Application of modified Pictet-Spengler reaction for the synthesis of thiazolo- and pyrazolo-quinolines

被引:64
作者
Duggineni, S [1 ]
Sawant, D [1 ]
Saha, B [1 ]
Kundu, B [1 ]
机构
[1] Cent Drug Res Inst, Div Med Chem, Lucknow 226014, Uttar Pradesh, India
关键词
thiazoloquinoline; pyrazoloquinoline; Pictet-Spengler reaction; C-C bond formation;
D O I
10.1016/j.tet.2006.01.063
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Two new thiazole and pyrazole-based arylamine substrate have been used for the Pictet-Spengler reaction. This is in contrast to the traditionally used indole/imidazole-based aliphatic amine substrates that has remained in use for the last similar to 100 years. The condensation of both the substrates with a variety of aldehydes in the presence of 2% TFA-DCM at 0 degrees for 30 min or pTsOH in toluene at reflux led to the synthesis of thiazoloquinolines and pyrazoloquinolines, respectively. Unlike aliphatic amine substrates, our substrates readily underwent Pictet-Spengler cyclization even with aldehydes having electron donating group. The studies are based on a new concept proposed by us that arylamines linked to an activated heterocyclic ring can lead to a variety of second-generation substrates for the Pictet-Spengler cyclization. Our studies open up new avenues for the application of Pictet-Spengler reaction beyond syntheses of the tetrahydroisoquinolines and tetrahydro-beta-carbolines. (c) 2006 Elsevier Ltd. All rights reserved.
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页码:3228 / 3241
页数:14
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