The N,N′-dioxide−Cu(OTf)2complexes were applied in the asymmetric amination reaction of N-acetyl enamides with dialkyl azodicarboxylate, giving the corresponding products in good yields with high enantioselectivities (up to 91% ee). Precursors of vicinal diamine were readily obtained with excellent diastereoselectivities (>95:5) by NaBH4 reduction.
We report realization of the first enantioselective Cope-type hydroamination of oximes for asymmetric nitrone synthesis. The ligand promoted asymmetriccyclopropene “hydronitronylation” process employs a Cu-based catalytic system and readily available starting materials, operates under mild conditions and displays broad scope and exceptionally high enantio- and diastereocontrol. Preliminary mechanistic
Elemental tellurium mediated synthesis of 2-(trifluoromethyl)oxazoles using trifluoroacetic anhydride as reagent
作者:Beibei Luo、Zhiqiang Weng
DOI:10.1039/c8cc05670f
日期:——
An elemental tellurium mediated synthesis of 2-(trifluoromethyl)oxazoles from the reaction of acetophenone oxime acetates with trifluoroacetic anhydride has been developed. This new tandem cyclization proceeds in good to excellent yields via a SET reduction followed by a 5-endo-trig pathway. Some of the title compounds showed fungicidal and insecticidal activities.
A novel ruthenium-catalyzed cyclization of ketoxime carboxylates with N,N-dimethylformamide (DMF) for the synthesis of tetrasubstituted symmetrical pyridines has been developed. A methyl carbon on DMF performed as a source of a one carbon synthon. And NaHSO3 plays a role in the reaction.
Novel Benzofuran and Benzothiophene Biphenyls as Inhibitors of Protein Tyrosine Phosphatase 1B with Antihyperglycemic Properties
作者:Michael S. Malamas、Janet Sredy、Christopher Moxham、Alan Katz、Weixin Xu、Robert McDevitt、Folake O. Adebayo、Diane R. Sawicki、Laura Seestaller、Donald Sullivan、Joseph R. Taylor
DOI:10.1021/jm990560c
日期:2000.4.6
tyrosine phosphatases (PTPases) have been shown to be negative regulators of the insulin receptor. Inhibition of PTPases may be an effective method in the treatment of Type 2 diabetes. We have identified two novel series of benzofuran/benzothiophenebiphenyl oxo-acetic acids and sulfonyl-salicylic acids as potent inhibitors of PTP1B with good oral antihyperglycemic activity. To assist in the design of these