(+)-Norgestrel 150200-16-1 18,19-Dinorpregn-4-en-20-yn-3-one, 13-ethyl-17-hydroxy-, (8-alpha,9-beta,10-alpha,13-alpha,14-beta)- 76497-12-6 797-64-8 Dextronorgestrel L-Norgestrel Norgestrel (+)-form