An unusual synthesis of tetrahydrobenzo[f]isoquinolines
作者:Ramendra Pratap、Resmi Raghunandan、P.R. Maulik、Vishnu Ji Ram
DOI:10.1016/j.tetlet.2007.09.059
日期:2007.11
A facile and short synthesis of 2-oxo-4-sec-amino-2,3,5,6-tetrahydrobenzo[f]isoquinoline-1-carbonitriles has been delineated through base catalyzed ring transformation of 5,6-dihydro-2-oxo-4-sec-amino-2H-benzo[h]chromene-3-carbonitrile by cyanoacetamide in excellent yields.
通过5,6-二氢-2-的碱催化环转化,描述了2-氧代-4-仲-氨基-2,3,5,6-四氢苯并[ f ]异喹啉-1-腈的简便快速合成方法氰基乙酰胺制备的oxo-4-仲-氨基-2 H-苯并[ h ]亚甲基-3-甲腈具有优异的收率。
Step-wise and one-pot synthesis of highly substituted conjugated trienes from 2-oxobenzo[<i>h</i>]chromenes/2<i>H</i>-pyran-2-ones
作者:Amr Elagamy、Ismail Althagafi、Ramendra Pratap
DOI:10.1039/d1ob00314c
日期:——
been developed for the construction of trienes. The mixture of the (E)- and (Z)-isomers of spirobutenolides undergoes decarboxylative rearrangement in the presence of sodium ethoxide as a base to yield the (E)-isomer of trienes, while the (E)-isomer of butenolides reacts to give a mixture of (2E,4E)- and (2E,4Z)-isomers of trienes in an almost steady ratio of 45 : 55 or 1 : 1.2. The structure and geometry
描述了通过硝基乙烷介导的 2-氧代苯并[ h ]色烯/2 H-吡喃-2-酮的环收缩,然后对所得螺丁烯内酯和丁烯内酯进行脱羧重排,合成共轭三烯的温和有效途径。三烯的( E )-异构体是通过逐步和一锅法从2-氧代苯并[ h ]色烯中获得的。丁烯内酯4a-l作为新的底物已被开发用于构建三烯。螺丁烯内酯的 ( E )- 和 ( Z )-异构体的混合物在乙醇钠作为碱存在下发生脱羧重排产生 ( E ))-三烯异构体,而丁烯内酯的 ( E )-异构体反应生成 (2 E ,4 E )- 和 (2 E ,4 Z )-三烯异构体的混合物,比例几乎稳定为 45 : 55或 1:1.2。所得丁烯内酯和三烯的结构和几何形状通过单晶 X 射线分析得到证实。
An expeditious protocol for sesquiterpene-cored functionalized arenes from S-(−)-citronellal
作者:Atul Goel、Deepti Verma
DOI:10.1016/j.tetlet.2009.02.117
日期:2009.5
An expeditious straightforward synthesis of sesquiterpene-cored arenes functionalized with electron-withdrawing or electron-donating substituents is described and illustrated by Michael addition of S(-)-citronellal on functionalized 2H-pyran-2-one in a single step at room temperature. The reaction was further generalized by synthesizing isoprenylated 9,10-dihydrophenanthrene-2-carbonitrile using 5,6-dihydro-2-oxo-4-sec-amino-2H-benzo[h]chromene-3-carbonitriles and S-(-)-citronellal under similar reaction conditions. (c) 2009 Elsevier Ltd. All rights reserved.
A non-catalytic approach to the synthesis of 5,6-dihydrobenzo[h]quinolines
作者:Ramendra Pratap、Vishnu Ji Ram
DOI:10.1016/j.tetlet.2007.02.049
日期:2007.4
A concise synthesis of highly functionalized 5,6-dihydrobenzo[h]quinoline-3-carbonitriles is delineated through base induced ring transformation of 4-sec-amino-2-oxo-5,6-dihydro-2H-benzo[h]chromene-3-carbonitriles with S-methylisothiourea sulfate and 1-carboxamidinepyrazole hydrochloride, separately, in DMF. Under analogous reaction conditions the ring transformation of 4-sec-amino-2-oxo-5,6-dihydro-2H-benzo[h]chromene-3-carbonitriles by formamidine acetate provided 4-sec-amino-benzo[h]quinoline-3-carbonitriles in moderate yields, while with benzamidine hydrochloride, the reaction followed the same mechanism to yield 2-phenyl-4-sec-amino-5,6-dihydrobenzo[h]quinoline-3-carbonitriles. (c) 2007 Elsevier Ltd. All rights reserved.
Economical synthesis of novel class of heteroatom containing partially reduced polycyclic aromatic hydrocarbons
作者:Ramendra Pratap、Vishnu Ji Ram
DOI:10.1016/j.tetlet.2009.03.161
日期:2009.6
An efficient and convenient synthesis of 2-oxa- and 2-thia-3,4,7,8-tetrahydro-1H-benzo[c]phenanthrenes has been described through base-induced rind, transformation of 2-oxo-4-sec.amino-5,6-dihydro-2H-benzo[h]chromene-3-carbonitriles by 4-oxotetrahydropyran and 4-oxotetrahydrothiopyran, respectively, in excellent yields. (C) 2009 Elsevier Ltd. All rights reserved.