119192-10-8Relevant articles and documents
High Turnover Pd/C Catalyst for Nitro Group Reductions in Water. One-Pot Sequences and Syntheses of Pharmaceutical Intermediates
Gallou, Fabrice,Li, Xiaohan,Lipshutz, Bruce H.,Takale, Balaram S.,Thakore, Ruchita R.
supporting information, p. 8114 - 8118 (2021/10/25)
Commercially available Pd/C can be used as a catalyst for nitro group reductions with only 0.4 mol % Pd loading. The reaction can be performed using either silane as a transfer hydrogenating agent or simply a hydrogen balloon (μ1 atm pressure). With this technology, a series of nitro compounds was reduced to the desired amines in high chemical yields. Both the catalyst and surfactant were recycled several times without loss of reactivity.
PROCESS FOR THE LARGE SCALE PRODUCTION OF RIZATRIPTAN BENZOATE
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Page/Page column 4; 8-9, (2008/06/13)
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.
IMPROVED PROCESS FOR THE PREPARATION OF RIZATRIPTAN BENZOATE
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Abstract, (2010/11/25)
Present invention discloses an improved and commercially viable process for the preparation of rizatriptan benzoate of formula (I). According to the present process the hydrazone intermediate derived from the phenylhydrazine of formula- (III) and 4- dimethylaminobutyraldehyde diethyl acetal is gradually heated to 60-70 °C in aqueous sulfuric acid medium and maintained for 3-4hr to get rizatriptan with less dimeric impurity of formula (X). The resultant rizatriptan is isolated and converted into the pharmaceutically acceptable benzoate salt. Present process produces less percentage of dimeric (less than 3 %) or polymeric impurities compared to the prior art process and more yield of rizatriptan. Rizatriptan benzoate produced according to the present process has more than 99.5 % purity with less than 0.1% dimeric impurity of formula (X) by HPLC. Rizatriptan benzoate is useful for the treatment of migraine.