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AssigneeRichter Gedeon Vegyeszeti Gyar Rt.
InventorsPeter Bod, Kalman Harsanyi, Ferenc Trischler, Eva Fekecs, Attila Csehi, Bela Hegedus, Eva Mersich nee Donat, Gyorgyi Szabo nee Komlosi, Erika Horvath nee Sziki
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The invention relates to carbazolone derivatives of the formula ##STR1## wherein A stands for a group of formula --CH.sub.2 --R (V), wherein R means a hydroxyl or 2-methyl-1H-imidazol-1-yl group; B represents a group of formula ##STR2## wherein R.sub.1 means hydrogen or a methyl or ethyl group; or A and B together form a group of formula ##STR3## wherein R.sub.2 means a methyl or ethyl group; or A and B together form a group of formula ##STR4## The above compounds are useful intermediates in the synthesis of ondansetron of formula ##STR5## chemically 9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-1,2,3,9-tetrahydro-4H-carba zol-4-one. The invention further relates to a novel process for the preparation of compounds of the formula (I) , wherein A and B are the same as in formula (I) but B may be also hydrogen. Thus, this novel process is suitable for the preparation of ondansetron itself.
A process for the preparation of ondansetron which process comprises
Dependencies are inferred from the claim text.