Invention relates to the field of bioorganic chemistry, particulary to preparation of 3-deoxy-3-azidobetulinic acid.A preparation process of 3-azidolupanes, particularly, diastereo-enriched 3β-azido-3-deoxybetulinic acid from 3-amino-3-deoxybetulinic acid by treatment with diazo transfer reaìent is elaborated.