D. F. Elliott
Oct 23, 1948
Citations
0
Influential Citations
3
Citations
Journal
Nature
Abstract
IN a communication to the editor of the Journal of the American Chemical Society1 which has just been received are described the conversion of DL-N-benzoylallothreonine methyl ester (I, R = Me; R′ = H) into the corresponding oxazoline (II, R=Me) by the action of thionyl chloride and hydrolysis of the oxazoline with acid to give DL-threonine (III). This discovery was anticipated by Attenburrow, Elliott and Penny2, who described not only the thionyl chloride method of inverting the configuration of DL-N-benzoylallothreonine ethyl ester (I, R=Et;, R′=H), but also a second and closely related method consisting of the treatment of the p-toluenesulphonyl derivative (I, R=Et; R′=Ts) with potassium acetate in boiling alcohol, followed by acid hydrolysis. The same oxazoline (II, R=Et) was produced in both cases, and the view was advanced that inversion of configuration took place simultaneously with ring closure. The trans structure was therefore assigned to the oxazoline on the basis of the known configuration of threonine3.