Tetraheterocyclic tetrahydroindeno[1',2':4,5]pyrrolo[1,2-a]imidazol-5(1H)-one derivatives as novel neonicotinoid candidates were designed and prepared by selective etherification, chlorination and esterification of ninhydrin-heterocyclic ketene aminals adducts. Some of the designed compounds showed excellent insecticidal activity against cowpea aphids (Aphis craccivora), brown planthopper (Nilaparvata lugens), and armyworm (Mythimna separata). In particular, the activity against armyworm (Mythimna separata) improved a lot in contrast with that of imidacloprid and cycloxaprid. The research here provides a novel neonicotinoid chemotype for further development.

Ninhydrin and heterocyclic ketene aminals (HKAs) are versatile building blocks in organic chemistry. Reactions of ninhydrin with HKAs initially produced the kinetic products indeno[1,2‐b]pyrrol‐4(1H)‐one derivatives, which could further isomerize to thermodynamic counterparts indeno[2,1‐b]pyrrol‐8(1H)‐ones. The isomerization showed a strong solvent dependency and occurred through a decomposition–reconstruction pathway. This is the first example of isomerization of ninhydrin‐constructed products. The conversion between kinetic and thermodynamic control may be applicable to similar reactions involving ninhydrin or HKAs.

An efficient and versatile method was developed for the access of multisubstituted 1,8-naphthyridine derivatives through a onepot, three-component protocol from heterocyclic ketene animals, malononitrile dimer, and aryl aldehydes in high yields. The 1,8-naphthyridines were formed via Knoevenagel condensation, aza-ene reaction, imine-enamine tautomerization, and intramolecular cyclization.

The image of construction of 2-aryl-1,3,4-oxadiazole derivatives from 1,1-dichloro-2-nitroethene and hydrazides.

An efficient synthetic methodology was developed for direct formation of quinazolinones with 2-nitromethyl substituent via 1,1-dichloro-2-nitroethene and anthranilamides. This strategy provides an alternative for quinazolinones construction with merits of proceeding in water, easy purification, and no addition of catalysts.