For 10 points, name these vitamins that include folic acid, niacin, and thiamine.
The synthesis of one of these compounds is inhibited by sulfa drugs. The only known eukaryotic riboswitch binds to a derivative of one of these compounds. Woodward and Eschenmoser first achieved the total synthesis of one of these compounds that has a corrin ring and a central cobalt. The third of these compounds is a precursor of the coenzyme NAD and was first produced from nicotine. Deficiencies in these compounds can result in conditions such as spina bifida, pellagra, and beriberi. For 10 points, name these vitamins that include folic acid, niacin, and thiamine. 
The synthesis of one of these compounds is inhibited by sulfa drugs.
B vitamins [accept specific ones; prompt on "vitamins"] 