18807-67-5Relevant articles and documents
Dynamic kinetic asymmetrie allylation of hydrazines and hydroxylamines
Mangion, Ian,Strotman, Neil,Drahl, Michael,Imbriglio, Jason,Guidry, Erin
supporting information; experimental part, p. 3258 - 3260 (2009/12/01)
Hydrazines and hydroxylamines have been found to be excellent nucleophiles for the palladium-catalyzed dynamic asymmetric allylic amination of vinyl epoxide, with good yields and enantioselectivities of up to 97% ee. This method is applicable to acyclic a
Doxorubicin immunoconjugates containing bivalent, lysosomally-Cleavable dipeptide linkages
Dubowchik, Gene M,Radia, Shilpa,Mastalerz, Harold,Walker, Michael A.,Firestone, Raymond A.,Dalton King, H.,Hofstead, Sandra J.,Willner, David,Lasch, Shirley J.,Trail, Pamela A.
, p. 1529 - 1532 (2007/10/03)
Bivalent doxorubicin (DOX)-dipeptides (16a-c) were prepared and conjugated to the monoclonal antibody BR96. The dipeptides are cleaved by lysosomal proteases following internalization of the resulting immunoconjugates. Conjugate 18b demonstrated antigen-s
Carbon Dioxide as a Phosgene Replacement: Synthesis and Mechanistic Studies of Urethanes from Amines, CO2, and Alkyl Chlorides
McGhee, William,Riley, Dennis,Christ, Kevin,Pan, Yi,Parnas, Barry
, p. 2820 - 2830 (2007/10/02)
Several carbamate esters were synthesized from amines, carbon dioxide, and alkyl chlorides.The effect of added base on the yield and selectivity of carbamate ester formation was found to be highly important with the use of sterically hindered guanidine bases giving the best results.Relative rate studies were carried out giving the following order of reactivity between carbamate anions in acetonitrile with benzyl chloride giving carbamate esters: Et2NCO2(-) = Bu2NCO2(-) > t-BuNHCO2(-) = CyNHCO2(-) = s-BuNHCO2(-) > PhNHCO2(-) > CyCH2NHCO2(-) = n-octylNHCO2(-) = n-BuNHCO2(-).Rate studies were carried out with the diethyl, s-butyl, phenyl, and n-butyl carbamates and activation parameters were determined to be Et2NCO2(-), ΔH(excit.) = 11.8 kcal/mol, ΔS(excit.) = -33 eu; s-BuNHCO2(-), ΔH(excit.) = 12.8 kcal/mol, ΔS(excit.) = -33 eu; PhNHCO2(-), ΔH(excit.) = 14.3 kcal/mol, ΔS(excit.) = -28 eu; n-BuNHCO2(-), ΔH(excit.) = 23.4 kcal/mol, ΔS(excit.) = -3 eu.The unusual results obtained from the use of n-BuNHCO2(-) prompted further studies which showed that the rate of the reaction was inversely dependent on carbon dioxide pressure (20 psig CO2, k = 4.84E-4 M-1 s-1; 120 psig CO2, k = 1.83E-4 M-1 s-1).Nitrogen NMR spectroscopy indicated, via a labeling study with 15N amines and 13C enriched carbon dioxide, the formation of doubly inserted product from the addition of two carbon dioxides to ethylamine in acetonitrile.
NOVEL UNSYMMETRICAL N,N-BIS(METHYLENE)BIPHOSPHONIC ACIDS OF α,ω-DIAMINES. PREPARATION AND CHARACTERIZATION OF BIS(METHYLENE)>-BIPHOSPHONIC ACID AND BIS(METHYLENE)>-BIPHOSPHONIC ACID
Redmore, Derek,Dhawan, Balram
, p. 233 - 238 (2007/10/02)
Reaction of ethylenediamine with phosphorous acid and formaldehyde in molar ratio 1:2:2 gives bis(methylene)>biphosphonic acid (2a) as the major product.Similarly, reaction of hexamethylenediamine with phosphorous acid and formaldehyde in molar ratio 1:2:2 yields bis(methylene)>biphosphonic acid (2b) which is isolated either as bis(methylene>biphosphonic acid (3b) or as bis(methylene)>biphosphonic acid (4b).Removal of the carbobenzoxy group with HBr 3b or the benzoyl group with HCl from 4b gives pure bis(methylene)>biphosphonic acid (2b).All compounds were characterized by 13C NMR, 31P NMR and elemental analysis.