通过在磷腈和腈官能团之间发生不寻常的氮杂-维蒂希反应并提供吡咯衍生的亚氨基磷腈,进行了α-EWG取代(吸电子基团,EWG)γ-叠氮基丁腈的转化。发现α-EWGs控制化学选择性,并取决于其性质,在氮杂-Wittig反应中充当CN基团活化剂(例如,酯,酰胺或腈)或竞争剂(例如,酮)。为了证明所得亚氨基磷腈作为N,N-双亲核试剂的合成效用,将其转化为吡咯稠合体系,即吡咯并[1,2- a ]咪唑和吡咯并[1,2- a ] [1,3]二氮杂s。执行。
An Acidic Layered Clay Is Combined with A Basic Layered Clay for One-Pot Sequential Reactions
摘要:
A Ti4+-exchanged montmorillonite (Ti4+-mont) and a hydrotalcite (HT) are strong solid Brønsted acid and base, and these two clay catalysts could be used in a single reactor without neutralization of active sites. Because the Ti4+-mont have active acid site in the narrow interlayers, the base sites of large HT particles show no interaction with the acid sites. A variety of acid and base reactions, such as esterification, acetalization, deacetalization, aldol reaction, Michael reaction, and epoxidation, proceeded using both the Ti4+-mont and the HT in a single reactor.
Lewis Acid Triggered Vinylcyclopropane–Cyclopentene Rearrangement
作者:Olga A. Ivanova、Alexey O. Chagarovskiy、Alexey N. Shumsky、Vasiliy D. Krasnobrov、Irina I. Levina、Igor V. Trushkov
DOI:10.1021/acs.joc.7b02351
日期:2018.1.19
donor–acceptor cyclopropanes, containing an alkenyl moiety and diverse electron-withdrawinggroup(s) at the adjacent positions, into substituted cyclopentenes. We have found that 1,1,2-trisubstituted cyclopent-3-enes were exclusively obtained in yield of 51–99% when cyclopropanes with a 2-substituted alkenyl group as a donor underwent isomerization. For cyclopropanes bearing a trisubstituted alkenyl group either
Search for Antimicrobial Activity Among Fifty-Two Natural and Synthetic Compounds Identifies Anthraquinone and Polyacetylene Classes That Inhibit Mycobacterium tuberculosis
作者:Luiz A. E. Pollo、Erlon F. Martin、Vanessa R. Machado、Daire Cantillon、Leticia Muraro Wildner、Maria Luiza Bazzo、Simon J. Waddell、Maique W. Biavatti、Louis P. Sandjo
DOI:10.3389/fmicb.2020.622629
日期:——
New antimicrobial drugs are required, derived from new chemical classes. Naturalproductsoffer extensive chemical diversity and inspiration for syntheticchemistry. Here, we isolate, synthesize and test a library of 52 natural and synthetic compounds for activity against Mycobacterium tuberculosis. We identify seven compounds as antimycobacterial, including the naturalproducts isobavachalcone and
Prospecting for cytotoxic and antiprotozoal 4-aryl-4<i>H</i>-chromenes and 10-aryldihydropyrano[2,3-<i>f</i>]chromenes
作者:Erlon F. Martin、Armelle T. Mbaveng、Milene H. de Moraes、Victor Kuete、Maique W. Biavatti、Mario Steindel、Thomas Efferth、Louis P. Sandjo
DOI:10.1002/ardp.201800100
日期:2018.10
Different studies reported that genetic predisposition or metabolic dysfunction are the risk factors for cancer. Infectious parasitic diseases were listed among factors that predispose to cancer. Because of the resemblance between the life cycle of cancer cells and some parasites, this study aimed to prepare pyran derivatives with cytotoxic and antiprotozoal potencies. Therefore, 7 chromenes, 10 pyranocoumarins
Phosphate naturel et phosphate trisodique : nouveaux catalyseurs solides de la condensation de Knoevenagel en Milieu Hétérogène
作者:Saïd Sebti、Ahmed Saber、Abdallah Rhihil
DOI:10.1016/s0040-4039(00)78552-2
日期:1994.12
The Knoevenagel condensation of aldehydes with active methylene compounds was carried out at room temperature, on a heterogenous media, in the absence of solvent or in the methanol, using phosphate ore or sodium phosphate as new catalysts.
Synthesis of (E)-α,β-unsaturated carboxylic esters derivatives from cyanoacetic acid via promiscuous enzyme-promoted cascade esterification/Knoevenagel reaction
lipase-catalyzed cascade toward (E)-α,β-unsaturatedcarboxylic esters is presented. The proposed methodology consists of elementary organic processes starting from acetals and cyanoacetic acid leading to the formation of desired products in a cascade sequence. The combination of enzyme promiscuous abilities gives a new opportunity to synthesize complex molecules in the one-pot procedure. Results of studies