Notestracted with an ether-hexane mixture (3:1) and the combined extracts were dried over anhydrous magnesium sulfate. Preparative thin layer chromatography on silica gel afforded 165 mg (52%) of pure (±)-or-turmerone (1): rmax (CHClj) 1685 (0=0), 1620 (C=CH-), 1515 (-C,Hi-). 819 cm'1 (p-C6H4-); nmr (CCI4) 7.00 (s, 4 H, p-CHsCeHj-), 5.90 [m, 1 H, -CH=C(CH3)2], 3.20 [m, 1 H, C,H,CH(CH3)-], 2.50 (m, 2 H, -CH2C0-), 2.25 (s, 3 H, p-CH3C6H6-), 2.08 [s, 3 H, ~COCH=C(CH3)2, methyl cis to carbonyl], 1.81 [s, 3 H, -COCH=C(CH3)2, methyl trans to carbonyl], 1.20 [d, 3 , , , ^)-]; mje 216. The analytical sample was obtained as a colorless oil by preparative tie followed by molecular distillation, bp (bath) 90°( 0.07 mm).

No abstract

Cycloaddition reactions of pentamethyleneketene to cyclopentadiene, dihydropyran, tetramethylallene, diisopropylcarbodiimide, IV-ferf-butylbenzylimine, and chloral have been investigated as routes to spiro compounds. Pentamethyleneketene is formed in situ from the triethylamine dehydrochlorination of cyclohexanecarboxyl chloride and the zinc dehalogenation of -bromocyclohexanecarboxyl chloride. Dimerization is a serious competing reaction and reactive cycloaddition partners are necessary to successfully compete for the ketene.

A convenient phase‐transfer catalysis in the N‐benzylation of adenine is described. The benzylation of adenine with benzyl halides in a two‐phase system containing phase‐transfer catalyst gave 9‐benzylated adenines as a major product accompanied with 3‐benzylated adenines.

cooled in ice water. The contents of the ampoule were then analyzed by vpc. Each sample was analyzed at least twice and and average value was taken. The average deviation was about 0.1-0.2%. In Table II the results of the analysis are given.Table II Equilibration of cisand