<prompt> Apart from occurring in nucleic acids, pyrimidines are also found inTheophyllineTheobromineFlavin mononucleotideThiamine  <response>: Usually, purine and pyrimidine are found in nucleic acids DNA and RNA as a part of nucleotides.Pyrimidines also occur in thiamine vitamin B1 and alloxan.Purine is also a structural component of a number of essential coenzymes, e.g. coenzyme-A, NAD, NADP and FAD. 