212248-62-9Relevant articles and documents
CONVERSION OF AROMATIC DIAZONIUM SALT TO ARYL HYDRAZINE
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Page/Page column 6-7, (2008/06/13)
The present invention relates to the preparation of aryl hydrazines and their salts by treating aryl diazonium salts with triphenyl phosphine followed by hydrolysis of the resulting triphenyl-aryl hydrazyl phosphonium salt to get aryl hydrazine or its sal
PROCESS FOR PREPARING RIZATRIPTAN
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Page 12-13; 15, (2008/06/13)
In particular, rizatriptan or a pharmaceutically acceptable salt thereof, which includes a) Preparation of the diazonium salt of the aniline hydrochloride (II); followed by reduction and acidification to give the hydrazine (III); b) reaction in situ of the hydrazine hydrochloride (III) with α-keto-δ-valerolactone, to give the hydrazone (IV); c) Fischer indole reaction of the hydrazone (IV), to give the pyranoindolone (V), optionally followed by a hydrolysis reaction to give (VI); d) Transesterification of (V) or esterification of its hydrolysis product (VI), to give (VII), where R means straight or branched C1-C4 alkyl chain; e) Conversion of the hydroxyl group of (VII) into dimethylamino, to give the indolecarboxylate (VIII), where R has the meaning defined above; f) Saponification of the 2-carboalkoxy group of (VIII) to give indolecarboxylic acid (IX); and g) Decarboxylation of the indolecarboxylic acid (IX) to give rizatriptan and, eventually, to obtain a pharmaceutically acceptable salt thereof. The invention also relates to synthesis intermediates to obtain rizatriptan.
