Chemistry By Design App for Android
'Chemistry By Design is an interactive virtual flashcard application that allows students to test their skills using known synthetic sequences. The goal is to display the reagents, starting materials and products for every single step used in constructing a natural product or pharmaceutical.
A continuously growing database, currently featuring hundreds of syntheses of natural products and pharmaceuticals, is now available for browsing and testing your organic chemistry skills. You can choose to start your browsing by selecting from various lists or using the search box.'
This is a free app