PURPOSE: To obtain the title compd. of high purity useful as an antibacterial agent in high yield by subjecting a teicoplanin compd. or a teicoplanin like compd. to strong acid hydrolysis in a uniform medium consisting of a specific org. aprotic solvent and a strong acid.

CONSTITUTION: Respective components of a teicopranin composite, a prepared product obtained by purifying the composite, a teicopolanin factor A2, a teicoplanin factor A3 and teicopranin factor A2, a teicoplanin like compd. represented by formula (R is H or 9-12C aliphatic acyl-D-glucosamine residue, R1 is H or N-acetyl-D-glucosamine residue, R2 is H or a D-mannose residue but R, R1 and R2 are not simultaneously H) or a mixture of them are subjected to strong acid hydrolysis in a uniform medium consisting of an org. aprotic solvent selected from DMF, hexamethylformamide, 1,3-dimethyl-3,4,5,6- tetrahydro-2 (1H) pyrimidone and/or dimethylsulfoxide and strong acid to obtain the objective compd.