Because much important work in organic chemistry was done during the early part of the twentieth century by German researchers, the synthesis you need may be included in a journal article written in German. Don't panic. You can often still get the information you need (perhaps from the abstract which is often available in English or from the diagrams of molecular structures). If you need to know a few key German words try one of these chemistry-specific resources:
The Merck Index by 
Handbook of Reagents for Organic Synthesis by 
Dictionary of Inorganic Compounds by 
Handbook of Data on Common Organic Compounds by