PROCESSES FOR THE PREPARATION OF AMINOALKYL PHENYLCARBAMATES

摘要

A process according to Scheme One wherein R1 to R5 are any atom or group, including the possibility that R1 and R2 and/or R3 and R4 together with the N to which they are attached form a ring. In particular, R1, R3, R4 and R5 are each methyl, R2 is ethyl and product 5 is obtained as a hydrogen tartrate salt, the product then being rivastigmine hydrogen tartrate. The process has the advantage of avoiding the preparation of zwitterionic intermediates which are very water soluble and need to be isolated by concentration of aqueous solvent. The process is therefore suited to industrial scale manufacture of aminoalkyl phenylcarbamates. The large amounts of sulfated ash residues left in the product when prepared by prior art processes and the use of pyrophoric and hazardous reagents such as sodium hydride may be avoided.