نتایج جستجو برای: stereochemistry

تعداد نتایج: 3446  

My half-century journey started from synthetic organic chemistry. During the first stage of my journey, my interest in stereochemistry was initiated through the investigation on the participation of steric effects in reactive intermediates, cylophanes, strained heterocycles, and organic compounds for photography. In chemoinformatics as the next stage of the journey, I proposed the concept of im...

Journal: :Structural Chemistry 2022

Abstract Kurt Mislow (1923–2017) and his family were refugees from Nazi Germany. He studied at Tulane University Caltech spent most of career Princeton as Hugh Stott Taylor Professor Chemistry (from 1988, Emeritus). excelled in research pedagogy stereochemistry, introduced the term “chirality” into chemical textbook literature, delineated some theoretical underpinning modern stereochemistry. sh...

Journal: :Annual Reports on the Progress of Chemistry 1905

Journal: :Organic & biomolecular chemistry 2009
Michael Butters Christopher D Davies Mark C Elliott Joseph Hill-Cousins Benson M Kariuki Li-ling Ooi John L Wood Stuart V Wordingham

Batzelladine C (3) is a tricyclic guanidine alkaloid of unknown stereochemistry at one centre as well as unknown absolute stereochemistry. The two possible diastereoisomers of the methyl ester corresponding to this compound have been synthesised, permitting the relative and absolute stereochemistry of this compound to be assigned.

Journal: :Angewandte Chemie 2009
Xiaoxing Wu Jingye Zhou Barry B Snider

An extremophilic challenge: Stereospecific condensation of a fully functionalized ketal aldehyde and a 2,6-dihydroxybenzoic acid is the key step in the synthesis of (-)-berkelic acid confirming Fürstner's reassignment of the stereochemistry at C18 and C19, establishing the absolute stereochemistry, and tentatively assigning the stereochemistry at C22.

Journal: :CEPS Journal : Center for Educational Policy Studies Journal 2023

This paper presents an analysis of the use multimedia and hands-on models on university students’ understanding stereochemistry. The relationship between scientific reasoning skills their stereochemistry was also determined. Two groups second-year chemistry students from State University Malang taking organic for 2020/21 academic year participated in this study. One group experienced teaching u...

2014
James C. Anderson Helen Grounds Suzanna Reeves Peter W. Taylor

The high-yielding synthesis of enantiomerically pure epicatechin gallate analogues where the A and/or B-ring hydroxylation is reduced or altered has been achieved by optimising routes to the catechin stereochemistry. The B-ring analogues were synthesised by using an electrophilic ring closure onto an enantiomerically enriched epoxide as a key step. The A and B-ring hydroxyl-deleted analogues we...

Journal: :Journal of the American Chemical Society 2016
Peter K Dornan Daniel Lee Robert H Grubbs

A tandem olefin metathesis/oxidative cyclization has been developed to synthesize 2,5-disubstituted tetrahydrofuran (THF) diols in a stereocontrolled fashion from simple olefin precursors. The ruthenium metathesis catalyst is converted into an oxidation catalyst in the second step and is thus responsible for both catalytic steps. The stereochemistry of the 1,5-diene intermediate can be controll...

2017
Ilia Brondz I. Brondz

Hyperforin is an antibiotic, antibacterial, antiprotozoal, antiviral, anticancer, and immunomodulatory substance. It is possibly a new and potent tool for curative treatment of a broad array of infection diseases. Despite the medical usefulness of Hypericum perforatum L., which has been known since ancient times, its constituents were not well studied until the middle of the 20 century. Several...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1997
issa yavari davood bori shargh hossein fallah bagher shaidaii mohsen dadgar

mndo semi-empirical scf mo calculations are used to study the pyramidal nitrogen atom inversion and configurational equilibria in the title compounds.

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