625852-58-6Relevant articles and documents
A new chiral anthracene for the asymmetric Diels-Alder/retro-Diels-Alder sequence
Burgess, Kerrie L.,Lajkiewicz, Neil J.,Sanyal, Amitav,Yan, Wanlin,Snyder, John K.
, p. 31 - 34 (2005)
(Chemical Equation Presented) (-)-(R)-9-(1,2-Dimethoxyethyl)anthracene (8) is successfully employed as a chiral template in the Diels-Alder/retro-Diels- Alder sequence for the preparation of α,β-unsaturated lactams. The cycloadditions proceed with complet
Facile and short synthesis of (±) 1-hydroxy indolizidine and (±) coniceine from picolinic acid ethyl ester via cross claisen condensation
Veeraswamy,Anjaiah,Yennam, Satyanarayana,Jayashree
, p. 1667 - 1670 (2015/03/04)
New short synthesis of (±) 1-hydroxy indolizidine (4) and (±) coniceine (5) are described starting from picolinic acid ethyl ester (6). The key steps are the conversion of the picolinic acid ethyl ester into β-keto ester 7 via cross Claisen condensation and hydrogenation of the β-keto ester in to hydroxy bicyclic amide (8) using PtO2/H2.
Carbamoylimidazolium and thiocarbamoylimidazolium salts: Novel reagents for the synthesis of ureas, thioureas, carbamates, thiocarbamates and amides
Grzyb, Justyna A.,Shen, Ming,Yoshina-Ishii, Chiaki,Chi,Brown, R. Stanley,Batey, Robert A.
, p. 7153 - 7175 (2007/10/03)
Carbamoylimidazolium salts act as efficient N,N-disubstituted carbamoylating reagents. These salts are readily prepared by the sequential treatment of secondary amines with N,N′-carbonyldiimidazole (CDI) and iodomethane. The carbamoylimidazolium salts are more efficient carbamoyl transfer reagents than the intermediate carbamoylimidazoles, as a result of the 'imidazolium' effect. Kinetic studies on the base promoted hydrolysis of both carbamoylimidazoles and carbamoylimidazolium salts reveal over a hundred-fold rate acceleration. The salts react with amines, thiols, phenols/alcohols, and carboxylic acids in high yields, without the need for subsequent chromatographic purification of the products, producing ureas, thiocarbamates, carbamates, and amides, respectively. Analogous thiocarbamoylimidazolium salts were also synthesized from secondary amines and N,N′-thiocarbonyldiimidazole (TCDI), followed by methylation with iodomethane.
Carbamoylimidazolium salts as diversification reagents: An application to the synthesis of tertiary amides from carboxylic acids
Grzyb, Justyna A.,Batey, Robert A.
, p. 7485 - 7488 (2007/10/03)
An efficient method for the preparation of tertiary amides from carbamoylimidazolium salts and carboxylic acids is described. The transformation occurs at room temperature and under relatively mild conditions. The carbamoylimidazolium salts are obtained from the reaction of secondary amines with N,N′-carbonyldiimidazole, followed by methylation with methyl iodide. The utility of this reaction was demonstrated in the formation of Weinreb amides and in a short synthesis of fused bicyclic amides. The introduction of this reaction now permits carbamoylimidazolium salts to be utilized in the formation of tertiary amides, ureas, carbamates and thiocarbamates under a single set of conditions.
Enantiocontrolled preparation of indolizidines: Synthesis of (-)-2-epilentiginosine and (+)-lentiginosine
Rasmussen,Delair,Greene
, p. 5438 - 5443 (2007/10/03)
A highly stereoselective approach to (-)-2-epilentiginosine and (+)-lentiginosine has been developed based on a diastereofacially selective cycloaddition of dichloroketene with a chiral dienol ether. The two naturally occurring indolizidines are each obtained enantioselectively (≥ 99:1) in ca. 8.5% overall yield.
