Showing papers in "Tetrahedron in 1974"

TL;DR: In this paper, it was concluded that the gauche-butane interaction has been incorrectly interpreted as to origin, and that the relationship between methyl groups is not the cause of the relative instability of gauche conformations.

TL;DR: In this article, the reaction paths found by different methods for different nucleophiles show some striking similarities that appear to be characteristic for the reaction type, and the results of recent experimental and theoretical studies of nucleophilic addition to carbonyl groups are described.

TL;DR: In this paper, a simple one-step conversion of carboxylic acids to urethanes was achieved by diphenyl phosphorazidate (DPPA) using a modified Curtius reaction.

TL;DR: In this paper, it was shown that the exo-anomeric effect offers an important resistance to rotation about the anomeric carbon to glycosidic bond (φ angles).

TL;DR: The relationship between the CD spectra of the chiral biaryls and their stereochemical configuration, as a function of the dihedral angle between the molecular planes of the aromatic moieties, has been investigated in this article.

TL;DR: The derivation and synthesis of 3,5,3′,5′-tetramethyl benzidine are described in this paper, which is a sensitive and specific agent for the detection of blood, and could displace the use of these substances for that purpose.

TL;DR: In this paper, a phase-transfer catalysis-based procedure for the preparation of ethers of both simple and highly hindered phenols is presented, which involves alkylation of the phenoxide ion with an alkyl halide or sulphate ester.

TL;DR: By the application of the Vilsmeier-Haack reaction to various o-hydroxyacetophenone derivatives, 4-oxo-4H-1-benzopyran-3-carboxaldehydes were synthesized in one step as discussed by the authors.

TL;DR: The correct quinoid structure for the dimer of triphenylmethyl radicals was proposed in 1904, and three independent lines of evidence supported this structure: acid-catalyzed aromatization, para-halogen lability, and radical chain autoxidation as mentioned in this paper.

TL;DR: The sponges Stelleta clarella, Tethya aurantia, Lissodendoryx noxiosa, Haliclona permollis and Halic lona sp. were examined for steroids as mentioned in this paper.

TL;DR: In this paper, the thermal racemisation in solution of hepta-, octa-and nonahelicene has been studied and a "conformational pathway" is suggested for these racemisations.

TL;DR: In this paper, 3-oxo esters were shown to react with the dimer of p -methoxyphenyl-thionophosphine sulfide (1) and elemental sulfur in anhydrous toluene at 110° to give the corresponding 3H-1,2-dithiole-3thiones (2 ) in nearly quantitative yields.

TL;DR: In this article, a new stereoselective synthesis of D -ribose (14 ) starting from L -glutamic acid (1 ) is described, by making use of the chiral center of 1 as that at C-4 of 14.

TL;DR: In this article, the thermal cracking of phenol and ortho and para-cresol at atmospheric pressure, between 665°c and 865°C has been studied with a contact time of 2·5 seconds.

TL;DR: In this paper, a steric arrangement of three syn-axial oxygen atoms on a 6-membered ring and three O atoms on three consecutive C atoms constituting a clockwise and an anti-clockwise gauche arrangement is proposed.

TL;DR: Aryliden-methandiphosphonsaureester lassen sich durch katalytische Hydrierung und/oder Reduktion mit Natriumborhydrid nahezu quantitativ in die entsprechenden gesattigten Verbindungen uberfuhren.

TL;DR: A survey of experimentally established conformations of saturated compounds containing the isolated ether group is given in this article, focusing on simple molecules, polymers, and medium and large rings.

TL;DR: Palladium compounds and metallic palladium combined with phosphine are active catalysts of selective hydrosilylation of terminal olefins as mentioned in this paper, and they give a 1:1 adduct and trimethylsilane affords a 1.2 adduct.

TL;DR: In this paper, photoelectron spectroscopy shows that in t-butoxybenzenes, but not in methoxy-, ethoxy- or isopropoxybenenes, there is a loss of p-π orbital overlap.

TL;DR: The chemical ionization mass spectra of configurational isomers of many cyclic diols give substantial differences which are characteristic of their stereochemistry as discussed by the authors, which is useful for maximizing stereochemical effects on CI spectra; conditions of lowest energy are usually, but not always, the most useful.

TL;DR: In this paper, the absolute configurations of both enantiomers of exo -brevicomin and their corresponding key materials were established, and the relationship between pheromone activity and chirality was clarified.

TL;DR: In this paper, a zur Berechung von Molekulgeometrien konjugierter Kohlenwasserstoffe entwickelte kombinierte π-SCF-LCAO-MO- and Kraftfeld-Methode wird vorgestellt und ihre Leistungsfahigkeit an einer Reihe von Beispielen aufgezeigt.

TL;DR: From the soft bodied coral Sarcophytum glaucum a crystalline compound-sarcophine (1), which is believed to be one of the repellents protecting the coral against predators, was isolated.

TL;DR: In this article, the UV, ORD and CD curves of the pure enantiomers are shown in Figs 1, 2, and 3, and the UV and ORD curves for the pure Enantiomers were obtained by repeated crystallisation under equilibnim conditions.

TL;DR: In this paper, a stable solution of the ZnCl4 catalyst in THF is described, and data are presented detailing the effects of varying temperature, time, and the concentrations of catalyst and chloromethyl methyl ether on the chlorometrication reaction.

TL;DR: In this article, an analysis of the possible transition state geometries for Cope and Claisen rearrangements of acyclic systems is given and methods which allow to distinguish between the various transition states are discussed.

TL;DR: In this article, stable conformations of several sesquiterpenes in solution were deduced with the aid of intramolecular nuclear Overhauser effects (NOE) in the NMR spectra.