The Synthesis and Photo-Induced Deprotection Reaction of Calix[4]resorcinarene Derivatives Containing t-Butyl Ester Moieties

Abstract

Abstract The syntheses and photoinduced deprotection reactions of calix[4]resorcinarene derivatives with pendant t-butyl ester moieties were examined. Calix[4]resorcinarenes, 1a–1h, were prepared by the condensation reaction of resorcinol with certain aldehydes in the presence of hydrochloric acid as a catalyst in ethanol at 80 °C for 30 min in good yields. The substitution reaction of 1a–1h with t-butyl bromoacetate using cesium carbonate as a base and tetrabutylammmonium bromide (TBAB) as a phase transfer catalyst was performed to afford the corresponding calix[4]resorcinarene derivatives, 2a–2h with pendant t-butyl ester groups. It was found that 2a, 2e, 2f, 2g, and 2h had film forming properties. The photo-induced deprotection reaction of calixarene derivatives 2a, 2e, 2f, 2g, and 2h was examined in the presence of bis-[4-(diphenylsulfonio)phenyl] sulfide (DPSP) as a photoacid generator in the film state upon UV irradiation for 5 min followed by heating at 170 °C. It was found that the deprotection reaction of the t-butyl ester groups of 2a, 2e, 2f, 2g, and 2h proceeded smoothly to produce the corresponding calixarene derivatives, 3a, 3e, 3f, 3g, and 3h with carboxylic acid groups, quantitatively.