A COF with both keto-enamine and ketimine linkages is reported for the first time, which shows high chemical and thermal stability.

A practical protocol for the construction of hydroxylated 2-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenols (PBIs) from N-phenyl-o-phenylenediamine with benzaldehydes was developed. The cascade reaction was enabled by heating a mixture of the two substrates in the presence of air as an oxidant and anhydrous Cu(OAc)2 as a catalyst in dimethyl sulfoxide, and a diverse series of PBIs were synthesized in moderate to good yields (69–81%). Furthermore, the synthesis of the PBIs was enabled via a one-pot cascade reaction that proceeded through subsequent dehydration condensation, intramolecular cyclization, and aromatic C–H hydroxylation. This protocol can be used for the synthesis of hydroxylated PBI via a one-pot annulation C–H hydroxylation reaction rather than through a series of multistep reactions, which provides the possibility of further modification.

A microwave-assisted DABCO-promoted strategy for the regioselective synthesis of pyrrolo[3,4-b]pyridine-4-ones derivatives has been developed from the [3 + 3] annulation of α-aminomaleimide with substituted ethyl 2-butynoate. The characteristic features of...