- CONVERSION OF AROMATIC DIAZONIUM SALT TO ARYL HYDRAZINE
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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
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- PROCESS FOR THE LARGE SCALE PRODUCTION OF RIZATRIPTAN BENZOATE
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The present invention provides a method for preparing pure Rizatriptan benzoate having purity more than 99.5% and dimer impurity less than 0.1% comprises, i) Condensation of 1,2,4-Triazole with 4-Nitro benzyl bromide to yield l-(4-nitrophenyl) methyl-1,2,4- triazole ii) Reducing the l-(4-nitrophenyl) methyl-1,2,4-triazole to give l-(4- aminophenyl) methyl-1,2,4-triazole iii) Converting l-(4-aminophenyl) methyl-1,2,4-triazole to l-(4-hydrazinophenyl) methyl-1,2,4-triazole hydrochloride iv) Condensing the hydrazine derivative with 4-(Dimethylamino) butanal diethylacetal to get Rizatriptan and v) Salification of Rizatriptan to Rizatriptan benzoate.
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- PROCESS FOR PREPARING RIZATRIPTAN
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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.
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