Conversion of N-acyl-2,3-dihydro-4-pyridones to 4-chloro-1,2-dihydropyridines using the Vilsmeier Reagent. Synthesis of (-)-coniine and (±)-lupinine
摘要:
The full details are given of a study on the conversion of dihydropyridones of the type 3 to 4-chloro-1,2-dihydropyridines 4 using a Vilsmeier reagent. The use of 1 equiv of Vilsmeier reagent under mild conditions (ClCHCCl2, rt) transformed several racemic N-acyl-2,3-dihydro-4-pyridones 3 to dihydropyridines 4 in very good to excellent yields (83-96%). A C-3 methyl group can be tolerated as was demonstrated in the preparation of 4-chloro-3-methyl-1,2-dihydropyridine 7 from dihydropyridone 6 in 90 % yield. The utility of this conversion was demonstrated in the synthesis of the piperidine alkaloid, (-)-coniine. The synthesis of (-)-coniine was completed in five steps from 4-methoxy-3-(triisopropylsilyl)pyridine in 54% overall yield. When 2,3-dihydro-4-pyridones are treated with excess Vilsmeier reagent, good yields of 4-chloro-3-formyl-1,2-dihydropyridines result. These heterocycles are useful intermediates for alkaloid preparation, as was shown by two syntheses of the quinolizidine alkaloid, (+/-)-lupinine, carried out in three and five steps, respectively.
Enantioselective Total Synthesis of (−)-Citrinadin A and Revision of Its Stereochemical Structure
作者:Zhiguo Bian、Christopher C. Marvin、Stephen F. Martin
DOI:10.1021/ja405547f
日期:2013.7.31
The first enantioselectivetotalsynthesis of (-)-citrinadin A has been accomplished in 20 steps from commercially available materials via an approach that minimizes refunctionalization and protection/deprotection operations. The cornerstone of this synthesis features an asymmetric vinylogous Mannich addition of a dienolate to a chiral pyridinium salt to set the initial chiral center. A sequence of
(-)-citrinadin A 的第一个对映选择性全合成是通过 20 个步骤从市售材料通过最小化再官能化和保护/脱保护操作的方法完成的。该合成的基石是将二烯醇盐不对称地加成到手性吡啶鎓盐中以设置初始手性中心。一系列底物控制的反应,包括高度立体选择性环氧化/开环序列和吲哚的氧化重排以提供螺吲哚,然后用于在 (-)-citrinadin A 的五环核心中建立剩余的立体中心。 citrinadin A 的成功合成导致了citrinadin 核心亚结构立体化学结构的修订。
DIHYDROPYRIDONE UREAS AS P2X7 MODULATORS
申请人:Brotherton-Pleiss Christine E.
公开号:US20100160388A1
公开(公告)日:2010-06-24
Compounds of the formula I:
or pharmaceutically acceptable salts thereof, wherein m, n, R
1
, R
2
, R
3
, R
4
and R
5
are as defined herein. Also disclosed are methods of making the compounds and using the compounds for treatment of diseases associated with the P2X7 purinergic receptor.
Compounds of the formula I:
or pharmaceutically acceptable salts thereof, wherein m, n, R
1
, R
2
, R
3
, R
4
and R
5
are as defined herein. Also disclosed are methods of making the compounds and using the compounds for treatment of diseases associated with the P2X7 purinergic receptor.
Enantiopure <i>N</i>-Acyldihydropyridones as Synthetic Intermediates: Asymmetric Syntheses of Indolizidine Alkaloids (−)-205A, (−)-207A, and (−)-235B
作者:Daniel L. Comins、Donald H. LaMunyon、Xinghai Chen
DOI:10.1021/jo971448u
日期:1997.11.1
addition of 4-(benzyloxy)butylmagnesium bromide, and vinyl triflate formation provided 13 in a stereoselective fashion. Catalytic reduction of the vinyl triflate moiety, simultaneous cleavage of the benzyl ether and Cbz groups, and cyclization to give amino alcohol 14 was effected via a one-pot reaction. Oxidation of 14 with the Dess-Martin reagent gave a 97% yield of amino aldehyde 4. Synthesis of each