Stereo- and Regioselective Addition of Arene to Alkyne Using Abnormal NHC Based Palladium Catalysts: Elucidating the Role of Trifluoroacetic Acid in Fujiwara Process
作者:Pradip Kumar Hota、Anex Jose、Swadhin K. Mandal
DOI:10.1021/acs.organomet.7b00649
日期:2017.11.27
(aNHC) based Pd catalysts have been used for the efficient hydroarylation of aromatic C–H bonds leading to new C–C bond formation through regio- and stereoselective addition to alkynes. The addition reaction has been realized by a catalytic amount of Pd (II) compound (0.5 mol %) in trifluoroacetic acid (TFA) under ambient conditions. Various arenes undergo transhydroarylation selectively across the triple
Improved Synthesis of Coumarins by Iron(III)-Catalyzed Cascade Reaction of Propiolic Acids and Phenols
作者:Tsugio Kitamura、Md. Kutubi、Takuya Hashimoto
DOI:10.1055/s-0030-1258473
日期:2011.4
presence of FeCl3/AgOTf catalyst proceeded efficiently in a mixed solvent of trifluoroacetic acid and 1,2-dichloroethane, and provided coumarins in good to high yields. This iron-catalyzed reaction offers a much-improved synthesis of coumarins. iron - hydroarylation - coumarins - propiolic acids - propynoic acids - phenols
The Effect of Phenyl Substituents on the Release Rates of Esterase-Sensitive Coumarin-Based Prodrugs.
作者:Yuan LIAO、Siska HENDRATA、Sung Yong BAE、Binghe WANG
DOI:10.1248/cpb.48.1138
日期:——
peptidomimetics. The drug release rates from this prodrug system were found to be dependent on the structural features of the drug moiety. In certain cases, the release can be undesirably slow for drugs that are secondary amines with relatively high pKa's. Aimed at finding ways to manipulate the release rates to suit the need of different drugs, we have examined the effect of the phenyl ring substitutions