Showing papers in "Tetrahedron in 1979"

TL;DR: The results obtained in this paper are valuable for the structure studies of plant-glycosides as well as carbohydrates, especially for determination of anomeric configurations of mannosides and rhamnosides which has been extremely difficult by other classical techniques.

TL;DR: In this article, it was observed that diborane, a hydride, reduces aldehydes and ketones with exceptional ease even at 0°, and since then various reagents have evolved for the convenient reduction of typical organic functional groups.

TL;DR: In this article, a general, rapid method is described for alkylation of phenols and alcohols to give ethers, for amides to give N-substituted amides, and for acids to give esters.

TL;DR: The formamide acetals as mentioned in this paper have been used in two main categories of reactions, namely alkylation and formylation, and are used in the synthesis of esters from acids, ethers and thioethers from phenols and aromatic and heterocyclic thiols.

TL;DR: In this paper, the S-configuration of the naturally occurring (+)-ipsdienol was described and a new synthesis of (R)-(+)-ipsenol 2″ and its antipode 2' was also described.

TL;DR: In this paper, the dimer of p-methoxyphenylthionophosphine sulfide, 1, in anhydrous xylene or toluene to give the corresponding thionolactones, 3a-d, in good yields.

TL;DR: In this paper, the modified Polonovski reaction was applied to anhydrovinblastine N b -oxide 4 led, after hydrolysis, to 5'-nor anhydronblastine 10a.

TL;DR: Ilimaquinone (1) is a new sponge metabolite of composition C22H30O4 whose structure, which was determined by spectral correlations and X-ray crystallography, comprises a rearranged drimane sesquiterpene moiety linked to a 2-hydroxy-5methoxybenzoquinone at C-3.

TL;DR: The orthosomycins as discussed by the authors are a family of antibiotics which contain in their structures one or more orthoester linkages associated with carbohydrate residues, which are known as orthosymcins.

TL;DR: The history of the investigation of the pigments of the toadstool Amanita muscaria is reviewed in this paper, where structural correlations between the betalains and mus-caflavin, the muscaurins, and muscapurpurin are put forward.

TL;DR: In this paper, the photoelectron spectra of crown ethers and their cation complexes were analyzed using the CNDO/2 method and the stability of the complex was reasonably explained by considering the hydrated species of the cation and the complex, indicating the important role of the solvation effect in the selectivity of the crown ether to the Cation.

TL;DR: In this paper, the 13 C NMR chemical shifts of eleven hydroxy-, two hydroxymethoxy xanthones, and xanthone- C -glucoside, mangiferin, are presented and analyzed.

TL;DR: Anhydrous THF solutions of LiS or LiS2 (or chemically equivalent species) are rapidly and quantitatively formed by the reaction of common yellow sulfur with appropriate stoichiometries of commercially available LiEt3BH.

TL;DR: In this paper, the structures of a 2,4-dichloro- trans -1-chloro-vinyl-1-methyl-5-methylene-cyclohexane, a 2.5-dicloro -4-bromo-trans - 1-chlorovinyl-1.5bromomethyl-cycloehexane are described.

TL;DR: Pyridinium chromate-on-silica gel and chromic acid on silica gel have been evaluated and evaluated as convenient off-the-shelf reagents for efficient oxidation of a variety of secondary and primary alcohols as discussed by the authors.

TL;DR: Pd catalyzed reaction of allylic alcohols with 2-bromothiophene provides 3-(2"-thienyl)aldehydes or ketones selectively together with the small amounts of 2-(2'-thienel)aldeohydes and ketones as discussed by the authors.

TL;DR: In this article, the structure of 8-O-methylbostrycoidin, the main pigment from Fusarium moniliforme, was established as 6,8-dimethoxy-5-hydroxy-3-methyl-2-azaanthraquinone.

TL;DR: In this paper, ausammenfassung O -Halogenacetophenone reagieren mit Schwefelkohlenstoff in Gegenwart von Natriumhydrid and einem Alkylierungsmittel zu den Keten-S,S-acetalen 3 and 4 1-Thiochromone 5 werden gebildet.

TL;DR: In this article, an asymmetric bromolactonisation of N-(α, β-unsaturated)acylproline((S) 5) derivable from 3 such as tiglic acid and trans-α methylcinnamic acid was found to proceed in a highly stereoselective and regiospecific manner.

TL;DR: The use of iminium reagents in the Mannich reaction is recommended because the yields are often good and the site of attachment on an unsymmetrical ketone is both predictable and controllable as mentioned in this paper.

TL;DR: By decomposition of alkyl hydroperoxides with ferrous sulfate-cupric acetate reagent, intramolecular functionalisation of remote non-activated C atom takes place and unsaturated alcohols with double bond mainly at δ-position are obtained.

TL;DR: In this paper, the authors reported the isolation, chemical characterization and structural elucidation of Ansamitocin, a new antitumor antibiotic obtained from Nocardia No. C-15003 (N-1).

TL;DR: The antibiotic, flambamycin, is shown to have the novel oligosaccharide structure associated with two orthoester linkages and is proposed to belong to a new family of antibiotics called the orthosomycins.

TL;DR: In this paper, a novel synthesis of E-1-trimethylsilylbuta-1,3-diene has been achieved, and its Diels-Alder reactions with maleic anhydride, diethyl maleate, dimethyl fumarate, methyl propiolate, acrolein and acrylonitrile have been investigated.

TL;DR: In this article, a mechanism involving an organocopper(III) intermediate was proposed for organocuprate conjugate addition, which involves an electron transfer process without the production of any long-lived paramagnetic intermediate species.