Azetidin-2-ones: structures of anti­mitotic compounds based on the 1-(3,4,5-tri­meth­­oxy­phen­yl)azetidin-2-one core

A series of related substituted 1-(3,4,5-tri­meth­oxy­phen­yl)azetidin-2-ones have been characterized: 3-(4-fluoro­phen­yl)-4-(4-meth­oxy­phen­yl)-1-(3,4,5-tri­meth­oxy­phen­yl)azetidin-2-one, C25H24FNO5 (1), 3-(furan-2-yl)-4-(4-meth­oxy­phen­yl)-1-(3,4,5-tri­meth­oxy­phen­yl)azetidin-2-one, C23H23NO6 (2), 4-(4-meth­oxyphen­yl)-3-(naphthalen-1-yl)-1-(3,4,5-tri­meth­oxy­phen­yl)azetidin-2-one, C29H27NO5 (3), 3-(3,4-di­meth­oxy­phen­yl)-4-(4-meth­oxy­phen­yl)-1-(3,4,5-tri­meth­oxy­phen­yl)azetidin-2-one, C27H29NO7 (4) and 4,4-bis­(4-meth­oxy­phen­yl)-3-phenyl-1-(3,4,5-tri­meth­oxy­phen­yl)azetidin-2-one, C32H31NO6 (5). All of the compounds are racemic. The lactam and 3,4,5-tri­meth­oxy­phenyl rings are approximately co-planar and the orientation of the lactam and the 4-meth­oxy­phenyl substituent is approximately orthogonal. The chiral centres, although eclipsed by geometry, have torsion angles ranging from −7.27 to 13.08° for the 3 position, and −8.69 to 13.76° for the 4 position of the β-lactam. The structures display intra­molecular C—H⋯O bonding between the 3,4,5-tri­meth­oxy­phenyl ring and the lactam ketone. Further C—H⋯O inter­actions are observed and form either an opposing meth­oxy `buckle' to join two mol­ecules together or a cyclic dimer.