A novel approach to 2,5-disubstituted 1,3,4-oxadiazoles derivatives via a decarboxylative cyclization reaction by photoredox catalysis between commercially available α-oxocarboxylic acids and hypervalent iodine(III) reagent is described. This powerful transformation involves the coupling reaction between two different kinds of radical species and the formation of C−N and C−O bonds.

An efficient synthesis of a variety of 2,5-disubstituted 1,3,4-oxadiazole derivatives via a cyclization reaction by photoredox catalysis between aldehydes and hypervalent iodine­(III) reagents is described. The reaction proceeds under mild conditions and affords various target compounds in excellent yields. The commercially available aldehydes without preactivation and a simple visible-light-promoted procedure without any catalysts make this strategy an alternative to the conventional methods.

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An efficient synthesis of a variety of 1,2-disubstituted-5,6-dihydropyrrolo[2,1-α]isoquinoline derivatives via an acidpromoted cyclization reaction between 1,2,3,4-tetrahydroisoquinoline (THIQ) and substituted α,β-unsaturated aldehyde derivatives is reported. This cycloaddition allows access to structurally diverse multisubstituted dihydropyrrolo[2,1-α]isoquinolines in moderate to good yields, which was the core scaffold of marine natural alkaloid lamellarins.

Abstract. This paper analyzed the mechanism of dilatation and high water retention of the independently researched new cementing material. It was proved by the experiment of dilatation and water retention behavior that the maximum water-solid ratio of this new material are 3:1 and the maximum volume dilatation rate of the backfill are 50.02%. The experiment of compression strength shows that the maximum uniaxial compression strength of the backfill can reach up to 9.73 MPa. The relationship of uniaxial compression strength with flexural strength and tensile strength were fitted by the least square method. Moreover, this paper explained the increasing law of the strength of the backfill in principal by analyzing its microstructure with Scanning Electron Microscope(SEM).