Copper complexes hydrolysis

Copper complexes, 5,533-750 acetylacetone hydrolysis, 2,379 photoreduction, 2.384 amidines... 

Micelle-forming copper complexes were found to effectively discriminate between enantiomers in the hydrolysis of a-amino esters (257). Hydrolysis of (.V)-phenylalanine p-nitrophenyl ester is 14-fold faster than its enantiomer, Eq. 223. Leucine affords 10-fold faster hydrolysis. The authors note that the micellar nature of these systems is extremely important for both rate of hydrolysis and selectivity (258). For example, the /V-mcthyl-dcrivcd ligand 419b leads to inhibition of the hydrolysis process, relative to catalysis by Cu(II) ion alone. 

A hydroxoaqua copper complex containing N, N, N, A -tetramethyl-1,2-diamino-ethane (250) is an excellent catalyst for the hydrolysis of sarin, O-isopropyl methylphosphonofluoridate (251), and diethyl p-nitrophenyl phosphate (252 R = Et). The mechanism of the reaction probably involves bound hydroxide attacking the phosphoryl group with concomitant electrophilic catalysis by copper. 

As the result of hydrolysis a complex mixture of all, or nearly all, the previously mentioned units is obtained. These have been isolated by various methods based upon the fractional crystallisation of the compounds themselves, or of their copper, silver and other salts. Only when one or more of the amino acids occurred in somewhat large amounts was their isolation and characterisation effected their amount seldom reached a value higher than 20 per cent, of the total quantity and the remainder was represented by uncrystallisable syrups of unknown nature. A great advance was made when Drechsel discovered that the protein molecule contained diamino acids as well as monoamino acids, and to Kossel and Kutscher we owe our chief knowledge concerning their isolation and estimation. Emil Fischer, in igoi, by his... 

Ibe principle found for zinc(II) was applied to ) complex models by Young et al. (25). The hydroxyl function of copper complex 27a deprotonates with a p value of 8.8 to yield 27b, which cleaves phosphodiester bis(2,4-dinitrophenyl) phosphate (BDP ) by transesterification to produce 28 ( (BDP ) = 7.2 x -1 M-1sec-1 at 25°C see Scheme 5). The analogous complex with a hydroxyethyl pendent cleaves the diester predominantly by hydrolysis, which suggests that the reactive species is not Cun-alkoxide, but —OH-. The rate A(BDP") of... 

Attempts to aziridinate alkenes with iron catalysts in an asymmetric manner have met with only limited success to date [101], In an early report on the use of various chiral metal salen complexes, it was found that only the Mn complex catalyzed the reaction whereas all other metals investigated (Cr, Fe, Co, Ni etc.) gave only unwanted hydrolysis of the iminoiodinane to the corresponding sulfonamide and iodoben-zene [102], Later, Jacobsen and coworkers and Evans et al. achieved good results with chiral copper complexes [103]. 

A solution of Li[GaH4] in diethyl ether is prepared by the standard methods,J1 and is stored in a needle-valve O-ring flask. The concentration of Li[GaH4]-ether solution is determined by hydrolysis of a known volume of the solution followed by gallium determination by ethylenediamine-tetraace-tic acid, disodium salt using copper-PAN [l-(2-pyridylazo)-2-naphthol copper complex] as the indicator.4 It is assumed that all the gallium is present as the tetrahydrogallate. Only an approximate concentration need be determined since an excess of sodium hydride or potassium hydride is used. 

---