A Useful Synthetic Method of dl-Threonine Using α-Isocyanoacetamides

Abstract
A reaction of .alpha.-isocyanoacetic acid amides with acetaldehyde provided a useful method for the synthesis of threonine. The reaction in the presence of KOH in methanol afforded predominantly trans-5-methyl-4-N''-substituted-aminocarbonyl-2-oxazoline, which was easily hydrolyzed to DL-threonine in a high yield. This method was extended to the synthesis of threo-.beta.-hydroxynorvaline and threo-.beta.-hydroxyleucine in excellent yields.