Abstract
A new antitumor antibiotic thrazarine was soluble in water and positive to anisaldehydesulfuric acid and ninhydrin color reactions. The absolute structure of thrazarine was determined to be O-((3R)-2-diazo-3-hydroxybutyryl)-L-serine by acid hydrolysis, spectroscopic analysis and X-ray crystallographic analysis. Structurally, thrazarine was a new member of azaserine group antibiotics.