1. Institute of Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University Frankfurt Max-von-Laue Str. 7 60438 Frankfurt Germany
2. German Cancer Consortium (DKTK) and DKFZ 69120 Heidelberg Germany
3. Department of Medicine 2, Hematology/OncologyGoethe University 60590 Frankfurt am Main Germany
4. Frankfurt Cancer Institute (FCI) 60590 Frankfurt am Main Germany
5. Institute of Chemistry and MetabolomicsUniversity of Luebeck Ratzeburger Allee 160 23562 Luebeck Germany