Search results for "PIP"

Front Cover: Stereocontrolled Synthesis of Fluorine-Containing Piperidine γ-Amino Acid Derivatives (Eur. J. Org. Chem. 12/2019)

2019

Phase selective synthesis of ZnS nanoparticles from structurally new dithiocarbamate precursor

2015

Abstract A phase selective solvothermal synthesis of ZnS (wurzite) nanoparticles with a flower-like morphology using a dithiocarbamate precursor, [Zn(4-dpmpzdtc)2(dpmpz)] (1) (where, dpmpz=(diphenylmethyl)piperazine), is described. The nanoparticles were identified as ZnS (wurzite) with the particle size of about 3 to 10 nm by scanning and transmission electron microscopy as well as powder X-ray diffraction (XRD). In addition, the precursor complex 1 was characterized using single crystal X-ray diffraction.

Iodonium complexes of the tertiary amines quinuclidine and 1-ethylpiperidine

2021

Iodonium complexes incorporating tertiary amines have been synthesised to study and explore why such species comprised of alkyl amines are relatively rare. The complexes were characterised in solution (1H and 15N NMR spectroscopy) and the solid state (SCXRD), and analysed computationally. peerReviewed

Umsetzungen von polyacroleinen mit methylenaktiven verbindungen. Polymere acroleine, 21. Mitt.1

1962

Redoxpolymerisate des Acroleins wurden unter den Bedingungen einer KNOEVENAGEL-Kondensation mit methylenaktiven Verbindungen umgesetzt. Als Katalysatoren dienten Piperidin im essigsauren Medium oder Kaliumfluorid. Mit Malonsauredinitril, Cyanessigsaureathylester, Benzylcyanid, Phenylnitromethan und Acetessigsaureathylester entstehen losliche Polyacrolein-Derivate. Die Reaktionen mit Nitroacetonitril, Malonsaurediathylester, Nitromethan und Acetonitril fuhren zu unloslichen Umsetzungsprodukten. Die Umsetzungen wurden durch Elementaranalysen und IR-Spektren verfolgt. The reaction of redoxpolymers of acrolein with methylenactive compounds was studied under the conditions of a KNOEVENAGEL-conde…

ChemInform Abstract: Stereoselective Synthesis of 3-Substituted and 3,4-Disubstituted Piperidine and Piperidin-2-one Derivatives.

2012

The reaction of various electrophiles with N-galactosylpyridinone derivatives proceeds with moderate to high diastereoselectivity to afford the target compounds.

Stereoselective Synthesis of Enantiomerically Pure Piperidine Derivatives byN-Galactosylation of Pyridones

2004

Stereoselective desymmetrization of 4-pyridone has been achieved through selective N-galactosylation, activation of the N-(galactosyl)pyridone by O-silylation and immediate addition of Grignard compounds. Chiral piperidine derivatives, e.g. (S)-(+)-coniine and (5S,9S)-(+)-indolozidine 167B, were synthesised in enantiomerically pure form using these highly regio- and stereoselective reactions. After N-galactosylation of 2-pyridone and O-silylation of the N-galactosyl-2-pyridone, addition of a Grignard compound proceeded with high 1,4-regioselectivity and complete diastereoselectivity, to furnish 4-substituted 5,6-dehydro-2-piperidones. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Ger…

Enantioselective organocatalytic intramolecular aza-Michael reaction: a concise synthesis of (+)-sedamine., (+)-allosedamine, and (+)-coniine

2007

The intramolecular aza-Michael reaction of carbamates bearing remote alpha,beta-unsaturated aldehydes under organocatalytic conditions took place with good yields and excellent ee's when Jorgensen catalyst IV was used in the process, giving rise to the enantioselective formation of several five- and six-membered heterocycles. The developed methodology was applied to the synthesis of three piperidine alkaloids.

Synthesis and characterization of a new spirooxindole grafted pyrrolidino/piperidine moiety

2021

In this text, we synthesized and characterized a new spirooxindole grafted pyrrolidino/piperidine moieties. The new hit obtained via one-pot reaction of the chalcone based cyclohexanone with the isatin and (R)-piperidine-2-carboxylic acid in MeOH under reflux for 48 h. The compound exclusively obtained in regio-selective and diastereo-selective manner. The chemical feature of the target compound is confirmed by 1H NMR and 13C NMR spectroscopy. In addition, we reported for the first time the X-ray single crystal structure of isatin. Its molecular packing  depends mainly on strong O…H hydrogen bonds and π-π stacking interactions as well as weak H…H and H…C contacts. Using DFT calculations, is…

Studies and Research on the Stress – Strain Analyses of the Polyethylene Pipe-Fitting Assemblies Accidentally Subjected to an External Force

2019

Abstract The paper aims at analyzing the behavior of the polyethylene pipe - fitting assembly in the case of accidental stress due to the accidentally occurring external forces (mechanized excavation in the assembly area). The study will identify the necessary computing relationships and the minimum value of the force to which the analyzed assembly breaks, as well as some solutions for avoiding these accidental stresses. A three-dimensional model of the assembly will be made by applying the external forces on three main directions, following the maximum stresses for the same value of the external force. Also, a welding of a polyethylene pipe-fitting assembly will be carried out and it will …

ChemInform Abstract: Aza-Henry Reaction of Isatin Ketimines with Methyl 4-Nitrobutyrate en Route to Spiro[piperidine-3,3′-oxindoles].

2016

A new enantioselective route to spiro[piperidine-3,3′-oxindoles] from isatin ketimines is described. The aza-Henry reaction of N-Boc-isatin ketimines with methyl 4-nitrobutyrate in the presence of a Ph2BOX-CuBr2 complex provided the corresponding nitro amino esters with good diastereoselectivity and excellent enantioselectivity (up to >99% ee). The aza-Henry adducts were transformed into spiro[piperidine-3,3′-oxindoles] after reduction of the nitro group to oxime, and cleavage of the N-Boc group and lactamisation.