Browsing by Author "Wenkert, Ernest"

Now showing 1 - 5 of 5
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    A carbon-13 nuclear magnetic resonance study of a series of cyclohexanol amines
    (1976) Slovin, Eliot Mark; Wenkert, Ernest
    A carbon-13 nuclear magnetic resonance spectral investigation of the monosubstituted-butylcyclohexyl alcohols, amines, and ammonium salts was undertaken and the resultant correlations were extended to a series of eight b-butylcyclohexanol amines and their hydrochloride salts. Among the effects examined were the substituent parameters of the mono- and difunctionalized t-butylcyclohexanes and the perturbations of the chemical shifts due to amine protonation in the cyclohexyl amines and the amino alcohols. An anomalous behavior was observed for the trans-2-ammonium salt.
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    Base catalyzed elimination of methyl enol ethers
    (1977) Moreno, Louis Norman (b. 1952); Wenkert, Ernest
    The formation of naphthalenes on treatment of enol ethers of tetralones with strong bases proceeded in good yields under moderate conditions. Dienol ethers of octalinones gave tetralins in lower yields and under more vigorous conditions. Monocyclic dienol di-ethers gave aryl ethers, while monocyclic enol ethers failed to give dienes. Attempts to generate trienes from bicyclic, non-aromatizable dienol ethers failed and resulted in isomerization of the double bonds.
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    Cyclopropanation of dienol ethers
    (1977) Ranu, Brindaban Chandra; Wenkert, Ernest
    The copper-catalysed, thermal decompositions of ethyl diazoacetate and diazoacetone in the presence of 1-methoxycyclohexa-1,3-diene, l-methoxy-4-methylcyclohexa-l,3-diene, 1-methoxybuta-l,3-diene, 1-ethoxybuta-l,3-diene and 1-trimethylsilyloxybuta-1,3-diene and the acid hydrolysis of the resultant cyclopropanes are described. These reactions constitute a simple, two-step procedure for the production of olefinic 1,4- and 1,6-dicarbonyl compounds, starting from dienol ethers of a,g -unsaturated aldehydes and ketones.
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    Indole alkaloid synthesis
    (1983) Simmons, Dana Philip; Wenkert, Ernest; Lewis, Edward S.; Storck, Roger L.
    Indole acetic acid and methyl 1,4,5,6-tetrahydronicotinylacetate obtained by hydrogenation of methyl nicotinylacetate were combined in the presence of base to yield methyl 1-(3-indoleacetyl)-1,4,5,6-tetrahydronicotinylacetate in 45% yield. This, upon heating in polyphosphoric acid, yielded in 73% 2-deethyl-5,17-diketo-2,16-dihydrovincadifformine with complete stereospecific formation of all five chiral centers. Reduction of the two keto functions led to 2-deethyl-2,16-dihydrovincadifformine, whereas reduction of the lactam and oxidation of the 2,16 carbon-carbon bond yielded 2-deethyl-16-ketovincadifformine. 16 ketopseudovincadifformine was prepared in the same manner starting from methyl 5-ethyl-nicotinylacetate.
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    Reactions of [Alpha]-Acyl-[Alpha] Diazoacetaldeydes
    (1980) Ananthanarayan, T. P.; Wenkert, Ernest; Lewis, Edward S.; Fukuyama, Tohru
    The copper-catalyzed thermolysis of ethyl diazoformylacetate and diazomalonaldehyde in n-butyl vinyl ether has been shown to produce ethyl 5-n-butoxy-4,5-dihydrofuran-3-carboxylate and 2-n-butoxy-2,3-dihydro-4-pyrone, respectively.