Weak C—H⋯X (X = O, N) hydrogen bonds in the crystal structure of di­hydro­berberine

Di­hydro­berberine, a reduced form of pharmacologically important berberine, crystallizes from ethanol without inter­stitial solvent. Although lacking classical O—H or N—H donors, the packing in the crystalline state is clearly governed by C—H⋯N and C—H⋯O hydrogen bonds involving the two acetal-type C—H bonds of the 1,3-dioxole ring. Di­hydro­berberine (systematic name: 9,10-dimeth­oxy-6,8-dihydro-5 H -1,3-dioxolo[4,5- g ]iso­quinolino­[3,2- a ]iso­quinoline), C 20 H 19 NO 4 , a reduced form of pharmacologically important berberine, crystallizes from ethanol without inter­stitial solvent. The mol­ecule shows a dihedral angle of 27.94 (5)° between the two arene rings at the ends of the mol­ecule, owing to the partial saturation of the inner quinolizine ring system. Although lacking classical O—H or N—H donors, the packing in the crystalline state is clearly governed by C—H⋯N and C—H⋯O hydrogen bonds involving the two acetal-type C—H bonds of the 1,3-dioxole ring. Each di­hydro­berberine mol­ecule is engaged in four hydrogen bonds with neighbouring mol­ecules, twice as donor and twice as acceptor, thus forming a two-dimensional sheet network that lies parallel to the (100) plane.