Search results for " Synthesis"

Catalytic Asymmetric Formal [3+2] Cycloaddition of 2-Isocyanatomalonate Esters and Unsaturated Imines: Synthesis of Highly Substituted Chiral γ-Lacta…

2017

[EN] Unlike their isocyano and isothiocyanato analogues, isocyanato esters remain almost unexplored as formal 1,3-dipoles in asymmetric catalytic reactions. The first asymmetric formal [3+2] cycloaddition involving isocyanato esters and electrophilic alkenes is reported. Diisopropyl 2-isocyanatomalonate reacts with a,b-unsaturated N-(o-anisidyl) imines in the presence of a Mg(OTf)2¿BOX complex to give highly substituted chiral pyrrolidinones featuring a conjugate exocyclic double bond with excellent yields and enantiomeric excesses up to 99%. Several transformations of the resulting heterocycles, including the synthesis of a pyroglutamic acid derivative, have been carried out.

Syntheses and catalytic oxotransfer activities of oxo molybdenum(vi) complexes of a new aminoalcohol phenolate ligand.

2017

The new aminoalcohol phenol 2,4-di-tert-butyl-6-(((2-hydroxy-2-phenylethyl)amino)methyl)phenol (H2L) was prepared by a facile solvent-free synthesis and used as a tridentate ligand for new cis-dioxomolybdenum(vi)(L) complexes. In the presence of a coordinating solvent (DMSO, MeOH, pyridine), the complexes crystallise as monomeric solvent adducts while in the absence of such molecules, a trimer with asymmetric Mo[double bond, length as m-dash]O→Mo bridges crystallises. The complexes can catalyse epoxidation of cis-cyclooctene and sulfoxidation of methyl-p-tolylsulfide, using tert-butyl hydroperoxide as oxidant.

Synthesis and gas chromatographic-mass spectrometric analysis of reduced compounds derived from 6 alpha- and 6 beta-hydroxy-11-deoxycorticosterone.

1989

Abstract A series of thirty two 6-hydroxylated steroids were synthesized by selective reduction of the 4–5 double bond, the 3-oxo group, and/or the 20-oxo group of 6α- and 6β-hydroxyDOC. The different reactions leading to the production of specific isomers are discussed. The gas chromatographic and spectrometric characteristics of the methoxime-trimethylsilyl (MO-TMS) or trimethylsilyl (TMS) derivatives of the isomers obtained are given. The gas chromatographic separation of the syn- and anti -isomers of the methoxime in position 3 was found to be characteristic of the configuration of the hydroxyl in position 6. The difference between methylene unit values of syn- and anti- isomers is much…

Microseparation techniques for the study of the enantioselectivity of drug-plasma protein binding.

2009

Stereoselectivity in protein binding can have a significant effect on the pharmacokinetic and pharmacodynamic properties of chiral drugs. The investigation of enantioselectivity of drugs in their binding with human plasma proteins and the identification of the molecular mechanisms involved in the stereodiscrimination by the proteins represent a great challenge for clinical pharmacology. In this review, the separation techniques used for enantioselective protein binding experiments are described and compared. An overview of studies on enantiomer–protein interactions, enantiomer–enantiomer interactions as well as chiral drug–drug interactions, including allosteric effects, is presented. The c…

Highly convergent total synthesis of (+)-anaferine and (−)-dihydrocuscohygrine

2019

A unified and highly convergent total synthesis of anaferine and dihydrocuscohygrine alkaloids has been devised, taking advantage of the dual role of N-sulfinyl amines as nucleophilic nitrogen sources and chiral auxiliaries. A bidirectional cross metathesis reaction followed by a double intramolecular aza-Michael reaction led us to create the whole skeleton of the natural products in a very simple manner.

Dual Role of Vinyl Sulfonamides as N -Nucleophiles and Michael Acceptors in the Enantioselective Synthesis of Bicyclic δ-Sultams

2018

DEVELOPMENT OF ELECTROCHEMICAL MICROFLUIC DEVICES FOR THE TREATMENT OF WASTEWATERS AND THE SYNTHESIS OF CHEMICAL

Measuring consumers’ level of satisfaction for online food shopping during COVID-19 in Italy using POSETs

2021

Abstract The pandemic COVID 19 has upset the economic, social, financial, and general behavioral systems. Global crisis has a large impact overall and related fallouts significantly affect existent structural paradigms in every country and region across the world. In particular, the spread of COVID-19 pandemic has led to having to rethink the way we produce and consume food. Within this global change, a rise in the number of consumers who purchase food products online in order to comply with the rules aimed at limiting the circulation of the virus should be emphasized. Consequently, probably causing a long-term positive effect on m-commerce. The purpose is to elaborate on the index of the s…

Electrochemical synthesis of C-glycosides as non-natural mimetics of biologically active oligosaccharides

2012

Natural oligosaccharides inhibitors of heparanase and selectins are emerging as promising drugs for cancer therapy. As an alternative tool to the natural ones, sulfated tri maltose C-C-linked dimers (alfa,alfa alfa,beta and beta,beta STMCs) were prepared by bromo-maltotriose electroreduction on silver cathode,1 followed by sulfation. The presence of an interglycosidic C-C bond makes STMCs less vulnerable to metabolic processing then their O-analogues. For this reason, STMCs have been studied as drug candidates and inhibitors of carbohydrate processing enzymes. Their activity as inhibitor of Pselectin in vivo and in the attenuation of metastasis both on B16-BL6 melanoma cells and on MC- 38 c…

Electrochemical Screening for Electroorganic Synthesis

2015

Electrochemical screening is usually strongly focused on electroanalytical data, while the parameters of organic synthesis are mostly not used as selection criteria. Typical parameters would be indication of the formation of the product and the efficiency of the electroorganic conversion. The latter data indicate the stability of the product under electrolysis conditions and represent the key for the accumulation of the desired product. We survey the current methods for electroorganic screening. In particular, parallel electrolysis under more defined conditions is discussed in detail since it represents a powerful tool for the development of electroorganic syntheses and processes.