CA1215976A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
New process for the synthesis of imidazo rifamycins
Assignee: Alfa Farmaceutici SpA
•
Filing: 1985-04-29
•
Granted: 1986-12-30
•
Expires: 2005-04-29
Abstract
Abstract ABSTRACT A process for the synthesis of imidazo rifamycins of for-mula wherein R is hydrogen or acetyl, R1 and R2 independently re-present hydrogen, (C1-4)-alkyl, benzyloxy, mono- or di-(C1-3)--alkylamino-(C1-4)-alkyl, (C1-3)-alkoxy-(C1-4)-alkyl, hydroxy--(C1-4)-alkyl, cyano, halogen, nitro, mercapto, (C1-4)-alkylthio, phenylthio, carbamoyl, mono- or di-(C1-4)-alkyl-carbamoyl, or R1 and R2 taken together with two consecutive carbon atoms of the pyridine nucleus form a benzene ring optionally substituted by 1 or 2 methyl or ethyl groups. The process comprises reacting the rifamycin S of formula II with a 2-aminopyridine of formula III wherein R1 and R2 have the above seen meanings.
Inventors
- 👤 Vincenzo Cannata
- 👤 Gain F. Tamagnone
- 👤 Manuela Campana
- 👤 Silvano Piani
- 👤 Giovanni Da Roit
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-11-05 02:15
CPC Classifications
—
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
181 words
1) A process for preparing imidazo rifamycins of formula I wherein R is hydrogen or acetyl; R1 and R2 independently represent hydrogen, (C1-4)-alkyl, benzyloxy, mono- or di-(C1-3)-alkylamino-(C1-4)-alkyl, (C1-3)--alkoxy-(C1-4)-alkyl, hydroxy-(C1-4)-alkyl, cyano, halogen, nitro, mercapto, (C1-4)-alkylthio, phenylthio, carbamoyl, mono-or di-(C1-3-alkyl-carbamoyl, or R1 and R2 taken together with two consecutive carbon atoms of the pyridine nucleus form a benzene ring optionally substituted by one or two methyl or ethyl groups, which comprises reacting a molar equivalent of rifamycin S of formula II with from about 1 to about 8 molar equivalents of a 2-amino-pyridine of formula III in the presence of from about 0.1 to about 4 molar equivalents of iodine or of a suitable system iodide/oxidizing agent, optionally in the presence of an acidic agent, in the presence of a solvent or of a solvent system, at a temperature comprised between the room temperature and the boiling temperature of the reaction mixture, for a period of time comprised between about 1 hour and about 120 hours, treating the reaction mixture with a suitable reducing agent and recovering the products from the reaction medium.
Claim 2
Dependent Claim
181 words
1) A process for preparing imidazo rifamycins of formula I wherein R is hydrogen or acetyl; R1 and R2 independently represent hydrogen, (C1-4)-alkyl, benzyloxy, mono- or di-(C1-3)-alkylamino-(C1-4)-alkyl, (C1-3)--alkoxy-(C1-4)-alkyl, hydroxy-(C1-4)-alkyl, cyano, halogen, nitro, mercapto, (C1-4)-alkylthio, phenylthio, carbamoyl, mono-or di-(C1-3-alkyl-carbamoyl, or R1 and R2 taken together with two consecutive carbon atoms of the pyridine nucleus form a benzene ring optionally substituted by one or two methyl or ethyl groups, which comprises reacting a molar equivalent of rifamycin S of formula II with from about 1 to about 8 molar equivalents of a 2-amino-pyridine of formula III in the presence of from about 0.1 to about 4 molar equivalents of iodine or of a suitable system iodide/oxidizing agent, optionally in the presence of an acidic agent, in the presence of a solvent or of a solvent system, at a temperature comprised between the room temperature and the boiling temperature of the reaction mixture, for a period of time comprised between about 1 hour and about 120 hours, treating the reaction mixture with a suitable reducing agent and recovering the products from the reaction medium.
Claim 3
Dependent Claim
27 words
A process as defined in claim 1, wherein for each mole of rifamycin S are used from 3 to 6 molar equi-valents of 2-aminopyridine of formula III.
Claim 4
Dependent Claim
36 words
A process as defined in claim 1, wherein the solvent or the solvent system is selected among lower halo-genated hydrocarbons, lower alkanols, lower alkyl esters of lower aliphatic acids, acetonitrile, dimethoxyethane, dioxane, tetrahydrofuran and aromatic hydrocarbons.
Claim 5
Dependent Claim
14 words
A process as defined in claim 3, wherein the solvent is the methylene chloride.
Claim 6
Dependent Claim
20 words
A process as defined in claim 1, wherein the reaction temperature is comprised between the room tempera-ture and about 60°C.
Claim 7
Dependent Claim
12 words
A process as defined in claim 1, in which R is acetyl.
Claim 8
Dependent Claim
14 words
A process as defined in claim 6, in which R1 is hydrogen or methyl.
Claim 9
Dependent Claim
27 words
A process as defined in claim 7, in which R2 is selected from -CH2OH, -CH2-CH2-N(CH3)2, -CH2-N(CH3)2, _OCH2C6H5, -NO2, -CH2-CH2-CH2-N(CH3)2, -CH2-CH2-N(CH3)2, -SH, -CH3, -cO-NH2, -CO-N(CH3)2, -CH2-N(CH3)2, and -S-C6H5.
Claim 10
Dependent Claim
25 words
A process as defined in claim 1 which compri-ses reacting rifamycin S with 2-amino-4-methyl pyridine; 2-amino-5-chloro pyridine; 2-amino-3,5-dibromo pyridine; 1-amino-isoquinoline; 2-amino-3,5-dichloro pyridine or 2-amino-3-methyl pyridine.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.