An efficient one-pot synthesis of pyrimido[2,1-b][1,3]thiazine derivatives by reaction of activated acetylenes, thiouracils, and isocyanides

Green Synthetic Strategies and Pharmaceutical Applications of Thiazine and its Derivatives: An Updated Review

Thiazines are a sizable class of organic heterocycles that are notable for their skeletal versatility and relative chemical simplicity, making them among the most flexible sources of biologically active compounds. The term "green synthesis" refers to implementing energy-efficient procedures for the nature-friendly production of materials and chemicals using green solvents, catalysts, and suitable reaction conditions. Considering the importance of green chemistry and the outstanding therapeutic profile of thiazines, the present work was designed to review the recent advances in green chemistry-based synthetic strategies of thiazine and its derivatives. The green synthetic approaches, including microwave-assisted, ultrasound-assisted, and various other synthetic methods for thiazine and its derivatives, were discussed and generalized. In addition, applications of thiazine and its derivatives in pharmaceutical sciences were explained with examples of marketed drugs.The discussed sustainable synthetic methods for thiazines and their derivatives could be useful in developing other medicinally important lead molecules. They could also aid in developing new synthetic schemes and apparatuses that may simplify chemical manufacturing processes and enable novel reactions with minimal by-products while questing for optimal, green solvents. This review can help anyone interested in this fascinating class of heterocycles to make decisions about selecting targets and tasks for future research.

Green Synthetic Methods of Oxazine and Thiazine Scaffolds as Promising Medicinal Compounds: A Mini-review

Medical researchers have paid close attention to the green synthesis of oxazine and thiazine derivatives since they provided a lead molecule for the creation of numerous possible bioactive compounds. This review provides more information on green synthesis, which will be very helpful to researchers in creating the most effective, affordable, and clinically significant thiazine and oxazine derivatives that are anticipated to have strong pharmacological effects. This has resulted in the identification of several substances with a wide range of intriguing biological functions. This article's goal is to examine the numerous green chemical processes used to create oxazine and thiazine derivatives and their biological activity. We anticipate that researchers interested in oxazine and thiazine chemicals will find this material to be useful. We anticipate that medicinal chemists looking for new active medicinal components for drug discovery and advance progress will find this review of considerable interest.

Synthesis of Novel Derivatives of (Benz)Imidazo[2,1-b]Pyrimido[4,5-d][1,3]Thiazine

Several derivatives of the novel heterocyclic systems 2-substituted-imidazo- and benzimidazo-[2,1- b]pyrimido[4,5- d][1,3]thiazine have been synthesised through the one-pot cyclocondensation of 2,4-dichloro-5-(chloromethyl)-6-methylpyrimidine with imidazolidine-2-thione and 1 H-benzimidazole-2(3 H)-thione and subsequently substituted by various secondary amines in moderately good yields.

Synthesis of new derivatives of 4-(4-methyl-5H-pyrimido[4,5-b][1,4]thiazin-2-yl)morpholine and 4-methyl-2-(piperidin-1-yl)-5H-pyrimido[4,5-b][1,4]thiazine

Several derivatives of the novel 4-(4-methyl-5 H-pyrimido[4,5- b][1,4]thiazin-2-yl)morpholine and 4-methyl-2-(piperidin-1-yl)-5 H-pyrimido[4,5- b][1,4]thiazine ring systems have been synthesised through cyclocondensation of 5-amino-6-methylpyrimidine-4-thiols and the appropriate α-haloketone in glacial acetic acid under reflux.

Bioactive Thiazine and Benzothiazine Derivatives: Green Synthesis Methods and Their Medicinal Importance

Thiazines are a group of heterocyclic organic compounds that are still largely unexplored for their pharmacological activities. There are different available methods for the synthesis of thiazine derivatives in the literature. In this review, we discuss available methods of thiazine preparation through green synthesis methods. Beside their synthesis, many thiazine derivatives are biologically active and play an important role in the treatment of various diseases and show promising results of varying degrees, where they act as antibacterial, antifungal, antitumor, antimalarial, antineoplastic, antiviral, anti-inflammatory, analgesic and anticancer agents and thus they represent an interesting class of heterocyclic medicinal compounds worthy of further exploration.

Isocyanide-based multicomponent reactions in the synthesis of heterocycles

In this review, we update our previous presentation, underscoring the recent applications of isocyanides as privileged synthons in the synthesis of various heterocyclic compounds, especially focused on those synthesizedviamulticomponent reactions.

In situ generation and protonation of the isocyanide/acetylene adduct: a powerful catalyst-free strategy for multicomponent synthesis of ketenimines, aza-dienes, and heterocycles

In addition to isocyanide-based Ugi, Passerini, van Leusen, and Orru multicomponent reactions, a new class of isocyanide/acetylene-based multicomponent reactions, using zwitterionic adducts, have emerged as powerful methods to synthesize biologically interesting molecules.