40752-00-9Relevant academic research and scientific papers
C-H borylation by platinum catalysis
Furukawa, Takayuki,Tobisu, Mamoru,Chatani, Naoto
supporting information, p. 332 - 342 (2017/05/09)
Herein, we describe the platinum-catalyzed borylation of aromatic C-H bonds. N-Heterocyclic carbene-ligated platinum catalysts are found to be efficient catalysts for the borylation of aromatic C(sp2)-H bonds when bis(pinacolato)diboron is used as the boron source. The most remarkable feature of these Pt catalysts is their lack of sensitivity towards the degree of steric hindrance around the C-H bonds undergoing the borylation reaction. These Pt catalysts allow for the synthesis of sterically congested 2,6-disubstituted phenylboronic esters, which are otherwise difficult to synthesize using existing C-H borylation methods. Furthermore, platinum catalysis allows for the site-selective borylation of the C-H bonds ortho to fluorine substituents in fluoroarene systems. Preliminary mechanistic studies and work towards the synthetic application of this platinum catalyzed C-H borylation process are described.
HIV REVERSE TRANSCRIPTASE INHIBITORS
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Page/Page column 37, (2010/10/20)
Compounds of Formula (I) are HIV reverse transcriptase inhibitors, wherein T is O or S; U is O, S, N(R4), or a direct bond linking V to the C(=T) moiety; V is optionally substituted C1-6 alkylene; W is C(O)N(R5) or a direct bond linking V to R3; and R1, R2, R3, R4 and R5 are defined herein. The compounds of Formula (I) and their pharmaceutically acceptable salts are useful in the inhibition of HIV reverse transcriptase, the prophylaxis and treatment of infection by HIV and in the prophylaxis, delay in the onset, and treatment of AIDS. The compounds and their salts can be employed as ingredients in pharmaceutical compositions, optionally in combination with other antivirals, immunomodulators, antibiotics or vaccines.
Mechanism of reaction of an arenediazonium ion in aqueous solutions of acetamide, N-methylacetamide, and N,N-dimethylacetamide. A potential method for chemically tagging peptide bonds at aggregate interfaces
Romsted, Laurence S.,Zhang, Jianbing,Zhuang, Lanzhen
, p. 10046 - 10054 (2007/10/03)
The mechanism of dediazoniation of 2,4,6-trimethylbenzenediazonium ion, 1-ArN2+, in concentrated aqueous solutions of acetamide, N-methylacetamide, and N,N-dimethylacetamide (peptide bond models) was probed by a combination of techniques including HPLC, GC/MS, and H218O isotopic labeling. The kinetics and product distributions are completely consistent with the heterolytic dediazoniation mechanism, i.e., rate-determining loss of N2 followed by trapping of the aryl cation intermediate, 1-Ar+, by H2O and the oxygens and nitrogens of the amides. Aryl imidates formed from trapping by amide O hydrolyze rapidly into aryl ester/amine and amide/phenol product pairs. The results were used to estimate the selectivity of 1-Ar+ toward the amide oxygens and nitrogens versus H2O. 1-Ar+ is only 10-40% more selective toward H2O than amide O, but it is more than 10 times more selective toward H2O than the amide N. 1-Ar+ is slightly more selective toward the N of acetamide than N-methylacetamide. However, within the HPLC detection limit, 1-At+ does not give a product from reaction with the N,N-dimethylacetamide nitrogen. The selectivities are interpreted by using a preassociation model, i.e., selective solvation by the different nucleophiles of the reactive diazonio group in the ground state. These results indicate that chemical tagging (trapping by N) and cleaving (trapping by O) of the peptide bonds and the weakly basic side chains of polypeptides and proteins bound to association colloids, vesicles and biomembranes, and emulsions may provide new information on their topologies and orientations at the aggregates' interfaces.
