150012-41-2Relevant academic research and scientific papers
Three bacteriorhodopsins with ring-didemethylated 6-s-locked chromophores and their properties
Groesbeek, M.,Galen, A. J. J. van,Ippel, J. H.,Berden, J. A.,Lugtenburg, J.
, p. 237 - 246 (1993)
Three novel, 6-s-locked rigidified retinals, racemic all-E 1,5-didemethyl-8,16-methanoretinal, all-E, 1,1-didemethyl-8,18-methanoretinal and all-E 8a,18-didehydro-1,1-didemethyl-8,18-methanoretinal were prepared in good yield in high purity on a 100-mg scale.For the preparation of the key intermediate in the synthesis of 1,5-didemethyl-8,16-methanoretinal, reductive cyanation of an unsaturated cyanohydrin to the corresponding conjugated nitrile was accomplished using triethylsilane and trifluoroacetic acid.The three locked retinals interact with bacterioopsin to form bacteriorhodopsin with about the same rate as the native chromophore.This work proves that steric interaction of the 1,1-dimethyl group in the chromophore is an important factor in binding to bacterioopsin.
Dihalocarbene insertion reactions into C-H bonds of compounds containing small rings: Mechanisms and regio- and stereoselectivities
Brinker, Udo H.,Lin, Guoying,Xu, Linxiao,Smith, William B.,Mieusset, Jean-Luc
, p. 8434 - 8451 (2007)
(Chemical Equation Presented) Novel insertion reactions of dichloro- and dibromocarbene into carbon-hydrogen bonds adjacent to cyclopropane rings are reported. It is found that the predominant isomers formed in the reactions with bicyclo[4.1.0]heptane result from insertion into the endo carbon-hydrogen bonds alpha to the three-membered ring. In the reactions of bicyclo[3.1.0]hexane, however, the exo dihalocarbene insertion products are formed as the major isomers. In some compounds cyclopropane rings "activate" adjacent carbon-hydrogen bonds, whereas other systems containing three-membered rings do not. Moreover, the influence of various substituents (methyl, geminal dimethyl, phenyl, methoxy, and ethoxy) attached to bicyclo-[3.1.0]hexane and bicyclo[4.1.0]heptane in dihalocarbene reactions has been studied. The findings can be explained by the concept of maximum orbital overlaps of Walsh orbitals of the cyclopropane rings and the α carbon-hydrogen bonds. In stark contrast, selective insertion into the tertiary carbon-hydrogen bonds of the cyclobutane ring in bicyclo[4.2.0]octane is observed.
Stoichiometric Reactions of Nonconjugated Dienes with Zirconocene Derivatives. Further Delineation of the Scope of Bicyclization and Observation of Novel Multipositional Alkene Regioisomerization
Negishi, Ei-ichi,Maye, John P.,Chouery, Daniele
, p. 4447 - 4462 (2007/10/02)
The reaction of n-Bu2ZrCp2 with nonconjugated dienes containing substituted vinyl groups can lead to either bicyclization or the formation of conjugated diene-zirconocenes via multipositional regioisomerization.
Deazetation of a Bicyclic Azo Compound: Resolution of a Stereochemical Ambiguity and Conformational Analysis of a Biradical
Samuel, Christopher J.
, p. 1259 - 1265 (2007/10/02)
Development of a new approach has permitted a fuller analysis of the stereochemistry of deazetation of the stereospecifically deuteriated azo compound (1d) than could be achieved previously, in that it has proved possible to analyse 2H2>octa-1,7-diene for E,E-, E,Z,-and Z,Z-content.This has given results for the thermal and photochemical reactions that can be rationalised in terms of partial conformational equilibration of the biradical.
ZIRCONOCENE-PROMOTED STEREOSELECTIVE BICYCLIZATION OF 1,6- AND 1,7-DIENES TO PRODUCE TRANS-ZIRCONABICYCLOOCTANES AND CIS-ZIRCONABICYCLONONANES.
Rousset, Christophe J.,Swanson, Douglas R.,Lamaty, Frederic,Negishi, Ei-ichi
, p. 5105 - 5108 (2007/10/02)
The Zr-promoted bicyclization of 1,6- and 1,7-dienes can stereoselectively produce trans-zirconabicyclooctanes and cis-zirconabicyclononanes, respectively; these compounds can be readily converted into protonolysis, halogenolysis, and carbonylation products.
