Showing papers in "Tetrahedron in 1971"

TL;DR: In this article, a method of converting furan derivatives via 2,3-dideoxy-DL -alk-2-enopyranos-4-uloses, a new class of sugar compounds, into methyl 2, 3-D-Dideoxy DL -alk 2-ENOPyranosides is described.

TL;DR: In this paper, a new method of homolytic alkylation of heteroaromatic bases is described, in which the silver-catalysed oxidative decarboxylation of acids by peroxydisulphate is used as a source of alkyl radicals.

TL;DR: In this article, five alkaloids, three trans-2-methyl-6-alkylpiperidines, and two unsaturated analogues, have been identified in the venom of the red form of the fire ant, Solenopsis saevissima.

TL;DR: In this article, the degenerate Cope rearrangement of 1,1-dideuteriohexa-1,5-diene to 3,3-Dideuteriahexa 1,5 diene was studied kinetically at four temp. 207·1, 217·8, 237·1 and 258·2°.

TL;DR: In this paper, a concerted cycloaddition involving an orthogonal approach of the ketene and olefin in accordance with Woodward and Hoffmann's suggestion was proposed.

TL;DR: In this article, the spectral properties of 18 phenyl carbamoylarylhydrazidic chlorides derived from coupling of diazotized anilines to α-chloroacetoacetanilide have been investigated.

TL;DR: Asymmetric induction has been observed in the reactions of organo-lithium and magnesium compounds complexed with a chiral tertiary diamine, (−)-sparteine as discussed by the authors.

TL;DR: In this paper, a new fragmentation pathway of 6-methoxyflavones is discussed, and the formation of (M−H)+ and (M −H3O)+ ions is discussed.

TL;DR: In this paper, a quantitative study concerning the nucleophilic character of the dioxanyl radical, carried out by measuring the relative rates of attack on 4-substituted quinolines, revealed in detail all the features of nucleophilicity substitutions.

TL;DR: The change in rate constants of acylation on going from the aqueous phase into the micellar phase is dependent on the nature (aliphatic or aromatic) and the size of the side group R of the carboxylate and is interpreted as due to a different orientation of the reagent molecules in the micelle.

TL;DR: In this article, a modele d'etatat de transition faisant intervenir le reactif de Reformatsky sous la forme enolate is proposed.

TL;DR: In this paper, the structure elucidation of three new limonoids of the meliacin type, azadirone (I), azadiadione (II), epoxyazadiradione(III), as well as the isolation from the same plant Melia azadiirachta L. of gedunin (IVa), having a ring D lactone, are described.

TL;DR: In this paper, the Pople-Santry MO theory of coupling constants has been applied to a series of monosubstituted ethanes and an equation has been derived which describes the dependence of the coupling constants on the dihedral angle between coupling protons and the electronegativity of the substituent.

TL;DR: In this article, the formation of peptides from glycine in the presence of trimetaphosphate proceeds mainly via peptide-N-phosphates as intermediates.

TL;DR: When a 1-phenyl substituted pyrrole, arsole, is reacted with an alkali metal in an inert solvent, the phenyl group is split off yielding the corresponding alkali heterocyclopentadienide as mentioned in this paper.

TL;DR: In this paper, the base-catalysed elimination of a series of substituted α-phenylethyl bromides have been determined in t-BuOK-t-BuOH, t -BuOKt-tBuOH-DMSO and EtONa-EtOH systems.

TL;DR: Ginsenoside-Rg 1, one of the neutral saponins of Ginseng root, has been purified via its crystalline deca-acetate (IV) as discussed by the authors.

TL;DR: In this paper, the synthesis of homolytic substitution of pyridine, quinoline and acridine by redox systems is discussed, and the synthetic aspects and the mechanism of the reduction of oxaziranes and homolyty substitution are discussed.

TL;DR: In this paper, sector rules for third (fourth,…) sphere contributions are proposed, whose nodal planes are composed of the nodal plane of the corresponding transitions plus those additional planes, which are required by the symmetry of the molecule.

TL;DR: Tetramethylammonium di-t-butyl phosphate (VI) was found to be a convenient phosphorylating reagent for organic halides in boiling dimethoxyethane.

TL;DR: In this article, the cycloaddition reactions of phenyl azide and butyl azides with monosubstituted electronpoor olefins are highly regioselective (if not regiospecific) and lead to 1,4-disubstitized Δ2-triazolines or products derived therefrom: aziridines, diazocompounds, pyrazolines and 1, 4-trisubstitiated triazoline.

TL;DR: Two new xanthones, gartanin and 8-desoxygartanin, have been isolated from very ripe fruits of Garcinia mangostana and their structures have been shown to be VIIa and X tespectively as discussed by the authors.

TL;DR: In this paper, a π-Elektronenpaar is defined as a Substituenteninkrement fur den Konjugationseffekt zusatzlich wirksamer polymethine polymers.

TL;DR: In this paper, a synthese du squalene et d'analogues est decrèce. André et al. propose a synthetse du qualene tritie a forte activite specifique.

TL;DR: In this article, five new sesquiterpenes were isolated from Acorus calamus L, in addition to calameone (or calamendiol), the structure of which was revised, and their structures were established.

TL;DR: In this article, the authors reported that the chroman chromophore gives a negative CD band if the absolute configuration at C 2 is R and its aryl substituent is in an equatorial position.

TL;DR: The mass spectra of 18 trimethylsilyl disaccharides containing only aldohexoses, connected via all possible linkages (1 → 1) to (1→ 6), were compared as mentioned in this paper.

TL;DR: A conformational analysis of dopamine hydrochloride has been performed by extended Huckel theory, potential energy functions and NMR spectroscopy as discussed by the authors, and the results show that dopamine has a trans population of 0·43 ± 0·05 over a 60° temperature range.

TL;DR: Polarographic half-wave potentials have been measured for a series of bridged ferrocenes and non-bridged model compounds and analysis of the results has shown that the oxidation potentials of ferrocene derivatives are sensitive to structural, conformational, electronic, and possibly field effects.

TL;DR: In this article, a number of oxidations of organic functions by chromium, manganese, iodine, lead (IV), vanadium(V), and halogens are considered in the light of the Zimmerman treatment of electrocyclic reactions.