20778-55-6Relevant academic research and scientific papers
Superacid-Catalyzed Alkylation of Adamantane with Olefins
Olah, George A.,Farooq, Omar,Krishnamurthy, V. V.,Prakash, G. K. Surya,Laali, Khosrow
, p. 7541 - 7545 (1985)
The superacid catalyzed alkylation of adamantane with lower olefins (ethene, propene, and butenes) was investigated.Alkyladamantanes obtained show that the reaction occurs by two pathways: (a) adamantylation of olefins by adamantyl cation formed through hydride abstraction from adamantane by alkyl cations (generated by the protonation of the olefins) and (b) direct ?-alkylation of adamantane by the alkyl cations via insertion into the bridgehead C-H bond of adamantane through a pentacoordinate carbonium ion.
Exhaustive One-Step Bridgehead Methylation of Adamantane Derivatives with Tetramethylsilane
Bonsir, Maxime,Davila, Christian,Geerts, Yves,Kennedy, Alan R.
supporting information, p. 5227 - 5237 (2021/10/19)
A methylation protocol of adamantane derivatives was investigated and optimized using AlCl3 and tetramethylsilane as the methylation agent. Substrates underwent exhaustive methylation of all available bridgehead positions with yields ranging from 62 to 86 %, and up to six methyl groups introduced in one step. Scaling-up of the reaction was demonstrated by performing the >40 gram-scale synthesis of 1,3,5,7-tetramethyladamantane with 62 % yield. For several substrates, rearrangements were observed, as well as cleavage of functional groups or Csp3?Csp2 bonds or even cyclohexyl-adamantyl bonds. Based on mechanistic studies, it is suggested that a reactive methylation complex is formed from tetramethylsilane and AlCl3. X-ray diffraction structures of hexamethylated bis-adamantyls reveal elongation or widening of sp3 carbon bonds between adamantyl moieties to 1.585(3) ? and 125.26(9)° due to repulsive H???H contacts.
Alkylation of adamantane with alkyl halides catalyzed by ruthenium complexes
Khusnutdinov,Schchadneva,Malikov,Dzhemilev
, p. 159 - 163 (2007/10/03)
The feasibility of catalytic alkylation of adamantane and 1-bromoadamantane with alkyl halides in the presence of ruthenium-containing catalysts was revealed. The optimum molar ratios between the catalyst components and the reactants, as well as the reaction conditions for the selective synthesis of mono-and dialkylsubstituted adamantane derivatives with a 70-98% yield, were determined. Nauka/Interperiodica 2006.
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.
Structure-Anti-Parkinson Activity Relationships in the Aminoadamantanes. Influence of Bridgehead Substitution
Henkel, James G.,Hane, Jeffrey T.,Gianutsos, Gerald
, p. 51 - 56 (2007/10/02)
A limited series of bridgehead alkyl-, dialkyl- and trialkyl-substituted amantadines was synthesized and tested for potential anti-Parkinson activity as dopamine (DA) agonists.The compounds were evaluated using a battery of three murine bioassays, including stimulation of locomotor activity, induction of circling in animals with unilateral striatal lesions, and reversal of reserpine/α-methyltyrosine induced akinesia.Apparent mechanistic differences were seen between the methyl-substituted series and the ethyl-substituted series.While activities in both series increase with increasing liphophilicity, the methyl series (1b-d), as well as amantadine itself (1a) exhibits only indirect DA agonist activity, as evidenced by ipsilateral rotation in the circling model and no significant difference from control in reversal of akinesia.The ethyl series (1e,f) exhibits weak but reprodicible direct DA agonist activity, as shown by contralateral rotation in the circling assay for 1e and reversal of akinesia by 1e and 1f.The 3-n-propyl derivative (1g) was devoid of any DA agonist activity.
