Functionalization of calix[4]arenes by alkylation with 2-(chloromethyl)pyridine hydrochloride

Structure of the partial cone conformer of 25,26,27,28-tetrakis[(2-pyridylmethyl)oxy]calix[4]arene

“…The title compound (I) displays an 1H NMR spectrum which has been interpreted in favour of a conformation in which the 'inverted' OCH2py moiety lies outside the cavity. This contrasts with our solid-state and solution studies of the tert-butylated partial cone conformer (II) which showed the 'inverted' pyridine moiety to be tightly accommodated inside the hydrophobic cavity as a selfinclusion complex (Pappalardo et al, 1992). In order to assess a possible influence of the para-substituent on the overall conformation of partial cone tetrakis[(2-pyridylmethyl)oxy]calix[4]arene conformers, the crystal structure of (I) (which is devoid of ten-butyl groups) was determined.…”

Self inclusion in a calix[5]arene structure; structure of the cone conformer of a pentahydroxy-p-tert-butylcalix[5]arene

“…Perrin & Lecocq (1991) report that two types of inclusion compounds have been found with calixarenes, with the guest either outside (as a solvate) or enclathrated within the calixarene cones [frequently described as cryptato-cavitate or tubulato-intercalato clathrates using the nomenclature proposed by Weber & Josel (1983)]. We have reported recently a third type of inclusion in calixarenes, in a partial-cone calix [4]arene conformer where one of the aromatic rings is rotated so that its pyridine moiety is tightly accommodated inside the hydrophobic cavity as a self-inclusion monomer (Pappalardo et al, 1992). The present structure is best described as a selfinclusion polymer (Fig.…”

Conformational Preferences of Bispicolyl-p-tert-butylcalix[4]arene Anions: Synthesis of Cone and Partial-cone Conformers of Bispicolyl-bis-(tert-butoxycarbonyl)methoxy-p-tert-butylcalix[4]arene

“…Analogous studies have been conducted previously with alkali metal carbonates, i.e. Li 2 CO 3 , Na 2 CO 3 , K 2 CO 3 , and Cs 2 CO 3 , with DMF and acetone as solvents [13][14][15]. When LiH was used as the base, reaction of deprotonated 2 with tert-butylbromoacetate led predominantly to the formation of compound 3a (24%).…”

“…The synthesis of the bispicolyl derivative 2 from the parent p-tert-butylcalix [4]arene 1 has been reported by several authors [13,14], but the conditions described in the experimental section avoid the use of the high-boiling solvent dimethylformamide (DMF), and allow the isolation of 2 in high yield. Its identity was established by melting point determination, NMR and IR spectroscopy.…”

“…Herein we report the effect of different alkali metal hydrides on the deprotonation and functionalisation of the previously reported 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-bis(2-pyridylmethoxy)calix [4]arene 2 [13,14], which adopts a cone conformation in the solid state. Reaction of the phenoxide groups of deprotonated 2 with tert-butylbromoacetate results in both cone 3a, and partial-cone 3b conformers of the tetrasubstituted 5,11,17,23-tetratert-butyl-25,27-bis[(tert-butoxycarbonyl)methoxy]-26,28-bis(2-pyridylmethoxy)calix [4]arene in varying ratios.…”