Chemical modification of plant alkaloids. I. Aminomethylation of barbituric acid derivatives by cytisine
摘要:
Reaction of cytisine with 1-mono- and 1,3-disubstituted 5-arylmethylbarbituric acids in the presence of formaldehyde results in aminomethylation of C-5 to form the corresponding 5-cytisylmethylbarbituric acids. The structures of the products are found using PMR spectroscopy mid mass spectrometry. 1-Phenyl-5-(2,4-dimethoxybenzyl)-5-cytisylmethylbarbituric acid is obtained as a mixture of two steroisomers in an approximately 2:1 ratio.
Diastereoselective Synthesis of Spirobarbiturate-Cyclopropanes through Organobase-Mediated Spirocyclopropanation of Barbiturate-Based Olefins with Benzyl Chlorides
Abstract The organobase-mediated diastereoselective spirocyclopropanation of barbiturate-based olefins with 2,4-disubstituted benzyl chlorides has been developed. The reactions were carried out efficiently to afford the desired spirobarbiturate-cyclopropanes in up to 95% yield with more than 20:1 dr in favor of anti-isomers. In order to extend synthetic utility of the spiro-products, a Lewis acid induced
Self-Assembled Pd<sub>6</sub>Open Cage with Triimidazole Walls and the Use of Its Confined Nanospace for Catalytic Knoevenagel- and Diels-Alder Reactions in Aqueous Medium
作者:Dipak Samanta、Sandip Mukherjee、Yogesh P. Patil、Partha Sarathi Mukherjee
DOI:10.1002/chem.201201679
日期:2012.9.24
the formation of a water‐soluble semi‐cylindrical cage with a hydrophobiccavity, which was separately crystallized with hydrophilic‐ and hydrophobic guests. The parent cage was found to catalyze the Knoevenagel condensation reaction of a series of aromatic mono‐aldehydes with active methylene compounds, such as Meldrum′sacid or 1,3‐dimethylbarbituric acid. The confined hydrophobic nanospace within
(L) was investigated with 90° cis-blocked Pd(II) acceptors and tetratopic Pd(NO3)2. Although the ligand is capable of binding in several different conformations (acting as a ditopic donor through the pyridyl nitrogens), the experimental results (including X-ray structures) showed that it adopts a particular conformation when it binds with 90° cis-blocked Pd(II) acceptors (two available sites) to yield
用90°顺式封端的Pd(II)研究了3-(5-(吡啶-3-基)-1 H -1,2,4-三唑-3-基)吡啶(L)的配位驱动自组装)受体和四位Pd(NO 3)2。尽管该配体能够以几种不同的构象结合(通过吡啶基氮充当对位供体),但实验结果(包括X射线结构)表明,当它与90°顺式阻断的Pd结合时,它会采用特定的构象。(II)受体(两个可用位点)产生[2 + 2]个自组装大环。另一方面,Pd(NO 3)2(存在四个可用位点),同一供体的不同构象异构体被选择性结合以形成分子立方笼。实验结果与密度泛函理论(B3LYP)的计算得到了很好的证实。四位Pd(NO 3)2产生[6 + 12]自组装的Pd 6 L 12分子立方体,其中包含被硝酸根和高氯酸根离子占据的潜在空隙。作为一种基于三唑的配体,笼内的自由空间富含几个sp 2杂化的氮原子与孤对电子杂交,充当路易斯碱性位点。几种芳香醛与活性亚甲基化合物的Knoe
2-Phenyl-2,3-dihydrobenzo[d]thiazole: A Mild, Efficient, and Highly Active in situ Generated Chemoselective Reducing Agent for the One-Pot Synthesis of 5-Monoalkylbarbiturates in Water
作者:Dibakar Deka、Subarna Kalita
DOI:10.1055/s-0036-1591725
日期:2018.3
protocol for the one-pot synthesis of 5-monoalkylbarbiturates from barbituric acids and aldehydes using the in situ generated chemoselectivereducingagent 2-phenyl-2,3-dihydrobenzo[ d ]thiazole from 2-aminothiophenol and benzaldehyde is described. The notable advantages of the protocol are operational simplicity, mild reaction conditions, high yield, short reaction time, and simple workup and purification
L-Proline based ionic liquid: A highly efficient and homogenous catalyst for synthesis of 5-benzylidene-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione and pyrano[2,3-d] pyrimidine diones under ultrasonic irradiation
作者:Paresh G. Patil、Yuvraj Satkar、Dhananjay H. More
DOI:10.1080/00397911.2020.1811987
日期:2020.12.16
Abstract A catalytic, practical, efficient procedure for the synthesis of 5-benzylidene-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione and pyrano[2,3-d] pyrimidine diones at roomtemperature was developed using L-Proline nitrate ionic liquid under ultrasonic irradiation. The L-Proline nitrate is homogeneous and green catalyst easy to prepare by mixing L-Proline and nitric acid possess excellent catalytic