Enantiomeric separation of carboxylic acids having chiral centers remote from the carboxyl group by labelling with a chiral fluorescent derivatization reagent
摘要:
Enantiomeric separations of 2-, 3-, 4-, 5- and 6-methyl fatty acids and 3-, 4- and 5-hydroxy fatty acids derivatized with (S)-(+)-2-(anthracene-2,3-dicarboximido)-1-propyl trifluoromethanesulfonate are described. Although there are 4-8 bond distances between the chiral centers of these diastereomeric derivatives, they are separated on HPLC and detected at fmol levels. (C) 1997 Elsevier Science Ltd.
Enantiomeric separation of carboxylic acids having chiral centers remote from the carboxyl group by labelling with a chiral fluorescent derivatization reagent
摘要:
Enantiomeric separations of 2-, 3-, 4-, 5- and 6-methyl fatty acids and 3-, 4- and 5-hydroxy fatty acids derivatized with (S)-(+)-2-(anthracene-2,3-dicarboximido)-1-propyl trifluoromethanesulfonate are described. Although there are 4-8 bond distances between the chiral centers of these diastereomeric derivatives, they are separated on HPLC and detected at fmol levels. (C) 1997 Elsevier Science Ltd.
Chemical transformation of Leustroducsins: synthesis of Leustroducsin B
作者:Hayao Matsuhashi、Kousei Shimada
DOI:10.1016/s0040-4020(02)00528-8
日期:2002.7
Chemical transformation of Leustroducsin H to Leustroducsin B has been successfully accomplished in 11 steps including enzymatic hydrolysis of phosphate ester. The process described here enables to differentiate all hydroxyl groups, amino and phosphate functionality so that this process would serve as a useful template for the preparation of whole different kinds of synthetic derivatives in structure
One new α-pyrone (nocapyrone R (1)), and three known γ-pyrones (nocapyrones B, H and L (2–4)) were isolated from the culture extract of a Nocardiopsis strain collected from marine sediment. Structures of these compounds were determined on the basis of spectroscopic data including NMR and MS. γ-Pyrones 2–4 were found to induce adiponectin production in murine ST-13 preadipocyte cells but the α-pyrone 1 had no activity. The absolute configuration of the anteiso-methyl branching in 4 was determined by HPLC comparison of a degraded product of 4 with standard samples as a 2:3 enantiomeric mixture of (R)- and (S)-isomers.
从海洋沉积物中采集的一种 Nocardiopsis 菌株的培养提取物中分离出了一种新的α-吡喃酮(nocapyrone R (1))和三种已知的γ-吡喃酮(nocapyrones B, H 和 L (2-4))。根据 NMR 和 MS 等光谱数据确定了这些化合物的结构。研究发现,γ-吡喃酮 2-4 能诱导小鼠 ST-13 前脂肪细胞产生脂肪生成素,但α-吡喃酮 1 没有活性。通过 HPLC 比较 4 的降解产物和标准样品,确定了 4 中的蚁异甲基分支的绝对构型,即 (R)- 和 (S)- 异构体的 2:3 对映异构体混合物。
Bulbimidazoles A–C, Antimicrobial and Cytotoxic Alkanoyl Imidazoles from a Marine Gammaproteobacterium <i>Microbulbifer</i> Species
作者:Md. Rokon Ul Karim、Enjuro Harunari、Naoya Oku、Kazuaki Akasaka、Yasuhiro Igarashi
DOI:10.1021/acs.jnatprod.0c00082
日期:2020.4.24
Three new alkanoyl imidazoles, designated bulbimidazoles A-C (1-3), were found from the culture extract of the gammaproteobacterium Microbulbifer sp. DC3-6 isolated from a stony coral of the genus Tubastraea. The absolute configuration of the anteiso-methyl substitution in 1 was established to be a mixture of (R)- and (S)-configurations in a ratio of 9:91 by applying the OhruiAkasaka method. Compounds 1-3 displayed unique broad-spectrum antimicrobial activity against Gram-positive and -negative bacteria and fungi with MICs ranging from 0.78 to 12.5 mu g/mL. They also exhibited cytotoxicity toward P388 murine leukemia cells with IC50 in the micromolar range.
Enantiomeric separation of carboxylic acids having chiral centers remote from the carboxyl group by labelling with a chiral fluorescent derivatization reagent
作者:Kazuaki Akasaka、Hiroshi Meguro、Hiroshi Ohrui
DOI:10.1016/s0040-4039(97)01616-x
日期:1997.9
Enantiomeric separations of 2-, 3-, 4-, 5- and 6-methyl fatty acids and 3-, 4- and 5-hydroxy fatty acids derivatized with (S)-(+)-2-(anthracene-2,3-dicarboximido)-1-propyl trifluoromethanesulfonate are described. Although there are 4-8 bond distances between the chiral centers of these diastereomeric derivatives, they are separated on HPLC and detected at fmol levels. (C) 1997 Elsevier Science Ltd.