Kineticvs. thermodynamiccontrol and steric hindrance are factors that determine the regioselectivity of the Pd(O)-catalyzed allylation of ambident heterocycles of the 3-hydroxyisoxazole, 5-isoxazolone and 5-pyrazolone series.
Palladium-catalyzed rearrangement of allylic esters of acetoacetic acid to give γ,δ-unsaturated methyl ketones
作者:Isao Shimizu、Toshiro Yamada、Jiro Tsuji
DOI:10.1016/s0040-4039(00)77444-2
日期:1980.1
Various allylic esters of acetoacetic acid undergo rearrangement to give γ,δ-unsaturated methyl ketones in high yields with elimination of carbon dioxide under mild conditions in the presence of catalytic amounts of Pd(OAc)2 and PPh3.
Facile methods for preparing diketide and triketide thioesters are disclosed. The resulting thioesters may be used as intermediates in the synthesis of desired polyketides, and may contain functional groups which ultimately reside in side chains on the resulting polyketide and thus can be used further to manipulate the polyketide so as form derivatives. The polyketides produced may also be tailored by glycosylation, hydroxylation and the like. New polyketides and their derivatives and tailored forms are thereby produced.
Facile methods for preparing diketide and triketide thioesters are disclosed. The resulting thioesters may be used as intermediates in the synthesis of desired polyketides, and may contain functional groups which ultimately reside in side chains on the resulting polyketide and thus can be used further to manipulate the polyketide so as form derivatives. The polyketides produced may also be tailored by glycosylation, hydroxylation and the like. New polyketides and their derivatives and tailored forms are thereby produced.
The present invention provides an anti-allergen agent that has excellent heat resistance, low coloration, excellent processability, and excellent water resistance, an anti-allergen product, and a method for processing same. The anti-allergen agent of the present invention comprises as an active ingredient an inorganic solid acid, and the inorganic solid acid preferably has an acid strength as pKa of 4.0 or less. Furthermore, it preferably further comprises a polyphenol compound, and in this case it preferably comprises the inorganic solid acid at 5 to 90 wt % relative to the total amount of the inorganic solid acid and the polyphenol compound.