Ultrasonic-Assisted Synthesis of Two t-Butoxycarbonylamino Cephalosporin Intermediates on SiO2

Herein, we describe a facile and high efficient strategy for the synthesis of two forms of the 7β-t-butoxycarbonylamino-3-chloromethyl-3-cephem-4-carboxylates using ultrasonic irradiation. By SiO2 as weak Lewis acid catalyst, 4-methoxybenzyl 7β-t-butoxycarbonylamino-3-chloromethyl-3-cephem-carboxylate (Boc-ACLE) and benzhydryl 7β-t-butoxycarbonylamino-3-chloromethyl-3-cephem-4-carboxylate (Boc-ACLH) were successfully synthesized through the efficient protection of the N-t-butoxycarbonyl (N-Boc), and the reactions occurred at low temperature requiring short reaction times and exhibiting excellent isolated yields (96% and 96.2%, resp.). The advantages of this reaction route including the usage of economical reagents and mild reaction conditions and high isolated yield make the two significant t-butoxycarbonylamino cephalosporin intermediates possible in large-scale production

Ultrasonic-Assisted Synthesis of Two t-Butoxycarbonylamino Cephalosporin Intermediates on SiO 2

Herein, we describe a facile and high efficient strategy for the synthesis of two forms of the 7 -t-butoxycarbonylamino-3-chloromethyl-3-cephem-4-carboxylates using ultrasonic irradiation. By SiO 2 as weak Lewis acid catalyst, 4-methoxybenzyl 7 -t-butoxycarbonylamino-3-chloromethyl-3-cephem-carboxylate (Boc-ACLE) and benzhydryl 7 -t-butoxycarbonylamino-3-chloromethyl-3-cephem-4-carboxylate (Boc-ACLH) were successfully synthesized through the efficient protection of the N-tbutoxycarbonyl (N-Boc), and the reactions occurred at low temperature requiring short reaction times and exhibiting excellent isolated yields (96% and 96.2%, resp.). The advantages of this reaction route including the usage of economical reagents and mild reaction conditions and high isolated yield make the two significant t-butoxycarbonylamino cephalosporin intermediates possible in large-scale production

A Facile Synthesis of Hexagonal Spinel λ-MnO2 Ion-Sieves for Highly Selective Li+ Adsorption

Ion-sieves are a class of green adsorbent for extraction Li+ from salt lakes. Here, we propose a facile synthesis of hexagonal spinel LiMn2O4 (LMO) precursor under mild condition which was first prepared via a modified one-pot reduction hydrothermal method using KMnO4 and ethanol. Subsequently, the stable spinel structured λ-MnO2 (HMO) were prepared by acidification of LMO. The as-prepared HMO shows a unique hexagonal shape and can be used for rapid adsorption-desorption process for Li+ adsorption. It was found that Li+ adsorption capacity of HMO was 24.7 mg·g−1 in Li+ solution and the HMO also has a stable structure with manganese dissolution loss ratio of 3.9% during desorption process. Moreover, the lithium selectivity ( α Mg Li ) reaches to 1.35 × 103 in brine and the distribution coefficients ( K d ) of Li+ is much greater than that of Mg2+. The results implied that HMO can be used in extract lithium from brine or seawater containing high ratio of magnesium and lithium

Adsorption Equilibrium, Kinetics, and Thermodynamic Studies of Cefpirome Sulfate by Using Macroporous Resin

The adsorption thermodynamics, kinetics, and isotherm parameters of cefpirome sulfate in aqueous solution on macroporous resin (XAD-16) were studied. Using static equilibrium tests, the fitting of resin adsorption data were calculated by the isothermal adsorption model. The fitting results show that Freundlich equation can adequately fit the adsorption isotherm. Meanwhile, the derived adsorption constants and their temperature dependencies from Freundlich isotherm had been used to calculate the corresponding thermodynamic quantities, such as the free energy of adsorption, heat, and entropy of adsorption. The thermodynamic data indicated that XAD-16 resin adsorption of cefpirome sulfate in aqueous solution was a spontaneous exothermic process, which was characterized by physical adsorption. The influences of initial concentration, bed height, and residence time on the breakthrough curve were examined by dynamic tests and the optimal parameters were defined