TY - JOUR
T1 - Product Distribution Control for Glucosamine Condensation
T2 - Nuclear Magnetic Resonance (NMR) Investigation Substantiated by Density Functional Calculations
AU - Jia, Lingyu
AU - Zhang, Zhenzhou
AU - Qiao, Yan
AU - Pedersen, Christian Marcus
AU - Ge, Hui
AU - Wei, Zhihong
AU - Deng, Tiansheng
AU - Ren, Jun
AU - Liu, Xingchen
AU - Wang, Yingxiong
AU - Hou, Xianglin
PY - 2017/3/22
Y1 - 2017/3/22
N2 - (Chemical Equation Presented) Selective conversion of glucosamine (GlcNH2) to deoxyfructosazine (DOF) and fructosazine (FZ) with additives was investigated. Significantly enhanced yield of DOF can be improved to 40.2% with B(OH)3 as the additive. Chemical shift titration (via one-dimensional nuclear magnetic resonance (1D 1H and 13C NMR)) and two-dimensional nuclear magnetic resonance (2D NMR) including 1H-13C HSQC and 1H-1H COSY are used to investigate intermolecular interactions between B(OH)3 and GlcNH2. Diffusion-ordered NMR spectroscopy (DOSY) was further employed to identify intermediate species. Mechanistic investigation by NMR combined with electron spray ionization-mass spectroscopy (ESI-MS) discloses that a mixed 1:1 boron complex was identified as the major species, shedding light on the promotional effects of B(OH)3, which is substantiated by density functional theory (DFT). Boron coordination effects make ring-opening and subsequent dehydration reaction thermodynamically and kinetically more favorable. Dehydration of dihydrofructosazine is a key step in controlling overall process (49.7 kcal/mol). Interestingly, chelating effect results in substantial reduction of this free-energy barrier (31.5 kcal/mol). Notably, FZ was gradually becoming the main product (yield up to 25.3%), with H2O2 as the oxidant.
AB - (Chemical Equation Presented) Selective conversion of glucosamine (GlcNH2) to deoxyfructosazine (DOF) and fructosazine (FZ) with additives was investigated. Significantly enhanced yield of DOF can be improved to 40.2% with B(OH)3 as the additive. Chemical shift titration (via one-dimensional nuclear magnetic resonance (1D 1H and 13C NMR)) and two-dimensional nuclear magnetic resonance (2D NMR) including 1H-13C HSQC and 1H-1H COSY are used to investigate intermolecular interactions between B(OH)3 and GlcNH2. Diffusion-ordered NMR spectroscopy (DOSY) was further employed to identify intermediate species. Mechanistic investigation by NMR combined with electron spray ionization-mass spectroscopy (ESI-MS) discloses that a mixed 1:1 boron complex was identified as the major species, shedding light on the promotional effects of B(OH)3, which is substantiated by density functional theory (DFT). Boron coordination effects make ring-opening and subsequent dehydration reaction thermodynamically and kinetically more favorable. Dehydration of dihydrofructosazine is a key step in controlling overall process (49.7 kcal/mol). Interestingly, chelating effect results in substantial reduction of this free-energy barrier (31.5 kcal/mol). Notably, FZ was gradually becoming the main product (yield up to 25.3%), with H2O2 as the oxidant.
U2 - 10.1021/acs.iecr.6b05057
DO - 10.1021/acs.iecr.6b05057
M3 - Journal article
SN - 0888-5885
VL - 56
SP - 2925
EP - 2934
JO - Industrial & Engineering Chemistry Research
JF - Industrial & Engineering Chemistry Research
IS - 11
ER -