نتایج جستجو برای: crafts
تعداد نتایج: 2058 فیلتر نتایج به سال:
Abstract This article presents the results of a study nonagricultural crafts peasants in postreform period northwestern region Russian Empire, which included Novgorod, Pskov, and St. Petersburg provinces. A general description craft activities during rapid formation development bourgeois relations country’s economy second half 19th early 20th centuries is given. The objects are most significant...
A facile synthesis of a series of benzene ring acylated analogues of harmaline has been achieved by Friedel-Crafts acylation under solvent-free conditions at room temperature using acyl halides/acid anhydrides and AlCl3. The reaction afforded 10- and 12-acyl analogues of harmaline in good yield, along with minor quantities of N-acyl-tryptamines and 8-acyl analogues of N-acyltryptamines.
A regioselective efficient synthetic approach to N-imino-γ-carbolinium ylides via AgOTf-catalyzed iminoannulation has been developed. This transformation proceeds via a silver(i) triflate-catalyzed consecutive Friedel-Crafts reaction/N-C bond formation sequence between the readily available indole derivatives and propargylic alcohols.
Regioselective methanesulfonylation of simple aromatics using methanesulfonic anhydride can be achieved over zeolite catalysts. For example, methanesulfonylation of toluene over various cation-exchanged zeolite beta catalysts affords higher para-selectivity in the synthesis of methyl tolyl sulfone than standard Friedel-Crafts methanesulfonylation utilising aluminium chloride.
An esterification/Friedel-Crafts-cyclization approach permitted the first successful synthetic entry into the oxacyclododecindione subclass of the dihydroxyphenylacetic acid lactone-type natural products. This route allowed the preparation of two highly active anti-inflammatory fungal secondary metabolites 14-deoxyoxacyclododecindione and 14-deoxy-4-dechlorooxacyclododecindione as well as their...
The asymmetric Povarov reaction of N-arylimines with 2- and 3-vinylindoles has been developed using a chiral phosphoric acid ((S)-TRIP) as catalyst. The peculiar reactivity of vinylindoles allowed also the disclosure of a Povarov Friedel-Crafts sequence, and the trapping of the reaction intermediate with nucleophilic species, thus providing a versatile platform for the preparation of highly ena...
Friedel-Crafts reactions of isopropyl-substituted benzenes with phthalic anhydride in the presence of aluminium trichloride, followed by cyclization of the products with strong sulfuric acid give, as expected, anthraquinones. The syntheses, however, often afford more than one anthraquinone. In some cases the isopropyl groups migrate cleanly to other ring positions; in other cases they are lost.
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