Synthesis of new thiazine and thiazole derivatives via cyclization reactions; investigating their electronic properties and determination of antioxidant properties

Abstract

4-[2,4-dimethoxyphenyl]-6-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl) (phenyl) methanone (1) have been prepared by Biginelli three-component cyclocondensation reaction of catalyzed with p-toluene sulfonic acid in ethanol. Pyrimido[2,1-b]thiazine (2) and thiazolo[3,2-a]pyrimidine (3) derivatives were obtained by a simple one-pot condensation reaction of starting compound 1 and 3-bromopropionic acid, bromoacetic acid and, respectively. By performing the reactions of compound 3 with heteroaromatic and aromatic aldehydes, arylidine-bicyclic thiazolo pyrimidine compounds (4-9) were synthesized. Theoretical calculations and molecular electrostatic potential maps of all synthesized compounds were performed using the Gaussian software package Density Functional Theory (DFT/6-31G: B3LYP). In addition, studies were carried out to determine the antioxidant properties of all the compounds obtained by the DPPH method, and compound 1 was found to be the most effective compound. The structures of the newly synthesized compounds were analyzed using spectroscopic methods such as IR, 1 H, and 13 C.

A review on pyrimidine‐based derivatives: Synthesis and their biological application

“…The % inhibition of 77 was 91.3 with respect to standard vitamin C. Ergan et al found the antioxidant property of one of the compounds 78 using the DPPH method [52]. This thioxopyrimidine compound exhibited the highest effectiveness among all the tested compounds; the inhibitory effect was 27%.…”

“…These interactions are essential for the proper functioning of nucleic acids, the transmission of genetic information, and a wide range of other cellular processes (Figure 3) [46]. Additionally, pyrimidine derivatives have a wide range of biological properties in the therapeutic industry, including antimicrobial [47], antibacterial [48], antifungal [49], anti‐inflammatory [50], antitumor [8], anticancer [51], antioxidant [52], antihypertension [53], anti‐HIV [54], antimalarial [55], antiviral [56], insecticide [57], antiplasmodial [58] activities.…”

Lewis base-catalyzed cascade [4 + 2]-annulation reaction of N-alkoxy acrylamides and acyl isothiocyanates: facile access to 2-imino-1,3-thiazinone derivatives

“…Highly functionalized 2-imino-1,3-thiazinones are ubiquitous subunits that are widely present in a vast array of natural products and biologically active molecules. 1 As exemplified in Scheme 1, BTZ043 and its closest congener PBTZ169 have been found to be anti-tuberculosis agents. 2 Compound I displays significant antifungal activity against Aspergillus niger and Fusarium oxysporum.…”

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“…Some of the thiazole molecules also showed inhibition against SARS-CoV-2 virus disease 14,15 . Several procedures for synthesizing thiazole derivatives are described in the literature [16][17][18][19][20][21][22][23] .…”