Method for selective extracting a 7-(hydrogen or substituted amino)-9-›(substituted glycyl) amido!-6-demethyl-6-deoxytetracycline compound

A method for selectively extracting a compound of formula I:

• ##STR8## wherein:
• R is hydrogen or --NR.sub.3 R.sub.4 ;
• and when R=--NR.sub.3 R.sub.4, R.sub.3 and R.sub.4 may be the same or different and are selected from hydrogen and straight or branched (C.sub.1 -C.sub.4)alkyl;
• R.sub.1 and R.sub.2 are selected from hydrogen and t-butyl;
• from an aqueous mixture comprising the compound of Formula I, its C-4 epimer and its oxidative by-products which method comprises treating the aqueous mixture with a non-ionic reverse phase resin at a pH range of 3.0 to 5.0;
• adding methylene chloride to the aqueous mixture at a concentration of 2-4 ml of methylene chloride per gram of compound of Formula I and at a pH between pH 6.5-8.0;
• and obtaining an extract consisting essentially of methylene chloride, the compound of Formula I, and its C-4 epimer, said epimer being present in an amount less than 3% of the amount of the compound of Formula I, said amount as measured by HPLC area percent.