Oxidation ammonium-directed metal-free

Ammonium-directed metal-free oxidation of cyclic allylic and homoallylic amines has been reviewed. Such reactions yield all four diastereoisomers of the corresponding 3-amino-1,2-diols, and have featured in recent syntheses of ( )-l-deoxynojirimycin and ( )-l-deoxyaltronojirimycin. ... 

Precautions should be taken in the course of the preparation of a cata lyst to keep it free from any contaminating substances other than those definitely desired in the catalyst. The catalyst should be prepared just as any pure substance is experience indicates that effort in this direction is well expended. When precipitation of the hydroxide or oxide may occur in the course of preparing a metal catalyst, it is desirable to use the nitrate of the metal and ammonium hydroxide as a precipitant when there are no other conflicting chemical reactions. In this way, any ammonium salts or excess hydroxide is easily volatilized by careful heating, ... 

The most widely used method for chemical initiation for graft copolymerization on polysaccharides has been with ceric salts such as CAN or ceric ammonium sulfate. Free radical sites are generated on a polymeric backbone by direct oxidation through ceric metal ions (e.g., Ce "). The ceric ion with low oxidation potential is the proper choice for the reaction. The proposed mechanism for such processes has been depicted by an intermediate formation of metal ion polymer complex (chelate type) [17, 21-24]. Such a complex formation is not restricted to all polymers. The plausible mechanism for ceric ion induced graft copolymerization by direct oxidation method is shown in Scheme 3.1. A series of four grades of Ag-g-PAM copolymers have been synthesized by the conventional method. 

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