Synthesis, X-ray crystal structure, Hirshfeld surface analysis and computational investigation into the potential inhibitory action of novel 6-(-tolyl)-2-((-tolyl)thio)methyl-7-[1.2.4]triazolo[5,1-][1,3,4]thiadiazine inhibits the main protease of COVID-19.

In recent times, the novel coronavirus disease (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has now become a worldwide pandemic. With over 71 million confirmed cases, even though the effectiveness and side effects of the specific drugs and vaccines approved for this disease are still limited. Scientists and researchers from all across the world are working to find a vaccine and a cure for COVID-19 by using large-scale drug discovery and analysis.

Crystal structure and Hirshfeld surface analysis of ethyl 2-({5-acetyl-3-cyano-6-methyl-4-[()-2-phenyl-ethen-yl]pyridin-2-yl}sulfan-yl)acetate.

In the title mol-ecule, CHNOS, the styryl and ester substituents are displaced to opposite sides of the plane of the pyridine ring. In the crystal, C-H⋯O hydrogen bonds form chains extending parallel to the axis direction, which pack with partial inter-calation of the styryl and ester substituents. A Hirshfeld surface analysis indicates that the most significant contributions to the crystal packing are from H⋯H (43.

Synthesis and Characterization of Novel Functionally Substituted Planar Pyrimidothienoisoquinolines and Nonplanar (3a, 4, 9a)-pyrazolo[3,4-]isoquinolines.

7-Acetyl-8-aryl-4-cyano-1,6-dimethyl-6-hydroxy-5,6,7,8-tetrahydroisoquinolin-3(2)-thiones , are prepared and dehydrated to give 7-acetyl-8-aryl-4-cyano-1,6-dimethyl-6-hydroxy-7,8-dihydrodroisoquinolin-3(2)-thiones , via a novel method by heating with acetyl chloride in acetic acid. The reaction of both compounds , and , with -aryl-2-chloroacetamides - under two different conditions gave the same corresponding products, 7-acetyl-8-aryl-3-(-aryl)carbamoylmethylsulfanyl-4-cyano-1,6-dimethyl-7,8-dihydroisoquinolines -, in high yields. On treatment of compounds ,, in methanol with a slightly excess molar amount of sodium methoxide, they underwent intramolecular Thorpe-Ziegler cyclization followed by spontaneous aromatization, providing the planar 7-acetyl-1-amino-6-aryl-2-(-aryl)carbamoyl-5,8-dimethyl-8,9-dihydrothieno[2,3-] isoquinolines ,, in good yield.

Synthesis, Characterization, and Crystal Structure of Some New Tetrahydroisoquinolines and Related Tetrahydrothieno[2,3-]isoquinolines.

The starting compounds 7-acetyl-8-aryl-4-cyano-1,6-dimethyl-6-hydroxy-5,6,7,8-tetrahydroisoquinoline(2)-3-thiones were synthesized and reacted with some -aryl-2-chloroacetamides in the presence of sodium acetate to produce 7-acetyl-8-aryl-3-(arylcarbamoylmethylsulfanyl)-4-cyano-1,6-dimethyl-6-hydroxy-5,6,7,8-tetrahydroisoquinolines . Upon heating in ethanol containing sodium ethoxide, they underwent intramolecular Thorpe-Zeigler cyclization, affording the corresponding 7-acetyl-1-amino-6-aryl-2-(-arylcarbamoyl)-5,8-dimethyl-8-hydroxy-6,7,8,9-tetrahydrothieno[2,3-]isoquinolines . Compounds were converted into the corresponding 1-(1-pyrrolyl) derivatives by heating with 2,5-dimethoxytetrahydrofuran in glacial acetic acid.

Crystal structure of (Z)-4-[1-(4-acetyl-anilino)ethyl-idene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one.

In the solid state, the title compound, C20H19N3O2, adopts the keto-amine tautomeric form, with the H atom attached to the N atom, which participates in an intra-molecular N-H⋯O hydrogen bond with an S(6) ring motif. The dihedral angles between the pyrazole ring and the phenyl and benzene rings are 3.69 (10) and 46.