Ab&raet-Enantioselective syntheses of a-alkenyl glycines of type 10 and of type 23 are described that provide these uncommon ammo acids with predictable conf&uration and with ec-values of ~~95%. Both approaches are based on the bislactim ether method developed by SchBllkopf et al. As for 10: The lithiated his-lactim ether 6 of cyclo(t-val-gly) is reacted with 2_i(dimethyl t-butyl)silyl]alkanals...

The aim of the study was to evaluate whether the addition of activated carbon in the photocatalytic oxidation of biologically pretreated greywater and of a polar aliphatic compound gives synergy, as previously demonstrated with phenol. Photocatalytic oxidation kinetics were recorded with fivefold concentrated biologically pretreated greywater and with aqueous tetraethylene glycol dimethyl ether...

Kalman filtering was applied to the current vs. time data obtained at the growing mercury drop of a DME under d.c. polarographic conditions, to separate the faradaic and capacitive components of the electrode current. Polarograms consisting of the pure faradaic current vs. applied d.c. potential were subjected to a four-parameter curve-fitting procedure to obtain the polarographic characteristi...

This paper deals with maximizing dimethyl ether (DME) production from methanol due to its industrial importance as a future diesel fuel. The high acidity and the micro-porous structure of the catalysts encouraged this reaction. Catalysts containg 6% CuO supported on H-ZSM-5 and H-MOR zeolites give high activities for DME production. The 6% CuO/HMOR is more selective for DME production, while th...

Dimethyl ether (DME) is a synthetically produced alternative fuel to diesel-based and could be used in ignition diesel engines due increasing energy demand. DME considered extremely clean transportation green because it has high cetane number (around 60), low boiling point (−25 °C), oxygen amount (35 wt%) which allow fast evaporation higher combustion quality (smoke-free operation 90% fewer NOx...

The title compound, C(39)H(37)NO(8), is a product of the Michael addition of the cyclic secondary amine subunit of aza-14-crown-4 ether to dimethyl acetyl-enedicarboxyl-ate. The piperidinone ring exhibits a distorted chair conformation and the dimethyl acetyl-enedicarboxyl-ate fragment has a cis configuration with a dihedral angle of 56.61 (5)° between the two carboxyl-ate groups. The crystal p...

The title compound, C(29)H(33)NO(8), is a product of the Michael addition of the cyclic secondary amine subunit of the aza-14-crown-4 ether to dimethyl acetyl-enedicarboxyl-ate. The piperidinone ring exhibits a distorted chair conformation, and the dimethyl ethylenedicarboxylate fragment has a cis configuration with a dihedral angle of 78.96 (5)° between the two carboxyl-ate groups. The crystal...