Electrospray mass spectrometric evidence of calixarenep-quinone methide formation
摘要:
Positive or negative mode electrospray mass spectrometry of various types of tris(p-tert-butyl)calix[4]arenes with an active methylene group at the upper rim resulted in most cases in the detection of the highly reactive tris(p-tert-butyl)calix[4]arenemono(p-quinonemethide). (C) 1998 John Wiley & Sons Ltd.
27-dimethoxycalix[4]arene that is 1a, showing the unusual coexistence of two basic conformations in the crystal, that is, cone and 1,2-alternate, is analyzed. In contrast to this conformational coexistence of crystallographically independent molecules, the predominant conformation in solution and also in the related toluene (1b) and toluene/acetonitrile (1c) solvates is the cone conformation. With the help