Domino reactions. One-pot preparation of fluoreno[2,3,4-ij]isoquinoline derivatives from conjugated ketene imines
摘要:
Iminophosphoranes 4, derived from ethyl alpha-azido-2-(allyloxy)-3-methoxycinnamates, react with ketenes to give the corresponding ketene imines, which by thermal treatment at 150-160-degrees-C undergo a consecutive electrocyclic ring closure/Claisen rearrangement/second ring closure/double aromatization process to give isoquinoline derivatives 7 and/or the previously unknown fluoreno[2,3,4-ij]isoquinolines 9 in moderate yields. Similarly, iminophosphoranes 14 derived from ethyl alpha-azido-2,3-disubstituted-4-(allyloxy)cinnamates reacted with diphenyl ketene to give the intermediate ketene imines, which at 150-160-degrees-C undergo a cascade of pericyclic reactions to give the isoquinolines 15 and the pentacyclic compounds 16 in moderate yields.
A diastereoselective cobalt-mediated synthesis of benzopyrans using a novel variation of an intramolecular Nicholas reaction in the key cyclisation step: optimisation and biological evaluation 1
of novel intramolecular cyclisation reactions between an organocobalt stabilised cation and a trisubstituted alkene have been accomplished that provide a concise route for the diastereoselective synthesis of a range of functionalised benzopyrans. In addition to the usual Lewis acids employed in the Nicholas reaction our studies have identified several other reagents for effecting the cyclisation reaction
Synthesis of Allyl- and Prenylcoumarins via Microwave-Promoted Tandem Claisen Rearrangement/Wittig Olefination
作者:Bernd Schmidt、Martin Riemer
DOI:10.1055/s-0035-1560501
日期:——
sequence of Claisenrearrangement, carbonyl olefination, and cyclization upon microwave irradiation in the presence of a stabilized ylide. The products are multiply substituted 6- or 8-allylated or prenylated coumarins (2H-chromen-2-ones). Allyl, dimethylallyl, crotyl, and prenyl ethers of various aromatic ortho-hydroxy carbonyl compounds undergo a tandem sequence of Claisenrearrangement, carbonyl olefination
摘要 各种芳族邻羟基羰基化合物的烯丙基,二甲基烯丙基,巴豆基和异戊烯基醚在稳定的内酯存在下进行微波辐射后,会经历克莱森重排,羰基烯烃化和环化的串联序列。产物是被多重取代的6-或8-烯丙基化或烯丙基化的香豆素(2 H -chromen-2-ones)。 各种芳族邻羟基羰基化合物的烯丙基,二甲基烯丙基,巴豆基和异戊烯基醚在稳定的内酯存在下进行微波辐射后,会经历克莱森重排,羰基烯烃化和环化的串联序列。产物是被多重取代的6-或8-烯丙基化或烯丙基化的香豆素(2 H -chromen-2-ones)。
ABCA1 elevating compounds
申请人:Abelman Matthew
公开号:US20070010544A1
公开(公告)日:2007-01-11
The present invention provides compounds useful for increasing cellular ATP binding cassette transporter ABCA1 production in mammals, and to methods of using such compounds in the treatment of coronary artery diseases, dyslipidiemias and metabolic syndrome. The invention also relates to methods for the preparation of such compounds, and to pharmaceutical compositions containing them.
A General Synthetic Procedure for N-Unsubstituted Isoxazolidines<i>via</i>Nitrone-Olefin Cycloaddition. Remarkable Catalytic Effect of Bu<sub>2</sub>SnO
作者:Atsushi Abiko
DOI:10.1246/cl.1995.357
日期:1995.5
The remarkable catalysis of Bu2SnO for nitrone formation in the nitrone-olefin cycloaddition reaction has been discovered, and has led to the development of a general method for the synthesis of N-unsubstituted isoxazolidine derivatives.
In situ mechanochemical synthesis of nitrones followed by 1,3-dipolar cycloaddition: a catalyst-free, “green” route to cis-fused chromano[4,3-c]isoxazoles
作者:Zigmee T. Bhutia、Geethika P.、Anurag Malik、Vikash Kumar、Amrita Chatterjee、Biswajit Gopal Roy、Mainak Banerjee
DOI:10.1039/c5ra21044e
日期:——
An efficient, catalyst free mechanochemical route to cis-fused chromano[4,3-c]isoxazoles has been developed via a simple mortar-pestle grinding method.