- Efficient syntheses of benzyl and n-octyl [1,3-13C 2]acetoacetates, and their application to syntheses of 13C-labelled pyrrole and 13C-labelled hymecromone
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Benzyl [1-13C]acetate (2a) was prepared via esterification of sodium [1-13C]acetate (1) with benzyl bromide in the presence of 18-crown-6-ether in 97% yield. n-Octyl [1-13C]acetate (2b) was rapidly obtained by microwave ir
- Iida, Katsumi,Ohtaka, Kuniaki,Komatsu, Takayuki,Makino, Tomoe,Kajiwara, Masahiro
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p. 167 - 169
(2008/09/19)
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- Photolysis of 1,2,3-Thiadiazole. Formation of Thiirene by Secondary Photolysis of Thioketene
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Iradiation of 1,2,3-thiadiazole together with diethylamine in liquid solution at room temperature or at 150 K gives rise to N,N-diethylthioacetamide in high yield which implies trapping of thioketene during photolysis.Experiments with -1,2,3-thiadiazole at room temperature demonstrate lack of carbon randomization the thioacetyl group of the trapping product.The excludes thiirene as a potential precursor for thioketene at this temperature.The products isolated after irradiation of -1,2,3-thiadiazole together with diethylamine in an EPA glass at 77 K show up to 37percent carbon randomization in the thioketene.This strongly supports a reaction mechanism where thiirene is formed by photolysis of thioketene in solid solution and rapidly reverts to thioketene, resulting in the observed carbon randomization.This process does not occur in liquid solution owing to the extremely small steady-state concentration of thioketene during photolysis.The photolytic reaction of 1,2,3-thiadiazole in EPA at 77 K was monitored by UV spectroscopy and the spectrum of thioketene is reported.
- Larsen, Bjarne Due,Eggert, Hanne,Harrit, Niels,Holm, Arne
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p. 482 - 486
(2007/10/02)
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