Total Synthesis and Structural Confirmation of (+)-Longicin
摘要:
A stereocontrolled total synthesis of (+)-longicin, a representative of the class of mono-THF-acetogenins, is described. The strategy involves the utilization of D- and L-glutamic acids as chirons that correspond to two five-carbon segments harboring stereogenic centers at C4 and at C17 of the C-32 polyketide-derived natural product. The use of Grubbs' RCM reaction as a novel "chain elongation" strategy for the synthesis of acetogenin-type structures and a new protocol for butenolide incorporation are also described.
Cheap, readily available, air stable, nontoxic, and environmentally benign iron salts such as Fe(acac)3 are excellent precatalysts for the cross-coupling of Grignardreagents with alkenyl triflates and acid chlorides. Moreover, it is shown that dichloroarene and -heteroarene derivatives as the substrates can be selectively monoalkylated by this method. All cross-coupling reactions proceed very rapidly
廉价,容易获得,空气稳定,无毒且对环境无害的铁盐,例如Fe(acac)3是格氏试剂与链烯基三氟甲磺酸酯和酰氯交叉偶联的出色的预催化剂。此外,显示出通过该方法可以将作为底物的二氯亚芳基和-杂亚芳基衍生物选择性地单烷基化。所有交叉偶联反应在特别温和的条件下均能非常快速地进行,结果证明与两个反应伙伴中的各种官能团均相容。对制备结果的详细分析表明,铁催化的碳键形成可以通过不同的途径发生。因此,甲基卤化镁的反应可能包含铁酸盐配合物作为活性成分,而格氏试剂与两个或多个碳原子的反应则受到形式组成[Fe(MgX)2 ]的高度还原的铁簇的影响。n原位生成。使用复杂的[Me 4 Fe] Li 2的对照实验证实了这一解释。
Discovery and SAR of potent, orally available and brain-penetrable 5,6-dihydro-4H-3-thia-1-aza-benzo[e]azulen- and 4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulen derivatives as neuropeptide Y Y5 receptor antagonists
from a potent Y5 antagonist (2) with thiazole fragments that exhibit weak Y5 affinities followed by lead optimisation led to the discovery of (5,6-dihydro-4H-3-thia-1-aza-benzo[e]azulen-2-yl)-piperidin-4-ylmethyl-amino and (4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulen-2-yl)-piperidin-4-ylmethyl-amino derivatives. Both classes of compounds are capable of delivering potent and selectiveorally and centrally
[EN] PRODRUGS OF 4'-C-SUBSTITUTED-2-HALO-2'-DEOXYADENOSINE NUCLEOSIDES AND METHODS OF MAKING AND USING THE SAME<br/>[FR] PROMÉDICAMENTS DE NUCLÉOSIDES DE 4'-C-SUBSTITUÉ-2-HALO-2'-DÉSOXYADÉNOSINE ET LEURS PROCÉDÉS DE FABRICATION ET D'UTILISATION
申请人:GILEAD SCIENCES INC
公开号:WO2021188959A1
公开(公告)日:2021-09-23
The present disclosure provides prodrugs of 4'-C-substituted-2- halo-2'-deoxyadenoside nucleosides, and compositions, methods and kits thereof. Such compounds can be useful for treating viral infections including, human immunodeficiency virus. The compounds have the following formula (I).
Development of a Multigram Asymmetric Synthesis of 2-(<i>R</i>)-2-(4,7,10-Tris <i>tert</i>-Butylcarboxymethyl-1,4,7,10-tetraazacyclododec-1-yl)-pentanedioic Acid, 1-<i>tert</i>-Butyl Ester, (<i>R</i>)-<i>tert</i>-Bu<sub>4</sub>-DOTAGA
作者:Stuart G. Levy、Vincent Jacques、Kevin Li Zhou、Shirley Kalogeropoulos、Kelly Schumacher、John C. Amedio、Jonathan E. Scherer、Steven R. Witowski、Richard Lombardy、Karsten Koppetsch
DOI:10.1021/op8002932
日期:2009.5.15
A process for the multigram asymmetricsynthesis of the chiral tetraazamacrocycle 2-(R)-2-(4,7,10-tris tert-butylcarboxymethyl-1,4,7,10-tetraazacyclododec-1-yl)-pentanedioic acid, 1-tert-butyl ester ((R)-tert-Bu4-DOTAGA, 4) has been devised and demonstrated. The nine-step synthesis features an improved synthesis of 2-(S)-5-oxotetrahydrofuran-2-carboxylic acid, tert-butyl ester 8, the precursor to the
Abstract l -Glutamic acid has been converted into a separable mixture of d -amicetono- and l -rhodinono-γ-lactones by a sequence involving transformation into (S)-γ-carboxy-γ-butyrolactone (2), conversion of 2, conversion of 2 into the corresponding methyl ketone by the diazoketone route, and selective reduction with zinc borohydride or borane-methyl sulfide. Reduction of the two lactones with di-isobutylaluminium