79802-79-2Relevant academic research and scientific papers
Facile synthesis of isodamascone and its analogs
Rangnekar, Dinesh W.,Kulkarni, Vikas S.,Ranade, Prasad V.,Sabnis, Ram W.
, p. 425 - 430 (2007/10/03)
Synthesis of isodamascone and its analogs, the commercially important aroma compounds, have been accomplished from the readily available 1,5,5-trimethyl-2-cyclohexen-1-ol via a short, facile, and simple sequence of reactions in excellent yield. Copyright Taylor & Francis Group, LLC.
Syn- and anti-selective prins cyclizations of δ,ε-unsaturated ketones to 1,3-halohydrins with Lewis acids
Miles, R. Brandon,Davis, Chad E.,Coates, Robert M.
, p. 1493 - 1501 (2007/10/03)
Ten acyclic and monocyclic δ,ε-unsaturated ketones, with and without methyl substituents on the double bond, underwent halide-terminated Prins (halo-Prins) cyclizations under anhydrous conditions in the presence of Lewis acids. TiCl4, TiBr4, BCl3, and BBr 3 promoted syn-selective cyclizations to sterically congested chloro- and bromohydrins, while SnCl4, SnBr4, InCl3, ZrCl4, and several other Lewis acids effected highly anti-selective reactions to furnish the corresponding trans halohydrins. The stronger Lewis acids (TiX4 and BX3) favor the syn process that involves axial delivery of a halide ligand. Competition experiments showed that substitution at the δ carbon (methallyl enones) led to increased rates (40-50-fold), while substitution at the ε position (cis and trans crotyl enones) retarded the rate and eroded the selectivity of the cyclizations. The trends in syn vs anti selectivity, reactivity, and effects of different Lewis acidic metal halides are rationalized by competitive reaction pathways proceeding through syn carbocation-halide ion pairs and a higher order transition state that leads to inversion of configuration and formation of trans halohydrins, along with cyclic olefins arising from proton elimination.
Synthesis and structure-affinity relationships of 1,3,5-alkylsubstituted cyclohexylamines binding at NMDA receptor PCP site
Jirgensons, Aigars,Kauss, Valerjans,Kalvinsh, Ivars,Gold, Markus R.,Danysz, Wojciech,Parsons, Chris G.,Quack, Gunter
, p. 555 - 565 (2007/10/03)
A series of 1,3,5-alkylsubstituted cyclohexylamines 2 were synthesized as ligands for the N-methyl-D-aspartate (NMDA) receptor phencyclidine (PCP) binding site. Pure diastereomers with defined configuration of amino group 2- ax and 2-eq were obtained. The optimal size of 1,3,5-substituents was determined for cyclohexylamines 2 with an equatorial amino group in the lowest energy conformation using Hansch analysis. According to the data, the lipophilic part of cyclohexylamines 2 does not discriminate between hydrophobic regions of the PCP binding site but rather recognizes this site as a whole lipophilic pocket. (C) 2000 Editions scientifiques et medicales Elsevier SAS.
Carbon-13 magnetic resonance: hydrogen involvement in γ-anti substituent effects
Forrest, T. P.,Thiel, J.
, p. 2870 - 2875 (2007/10/02)
Chemical shifts have been determined for the carbons in a series of 3,3-dimethylcyclohexyl derivatives, (substituent = H, CH3, NH2, OH, Cl, Br, I).Comparison of the γ-anti substituent effects at carbons 3 and 5 indicates that presence of axial protons on these carbons causes increased shielding by all of the above substituents.The shielding by γ-anti substituents is decreased by the replacement of either the α or γ protons by methyl groups; the extent of the decrease is dependent upon the substituent and upon the position of the hydrogen which is replaced.
