53398-55-3Relevant articles and documents
Influence of alkyl substitution on the gas-phase stability of 1-adamantyl cation and on the solvent effects in the solvolysis of 1-bromoadamantane
Takeuchi,Okazaki,Kitagawa,Ushino,Ueda,Endo,Notario
, p. 2034 - 2043 (2007/10/03)
1-Adamantyl cations having three methyl groups or one, two, or three isopropyl groups on the 3-, 5-, and 7-positions were found by FT ICR to be more stable than the 1-adamantyl cation and that the stability increases with the number of isopropyl group. The relative stabilities calculated by PM3 were in good agreement with the experimental results. In contrast, the sequence of the rates for the solvolysis in nonaqueous solvents are 3,5,7-(Me)3-1-AdBr 3-1-AdBr 3-1-AdBr. The rates of solvolysis of 3,5,7-(i-Pr)3-1-AdBr and 3,5,7-(n-Pr)3-1-AdBr relative to 1-AdBr at 25 °C are 15 and 3.8 in EtOH, respectively, but markedly decreases with the increase in the amount of added water, reaching 0.84 and 0.15, respectively, in 60% EtOH. Reflecting these effects of water, the Grunwald-Winstein (GW) relationship for 3,5,7-(i-Pr)3-1-AdBr and 3,5,7-(n-Pr)3-1-AdBr against YBr is linear for nonaqueous alcohols (EtOH, MeOH, TFE-EtOH, TFE, 97% HFIP), but marked downward deviations are observed for aqueous organic solvents, in particular, aqueous ethanol and aqueous acetone. The effect of the alkyl substituents to diminish relative solvolytic reactivity in EtOH-H2O mixtures may be ascribed to a blend of steric hindrance to Bronsted base-type hydration to the β-hydrogens and hydrophobic interaction of the alkyl groups with ethanol to make the primary solvation shell less ionizing. The introduction of one nonyl group to the 3-position showed much smaller deviations in the GW relationship than the case of 3,5,7-(n-Pr)3-1-AdBr. The markedly decelerated solvolysis of alkylated 1-bromoadamantanes in aqueous organic solvents is a kinetic version of anomalously diminished dissociation of alkylbenzoic acids in aqueous ethanol and aqueous tert-butyl alcohol that was demonstrated by Wepster and co-workers a decade ago and ascribed to hydrophobic effects.
Reaction of Adamantane Alcohols with Bromine
Baklan,Khil'chevskii,Kukhar'
, p. 498 - 505 (2007/10/03)
1-Hydroxyadamantane and 1-hydroxy-3,5,7-trimethyladamantane in the medium of liquid bromine are converted, correspondingly, into 1-bromoadamantane and 1-bromo-3,5,7-trimethyladamantane by substitution of the hydroxy group with molecular bromine. 1-Hydroxyalkyl derivatives of adamantane afford alkyl bromides by means of substitution of the hydroxy groups for bromine with both molecular bromine and, possibly, hydrogen bromide formed upon oxidation of alcohols with bromine. A scheme of substitution of the hydroxy group with molecular bromine is suggested.
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Baklan, V. F.,Antipenkova, L. S.,Zakharchenko, L. I.,Fesenko, T. E.,Kukhar, V. P.
, p. 1102 - 1105 (2007/10/02)
Liquid bromine as an electrophilic medium gives rise to skeletal rearrangements in a series of substrates: The Beckmann rearrangement of methyl 1-adamantyl ketone oxime to 1-acetamidoadamantane; the pinacone-pinacoline rearrangement; the cyclization of me