Synthesis, Crystal Structure, and Biological Activity of Ethyl 4-Methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate Polymorphic Forms

• Published in: Scientia pharmaceutica Vol. 86; no. 2; pp. 21 - 17
• Main Authors: Ukrainets, Igor, Burian, Anna, Baumer, Vyacheslav, Shishkina, Svitlana, Sidorenko, Lyudmila, Tugaibei, Igor, Voloshchuk, Natali, Bondarenko, Pavlo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 30-05-2018; MDPI
• Subjects: 2,1-benzothiazine; 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid; Acids; Alcohol; alkylation; analgesic activity; Analgesics; anti-inflammatory action; Chemistry; Crystal structure; esters; Methods; NMR; Nuclear magnetic resonance; Pain; Pharmaceuticals; Phenols; polymorphism; United Kingdom > UK; United States > US; Germany
• ISSN: 2218-0532; 0036-8709; 2218-0532
• DOI: 10.3390/scipharm86020021

The data obtained from the powder diffraction experiments were compared to the data calculated from the single crystal structures and showed clearly that both polymorphic modifications were pure and did not contain any impurities. [...]it may be expected that the biological experiment was informative and reasonably carried out. 3.2.Evaluation ofthe Anti-Inflammatory and Analgesic Activity The analysis of the results of our tests (Tables 2 and 3) suggests that the dialkylation product of salt 1, i.e.,ethyl 1-ethyl-4-methyl-2,2-dioxo-1H-2A6,1-benzothiazine-3-carboxylate (3), is of little interest as an object for further pharmacological study. The interaction energy of the basic molecule with all the neighboring molecules within the layer was -53.5 kcal/mol (68.5%), while the interaction energy with molecules of the neighboring layer was only -9.9 kcal/mol (12.7%). [...]the monoclinic crystal structure of ester 2 was built by the molecules as building units and may be divided on two levels of organization from the viewpoint of interaction energies between molecules: chains as the primary level of organization and layers of strongly interacting chains as the secondary level of organization. The interaction energy with thee neighboring layers was much weaker: -15.0 kcaVmol or 12.4%. [...]the orthorhombic crystal structure of the ester 2 was built by thr dimers oe steongly bound molecules as building units and only one: level of organization was able to br separated out.