Search results for "imines"

K-region oxides and imines derived from alkylated benz[α]anthracene congeners: synthesis, stability in aqueous media and mutagenicity

1994

The K-region oxides and imines of benz[a]anthracene, 1-methylbenz[a]anthracene, 7-methylbenz[a]anthracene, 7-ethylbenz[a]anthracene and 7,12-dimethylbenz[a]anthracene were synthesized and characterized (melting point, 1H-NMR and electron impact mass spectra, elemental analysis, IR spectroscopy). All 10 compounds showed high mutagenic activity in Salmonella typhimurium (reversion of his- strains TA97, TA98, TA100 and TA104). The arene imines were more potent than the corresponding arene oxides. Alkyl substitutions strongly influenced the activities. Furthermore, all compounds were more active when exposure took place in the absence of inorganic ions than when KCl (125 mM) was present. The in…

Rhenium(I) and platinum(II) complexes with diimine ligands bearing acidic phenol substituents: hydrogen-bonding, acid-base chemistry and optical prop…

2010

Tricarbonylchloro-rhenium(i) (1-4) and catecholato-platinum(ii) complexes (6, 7) of diimine ligands bearing phenol and O-protected phenol substituents have been prepared and fully characterised including single crystal structure analyses of 1, 4 and 7. The redox behaviour of the catecholato platinum(ii) complexes 6 and 7 has been probed by cyclic voltammetry, preparative oxidation and EPR spectroscopy (6˙(+), 7˙(+)). Reversible deprotonation of the hydroxy substituted complexes 1, 3 and 6 to 1(-), 3(-) and 6(-) resulted in significant changes in their electronic spectra. The luminescence properties of the diamagnetic complexes have been investigated using emission spectroscopy. DFT and TD-D…

Diastereoselective Intramolecular Additions of Allyl- and Propargylsilanes to Iminium Ions: Synthesis of Cyclic and Bicyclic Quaternary Amino Acids

2010

Chiral imino lactones derived from (R)-phenylglycinol containing an allyl- or propargyltrimethylsilyl group in the side chain readily cyclized in the presence of acidic reagents to afford spirocyclic compounds with high diastereoselectivity. Removal of the chiral auxiliary produced 2-substituted 1-aminocycloalkanecarboxylic acids, whereas further cyclizations by means of metathesis or hydroamination reactions led to bicyclic derivatives of pipecolic acid and proline.

Water-soluble isoindolo[2,1-a]quinoxalin-6-imines: In vitro antiproliferative activity and molecular mechanism(s) of action

2015

Abstract Water-soluble isoindoloquinoxalin (IIQ) imines and the corresponding acetates were conveniently prepared from the key intermediates 2-(2′-aminophenyl)-2H-isoindole-1-carbonitriles obtained by a Strecker reaction between substituted 1,2-dicarbaldehydes and 1,2-phenylenediamines. Both series were screened by the National Cancer Institute (Bethesda, MD) and showed potent antiproliferative activity against a panel of 60 human tumor cell lines. Several of the novel compounds showed GI50 values at a nanomolar level on the majority of the tested cell lines. Among IIQ derivatives, methoxy substituents at positions 3 and 8 or/and 9 were especially effective in impairing cell cycle progressi…

Catalytic Enantioselective Total Synthesis of (+)-Lycoperdic Acid.

2020

A concise enantio- and stereocontrolled synthesis of (+)-lycoperdic acid is presented. The stereochemical control is based on iminium-catalyzed Mukaiyama–Michael reaction and enamine-catalyzed organocatalytic α-chlorination steps. The amino group was introduced by azide displacement, affording the final stereochemistry of (+)-lycoperdic acid. Penultimate hydrogenation and hydrolysis afforded pure (+)-lycoperdic acid in seven steps from a known silyloxyfuran. peerReviewed

Immunoassays for trifloxystrobin analysis. Part I. Rational design of regioisomeric haptens and production of monoclonal antibodies

2014

Trifloxystrobin is one of the main active principles belonging to the strobilurin family of crop protection compounds. In this article, the synthesis of a battery of regioisomeric functionalized derivatives of trifloxystrobin is described. The same aliphatic linear carboxylated chain was introduced as spacer arm in all of the synthesized haptens, but it was located at different positions of the parent molecule. N,N′-Disuccinimidyl carbonate was employed for hapten activation, so the resulting N-hydroxysuccinimyl ester could be readily purified and efficiently coupled to proteins. After immunization and hybridoma generation, a collection of 20 mouse monoclonal antibodies from different immun…

Probing the non-innocent nature of an amino-functionalised β-diketiminate ligand in silylene/iminosilane systems.

2020

Electron-rich β-diketiminate ligands, featuring amino groups at the backbone β positions (“N-nacnac” ligands) have been employed in the synthesis of a range of silylene (SiII) complexes of the type (N-nacnac)SiX (where X = H, Cl, N(SiMe3)2, P(SiMe3)2 and Si(SiMe3)3). A combination of experimental and quantum chemical approaches reveals (i) that in all cases rearrangement to give an aza-butadienyl SiIV imide featuring a contracted five-membered heterocycle is thermodynamically favourable (and experimentally viable); (ii) that the kinetic lability of systems of the type (N-nacnac)SiX varies markedly as a function of X, such that compounds of this type can be isolated under ambient conditions …

An Easy Stereoselective Access to β,γ-Aziridino α-Amino Ester Derivatives via Mannich Reaction of Benzophenone Imines of Glycine Esters with N-Sulfon…

2007

Mannich-type addition of benzophenone imine glycinates across newly synthesized N-(p-toluenesulfonyl) alpha-chloroaldimines afforded gamma-chloro-alpha,beta-diamino ester derivatives with moderate diastereoselectivity as separable mixtures of anti and syn diastereomers. The gamma-chloro-alpha,beta-diamino esters were efficiently cyclized under basic conditions to the corresponding beta,gamma-aziridino alpha-amino ester derivatives, representing a new class of conformationally constrained heterocyclic alpha,beta-diamino acid derivatives. The relative configuration of the aziridines was determined via X-ray diffraction analysis. Mechanisms and intermediate transition states to explain the ste…

N‐Heterocyclic Carbene Catalyzed Asymmetric Synthesis of Pentacyclic Spirooxindoles via [3+3] Annulations of Isatin‐Derived Enals and Cyclic N‐Sulfon…

2019

Halogen‐Imparted Reactivity in Lithium Carbenoid Mediated Homologations of Imine Surrogates: Direct Assembly of bis‐Trifluoromethyl‐β‐Diketiminates a…

2020

The selective formal insertion (homologation) of a carbon unit bridging the two trifluoroacetamidoyl chlorides (TFAICs) units is reported. The tactic is levered on a highly chemoselective homologation-metalation-acyl nucleophilic substitution sequence which precisely enables to assemble novel trifluoromethylated β-diketiminates within a single synthetic operation. Unlike previous homologations conducted with LiCH2Cl furnishing aziridines, herein we exploit the unique capability of iodomethyllithium to act contemporaneously as a C1 source (homologating effect) and metalating agent. The mechanistic rationale grounded on experimental evidences supports the hypothesized proposal and, the struct…