A facile and highly atom-economic approach to biaryl-containing medium-ring bislactones

Small molecular inhibitors of miR-1 identified from photocycloadducts of acetylenes with 2-methoxy-1,4-naphthalenequinone

Small molecules which can modulate endogenous microRNAs are important chemical tools to study microRNA regulational network. In this Letter we screened the [2+2] photocycloadducts of 2-methoxy-1,4-naphthalenequinone with a series of aryl acetylenes on their activity to modulate endogenous microRNAs. A potent inhibitor of the muscle-specific miR-1 which is closely related with cardiac development and disease was identified. The small molecular inhibitor was the cyclobutene type product derived from the photocycloaddition of 2-methoxy-1,4-naphthalenequinone with tert-butyl (5-(phenylethynyl)quinolin-8-yl) carbonate. Analogues of the small molecular inhibitor were then prepared using similar photocycloaddition reactions for evaluation on inhibition activity on miR-1 to provide structure-activity relationship of the miR-1 inhibitor.

Photo-induced cycloaddition reactions of α-diketones and transformations of the photocycloadducts

Photocycloaddition, along with subsequent transformation of the photocycloadducts, provides expeditious ways to construct various structures. The photo-induced reactions of α-diketones have been reported to proceed via different reaction pathways with the involvement of one or two of the carbonyl groups. Photoinduced reactions of cyclic α-diketones including N-acetylisatin, phenanthrenequinone and isoquinolinetrione with different C=C containing compounds could take place via [2 + 2], [4 + 2] or [4 + 4] photocycloaddition pathways. We have investigated the photoreactions of these cyclic α-diketones with different types of alkenes and alkynes, with a focus on the unusual cascade reactions initiated by the photocycloaddition reactions of these cyclic α-diketones and the applications of these photocycloaddition reactions along with the transformation of the photocycloadducts. In this paper, we discuss the diverse photo-cycloaddition pathways found in the photocycloaddition of o-diones leading to various photocycloadducts and the potential applications of these reactions via further transformation reactions of the adducts.

Direct C-H functionalization of enamides and enecarbamates by using visible-light photoredox catalysis

Direct C-H functionalization of various enamides and enecarbamates was realized through visible-light photoredox catalyzed reactions. Under the optimized conditions using [Ir(ppy)(2)(dtbbpy)PF(6)] as photocatalyst in combination with Na(2)HPO(4), enamides such as N-vinylpyrrolidinone could be easily functionalized by irradiation of the reaction mixture overnight in acetonitrile with visible light. The scope of the reaction with respect to enamide and enecarbamate substrates by using diethyl 2-bromomalonate for the alkylation reaction was explored, followed by an investigation of the scope of alkylating reagents used to react with the enamides and enecarbamates. The results indicated that reaction takes place with quite broad substrate scope, however, tertiary enamides with an internal C=C double bond in the E configuration could not be alkylated. Alkylation of N-vinyl tertiary enamides and enecarbamates gave monoalkylated products exclusively in the E configuration. Alkylation of N-vinyl secondary enamides gave doubly alkylated products. Double bond migration was observed in the reaction of electron-deficient bromides such as 3-bromoacetyl acetate with N-vinylpyrrolidinone. A mechanism is proposed for the reaction that is different from reported reactions of SOMOphiles with a nonfunctionalized C=C double bond. Further tests on the trifluoromethylation and arylation of enamides and enecarbamates under similar conditions showed that the reactions could serve as a mild, practical, and environmentally friendly approach to various functionalized enamides and enecarbamates.

A universal activator of microRNAs identified from photoreaction products

A small molecule activator of microRNAs has been identified from photoreaction products of naphthalene-1,4-dione with acetylenes and the universal activation on miRNAs was realized through significant promotion on the processing of precursor microRNAs by the compound.

1-(2-Bromophenyl)ethane-1,2-diyl 1,1'-biphenyl-2,2'-dicarboxylate

In the title compound, C(22)H(15)BrO(4), the bromo-benzene ring is inclined at dihedral angles of 23.87 (11) and 52.37 (11)° with respect to the planes of the two benzene rings. The two benzene rings of the biphenyl unit form a dihedral angle of 49.08 (11)°. In the crystal, mol-ecules are linked into [100] chains by C-H⋯O hydrogen bonds.

1-Phenylethane-1,2-diyl 1,1'-biphenyl-2,2'-dicarboxylate

In the title compound, C(22)H(16)O(4), the 7-phenyl ring is inclined at dihedral angles of 36.73 (9) and 69.37 (9)° with respect to the biphenyl benzene rings. The two benzene rings of the biphenyl unit form a dihedral angle of 55.99 (8)°. There are no significant hydrogen bonds observed in the crystal of this compound.