- Synthesis of new optically active 2-pyrrolidinones
-
A new class of optically active 2-pyrrolidinones was synthesized, starting from S-pyroglutamic acid, a well known natural chiral synthon. The synthetic design followed led to the insertion of various substituents at positions 1 and 5 of the 2-pyrrolidinone ring, including the imidazole moiety. Some of them possess two or three stereogenic centers, the configuration of which was retained under the mild conditions used. The new compounds also carry an imidazole moiety, which, along with the 2-pyrrolidinone template, may prove pivotal to several biological processes.
- Moutevelis-Minakakis, Panagiota,Papavassilopoulou, Eleni,Mavromoustakos, Thomas
-
-
- Reduction of carboxylic acids using esters of benzotriazole as high-reactivity intermediates
-
Herein, we describe a simple and practical protocol for the reduction of carboxylic acids via the in situ formation of hydroxybenzotriazole esters followed by reaction with sodium borohydride to give the corresponding alcohols. The reaction proceeds with excellent yields in the presence of water. Georg Thieme Verlag Stuttgart - New York.
- Morales-Serna, Jose Antonio,Garcia-Rios, Erendira,Bernal, Jorge,Paleo, Ehecatl,Gavino, Ruben,Cardenas, Jorge
-
scheme or table
p. 1375 - 1382
(2011/06/19)
-
- 1-substituted, 3-carboxylic acid piperidine derivatives
-
The present invention relates to therapeutically active azaheterocyclic compounds, a method of preparing the same and to pharmaceutical compositions comprising the compounds. The novel compounds are useful in treating a central nervous system ailment related to the GABA uptake.
- -
-
-
- Alkyl Ether and Enol Ether Analogs of (Z)-5-Decenyl Acetate, a Pheromone Component of the Turnip Moth, Agrotis segetum: Probing a Proposed Bioactive Conformation for Chain-Elongated Analogs
-
In order to test a previous conclusion that chain-elongated analogs of (Z)-5-decenyl acetate (1), a pheromone component of the turnip moth, Agrotis segetum, adopt a loop conformation of the terminal alkyl chain in the bioactive conformation, a series of alkyl ether and enol ether analogs of 1 and (Z)-5-dodecenyl acetate (2) have been synthesized and tested using single-cell electrophysiology. In these analogs a methylene group in positions 7 and 9 of 1 and in positions 7 and 11 in 2 have been replaced by an oxygen atom in order to energetically facilitate the formation of a loop conformation in the chain-elongated analogs. The electrophysiological results in combination with molecular mechanics (MM2 and MM3) calculated conformational energies show that the activity decreases of the chain-elongated ether analogs are significantly smaller than that for 2 and that these activity decreases parallel the conformational energies for a loop formation of the terminal chains in the analogs. The results support our previous conclusion that the terminal chain of chain-elongated analogs of 1 adopts a loop conformation in their bioactive conformations.
- Gustavsson, Anna-Lena,Liljefors, Tommy,Hansson, Bill S.
-
p. 815 - 832
(2007/10/03)
-
- Anti-ferroelectric liquid crystal and liquid crystal display device
-
A novel anti-ferroelectric liquid crystal of the formula (I), STR1 wherein: is an integer of 3 to 8, each of X and Y is independently a hydrogen atom or a fluorine atom, Z is --CF3, --CH3 or --C2 H5, q is 0 or 5, m is 0 or 1, n is an integer of 2 to 8, and C* is an asymmetric carbon, provided that when m is 0, q is 0 and n is an integer of 4 to 8 and that when m is 1, q is 5 and z is --CF3, and use of tile above liquid crystal as a liquid crystal display device.
- -
-
-
- Hydrogen Bonds involving Polar CH Groups. Part 9. Optimum Structural Parameters, and Unequivocal Demonstration of such Intramolecular Interactions in 2-Substituted 1,3-Dithian 1,1,3,3-Tetraoxides
-
A series of 2-monosubstituted 1,3-dithian 1,1,3,3-tetraoxides have been prepared, having side chains with 2-6 carbon atoms, and bearing alkyl, aryl, methoxy, dialkylamino, and pyridyl terminal substituents, as models for intramolecular C-H...X hydrogen bonds.Methoxy- and amino-substituents, in compounds having two or three carbon atoms in the side chain, show significant intramolecular interaction with the disulphone methine hydrogen in dichloromethane, as evidenced by a downfield shift of the 1H n.m.r. signals; shifts of up to 2.0 p.p.m. have been observed.Intramolecular H-bonds are disrupted in acetone and in pyridine owing to competing intermolecular interactions with the solvents, and in trifluoroacetic acid owing to protonation of the donor atom.
- Li, Chuen,Sammes, Michael P.
-
p. 1303 - 1310
(2007/10/02)
-