New discoveries in chemical research and development in 2021, Chemistry involves the study of all things chemical – chemical processes, how they change and how they react in certain situations. 91-10-1, Name is 2,6-Dimethoxyphenol, SMILES is COC1=CC=CC(OC)=C1O, in an article , author is OHKATA, K, once mentioned of 91-10-1, Safety of 2,6-Dimethoxyphenol.
A series of 10-S-3 type sulfuranes, tetraazathiapentalenes (10 a-i, 11 a-f, 12, and 17) fused with pyrimidine ring and/or pyridine ring, were prepared by oxidation of the corresponding thioureas. The restricted internal rotation of the pyrimidine ring was observed by temperature dependent H-1 NMR spectrum which gave the kinetic parameters of Delta G(298)(double dagger)=16.6 kcal/mol, Delta H-double dagger=15.9 kcal/mol, and Delta S-double dagger=-2.4 eu at 25 degrees C for the rotational barrier in 10a, The substituent effect to the kinetic data can be reasonably explained in terms of electronic balance of the N-S-N hypervalent bond or the different degree of contribution of resonance canonical structures. Comparison of the rotational barrier of 10a with that of model compounds (18 and 24) suggests that hypervalent N-S-N stabilization in 10a is more than 6 kcal/mol. Methylation of these 10-S-3 type sulfuranes (10a, 10d, and 11a) was investigated to clarify the electronic effect in these molecules. The crystal structure of the neutral symmetric sulfurane 10a reveals to be a planar molecule in which the sulfur atom was found to be in the same plane of the two pyrimidine rings. The S-N bond lengths 1.948(3) and 1.938(3) Angstrom are longer than the sum of the covalent bond radii, consistent with a bond order less than unity. The crystal structures of the dicationic symmetric sulfurane 17 and the unsymmetrical sulfurane 11a also show to be planar molecules. The S-N distances in 11a were different each other due to the electronic imbalance between the apical ligands. Semi-empirical calculation (AM 1) of these systems (10a and 17) indicate the expected electronic features of the hypervalent molecules (10-S-3 sulfuranes) and the small contribution of pi-overlapping in the N-S-N bonds.
Each elementary reaction can be described in terms of its molecularity, the number of molecules that collide in that step. If you are hungry for even more, make sure to check my other article about 91-10-1, Safety of 2,6-Dimethoxyphenol.
Reference:
Isothiazole – Wikipedia,
,Isothiazole – ScienceDirect.com