l-Form has been found in the urine of humans with pentosuria. Prepn of dl-form: Gascoigne, Chem. Ind. (London) 1959, 402; of d-form: Mendicino, J. Am. Chem. Soc. 82, 4975 (1960); of l-form: Wolfrom, Bennett, J. Org. Chem. 30, 458 (1965). Isoln of dl-form from the acid hydrolysate of bagasse hemicellulose: Banerjee et al., Sci. Cult. 27, 498 (1961), C.A. 56, 11682d (1962). Enzymic prepn of l-form: Hough, Jones, Chem. Ind. (London) 1952, 907; eidem, J. Chem. Soc. 1952, 4047. Formation of l-form in normal humans and guinea pigs, and its utilization by guinea-pig liver prepns: Touster et al., J. Am. Chem. Soc. 76, 5005 (1954). Reviews: The Carbohydrates, W. Pigman, Ed. (Academic Press, New York, 1957) pp 80, 86-87, 759, 795; Methods in Carbohydrate Chemistry vol. 1, R. L. Whistler, M. L. Wolfrom, Eds. (Academic Press, New York, 1962) pp 94-101.