The effects of 5,11,17,23- and 25,26,27,28-substitutents on the relative stability of four conformers of calixarene are discussed on the basis of a computational method using molecular mechanics (MM3) calculations. It is shown that a substituent in the lower rim site has a decisive role in the determination of the stability order among four conformers of calixarene, while a substituent in the upper rim site only slightly affects the energy differences. It is also shown that in metacyclophanes with no substituent in the lower rim the structure of 1,2-alternate conformers is very different from the typical 1,2-alternate structure common to calixarenes.
All Science Journal Classification (ASJC) codes
- Drug Discovery
- Organic Chemistry