ation by splitting offaldeh5de even when, as in the case of the formaldehyde compound, the b. p. of the hemiacetal ( 3~) is higher than that of the acctal (2a). With amines, hydrazines, and thiols, the corresponding types ofmixed acetal are formed, viz. (4)-(7), e . g . from (Zo): RO-RN-CH-NR'?(4) R =-CH,, R I N = pipertdine, b p. 61-62 "CjIO mni RO-RN-CHI N R -NRI ( 5 ) R=-CH,, h.p. 46"C/t2mni RO-RN-CHz SR' (6) R = CH?, R'= C4H9, b.p. 74 'C/IOnim o r from (3151 RO-RN -C H R S R (7) K CH,, R' -C T H~, b.p. 101 'C/23 iniii The acetals can be split by acyl chloridcs, just as Bu/inw and Haitke [3] found for aminals, e.g.: + Ph-CO CI + Ph -CO-NR-OR -1-RO CO -CI i RO-CO-NR-OR ( 2 a) --f RO RN C H z -C I Received, M a y Ihth, 1963 [Z 5081339 IE] German version: Angew. Chem. 75, 640 (1963).