5,11,17,23-Tetrabromo-25,26,27,28-tetrahydroxycalix[4]-arene (31). A solution of 0.5 g of 5,11,17,23-tetrabromo-25,26,27,28-tetramethoxycalix[4]arene (15) in 40 mL of benzene was treated dropwise with 15 mL of BBr?' in CH2C12, and the mixture was stirred at r c " temperature for 18 h in an atmosphere protected from moisture. The reaction mixture was poured into 100 mL of H20, stirred for 1.25 h, and the organic layer was evaporated and triturated with acetone to leave 0.39 g (84%) of a white powder. Crystallization from pyridine/toluene yielded a yellow powder as the first fraction and a white powder as the second fraction: mp >480 "C; IR (KBr) 3135 cm-' (OH stretching); 'H NMR (pyridine-d,) b 9.72 (s, 4, OH), 7.25 (s, 8, Ar H), 4.0 (br (37) Tashiro, M.; Yoshiya, H.; Fukatas, G.Methods for the preparation of a variety of para-substituted calix[4]arenes via the Claisen rearrangement route are described. Starting with the readily available p-tert-butylcalix[4]arene 1, the tert-butyl groups are removed by an AlCl,-catalyzed retro-Friedel-Crafts reaction, and the calix[4]arene 2 that is formed is converted to the tetraallyl ether 3. This compound undergoes a heat-induced Claisen rearrangement to yield p-allylcalix[4]arene 4, which is a useful starting material for the introduction of functional groups. Along one route, the tosylate of 4 is ozonized to the aldehyde 7, the aldehyde is reduced to the alcohol 8, the alcohol is converted to the bromide 10 and then to the azide 11, and the azide is reduced with diborane to p-(2-aminoethyl)calix[4]arene 12, a compound of interest as a chelating species. Along a second route, the tosylate of 4 is rearranged to p-(l-propenyl)calix[4]arene 16 and ozonized to p-formylcalix[4]arene 17 from which the oxime 18 can be prepared.

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a protected form, thus permitting further elaboration of the carboxylic acid residue. Experimental SectionGeneral Procedure for Formation of JV-t-Boc Derivatives. To a 0.50 M solution of N-benzylbenzamide (2.0 g, 9.47 mmol) in methylene chloride were added triethylamine (1.32 mL, 9.47 mmol), di-tert-butyl dicarbonate (4.13 g, 18.94 mmol), and 4-(dimethylamino)pyridine (1.16 g, 9.47 mmol). The solution was stirred for 7 h at 25 °C under an argon atmosphere. The volatiles were removed, and the residue was purified by rapid chromatography on silica gel. Elution with hexane/ether (6:1) afforded 2.63 g (90%) of the desired N-iert-butoxycarbonyl-N-benzylbenzamide: IR (CHClg) 1725,1670 cm"1; NMR (CDC13) 1.08 (s, 9 H), 4.96 (s, 2 H), 7.24-7.64 (m, 10 H).General Procedure for Hydrolysis of -t-Boc Derivatives. To a 0.20 M solution of TV-tert-butoxycarbonyl-N-benzylbenzamide (1.09 g, 3.51 mmol) in tetrahydrofuran was added 10.54 mL (10.54 mmol) of a 1.0 N solution of lithium hydroxide. The solution was stirred for 6 h at 25 °C. After removal of tetrahydrofuran in vacuo, the basic aqueous residue was acidified by the addition of 10% acetic acid and extracted with ether. Drying (MgS04) and concentration afforded 883 mg of crude material.The acid was characterized by esterification: the crude acid was dissolved in 10.0 mL of ether and treated with excess ethereal diazomethane. After 10 min the excess diazomethane was quenched with glacial acetic acid, and the volatiles were removed in vacuo. Chromatography (silica gel, pentane/ether, 20:1) afforded 396 mg (83%) of methyl benzoate.General Procedure for Methanolysis of -t-Boc Derivatives. A solution of iV-iert-butoxycarbonyl-jV-benzylbenzamide (981 mg, 3.15 mmol) in 1.40 mL of methanol, under an argon atmosphere, was cooled to 0 6C. To this solution was added 1.75 mL (3.47 mmol) of a 2.0 M solution of sodium methoxide in methanol. After 10 min the solution was poured into brine and extracted with ether. After drying (MgS04) and concentration, the residue was chromatographed on silica gel. Elution with pentane/ether, 20:1, afforded 402 mg (94%) of methyl benzoate.

Bei dem Versuch, das K‐Salz des Cyclopentandions (IIa) bzw. das Tl‐Salz von Dimedon (IIb) mit dem Chlormethyläther (III) zu den Produkten (Ia) bzw. (Ib) an einem C‐Atom zu alkylieren, tritt O‐Alkylierung zu den Äthern (IVa) bzw. (IVb) ein.