C9H11NO4

from The Collaborative International Dictionary of English v.0.48

levodopa \le`vo*do"pa\ (l[=e]`v[-o]*d[=o]"p[.a]), a. [Levo- +
   DOPA, dihydroxyphenylalanine.] (Chem. & Biochem.)
   A substance used as a therapy for {Parkinson's Disease}; the
   L form of Dopa; L-dihydroxyphenylalanine; L-hydroxytyrosine
   ({C9H11NO4}); also called {L-dopa}. In the body it is
   converted by the enzyme dopa-decarboxylase into dopamine, the
   form in which it is active in the brain, affecting neural
   impulse transmission.
   [PJC]