Reaction products of NAD with 3-propiolactone at pH 6 showed that 3-propiolactone not only alkylates at the N-1 position of the adenine ring of NAD, but also reacts with other positions on NAD and its derivatives. Modifications other than the N-1 alkylation lowered the yield of N6-(2-carboxyethyl)-NAD. To improve the selectivity of the reaction of NAD with 3-propiolactone, reaction conditions were examined. The reaction at pH 3.5 gave pure 1-(2-carboxyethyl)-NAD in a yield of 73%, and the overall yield of N6-(2-carboxyethyl)-NAD was about 50%. © 1986.
Sakamoto, H., Nakamura, A., Urabe, I., Yamada, Y., & Okada, H. (1986). Analysis of improvement of the synthesis of N6-(2-carboxyethyl)-NAD. Journal of Fermentation Technology, 64(6), 511–516. https://doi.org/10.1016/0385-6380(86)90075-0