In this procedure, is there any reason why D-alanine is used? Given the different fractions of product collected upon distillation, SWIM assumes the stereochemistry is not preserved(?).
If D-alanine MUST be used, this sort of puts a damper on the OTC factor.
xoxo-Julia
(R)-2-Bromopropionic acid: 50 g D-Alanine (.56 mol) was dissolved in a mixture of 580 ml of 48% aqueous HBr and 1 L of water, and cracked ice added to give a total volume of 3 L. 104.3 g NaNO2 (1.51 mol ) was added in small portions with stirring, followed by 700 g of Na2SO4. When the stirred reaction had warmed to 15 degrees C, it was decanted from solids and extracted with five 500 ml portions of Et2O. Drying of Na2SO4 and then CaCl2 and concentration in vacuo gave 65 g of oil as residue. this was distilled at 25 torr collecting the forerun between 40-70 degrees C, and three fractions distilling at 104-8 degrees C (25 torr) totalling 51.3 grams.