Synthesis and photoinduced deprotection of calixarene derivatives containing certain protective groups

Calixarene derivatives la, Ib, and Ic containing pendant tert-butoxycarbony l (t-BOC) groups were synthesized in 81, 93, and 83% yields, respectively, by the reaction of C-methylcalix[4] resorcinarene (CRA), p-methylcalix[6] a rene (MCA), and p-tert-butylcalix[8] arene (BCA) with di-tert-butyl dicarbo nate using triethylamine as a base in pyridine. Calixarene derivatives 2a, 2b, and 2c containing pendant trimethylsilyl ether (TMSE) groups were obtai ned in 58, 50, and 82% yields, respectively, by the reaction of CRA, MCA, a nd BCA with 1,1,1,3,3,3-hexamethyldisilazane using chlorotrimethylsilane as an accelerator in tetrahydrofuran. Calixarene derivatives 3a, 3b, and 3c c ontaining pendant cyclohexenyl ether (CHE) groups were also prepared in 65, 78, and 84% yields, respectively, by the reaction of CRA, MCA, and BCA wit h 3-bromocyclohexene using potassium hydroxide as a base as well as tetrabu tylammonium bromide as a phase-transfer catalyst in N-methyl-2-pyrolidone. The photoinduced deprotection of calixarene derivatives 1a-e was examined w ith bis-[4-(diphenylsulfonio)phenyl]sulfide bis(hexafluorophosphate) as a p hotoacid generator on W irradiation followed by heating in the film state, and it was found that the deprotection of the t-BOC groups of la proceeded smoothly in high conversion. The deprotection rates of the t-BOC groups of 1b and 1c were much lower than that of 1a under the same irradiation condit ions. The photoinduced deprotection of calixarenes 2b-c containing tetramet hylsilane groups as well as 3a-c containing CHE groups were also examined u nder similar reaction conditions in the film state, and it was found that t he deprotection rates of calixarenes 2b-c and 3a-c were lower than those of the corresponding 1a-e calixarenes. (C) 2001 Jokn Wiley & Sons, Inc.