e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Tetrahedron
Calixarenes with exo-hydroxy groups: Synthesis, crystal and molecular structure of ortho-tert-butylphenol-based calix [4]-, calix [6]-and calix [8] arenes
…, C Porta, F Bigi, R Maggi, F Peri, E Marzi, M Lanfranchi…
Ortho-tert-butylcalixarenes 3, 4 and 5 with exo-hydroxy groups were synthesised by tin tetrachloride-promoted condensation of 2, 2′-dihydroxy-3, 3′-di-tert- butyldiphenylmethane 6 with formaldehyde. While 1H NMR analysis of compounds 3, 4 and 5 revealed a considerable annular flexibility in CDCl3 solution, their X-ray single crystal analysis showed the presence of a strong intramolecular hydrogen bonds between the ...