A joint theoretical and experimental structural study of two novel 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine derivatives

Abstract

In this study, two novel 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine derivatives, 3-[2-(4-methoxyphenyl)ethyl] -6-phenyl-7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine (compound 1) and 3-[2-(3,4,5-trimethoxyphenyl)ethyl]-6-phenyl-7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine (compound 2), having analgesic-anti-inflammatory activity were synthesized and characterized by IR, 1 H-NMR, and mass spectroscopic techniques besides elementary analysis. Additionally, the structures and molecular packings of the mentioned compounds have been investigated by X-ray single crystal diffraction. The six-membered thiadiazine ring adopts the screw boat conformation in both the compounds. In the crystal packings of the compounds 1 and 2, C-HÁÁÁN and C-HÁÁÁO interactions link the molecules into a twodimensional network and generate infinite chains. Furthermore, C-HÁÁÁp intermolecular interactions provide further stability to the molecular packing in both the molecules. The conformers have been predicted by the potential energy surface scan employing the AM1 method. Geometry optimizations and electrostatic properties have been obtained using AM1 and ab initio quantum methods.

Structure elucidation of 3-[1-(6-methoxy-2-naphtyl)ethyl]-6-(2,4-dichlorophenyl)-7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine, C23H18Cl2N4OS from synchrotron X-ray powder diffraction

“…In the title compound, all of the bond lengths and angles in the phenyl rings are in the normal range. In the 1,2,4-triazole ring, the C = N bond lengths are 1.347(13) Å and 1.354(11) Å, which are longer than that found in the 1,2,4-triazole ring-containing structures (Abdel-Aziz et al , 2011; Aytaç et al ., 2009; Fun et al , 2012; Kaynak et al ., 2010; Khan et al ., 2014a). The N–N bond length is 1.356(9) Å, which is shorter than the 1,2,4-triazole ring-containing structures cited previously.…”

“…The N–N bond length is 1.356(9) Å, which is shorter than the 1,2,4-triazole ring-containing structures cited previously. In the 1,3,4 thiadiazine ring, the bond lengths are compatible with the 1,2,4-triazole ring and the 1,3,4 thiadiazine ring-containing structures (Aytaç et al ., 2009; Kaynak et al ., 2010; Abdel-Aziz et al ., 2011; Fun et al ., 2012), except the N–N bond length with 1.325(12) Å. The 1,3,4-thiadiazine ring is not planar and the r.m.s.…”

Bicyclic 5-6 Systems With One Bridgehead (Ring Junction) Nitrogen Atom: Four Extra Heteroatoms 2:2

“…For the latter, the dihedral angle between the bicyclic system and the 2,4dichlorophenyl substituent is 50.74°. [18][19] <Figure 5 near here>…”

Interplay of thermochemistry and Structural Chemistry, the journal (volume 21, 2010) and the discipline

“…In the study by Kaynak et al [204] synthesis, characterization including X-ray structural characterization and theoretical investigations of two novel derivatives of 1,2,4-triazolo [3,4- The six-membered thiadiazine ring adopts the screw boat conformation in both compounds. Potential energy surface scans were drawn.…”