109433-73-0Relevant academic research and scientific papers
Boranes in Synthesis. 5. The Hydroboration of Enamines with Mono- and Dialkylboranes. Asymmetric Synthesis of β-Amino Alcohols of Moderate Enantiomeric Purity from Aldehyde Enamines
Fisher, Gary B.,Goralski, Christian T.,Nicholson, Lawrence W.,Hasha, Dennis L.,Zakett, Donald,Singaram, Bakthan
, p. 2026 - 2034 (1995)
The hydroboration of both acyclic and cyclic aldehyde and ketone enamines with such representative mono- and dialkylboranes as thexylborane and dicyclohexylborane, followed by an oxidative workup, yields the corresponding β-amino alcohols in good to excellent isolated yields.The hydroboration of ketone and aldehyde enamines with the asymmetric hydroboration reagents monoisopinocampheylborane (dIpeBH2) and diisopinocampheylborane (dIpc2BH) was also investigated. dIpc2BH is highly effective for the asymmetric hydroboration of acyclic aldehyde enamines, such as 1-(4-morpholino)-3-phenyl-1-propene and 1-(1-pyrrolidino)-1-octene.Oxidation of the intermediate trialkylborane furnishes the corresponding β-amino alcohols in 50-86percent ee.The stereogenic center of the carbinol carbon is consistently enriched in the R-enantiomer when dIpc2BH prepared from (+)-α-pinene is used as the hydroboration reagent.The enantiomeric excesses of the β-amino alcohols synthesized in this study were determined by HPLC using a chiral stationary phase.The absolute configuration of some of the β-amino alcohols synthesized in this study were determined by chiral HPLC comparison with authentic β-amino alcohols prepared from chiral epoxides of known absolute configuration.
Hydroboration. 81. Synthesis of 2-(Dialkylamino)boronic Esters and Acids via Hydroboration of Enamines. A Convenient Preparation of β-Dialkylamino Alcohols
Goralski, Christian T.,Singaram, Bakthan,Brown, Herbert C.
, p. 4014 - 4019 (1987)
Hydroboration of representative enamines with 1 equiv of borane-dimethyl sulfide (BMS) in tetrahydrofuran affords as the major product the corresponding boranes, which are charakterized by B NMR spectroscopy.These intermediates on methanolysis give the corresponding boronic acids in essentially quantitative yields.The boronic acids thus obtained can be reestrified with 1,3-propanediol to give the corresponding 2--1,3,2-dioxaborinanes.Consequently, it is now possible to prepare dialkyloamino-substituted organoborane compounds with the potential to be elaborated to a wide variety of functionalized tiralkylamines.Alkaline hydrogen peroxide oxidation of these organoborane intermediates affords the corresponding β-dialkyloamino alcohols.The hydroboration of enamines, methanolysis of the intermediate borane derivatives, and oxidation of the boronate esters is accompanied by side reactions such as elimination and protonolysis.The magnitude of these side reactions varies considerably with the structures of the anamines.However, moderate to excellent yields of the desired organoboron compounds can frequently be achieved.The use of trimethylamine N-oxide dihydrate for the oxidation of the 2-(dialkylamino)boronate esters greatly suppresses the side reactions and vastly improves the yields of the β-dialkylamino alcohols.
Chemoenzymatic preparation of optically active trans-cyclohexane-1,2- diamine derivatives: An efficient synthesis of the analgesic U-(-)-50,488
Gonzalez-Sabin, Javier,Gotor, Vicente,Rebolledo, Francisca
, p. 5788 - 5794 (2007/10/03)
Stereoespecific syntheses of (±)-trans-N,N-cyclohexane-1,2-diamines ((±)-4a-g) were carried out from the corresponding (±)-trans-N,N- dialkylaminocyclohexanols by successive treatment with mesyl chloride and aqueous ammonia. The stereochemical outcome indicates the formation of a meso-aziridinium ion intermediate, Kinetic resolutions of diamines (±)-4 were efficiently accomplished in aminolysis reactions catalyzed by lipase B from Candida antarctica with ethyl acetate as the solvent and acyl donor. Acetamides and the remaining diamines, isolated as the benzyloxycarbonyl derivatives, were obtained with very high ee values (92-99%), One of the carbamates was used as a precursor of the analgesic U-(-)-50,488.
Synthesis, in Vitro Acetylcholine-Storage-Blocking Activities, and Biological Properties of Derivatives and Analogues of trans-2-(4-Phenylpiperidino)cyclohexanol (Vesamicol)
Rogers, Gary A.,Parsons, Stanley M.,Anderson, D. C.,Nilsson, Lena M.,Bahr, Ben A.,et al.
, p. 1217 - 1230 (2007/10/02)
Eighty-four analogues and derivatives of the acetylcholine-storage-blocking drug trans-2-(4-phenylpiperidino)cyclohexanol (vesamicol) were synthesized, and their potencies were evaluated with the acetylcholine active-transport assay utilizing purified synaptic vesicles from Torpedo electric organ.The parent drug exhibits enantioselectivity, with (-)-vesamicol being 25-fold more potent than (+)-vesamicol.The atomic structure and absolute configuration of (+)-vesamicol were determined by X-ray crystallography.The absolute configuration of (-)-vesamicol is 1R,2R.Structure-activity evidence indicates that (-)-vesamicol does not act as an acetylcholine analogue.Alterations to all three rings can have large effects on potency.Unexpectedly, analogues locking the alcohol and ammonium groups trans-diequatorial or trans-diaxial both exhibit good potency.A potent benzovesamicol family has been discovered that is suitable for facile elaboration of the sort useful in affinity labeling and affinity chromatography applications.A good correlation was found between potencies as assessed by the acetylcholine transport assay and LD50 values in mouse.
