Showing papers in "Tetrahedron in 1958"
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TL;DR: In this paper, the insertion of a single carbon atom between the two of the original double bond was proposed as a novel way of increasing carbon chain length by one atom, which represents a novel method of increasing the number of carbon atoms in a carbon chain.
123 citations
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TL;DR: Aromatic character of perinaphthene is correlated with the development, in the appropriate transition state, of a stable π-electron system (sextet) in the five- or the seven-membered ring as mentioned in this paper.
116 citations
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TL;DR: The Friedel and Crafts methylation of benzene and its methyl homologues is 1,1,2,3,4,5,6-heptamethylbenzenonium ion (I), a new comparatively stable carbonium ion as discussed by the authors.
100 citations
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TL;DR: In this paper, the results of the investigation of MeO-3,4,5,6 and 7 participation in solvolytic substitution were summarized and the ratio of anchimerically assisted and unassisted solvocalization rates (k Δ/k s ) were derived.
90 citations
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89 citations
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TL;DR: An aromatic sesquiterpene, cuparene (IV), has been isolated from Chamaecyparis thyoides, Biota orientalis and Widdringtonia.
87 citations
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TL;DR: In this article, the isolation from the aqueous decoction of chicory leaves of a new optically active crystalline substance is described, for which the name chicoric acid is proposed.
84 citations
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77 citations
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TL;DR: In this article, the infrared and ultraviolet carbonyl absorptions of 2-bromo cyclo hexanone have been examined in a variety of solvents and the data are consistent with an equilibrium axial -2bromomethane cyclohexanone for which the equilibrium constant varies as a function of solvent over the range 0·3−1·0.
76 citations
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TL;DR: In this paper, the following new alkaloids were isolated: (+)-quebrachamine (IV), an optical isomer of the known (−)-QBamine; iso voacangine (IIIa); and tabernanthine and ibogamine.
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TL;DR: In this article, the extent of intramolecular hydrogen-bonding, as determined by infra-red spectroscopy in the hydroxyl stretching region, in certain vicinal diols of cyclo hexane, cyclo pentane, tetrahydropyran, and in related compounds provides evidence for the stabilities of different conformations.
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TL;DR: In this article, the secretions de 4 especes de Dipterocarpus Viet-Namiens ont fourni un triterpene tetracyclique, identifie au diptersocarpol de van Itallie et a l'hydroxy-dammarenone-II (I) de Mills.
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TL;DR: Fission of 3β-acetoxy-5α-,6α-epoxides in the cholestane, androstane and pregnane series with boron trifluoride etherate afforded the corresponding 6β-fluorocholestenone compounds as discussed by the authors.
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TL;DR: The nuclear magnetic resonance spectra of N-methyldihydronicotinamide and its 2-deutero and 6-deuteric derivatives, amply confirm the 1,4-dihydropyridine structures assigned to these compounds as discussed by the authors.
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TL;DR: This article showed that perinaphthyl radicals with no Kekule structures can go over either into the stable red hydrocarbon zethrene (XIX) with two fixed double bonds in the centre or into the diradical with no kekule structure.
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TL;DR: From the volatile component of sweet potatoes infected by Ceratostomella fimbriata (black rotted) disease, four β-substituted furans, viz. ipomeamarone (1), batatic acid (45), ipomeanine (47), and β-furan carboxylic acid were isolated as discussed by the authors.
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TL;DR: In this article, a large number of natural essentially non-terpenoid compounds contain isoprene units, which can undergo a number of modifications giving rise to types of compounds listed below under (A) to (F) in increasing order of complexity.
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TL;DR: A brief survey of the history of sesquiterpenoid hydrocarbons can be found in this article, with a summary of the results of their characterization and their properties.
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TL;DR: In the presence of a strong base, oxygen is slowly absorbed, and ketones or acids are formed in fair to excellent yields, depending upon the nitrile used as mentioned in this paper.
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TL;DR: In this article, a theory of the electronic spectra of organic molecules is outlined and the wave-mechanical resonance characteristic for the excited states of polyelectronic systems involves a fluctuation of the transition energy and, in this sense, represents a physical phenomenon which is absent in ground states.
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BP1
TL;DR: The major primary product of co-oxidation of indene and thiophenol is trans-2-phenylmercapto-1-indanyl hydroperoxide, which spontaneously rearranges to the two racemes of trans -2phenylsulphinyl- 1-indanol as discussed by the authors.
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TL;DR: Two isomeric dimethyl ethers of dicoumarol and derivatives substituted in the methylene group [formulae (XX) and (XXI)] were obtained.
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TL;DR: In this article, the preparation, purification and properties of 3-hydroxypyridine-2-aldehyde, 3-methoxymethylpyridine and their derivatives and some new intermediates are reported.
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TL;DR: In this paper, the constitution and stereochemistry of alnusenone have been established and a partial synthesis of ALNUSENONE (II) from friedelin is described.
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TL;DR: In this paper, it was shown that 3-D-3-methyl-2-butyl p-toluenesulfonate is a marginal system with a relatively high ratio of (kΔ/k) for anchimerically assited and unassisted solvolysis processes.
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TL;DR: In this paper, the authors executees les mesures d'absorption U.V. et I.R. de la yangonine (IIa), de la pseudoyangonines (IIIa) and des composes apparentes (IIb, c, d et IIIb,c, d).