نتایج جستجو برای: hemiterpene ether derivatives

تعداد نتایج: 125607  

Journal: :The Journal of antibiotics 1998
K I Kurihara K Ajito S Shibahara O Hara M Araake S Omoto S Inouye

Five novel 3-hydroxyl derivatives of sixteen-membered macrolide possessing 4-O-acyl-alpha-L-cladinose as a neutral sugar moiety were synthesized by using a combination of structurally stable silyl acetal protection and selective hydrogenolysis of a 3"-methylthiomethyl ether to a 3"-OMe group. Several derivatives having n-butyryl, i-butyryl and n-valeryl substituent at the 4"-OH group exhibited ...

2012
Zhi-Cong Geng Jian Chen Ning Li Xiao-Fei Huang Yong Zhang Ya-Wen Zhang Xing-Wang Wang

The catalytic synthesis of nitrogen-containing heterocycles is of great importance to medicinal and synthetic chemists, and also a challenge for modern chemical methodology. In this paper, we report the synthesis of pyrazolidine derivatives through a domino aza-Michael/hemiacetal sequence with chiral or achiral secondary amines as organocatalysts. Thus, a series of achiral pyrazolidine derivati...

Journal: :Journal of lipid research 1989
F Stellaard S A Langelaar R M Kok C Jakobs

Combined capillary gas-liquid chromatography-electron capture negative chemical ionization mass spectrometry of pentafluorobenzyl ester-TMSi ether derivatives of bile acids and isotope dilution using deuterated internal standards are introduced as a sensitive and selective analysis technique for plasma bile acids. As a result of the high ionization efficiency of pentafluorobenzyl derivatives un...

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