Also referred to as vitamin B4: Lecoq, Int. Z. Vitaminforsch. 27, 291 (1957). Widespread throughout animal and plant tissues combined with niacinamide, d-ribose, and phosphoric acids; a constituent of nucleic acids and coenzymes, such as codehydrase I and II, adenylic acid, coalaninedehydrase. Isoln from bovine pancreas: Kossel, Ber. 18, 79, 1928 (1885). Syntheses: Fischer, ibid. 30, 2226 (1897); Traube, Ann. 331, 64 (1904); Hoffer, Jubilee Vol. Emil Barell 1946, 428-434; Taylor et al., Ciba Found. Symp. Chem. Biol. Purines 1957, 20, C.A. 53, 6238b (1959); Bredereck et al., Angew. Chem. 71, 524 (1959); Morita et al., Chem. Ind. (London) 1968, 1117; Sekiya, Suzuki, Chem. Pharm. Bull. 20, 209 (1972); N. J. Kos et al., J. Org. Chem. 44, 3140 (1979) DOI. Toxicity study: Philips et al., J. Pharmacol. Exp. Ther. 104, 20 (1952) PubMed. Review: Ts'o, “Bases, Nucleosides and Nucleotides” in Basic Principles in Nucleic Acid Chemistry vol. 1, P. O. P. Ts'o, Ed. (Academic Press, New York, 1974) pp 453-584.