile approach provides the diversified thiazole derivatives featuring orthogonal substitution patterns at the C-2, C-4 and C-5 positions from mono-substituted (2- or 4-substituted) thiazole derivatives or even more challenging simple thiazole.

Cu(i)-Catalyzed oxidative homo-coupling of thiazoline-4-carboxylates: synthesis of 4,4′-bithiazoline derivatives

Cu(i)-Catalyzed oxidative homo-coupling of thiazoline-4-carboxylates with good functional group tolerance has been developed.