Synthesis of upper rim-double-bridged calix[4]arenes bearing seven membered rings and related compounds

Abstract

Calix[4]arenes bearing one or two bridges on the upper rim were prepared as novel inherently chiral derivatives potentially capable of chiral recognition.

Synthesis and Structure of Functionalized Zigzag Hydrocarbon Belts

“…Spectroscopic data supported that the products were a pair of isomers. Conformational structures of 1,2‐alternate 7 and cone 8 were determined unambiguously with X‐ray diffraction analysis of single crystals of 7 and the derivatives of 8 (Figure ). It should be addressed that the synthesis of products 7 and 8 was very sensitive to the reaction conditions.…”

Directmetasubstitution of calix[4]arenes

“…Unfortunately, the reaction of 89a and 89b with POCl 3 in toluene under reflux, the conditions previously used for monosubstituted derivatives of type 87 , led to a complex reaction mixture with a low yield of the expected bis-bridged products 90 . 54 Nevertheless, under milder reaction conditions (triflic anhydride Tf 2 O and 2-chloropyridine 2-ClPyr in CH 2 Cl 2 at −78 °C) the bis-bridged product 90b was obtained in 66% yield (Fig. 27).…”

The atropisomeric dynamic behaviour of symmetrical N-acylated amine-bridged calix[4]arenes

“…Melting points were measured on Heiztisch Mikroskop -Polytherm A (Wagner & Munz, Germany). NMR spectra were obtained on Agilent 400-MR DDR2 ( 1 H: 400 MHz, 13 C: 100 MHz), Bruker Avance III 500 MHz (operating at 500.13 MHz for 1 H, and 125.77 MHz for 13 C) and Bruker Avance III 600 MHz (600.13 MHz for 1 H and 150.92 MHz for 13 C). Deuterated solvents used are indicated in each case.…”

“…2a). Moreover, bridging of the two proximal rings can form a square 13 (Fig. 2b) or distorted 14–16 (Fig.…”