Four related benzazepine derivatives in a reaction pathway leading to a benzazepine carboxylic acid: hydrogen-bonded assembly in zero, one, two and three dimensions

Four related compounds exemplify the reaction sequence from a 1,4-ep­oxy­benzazepine ester via its reduction product, a benzazepin-4-ol ester, and the corresponding hy­droxy carb­oxy­lic acid, to a lactone as formed by intra­molecular condensation.