US3963760A
Expired / Lapsed
US
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Selective demethylation of anthracycline derivatives
Assignee: Pfizer Italia SRL
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Filing: 1975-09-15
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Granted: 1976-06-15
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Expires: 1995-09-15
Abstract
Abstract Anthracycline derivatives of the formula ##SPC1## Wherein R 1 , R 2 , R.sub. 3 and R 4 are independently selected from the group consisting of hydrogen, chlorine, bromine and methoxy, with the proviso that at least one of the substituents is methoxy, and wherein R 5 is selected from the group consisting of hydrogen, OH OR and OCOR; R being an alkyl group of 1 to 4 carbon atoms are prepared, in a single step, by selectively demethylating a compound of the formula: ##SPC2## Wherein R 1 , R 2 , R 3 , R 4 and R 5 are as defined above by treating same with an aluminum halide in the presence of a suitable solvent at a temperature of 0° to 50°C.
Inventors
- 👤 Luigi Bernardi
- 👤 Bianca Patelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:39
CPC Classifications
C; C07; C07C; C07C69/00; C07C69/95
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
153 words
A process for preparing an anthracycline derivative of the formula ##SPC6## wherein R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of hydrogen, chlorine, bromine and methoxy group, with the proviso that at least one of R 1 , R 2 , R 3 and R 4 is methoxy; and wherein R 5 is selected from the group consisting of hydrogen, OH, OR and OCOR, in which R is an alkyl group of 1 to 4 carbon atoms; said process comprising reacting a compound of the formula ##SPC7## wherein R 1 , R 2 , R 3 , R 4 and R 5 are as defined above with an aluminum halide in the presence of a solvent selected from the group consisting of chlorobenzene, bromobenzene, and nitrobenzene, at a temperature of from 0° to 50°C., and isolating the demethylated product from the reaction mixture.
Claim 2
Dependent Claim
153 words
A process for preparing an anthracycline derivative of the formula ##SPC6## wherein R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of hydrogen, chlorine, bromine and methoxy group, with the proviso that at least one of R 1 , R 2 , R 3 and R 4 is methoxy; and wherein R 5 is selected from the group consisting of hydrogen, OH, OR and OCOR, in which R is an alkyl group of 1 to 4 carbon atoms; said process comprising reacting a compound of the formula ##SPC7## wherein R 1 , R 2 , R 3 , R 4 and R 5 are as defined above with an aluminum halide in the presence of a solvent selected from the group consisting of chlorobenzene, bromobenzene, and nitrobenzene, at a temperature of from 0° to 50°C., and isolating the demethylated product from the reaction mixture.
Claim 3
Dependent Claim
16 words
A process according to claim 1, wherein the aluminum halide is aluminum chloride or aluminum bromide.
Claim 4
Dependent Claim
11 words
A process according to claim 1, wherein the solvent is nitrobenzene.
Claim 5
Dependent Claim
14 words
A process according to claim 1, wherein the temperature is not more than 20°C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-15 | 1979-12-15 | 1980-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-15 | 1983-12-15 | 1984-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-15 | 1987-12-15 | 1988-06-15 | $7700.00 | Window Closed / Lapsed |