Genetic regulation of pituitary gland development in human and mouse

Normal hypothalamopituitary development is closely related to that of the forebrain and is dependent upon a complex genetic cascade of transcription factors and signaling molecules that may be either intrinsic or extrinsic to the developing Rathke’s pouch. These factors dictate organ commitment, cell differentiation, and cell proliferation within the anterior pituitary. Abnormalities in these processes are associated with congenital hypopituitarism, a spectrum of disorders that includes syndromic disorders such as septo-optic dysplasia, combined pituitary hormone deficiencies, and isolated hormone deficiencies, of which the commonest is GH deficiency. The highly variable clinical phenotypes can now in part be explained due to research performed over the last 20 yr, based mainly on naturally occurring and transgenic animal models. Mutations in genes encoding both signaling molecules and transcription factors have been implicated in the etiology of hypopituitarism, with or without other syndromic features, in mice and humans. To date, mutations in known genes account for a small proportion of cases of hypopituitarism in humans. However, these mutations have led to a greater understanding of the genetic interactions that lead to normal pituitary development. This review attempts to describe the complexity of pituitary development in the rodent, with particular emphasis on those factors that, when mutated, are associated with hypopituitarism in humans

Iron-catalyzed intramolecular cyclotrimerization of triynes to annulated benzenes

An iron species derived from FeCl2 or FeCl3 by in situ reduction with zinc powder in the presence of imidazol-2-ylidene or bidentate nitrogen ligand could effectively catalyze intramolecular cycloisomerization of triynes to annulated benzenes. With a 2-iminomethylpyridine ligand, hydrates of FeCl2 and FeCl3 as well as their anhydrous ones could be used

Allylic substitution reactions with Grignard reagents catalyzed by imidazolium and 4,5-dihydroimidazolium carbene–CuCl complexes

Imidazolium and 4,5-dihydroimidazolium carbene–CuCl complexes effectively catalyzed the substitution reaction of allylic compounds with Grignard reagents in an SN2′-selective fashion. It was noteworthy that the amount of the imidazolium carbene-CuCl complex could be reduced to 0.001 mol% and the catalysis recorded a high TON (105). Based on the experimental results, the ate-type complex(es) such as [(imidazolium carbene)-CuR2]−(MgX)+ was postulated as an active species

Synthesis of N-substituted 2-arylpyrroles by the reaction of (η2-imine)titanium complexes with 3,3-diethoxypropyne

(η2-Imine)Ti(O-i-Pr)2 complexes generated from arylaldehyde imines and a divalent titanium reagent, Ti(O-i-Pr)4/2i-PrMgCl, reacted with 3,3-diethoxypropyne to afford 2-arylpyrroles