5-(6,7-Dimethoxy-1,2,3,4-tetrahydroisoquinolin-2-yl)-4-phenyl-1,2,5-oxadiazole N-oxide

Abstract

In the molecule of the title compound, C20H21N3O4, the six-membered heterocyclic ring has a flattened boat form. Intermolecular C—H...O hydrogen bonds link the molecules into dimers, which may be effective in the stabilization of the crystal structure.

Crystal structure of 2-methyl-1,2,3,4-tetrahydroisoquinoline trihydrate

“…The aromatic ring (C4/C5/C7-C10) is planar as expected, while the non-aromatic ring (N1/C2-C6) has a half-boat conformation and can be described with the Cremer-Pople parameters with a total puckering amplitude of Q T = 0.5067 (11) Å , an azimuthal angle () of 133.22 (12) and a zenithal angle (È) of 208.82 (18) . The structure is comparable with those of other tetrahydroisochinoline derivatives such as 2-(2-chloroacetyl)-6,7-dimethoxy-1,2,3,4tetrahydroisoquinoline (Ling et al, 2006) or 5-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolin-2-yl)-4-phenyl-1,2,5-oxadiazole N-oxide (Xu et al, 2006), that also show a half-boat conformation of the non-planar ring. The nitrogen atom displays a tetrahedral environment, which indicates an sp 3 hybridization, as is to be expected for a tertiary amine.…”

“…A survey of the Cambridge Crystallographic Database (CSD, Version 5.40, September 2019; Groom et al, 2016) shows about 1000 results for structures where the investigated amine is a substructure of a more complex structure. The beforementioned compounds C 13 H 16 ClNO 3 (Ling et al, 2006) and C 20 H 21 N 3 O 4 (Xu et al, 2006) are two examples of this. Moreover, some others are C 19 H 17 NO 5 (Aree et al, 2003), C 24 H 23 NO 2 (Philippe et al, 2000), C 15 H 17 NO 3 (Li et al, 2011) 300 View along the a axis through the crystal packing shows the hydrogenbonding network.…”