Reinvestigation of the reaction of 2,3-butanedione with ethanolamine a
fforded the known is-4a,8a-dimethyl[1,4]-oxazino-[3,2-b][1,4]oxazine a
s well as two new tricyclic products: tricycle[4,4,4,0(I,6)]trans-tetr
adecan-12-13-diol, and N,N'-[(4'',5''-dimethyl) 1'',2''-phenylene]-2,2
'-dimethyl-bisoxazolidine as established by X-ray analysis.