Design, synthesis, and discovery of 5-piperazinyl-1,2,6,7-tetrahydro-5H-azepino[3,2,1-hi]indol-4-one derivatives: a novel series of mixed dopamine D2/D4 receptor antagonist

Expanding Stereoelectronic Limits of endo-tet Cyclizations: Synthesis of Benz[b]azepines from Donor-Acceptor Cyclopropanes

The importance of intramolecular constraints in cyclic transition-state geometries is especially pronounced in n-endo-tet cyclizations, where the usual backside approach of a nucleophile to the breaking bond is impossible for the rings containing less than eight atoms. Herein, we expand the limits of endo-tet cyclizations and show that donor-acceptor cyclopropanes can provide a seven-membered ring via a genuine 6-endo-tet process. Substrates containing a N-alkyl-N-arylcarbamoyl moiety as an acceptor group undergo Lewis acid-induced cyclization to form tetrahydrobenz[b]azepin-2-ones in high yields. The reaction proceeds with the inversion of the configuration at the electrophilic carbon. In this process, a formally six-membered transition state yields a seven-membered ring as the pre-existing cycle is merged into the forming ring. The stereochemistry of the products can be controlled by the reaction time and by the nature of Lewis acid, opening access to both diastereomers by tuning of the reaction conditions.

Recent findings leading to the discovery of selective dopamine D4 receptor ligands for the treatment of widespread diseases

Since its discovery, the dopamine D₄ receptor (D₄R) has been suggested to be an attractive target for the treatment of neuropsychiatric diseases. Novel findings have renewed the interest in such a receptor as an emerging target for the management of different diseases, including cancer, Parkinson's disease, alcohol or substance use disorders, eating disorders, erectile dysfunction and cognitive deficits. The recently resolved crystal structures of D₄R in complexes with the potent ligands nemonapride and L-745870 strongly improved the knowledge on the molecular mechanisms involving the D₄R functions and may help medicinal chemists in drug design. This review is focused on the recent development of the subtype selective D₄R ligands belonging to classical or new chemotypes. Moreover, ligands showing functional selectivity toward G protein activation or β-arrestin recruitment and the effects of selective D₄R ligands on the above-mentioned diseases are discussed.

Facile construction of hydrogenated azepino[3,2,1-hi]indoles by Rh(iii)-catalyzed C–H activation/[5 + 2] annulation of N-cyanoacetylindolines with sulfoxonium ylides

Rh(iii)-catalyzed regio- and chemoselective [5 + 2] annulation has been realized, leading to efficient construction of seven-membered rings under mild conditions.

(2R*,4S*)-2-(pyridin-3-yl)-2,3,4,5-tetrahydro-1H-1-benzazepin-4-ol: a three-dimensional framework built from O-H···N, C-H···O and C-H···π(arene) hydrogen bonds

The title compound, C(15)H(16)N(2)O, crystallizes in the space group P2(1)2(1)2(1) with Z' = 1. The seven-membered ring adopts a chair-type conformation with the hydroxy and pyridyl substituents in equatorial sites. Molecules are linked into a three-dimensional framework structure by a combination of O-H···N, C-H···O and C-H···π(arene) hydrogen bonds, but N-H···O and N-H···π(arene) interactions are absent from the structure. Comparisons are made with some related compounds.