his group were able to determine its chemical properties. This included being isomeric with ergosterol with a hydroxyl group and three conjugated double bonds; the correct structure was confirmed in 1936.The possibility of polymerization was tested to be inaccurate through evaluating the molecular weight, and were also able to denounce certain isomerization. The secondary alcohol displacing to a double bond via Zerewitinoff's method (see image) was shown to not occur, as well as the double bond transforming to a steric rearrangement didn't occur under observance of titration and catalytic hydrogenation. Ergosterol was originally found in fungi and not animal organisms, so the question of obtaining Vitamin D from sunlight was still in question and studied by Windaus long after receiving the Nobel Prize. In isolating and identifying 7-dehydrocholesterol in hog skin, and later human skin, whole milk, and animal liver, it too was antirachitic upon irradiation. This was already a known compound derived from cholesterol, and the new irradiation product was named Vitamin D3, or cholecalciferol (see image). Windaus established the structure by investigating the photochemical reactions within its formation. References Notes Sources External links including the Nobel Lecture, 12 December 1928 Constitution of Sterols and Their Connection with Other Substances Occurring in Nature 1876 births 1959 deaths 20th-century German chemists German Nobel laureates Nobel laureates in Chemistry Scientists from Berlin People from the Province of Brandenburg Recipients of the Pour le Mérite (civil class) University of Freiburg alumni Academic staff of the University of Freiburg Humboldt University of Berlin alumni Academic staff of the University of Innsbruck Academic staff of the University of Göttingen Knights Commander of the Order of Merit of the Federal Republic of Germany Französisches Gymnasium Berlin alumni