- Highly enantioselective hydrogenation of quinoline and pyridine derivatives with iridium-(P-Phos) catalyst
-
The use of a chiral iridium catalyst gener-ated in situ from the (cyclooctadiene)iridium chlo-ride dimer, [Ir(COD)Cl]2, the P-Phos ligand [4, 4'-bis(diphenylphosphino)-2, 2', 6, 6'-tetramethoxy-3, 3'-bi-pyridine] and iodine (I2) for the asymmetric hydroge-nation of 2, 6-substituted quinolines and trisubstituted pyridines [2-substituted 7, 8-dihydroquinolin-5(6H)-one derivatives] is reported. The catalyst worked ef-ficiently to hydrogenate a series of quinoline deriva-tives to provide chiral 1, 2, 3, 4-tetrahydroquinolines in high yields and up to 96% ee. The hydrogenation was carried out at high S/C (substrate to catalyst) ratios of 2000-50000, reaching up to 4000 h-1 TOF (turnover frequency) and up to 43000 TON (turn-over number). The catalytic activity is found to be additive-controlled. At low catalyst loadings, de-creasing the amount of additive I2 was necessary to maintain the good conversion. The same catalyst system could also enantioselectively hydrogenate tri-substituted pyridines, affording the chiral hexahydro-quinolinone derivatives in nearly quantitative yields and up to 99% ee. Interestingly, increasing the amount of I2 favored high reactivity and enantiose-lectivity in this case. The high efficacy and enantiose-lectivity enable the present catalyst system of high practical potential.
- Tang, Wei-Jun,Tan, Jing,Xu, Li-Jin,Lam, Kim-Hung,Fan, Qing-Hua,Chan, Albert S. C.
-
supporting information; experimental part
p. 1055 - 1062
(2010/06/15)
-
- Highly efficient and enantioselective hydrogenation of quinolines and pyridines with Ir-Difluorphos catalyst
-
The combination of the readily available chiral bisphosphine ligand Difluorphos with [Ir(COD)Cl]2 in THF resulted in a highly efficient catalyst system for asymmetric hydrogenation of quinolines at quite low catalyst loadings (0.05-0.002 mol%), affording the corresponding products with high enantioselectivities (up to 96%), excellent catalytic activities (TOF up to 3510 h-1) and productivities (TON up to 43000). The same catalyst was also successfully applied to the asymmetric hydrogenation of trisubstituted pyridines with nearly quantitative yields and up to 98% ee. In these two reactions, the addition of I2 additive is indispensable; but the amount of I2 has a different effect on catalytic performance. The Royal Society of Chemistry 2010.
- Tang, Weijun,Sun, Yawei,Lijin, Xu,Wang, Tianli,Qinghua Fan,Lam, Kim-Hung,Chan, Albert S.C.
-
supporting information; experimental part
p. 3464 - 3471
(2010/08/21)
-
- 5-PHENYL-5,6,7,8-HYDROQUINOLINE TACHYKININ RECEPTOR ANTAGONISTS
-
The present invention is directed to certain 5-phenyl-5,6,7,8-hydroquinoline compounds which are useful as neurokinin-1 (NK-1) receptor antagonists, and inhibitors of tachykinin and in particular substance P. The invention is also concerned with pharmaceutical formulations comprising these compounds as active ingredients and the use of the compounds and their formulations in the treatment of certain disorders, including emesis, urinary incontinence, depression, and anxiety.
- -
-
Page/Page column 21
(2010/11/08)
-
- Nitrogen fixation: Synthesis of heterocycles using molecular nitrogen as a nitrogen source
-
Nitrogen fixation using transition metals is a fascinating process. We have already reported on the incorporation of molecular nitrogen into organic compounds using a titanium-nitrogen complex reported by Yamamoto. We developed a novel titanium-catalyzed nitrogenation procedure using TiCl4 in the presence of an excess amount of Li and TMSCl. In this reaction, a 1 atm pressure of nitrogen gas can be used and the reaction proceeds at room temperature. The procedure is very simple. A THF solution of TiCl4 or Ti(O iPr)4 (1 equiv.), Li (10 equiv.), and TMSCl (10 equiv.) was stirred under an atmosphere of nitrogen at room temperature overnight to give titanium-nitrogen complexes. Although the structures of the titanium-nitrogen complexes have not yet been determined, they would consist of N(TMS)3, X2TiN(TMS)2, and XTi=NTMS. Using this procedure, various heterocycles, such as indole, quinoline, pyrrole, pyrrolizine, and indolizine derivatives, could be synthesized from molecular nitrogen in good-to-moderate yields as a stoichiometric reaction based on a titanium complex by a one-pot reaction. Furthermore, monomorine I and pumiliotoxin C were synthesized from molecular nitrogen as a nitrogen source. This procedure was further extended for the syntheses of heterocycles using a catalytic amount of titanium complex; also, indole and pyrrole derivatives were obtained in high yields.
- Mori, Miwako,Akashi, Masaya,Hori, Masanori,Hori, Katsutoshi,Nishida, Mayumi,Sato, Yoshihiro
-
p. 1655 - 1670
(2007/10/03)
-
- Preparation of quinoline derivatives
-
A new process for preparing 5-oxo-tetrahydroquinolines comprises condensing a compound of formula II with a STR1 compound of formula III to obtain a compound of formula I wherein R, R1, R2 and R3 are selected from hydrogen and lower alkyl. Compounds of formula I are intermediates for pharmaceuticals.
- -
-
-
- Preparation of quinoline derivatives
-
A new process for preparing 5-oxo-tetrahydroquinolines comprises condensing a compound of formula II with a STR1 compound of formula III to obtain a compound of formula I wherein R, R1, R2 and R3 are selected from hydrogen or alkyl, aralkyl or aryl groups, Y is NH2 or OH accompanied by an ethylenic bond or Y is oxo and the double bond is absent and A is an amino or lower alkoxy group of 1-4 carbon atoms at least one of Y or A being amino. Compounds of formula I are intermediates for pharmaceuticals.
- -
-
-