Title: Process for preparing rifamycin S by hydrolysis of rifamycin O

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Claims: What we claim is:

1. A process for preparing a rifamycin S comprising the steps of dissolving rifamycin O at a concentration higher than 60,000.gamma. /ml in a mixture of a water immiscible chlorinated organic solvent and a water miscible alcohol at a temperature in the range of about 0.degree.-30.degree.C and which mixture forms a heterogeneous phase, adding a strong mineral acid in a ratio of about 1:10-1.5:1 by weight to the amount of treated rifamycin O to the mixture then hydrolyzing said rifamycin O in said heterogeneous phase while thoroughly stirring the reaction mass for a time in the range of about 40 minutes to about 3.5 hours and at a temperature in the above range, washing the reaction mass with water and then vacuum concentrating the reaction mass to dryness, the solid obtained then being taken up with a water miscible alcohol, and finally cooling to crystallize rifamycin S.

2. A process as set forth in claim 1 wherein the temperature at which the hydrolysis of the rifamycin O is carried out is in the range of about 18.degree.-20.degree.C.

3. A process as set forth in claim 1 wherein the strong mineral acid is added in a same amount by weight as the rifamycin O being treated in the process.

4. A process as set forth in claim 1 wherein the reaction mass is washed with slightly basic water.

Other info:

Inventors: Pasqualucci, Carmine (Milan, IT)
Scarpitta, Giuseppe (Pavia, IT)
Bonfanti, Giovanni (Milan, IT)

Application Number: 517834
Filing Date: 1974-10-24
Publication_date: 1976-01-20
Assignee: Archifar Industrie Chimiche Del Trentino S.p.A. (Rovereto, IT)
Primary Class(es): 540/458
Other Classes:
US Patent Ref:
Other Refs: 924,472

Apr, 1963	UK

Primary Examiner: Jiles, Henry R.
Assistant Examiner: Bond, Robert T.
Attorney: Waters, Schwartz & Nissen