Microcosamine A、Microgrewiapine A 和 Microgrewiapine B:三种同手性生物碱?
摘要:
报道了microcosamine A、microgrewiapine A 和 microgrewiapine B(Microcos paniculata生物碱)的不对称合成。将锂 ( S ) -N-苄基-N- (α-甲基苄基)酰胺与巴豆酸叔丁酯共轭加成,然后烯醇氧化生成靶标的 C(2) 和 C(3) 立体中心,随后非对映选择性分子内还原胺化用于形成哌啶环,同时产生 C(6) 立体中心。1 H NMR 3 J耦合常数和 nOe 分析允许明确分配生物碱的相对构型。microcosamine A 和 microgrewiapine B 的比旋光度数据的比较与两者都具有绝对 (2 S ,3 R ,6 S )-构型一致。对于 microgrewiapine A,揭示了关于绝对构型的相互矛盾的数据:在隔离研究中,Mosher 的分析得出 (2 S ,3 R ,6 S )-构型的结论,但比旋光度数据的比较表明
Alkaloids from <i>Microcos paniculata</i> with Cytotoxic and Nicotinic Receptor Antagonistic Activities
作者:Patrick C. Still、Bitna Yi、Tatiana F. González-Cestari、Li Pan、Ryan E. Pavlovicz、Hee-Byung Chai、Tran Ngoc Ninh、Chenglong Li、Djaja Djendoel Soejarto、Dennis B. McKay、A. Douglas Kinghorn
DOI:10.1021/np3007414
日期:2013.2.22
Microcos paniculata is a large shrub or small tree that grows in several countries in South and Southeast Asia. In the present study, three new piperidinealkaloids, microgrewiapines A–C (1–3), as well as three known compounds, inclusive of microcosamine A (4), 7′-(3′,4′-dihydroxyphenyl)-N-[4-methoxyphenyl)ethyl]propenamide (5), and liriodenine (6), were isolated from cytotoxic fractions of the separate
Synthesis and Configuration of <i>O</i>-Acetyl Microgrewiapine A: Phantomization of <i>O</i>-Acetyl 6-<i>epi</i>-Microgrewiapine A
作者:Stephen G. Davies、Ai M. Fletcher、Paul M. Roberts、Cameron E. Taylor、James E. Thomson
DOI:10.1021/acs.jnatprod.1c00847
日期:2022.1.28
synthetic microgrewiapine A) followed by O-acetylation, exhibit NMR data that are identical to those of the authentic sample. The previous report that this two-step transformation proceeds with epimerization at C-6 is thus shown to be in error: the purported sample of O-acetyl 6-epi-microgrewiapine A is structurally misassigned and is, in fact, O-acetyl microgrewiapine A. A plausible rationale for the
研究了O-乙酰 microgrewiapine A的形成。对源自天然产物的真实样品的 NMR 数据进行校正。由合成 microcosamine A 的还原性N-甲基化(产生合成 microgrewiapine A)然后O-乙酰化产生的全合成样品显示出与真实样品相同的 NMR 数据。先前的报告表明,这种两步转化在 C-6 处进行差向异构化是错误的:据称O-乙酰 6 - epi -microgrewiapine A 的样品在结构上分配错误,实际上是O-乙酰 microgrewiapine A. 提出了结构错配的合理理由。
Microcosamine A, Microgrewiapine A and Microgrewiapine B: three homochiral alkaloids?
作者:Stephen G. Davies、Ai M. Fletcher、Paul M. Roberts、Cameron E. Taylor、James E. Thomson
DOI:10.1016/j.tet.2021.132056
日期:2021.6
nOe analyses allow unambiguous assignment of relative configuration of the alkaloids. Comparison of specific rotation data for microcosamine A and microgrewiapine B is consistent with both possessing the absolute (2S,3R,6S)-configuration. For microgrewiapine A, conflicting data regarding the absoluteconfiguration are revealed: in the isolation study a Mosher’s analysis concludes a (2S,3R,6S)-configuration
报道了microcosamine A、microgrewiapine A 和 microgrewiapine B(Microcos paniculata生物碱)的不对称合成。将锂 ( S ) -N-苄基-N- (α-甲基苄基)酰胺与巴豆酸叔丁酯共轭加成,然后烯醇氧化生成靶标的 C(2) 和 C(3) 立体中心,随后非对映选择性分子内还原胺化用于形成哌啶环,同时产生 C(6) 立体中心。1 H NMR 3 J耦合常数和 nOe 分析允许明确分配生物碱的相对构型。microcosamine A 和 microgrewiapine B 的比旋光度数据的比较与两者都具有绝对 (2 S ,3 R ,6 S )-构型一致。对于 microgrewiapine A,揭示了关于绝对构型的相互矛盾的数据:在隔离研究中,Mosher 的分析得出 (2 S ,3 R ,6 S )-构型的结论,但比旋光度数据的比较表明
Total Synthesis and Absolute Stereochemical Assignment of Microgrewiapine A and Its Stereoisomers
作者:Lingamurthy Macha、Hyun-Joon Ha
DOI:10.1021/acs.joc.8b02342
日期:2019.1.4
Total synthesis of both enantiomers of (−)-(2S,3R,6S)- and (+)-(2R,3S,6R)-microgrewiapine A along with (+)-microcosamine A and (−)-6-epi-microgrewiapine A from chiral 1-(α-methylbenzyl)-aziridine-2-carboxylate was accomplished for the first time. Key steps involved in this synthesis include one-pot reductive ring-opening of aziridine, debenzylation, intramolecular N-alkylation to obtain the key piperidine