Chemoenzymatic Synthesis of Pyrrolo[2,1-b]quinazolinones: Lipase-Catalyzed Resolution of Vasicinone
摘要:
A facile synthesis of bronchodilatory pyrrolo [2,1-b] quinazoline alkaloids by azidoreductive cyclization strategy employing TMSCl-NaI and bakers' yeast is described. Both the chemical and enzymatic methods are mild and take place at room temperature in good yields. Further, synthesis and resolution of vasicinone has been carried out by employing different lipases. It has been observed that lipase PS provides acetate of (S)-vasicinone in 98% ee.
FeCl3/NaI has been employed for an efficientreduction of a variety of azides. This method is selective in the presence of a nitro functionality and has been extended for the synthesis of fused [2,1-b]quinazolinone ring systems such as deoxyvasicinone.
FeCl 3 / NaI已用于有效还原各种叠氮化物。该方法在硝基官能团存在的情况下是选择性的,并且已经扩展为合成稠合的[ 2,1- b ]喹唑啉酮环系统,例如脱氧维辛酮。
Chemoselective Aromatic Azido Reduction with Concomitant Aliphatic Azide Employing Al/Gd Triflates/NaI and ESI-MS Mechanistic Studies
triflates catalyze the chemoselective reduction of aromatic azides to the corresponding amines in combination with sodium iodide. This mild chemoselective method has been applied to the synthesis of various aryl amines, C2‐azido‐substituted pyrrolo[2,1‐c][1,4]benzodiazepines, and fused[2,1‐b]quinazolinones by an intramolecular azido reduction tandem cyclization reaction. Interestingly, this methodology
铝和ado三氟甲磺酸盐与碘化钠一起催化将芳族叠氮化物化学选择性还原为相应的胺。这种温和的化学选择性方法已应用于各种芳基胺的合成,C2叠氮基取代的吡咯并[2,1- c ^ ] [1,4]苯二氮,和稠合[2,1- b通过分子内还原叠氮]喹唑啉酮串联环化反应。有趣的是,这种方法选择性地还原了芳基叠氮化物,提高了产率,并且比以前的策略在较短的反应时间内进行。已对机理进行了研究,并通过ESI-MS在线监测反应来拦截和表征与这种选择性转化有关的中间体。
A Polymer-Assisted Solution-Phase Strategy for the Synthesis of Fused [2,1-<i>b</i>]Quinazolinones and the Preparation of Optically Active Vasicinone
作者:Ahmed Kamal、V. Devaiah、N. Shankaraiah、K. Reddy
DOI:10.1055/s-2006-951482
日期:2006.9
An efficient preparation of fused [2,1-b]quinazolinones has been developed utilizing polymer-supported reagents. (±)-Vasicinone was converted into its dione by oxidation with poly (4-vinylpyridiniumdichromate). An efficient method has been developed for the synthesis of (d)- and (l)-vasicinone via asymmetric reduction of pyrrolo[2,l-b]quinazoline-3,9-dione by employing NaBH 4 /Me 3 SiCl as the reducing
One pot conversion of azido arenes to N-arylacetamides and N-arylformamides: synthesis of 1,4-benzodiazepine-2,5-diones and fused [2,1-b]quinazolinones
Sodium iodide in acidic media has been employed for the synthesis of N-arylformamides and N-arylacetamides. The NaI/acetic acid reagent system has also been extended for the synthesis of 1,4-benzodiazepine-2,5-diones, pyrrolo[2,1-c][1,4]benzodiazepine-5,11-diones, and fused [2,1-b]quinazolinones. (C) 2004 Published by Elsevier Ltd.