No abstract

Oligosaccharides have been used for an environmentally friendly insect control in the agricultural industry. In order to discover novel eco-friendly pesticides, a series of partially acetylated oligorhamnoses mezzettiasides, 2–8, and their analogues, 9–14, with biosurfactant characteristics were designed and synthesized, some of which exhibited comparable to or even stronger aphicidal activity than pymetrozine. Preliminary SAR studies demonstrated that the aphicidal activity of mezzettiasides analogs is highly dependent on their structures, including both the sugar length and the substitutes on the sugar. Among them, trirhamnolipid 9 displayed the strongest aphicidal activity, with an LC50 of 0.019 mmol/L, indicating that the biosurfactant 9 may have potential for use as an environmentally friendly agricultural pesticide.

Tuning the photophysical properties of π-conjugated oligomers by functionalization of skeleton, to achieve an optically and electronically advantageous building block for organic semiconductor materials is a vital yet challenging task. In this work, a series of structurally well-defined polyarylfunctionalized α-oligofurans, in which aryl groups are introduced precisely into each of the furan units, are rapidly and efficiently synthesized by de novo metal-free synthesis of αbi(arylfuran) monomers for the first time. This new synthetic strategy nicely circumvents the cumbersome substituent introduction process in the later stage by the preinstallation of the desired aryl groups in the starting material. The characterization of α-oligo(arylfuran)s demonstrates that photoelectric properties of coplanar α-oligo(arylfuran)s can be tuned through varying aryl groups with different electrical properties. These novel α-oligo(arylfuran)s have good hole transport capacity and can function as hole-transporting layers in organic light-emitting diodes, which is indicative of significant breakthrough in the application of α-oligofurans materials in OLEDs. And our findings offer an avenue for the ingenious use of α-oligo(arylfuran)s as p-type organic semiconductors for OLEDs.