The present invention provides cyclic depsipeptide compounds of formula (I) wherein the stereochemical configuration of at least one carbon atom bearing the groups Cy1, Cy2, R1, R2, R3, R4, Ra and Rb is inverted compared with the naturally occurring cyclic depsipeptide PF1022A. The invention also provides compositions comprising the compounds that are effective against parasites that harm animals. The compounds and compositions may be used for combating parasites in or on mammals and birds. The invention also provides for an improved method for eradicating, controlling and preventing parasite infestation in birds and mammals.
9-Amino-(9-deoxy)cinchona alkaloid-derived new chiral phase-transfer catalysts
作者:Wenwen Peng、Jingwei Wan、Bing Xie、Xuebing Ma
DOI:10.1039/c4ob01648c
日期:——
9-amino-(9-deoxy)cinchona alkaloid-derived chiralphase-transfercatalysts bearing amino groups was developed by using known cinchona alkaloids as the starting materials. Due to the transformation of the 9-hydroxyl group into a 9-amino functional group, the catalytic performances were significantly improved in comparison with the corresponding first generation phase-transfercatalysts, and excellent yields (92–99%)
Evidence of the Electronic Factor for the Highly Enantioselective Catalytic Efficiency of <i>Cinchona</i>-Derived Phase-Transfer Catalysts
作者:Mi-Sook Yoo、Byeong-Seon Jeong、Jeong-Hee Lee、Hyeung-geun Park、Sang-sup Jew
DOI:10.1021/ol050123u
日期:2005.3.1
evaluated as phase-transfercatalysts in the enantioselective alkylation of glycine imine ester 1. The N-oxypyridine and cyanobenzene moieties might play an important role to form a rigid conformation by coordinating with H(2)O via hydrogen bonding leading to high enantioselectivity (97 approximately >99% ee), which provides evidence of an electronic factor for the high enantioselective catalytic efficiency
A new asymmetric two-center phase-transfercatalyst was designed and a catalyst library containing more than 40 new two-center catalysts was constructed. The catalysts were applied in phase-transferalkylations and Michael additions to afford the corresponding products in up to 93% ee and 82% ee, respectively.
We developed a versatile synthetic process for aeruginosin 298-A as well as several attractive analogues, in which all stereocenters were controlled by a catalytic asymmetric phase-transfer reaction and epoxidation. Furthermore, drastic counteranion effects in phase-transfer catalysis were observed for the first time, making it possible to three-dimensionally fine-tune the catalyst (ketal part, aromatic