Two Isomeric [2.1]Cryptahemispherand Diamides

The geometrical isomers of 33,34,35-trimethoxy-5,10,15-trimethyl-22,25,30-trioxa-1,19- diazapentacyclo [17.8.5.1^3,7,1^8,12.1^13,17] pentatriaconta-3,5,7(35),8,10,12 (34),13,15,17 (33)-nonaene-2,18-dione, C₃₆H₄₄N₂O₈, are intermediates in the synthesis of reduced cryptahemispherands. Their amide groups are characteristically coplanar with their attached atoms. Consequently, the N atoms in these structures are neither exo nor endo, unlike the N atoms in most other cryptands and cryptahemispherands. In the isomer formed in smaller amount, (II), the N atoms are about 1 Å closer to each other than they are in the other structure, (I), because the five-atom bridge between these N atoms is so constrained as to draw them together. Structure (I) is more dense than structure (II) by about 9%.

-1