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US 5,864,048 AGranted
Rhein derivatives and new processes for producing rhein derivatives
AssigneeLaboratoire Medidom S.A.
InventorGuido Di Napoli
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Abstract
The present description relates to new anthraquinone-derivatives endowed with inhibitory activity of the serine proteinase enzymes, useful for the treatment of rheumatoid arthritis, acute respiratory syndrome of adult, and pulmonary emphysema, and to new processes for the preparation of rhein derivatives.
Claims17
A process for the preparation of a rhein derivative of formula (XV) ##STR23## wherein R.sub.1 is selected among --ORa and --OCORa, and R.sub.8 is selected among --ORb and --OCORb, wherein Ra and Rb, equal or different one from another, are selected from the group consisting of H, alkyl group and aromatic group;
- R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.7, equal or different one from another, are selected among H, alkyl, alkenyl, alkinyl, hydroxy, alkoxy, acyloxy, arylalkyl, aromatic and cyano group,
- provided that at least one of R.sub.5 and R.sub.7 is H,
- comprising the following steps:
- e) subjecting to mono-nitration an anthraquinone derivative of formula (XVI) ##STR24## wherein R.sub.1, R.sub.8, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.7, are as above defined for compound of formula (XV),
- by treating the compound of formula (XVI) with an essentially stoichiometric amount of nitric acid, thus affording the corresponding mono-nitro derivative selected from the group consisting of compound of formula (XVII)A, compound of formula (XVII)B and mixtures thereof, ##STR25## wherein R.sub.1, R.sub.8, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.7, are as above defined for compound of formula (XVI);
- f) treating the mono-nitro derivative obtained from the preceding step with cyanide ions, to give the carboxy anthraquinone derivative of formula (XV) as above defined.
3 more elements
Dependencies are inferred from the claim text.