621-19-2Relevant academic research and scientific papers
Hypervalent iodine(iii) induced oxidative olefination of benzylamines using Wittig reagents
Ramavath, Vijayalakshmi,Rupanawar, Bapurao D.,More, Satish G.,Bansode, Ajay H.,Suryavanshi, Gurunath
, p. 8806 - 8813 (2021/05/26)
We have developed hypervalent iodine(iii) induced oxidative olefination of primary and secondary benzylamines using 2C-Wittig reagents, which provides easy access to α,β-unsaturated esters. Mild reaction conditions, good to excellent yields with high (E) selectivity, and a broad substrate scope are the key features of this reaction. We have successfully carried out the gram-scale synthesis of α,β-unsaturated esters.
Solvent role in the lipase-catalysed esterification of cinnamic acid and derivatives. Optimisation of the biotransformation conditions
Suárez-Escobedo, Laura,Gotor-Fernández, Vicente
, (2021/02/05)
The esterification of cinnamic acid has been deeply investigated using ethanol as nucleophile and Candida antarctica lipase type B (CAL-B) as suitable biocatalyst. Special attention has been paid to the role that the solvent plays in the production of ethyl cinnamate. Therefore, volatile organic solvents and deep eutectic mixtures were employed in order to find optimal reaction conditions. Once that hexane was selected as the solvent of choice, other parameters that affect the enzyme activity were investigated in order to produce ethyl cinnamate with excellent yield. The CAL-B loading, nucleophile equivalents, temperature and reaction time have been identified as key parameters in the enzyme efficiency, and the potential of lipase-catalysed esterification has been finally exploited to produce a series of ethyl esters with different pattern substitutions on the aromatic ring.
1,3-Diphenyldisiloxane Enables Additive-Free Redox Recycling Reactions and Catalysis with Triphenylphosphine
Buonomo, Joseph A.,Cole, Malcolm S.,Eiden, Carter G.,Aldrich, Courtney C.
, p. 3583 - 3594 (2020/09/15)
The recently reported chemoselective reduction of phosphine oxides with 1,3-diphenyldisiloxane (DPDS) has opened up the possibility of additive-free phosphine oxide reductions in catalytic systems. Herein we disclose the use of this new reducing agent as an enabler of phosphorus redox recycling in Wittig, Staudinger, and alcohol substitution reactions. DPDS was successfully utilized in ambient-temperature additive-free redox recycling variants of the Wittig olefination, Appel halogenation, and Staudinger reduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalytic Staudinger reductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters. These results demonstrate the utility of DPDS as an excellent reducing agent for the development of phosphorus redox recycling reactions.
Extended architectures constructed of thiourea-modified SBA-15 nanoreactor: A versatile new support for the fabrication of palladium pre-catalyst
Alamgholiloo, Hassan,Noroozi Pesyan, Nader,Rostamnia, Sadegh
, (2020/02/04)
We designed and synthesized a novel catalyst consisting of ordered mesoporous silica (SBA-15) functionalized with bis(thiourea) (BTU) linker. The regular and unique pore channels of BTU-SBA-15 ensure proper control of the size and homogeneous distribution of palladium nanoparticles. The physiochemical properties of the hybrid Pd?BTU-SBA-15 pre-catalyst were investigated using various techniques. The proposed catalyst is found to be very active, reusable, stable and scalable, and has excellent reactivity and selectivity for Suzuki and Heck coupling reactions under very mild and sustainable reaction conditions.
Synthesis of Nitrogen-Containing Goniothalamin Analogues with Higher Cytotoxic Activity and Selectivity against Cancer Cells
Meirelles, Matheus A.,Braga, Carolyne B.,Ornelas, Catia,Pilli, Ronaldo A.
supporting information, p. 1403 - 1417 (2019/08/01)
Two series of racemic goniothalamin analogues displaying nitrogen-containing groups were designed and synthesized. A total of 19 novel analogues were evaluated against a panel of four different cancer cell lines, along with the normal prostate cell line PNT2 to determine their selectivity. Among them, goniothalamin chloroacrylamide 13 e displayed the lowest IC50 values for both MCF-7 (0.5 μm) and PC3 (0.3 μm) cells, about 26-fold more potent than goniothalamin (1). Besides its higher potency, compound 13 e also displayed much higher selectivity than goniothalamin. In contrast, goniothalamin isobutyramide 13 c was the most potent analogue against Caco-2 cells (IC50=0.8 μm), about 10-fold more potent and 17-fold more selective than 1. These results reveal the potential of compounds 13 c and 13 e for further in vivo studies, representing the first goniothalamin analogues with IC50 values in the low micromolar range and high selectivity against MCF-7, Caco-2, and PC3 cancer cell lines.
Biocatalytic dynamic kinetic reductive resolution with ketoreductase from: Klebsiella pneumoniae: The asymmetric synthesis of functionalized tetrahydropyrans
Barik, Rasmita,Halder, Joydev,Nanda, Samik
supporting information, p. 8571 - 8588 (2019/10/02)
Ketoreductase from growing cells of Klebsiella pneumoniae (NBRC 3319) acts as an efficient reagent for converting racemic α-benzyl/cinnamyl substituted-β-ketoesters to the corresponding β-hydroxy esters with excellent yields and stereoselectivities (ee and de >99 %). The reactions described herein followed a biocatalytic dynamic kinetic reductive resolution (DKRR) pathway, which is reported for the first time with such substrates. It was found that the enzyme system can accept substituted mono-aryl rings with different electronic natures. In addition, it also accepts a substituted naphthyl ring and heteroaryl ring in the α-position of the parent β-ketoester. The synthesized enantiopure β-hydroxy esters were then synthetically manipulated to valuable tetrahydropyran building blocks.
Catalytic Diastereo- and Enantioselective Fluoroamination of Alkenes
Mennie, Katrina M.,Banik, Steven M.,Reichert, Elaine C.,Jacobsen, Eric N.
supporting information, p. 4797 - 4802 (2018/04/17)
The stereoselective synthesis of syn-β-fluoroaziridine building blocks via chiral aryl iodide-catalyzed fluorination of allylic amines is reported. The method employs HF-pyridine as a nucleophilic fluoride source together with mCPBA as a stoichiometric oxidant, and affords access to arylethylamine derivatives featuring fluorine-containing stereocenters in high diastereo- and enantioselectivity. Catalyst-controlled diastereoselectivity in the fluorination of chiral allylic amines enabled the preparation of highly enantioenriched 1,3-difluoro-2-amines bearing three contiguous stereocenters. The enantioselective catalytic method was applied successfully to other classes of multifunctional alkene substrates to afford anti-β-fluoropyrrolidines, as well as a variety of 1,2-oxyfluorinated products.
Gold catalyzed Heck-coupling of arenediazonium o-benzenedisulfonimides
Barbero, Margherita,Dughera, Stefano
, p. 295 - 301 (2018/01/12)
Diazonium salts, and precisely arenediazonium o-benzenedisulfonimides, have been used for the first time as efficient electrophilic partners in gold catalyzed Heck-coupling reactions. The synthetic protocol was general, easy and gave the target products in satisfactory yields. Mechanistic insights revealed the fundamental roles of the o-benzenedisulfonimide anion as an electron transfer agent thath promotes a radical pathway that does not require the presence of photocatalysts or external oxidants.
Stepwise post-modification immobilization of palladium Schiff-base complex on to the OMS-Cu (BDC) metal–organic framework for Mizoroki-Heck cross-coupling reaction
Alamgholiloo, Hassan,Rostamnia, Sadegh,Hassankhani, Asadollah,Khalafy, Jabbar,Baradarani, Mehdi M.,Mahmoudi, Ghodrat,Liu, Xiao
, (2018/09/06)
Palladium ions were successfully immobilized within the pores of open metal site (OMS) metal organic frameworks (MOFs) with Schiff-base (2-Py-SI) grafted in OMS-Cu (BDC) using the hydrothermal method. This Schiff-base complex on the Cu (BDC) greatly increased catalytic activity and acted as an efficient stabilizer of Pd ions. The hydrothermal method was a more efficient method for generating small metal ions in the MOF structures. The results revealed that the PdII@Cu (BDC)/2-Py-SI is a promising catalyst for the Mizoroki-Heck coupling reaction. The proposed catalyst has better recyclability and can be reused several times without apparent loss of activity.
5,6-dihydropyrrolo[2,1-a]isoquinolines as alternative of new drugs with cytotoxic activity
Chávez-Santos, Rosa María,Torres-Ochoa, Rubén Omar,Ramírez-Apan, María Teresa,Martínez, Roberto,Reyes-Gutiérrez, Paul Eduardo
, p. 973 - 981 (2018/11/02)
In this study, the pyrrolo[2,1-a]isoquinolines 4a–n were synthesized in good yields in a three steps synthesis from the corresponding α,β-unsaturated esters starting materials. These compounds were tested on six human cancer cells lines to measure the cyt
