- PROCESS FOR THE PREPARATION OF SILDENAFIL AND INTERMEDIATES THEREOF
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The present invention discloses a process for preparing sildenafil and its intermediates having the structures outlined below: In particular, the present invention provides a process for preparing the compound of formula (I) and its intermediates, i.e. the compounds of formula (I), (II), (III) and (IV). The compound of formula (I) is obtained from the compound of formula (II); the compound (II) is obtained from the compound of formula (III) and methylpiperazine; the compound (III) is obtained by treating the compound of formula (IV) with chlorosulfonic acid; the compound (IV) is obtained though treating the compound of formula (V) in the presence of at least one selected from POX3, PX3, PX5 and their mixtures in any ratio. The process for preparing the compound of formula (I) according to the present invention reduces the side reactions in the processes of the prior art. These improvements lead to higher yields and a better industrial applicability with easier controlling of the reaction.
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Page/Page column 7-8
(2010/03/31)
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- PROCESS FOR THE PREPARATION OF SILDENAFIL
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The present invention is directed to a process for the preparation of the compound of Formula (I) : comprising the step of converting a compound selected from the group consisting of the compounds of formulae (II), (III) and (IV) : wherein X is halogen, in one or more steps to give the compound of formula (I). The invention is also directed to a process for the preparation of a pharmaceutical composition comprising the compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof. Moreover, the invention relates to intermediates suitable for use in the above processes as well as processes for their preparation.
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Page/Page column 19; 26
(2008/12/06)
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- Synthesis, spectral studies and biological activity of novel 3H-1,5-benzodiazepine derivatives
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Chlorination of 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1, 6-dihydro-7H-pyrazolo [4, 3-d] pyrimidin-7-one 1 with POCl3 affords 5-(2-ethoxyphenyl)-1-methyl-7-chloro-1H-pyrazolo [4, 3-d] pyrimidine 2. Further compound 2 is condensed with different β-diketones / β-ketoesters3a-e, to obtain new β-diketones/β-ketoesters 4a-e. The synthesized new β-diketones/β-ketoesters (4a-e) and o-phenylenediamine (o-PDA) gives biologically active 3H-1,5-benzodiazepines 5a-e. All the newly synthesized compounds are characterized by elemental analysis and spectral studies. The compounds 5a-e have been screened for antimicrobial, antifungal and anthelmintic activity.
- Kumar, Rajesh,Joshi
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p. 2021 - 2025
(2008/09/18)
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