2-Hydroxybenzaldehydes smoothly and efficiently react with various internal and terminal alkynes accompanied by cleavage of the aldehyde C–H bond by using a rhodium-based catalyst system of [RhCl(cod)]2/dppf/Na2CO3 [cod = 1,5-cyclooctadiene; dppf = 1,1′-bis(diphenylphosphino)ferrocene] to give the corresponding 2-alkenoylphenols in good to excellent yields. The regioselectivity of the reaction depends on the substituents of acetylene; an oxygen function on the propargylic position shows a considerable directing effect. The aldehydes can also react with some alkenes or allenes, such as triethylvinylsilane and 2-norbornene or 3-methyl-1,2-butadiene and 1,2-nonadienes, in place of alkynes.
Direct Syntheses of Benzofuran-2(3<i>H</i>)-ones and Benzofuran-3(2<i>H</i>)-ones from 1-(2-Hydroxyphenyl)alkan-1-ones by CuBr<sub>2</sub>or CuCl<sub>2</sub>
New syntheses of benzofuran-2(3H)-ones and benzofuran-3(211)-ones from l-(2-hydroxyphenyl)alkan-1-ones via oxidative cyclization by CuBr 2 or CuCl 2 are described. A new synthesis of 1H-isochromene-1,4(3H)-diones via similar procedures is also described.
The invention relates to the use of a skin permeating compound such as phloretin for controlling transgene expression under control of the Pseudomonas putida DOT-T1 E-derived bacterial repressor TtgR, to a vector comprising the genetic code for the repressor TtgR fused to a transactivation or a transrepressor domain, to a vector comprising a TtgR-specific operator sequence (OTtgR), a promoter and a polynucleotide coding for an endogenous or exogenous protein, and to a mammalian cell transiently or constitutively transfected with the mentioned vectors, and to mammals comprising such cells in nano- or microcontainers.