Wnt2bb signaling promotes pharyngeal chondrogenic precursor proliferation and chondrocyte maturation by activating Yap expression in zebrafish.

Pharyngeal cartilage morphogenesis is crucial for the formation of craniofacial structures. Cranial neural crest cells are specified at the neural plate border, migrate to pharyngeal arches, and differentiate into pharyngeal chondrocytes, which subsequently flatten, elongate, and stack like coins during maturation. Although the developmental processes prior to chondrocyte maturation have been extensively studied, their subsequent changes in morphology and organization remain largely elusive.

Synthesis of 1,4-diazepinone derivatives via a domino aza-Michael/S2 cyclization of 1-azadienes with α-halogenoacetamides.

A novel cyclization of α-halogenoacetamides with 1-azadienes has been developed for the efficient preparation of monocyclic 1,4-diazepinones in one step under transition metal-free conditions. Various α-halogenoacetamides and 1-azadienes are well tolerated and give the desired products in good to excellent yields. This cyclization also demonstrates potential synthetic utility on a gram-scale and further transformation.