The ability of several density-functional theory methods to describe the kinetics and energetics of a series of ring-opening reactions of cyclopropyl and cyclobutyl-type radicals was explored. PBE, B971 and B3LYP perform quite well in their ability to replicate experiment, based upon the ring opening of cyclopropylcarbinyl, two α-trialkylsilyloxycyclopropylmethyl radicals, pentamethylcyclopropy...

Density function M06 method has been used to optimize the geometries of shikonin -thymine at 6-311++G** basis. Finally, fourteen stabilized complexes have been obtained. Theories of atoms in molecules (AIM) and natural bond orbital (NBO) have been utilized to investigate the hydrogen bonds involved in all the systems. The interaction energies of all the complexes were corrected by basis set sup...

Facultad de Qúımica, Departamento de Nacional Autónoma de México, México DF 0 Department of Chemistry, Thompson Rive Canada. E-mail: [email protected] † Electronic supplementary information Fig. S1 to S4; 21 pages. hSi values for the solvents studied (Table S1); calculated ra the repair reactions of N-formyl-leucinam S2); optimized structures of the N-fo (repaired radicals with the two sites of DH t...

Other information on the differences between peroxides and ketals ---------------------------S2 Lack of stabilization on sulphonyl compounds------------------------------------------------------S2 PES relaxed scan for both COCO dihedrals in dimethoxy-methane simultaneously--------S3 PES relaxed dihedral scans for fluoroperoxides-----------------------------------------------------S3 More detail...

By reaction of 1,4-dipotassio-1,1,4,4-tetrakis(trimethylsilyl)tetramethyltetrasilane with PbBr(2) in the presence of triethylphosphine a base adduct of a cyclic disilylated plumbylene could be obtained. Phosphine abstraction with B(C(6)F(5))(3) led to formation of a base-free plumbylene dimer, which features an unexpected single donor-acceptor PbPb bond. The results of density functional comput...

The 1,3-dipolar cycloaddition between glycine-derived azlactones with maleimides is efficiently catalyzed by the dimeric chiral complex [(S a)-Binap·AuTFA]2. The alanine-derived oxazolone only reacts with tert-butyl acrylate giving anomalous regiochemistry, which is explained and supported by Natural Resonance Theory and Nucleus Independent Chemical Shifts calculations. The origin of the high e...

Purpose There are three classes of HIV-1 based on diversity of the viral envelope: M (major), O (outlying) and N (new). The M group is subclassified into nine major subtypes including A—D, F—H, J and K, as well as several recombinant forms. There is a growing need to evaluate antiretroviral (ARV) treatment in these diverse subtypes. Methods M06-802 was an open-label, global, 48-week phase III t...

Selenium presents some similarities with de sulfur reactivity and has been described in diverse biological systems. The selenocystein (Sec) residue is the one which characterizes the selenoproteins. These proteins has been asociated with many cellular mechanisms, for intance, redox signalling and oxydative stress. In biology, selenium compounds such as selenocystine (Sec-Sec) were associated wi...

A conformational analysis of nine macrocyclic thioether musks has been carried out using molecular mechanics (MMFF), density functional theory (DFT) using both B3LYP and M06 functionals, as well as Hartree-Fock and post-Hartree-Fock (MP2) ab initio methods. 6-Thia-, 10-thia- and 4-methyl-5-thia-14-tetradecananolide, 4-thia-, 7-thia-, 11-thia- and 12-thia-15-pentadecanolide and 6-thia- and 12-th...

The molecular dynamics of the triplet-state Zimmerman di-π-methane rearrangement of dibenzobarrelene were computed with B3LYP and M06-2X density functionals. All productive quasiclassical trajectories involve sequential formation and cleavage of C-C bonds and an intermediate with lifetimes ranging from 13 to 1160 fs. Both dynamically concerted and stepwise trajectories are found. The average li...