Alexander Robertus Todd (1907-1997) was awarded the 1957 Nobel Prize for Chemistry for his work on nucleotides and nucleotide coenzymes. Todd began to work on nucleosides in the late 1930s and subsequently synthesized adenosine triphosphate, flavin adenine dinucleotide (a derivative of riboflavin, a compound of vitamin B), and uridine triphosphate. Later, he elucidated the structure of vitamin B12. Todd also worked on the structure and synthesis of vitamin B1, vitamin E, and alkaloid substances found in marijuana and hashish. He studied other alkaloids as well, plant and insect pigments, and mold products, including penicillin.