The Experts below are selected from a list of 1137 Experts worldwide ranked by ideXlab platform
Edward J Valente - One of the best experts on this subject based on the ideXlab platform.
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side chain entropy and the activation of organocobalamins for carbon cobalt bond homolysis synthesis characterization and thermolysis of the neopentyl derivative of a unique cobalamin analog lacking a c side chain
Inorganic Chemistry, 1997Co-Authors: Kenneth L Brown, Shifa Cheng, Jeffrey D Zubkowski, Edward J ValenteAbstract:Hydrodeamination of the c-amino derivative, 5, of cyanocobalamin (CNCbl) with Hydroxylamine-O-Sulfonic Acid in aqueous base leads to an extensively rearranged product instead of the c side chain truncated derivative, 1, expected from simple deamination. The rearranged product (CNCbl-8-butanamide) crystallizes in the orthorhombic system, space group P212121 with unit cell dimensions a = 16.041(11), b = 21.94(2), and c = 25.43(2) A. It is devoid of substituents at corrin ring C(7) but quarternized at C(8) with an “upwardly” pseudoaxial methyl group and a d side chain expanded by one methylene group to a butanamide. The corrin ring of this rearranged derivative is significantly flatter (corrin ring fold angle 9.9°) than CNCbl itself (fold angle 18.0°). Conversion of CNCbl-8-butanamide to its neopentyl derivative (NpCbl-8-butanamide), a NpCbl analog which lacks a c acetamide side chain, permits a quantitative assessment of the influence of thermal motions of the c side chain on the entropy of activation for c...
Kenneth L Brown - One of the best experts on this subject based on the ideXlab platform.
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side chain entropy and the activation of organocobalamins for carbon cobalt bond homolysis synthesis characterization and thermolysis of the neopentyl derivative of a unique cobalamin analog lacking a c side chain
Inorganic Chemistry, 1997Co-Authors: Kenneth L Brown, Shifa Cheng, Jeffrey D Zubkowski, Edward J ValenteAbstract:Hydrodeamination of the c-amino derivative, 5, of cyanocobalamin (CNCbl) with Hydroxylamine-O-Sulfonic Acid in aqueous base leads to an extensively rearranged product instead of the c side chain truncated derivative, 1, expected from simple deamination. The rearranged product (CNCbl-8-butanamide) crystallizes in the orthorhombic system, space group P212121 with unit cell dimensions a = 16.041(11), b = 21.94(2), and c = 25.43(2) A. It is devoid of substituents at corrin ring C(7) but quarternized at C(8) with an “upwardly” pseudoaxial methyl group and a d side chain expanded by one methylene group to a butanamide. The corrin ring of this rearranged derivative is significantly flatter (corrin ring fold angle 9.9°) than CNCbl itself (fold angle 18.0°). Conversion of CNCbl-8-butanamide to its neopentyl derivative (NpCbl-8-butanamide), a NpCbl analog which lacks a c acetamide side chain, permits a quantitative assessment of the influence of thermal motions of the c side chain on the entropy of activation for c...
Gustavo Mouraletts - One of the best experts on this subject based on the ideXlab platform.
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direct synthesis of nitriles from aldehydes with Hydroxylamine o sulfonic Acid in Acidic water
Tetrahedron Letters, 2016Co-Authors: Dyla J Qui, Graham J Hau, Gustavo MouralettsAbstract:Abstract Herein is reported the selective transformation of aldehydes to nitriles in the presence of Hydroxylamine- O -sulfonic Acid (NH 2 OSO 3 H) as a source of the N atom and Acidic water. The reaction works with high yields for a large array of aromatic and aliphatic aldehydes, as well as hindered aldehydes and conjugated aldehydes without purification. The reaction conditions are very mild and tolerate a wide array of functional groups. In principle, the reaction can be completed in vinegar.
Jawahar L Jat - One of the best experts on this subject based on the ideXlab platform.
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cu otf 2 catalyzed beckmann rearrangement of ketones using Hydroxylamine o sulfonic Acid hosa
Synthesis, 2019Co-Authors: Sailu Munnuri, Saumya Verma, Dinesh Chandra, Raghunath Reddy Anugu, John R Falck, Jawahar L JatAbstract:The Beckmann rearrangement (BKR) of ketones to secondary amides often requires harsh reaction conditions that limit its practicality and scope. Herein, the Cu(OTf)2-catalyzed BKR of ketones under mild reaction conditions using Hydroxylamine-O-Sulfonic Acid (HOSA), a commercial water soluble aminating agent, is described. This method is compatible with most functional groups and directly provides the desired amides in good to excellent yields.
Jing Yuan - One of the best experts on this subject based on the ideXlab platform.
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regioselective functionalization 7 1 unexpected preferences for bridgehead migration in schmidt rearrangement syntheses of novel 2 6 diazabicyclo 3 2 x alkan 3 ones x 1 3
Journal of Organic Chemistry, 1999Co-Authors: Grant R. Krow, Steven W. Szczepanski, Jee Y. Kim, Nian Liu, Askia Sheikh, Yushi Xiao, Jing YuanAbstract:Regioselective syntheses of 2,6-diazabicyclo[3.2.x]alkan-3-ones (x = 1−3) 34 by insertion of nitrogen next to the bridgehead (BH) of 2-azabicyclo[2.2.x]alkanones 32 with Hydroxylamine-O-Sulfonic Acid are described. The ketones 32 under Schmidt reaction conditions (HN3/H2SO4) afford major amounts of BH migrated lactams 34 but also, when x = 2 or 3, the methylene (M) migrated lactams, 3,6-diazabicycl[3.2.x]alkan-2-ones 37. The present N-insertion reactions favoring BH migration with azabicyclic ketones contrast markedly with reactions of the related carbocycles 1a,b, which give only methylene migrated lactams 2a,b with HN3/H2SO4. Schmidt reactions of 3-anti/syn-methyl- and 3-anti-phenyl-2-azabicyclo[2.2.2]octan-5-ones 17, 20, and 23 (64:36 ± 9, BH:M) follow the reaction pattern of the parent ketone 14, but the 3-syn-phenyl ketone 26 gives major (65%) methylene migration. The results offer insights into the BH vs M migration dichotomy for the Beckmann and Schmidt reactions of bridged bicyclic ketones.
