N-Methylisosalsoline from Hammada scoparia

The title compound (systematic name: 1,2-dimethyl-6-methoxy-1,2,3,4-tetrahydroisoquinolin-7-ol), C12H17NO2, is a major alkaloid isolated from Hammada scoparia leaves. It belongs to the isoquinoline family and it was characterized by NMR spectroscopy and X-ray crystallographic techniques. The absolute configuration could not be reliably determined. An intermolecular O—H⋯N hydrogen bond is present in the crystal structure.

The title compound (systematic name: 1,2-dimethyl-6-methoxy-1,2,3,4-tetrahydroisoquinolin-7-ol), C 12 H 17 NO 2 , is a major alkaloid isolated from Hammada scoparia leaves. It belongs to the isoquinoline family and it was characterized by NMR spectroscopy and X-ray crystallographic techniques. The absolute configuration could not be reliably determined. An intermolecular O-HÁ Á ÁN hydrogen bond is present in the crystal structure.
The current study describes the isolation and the structure elucidation of N-methylisosalsoline. The structure of the title compound was established principally by two-dimensional NMR spectroscopy and through X-ray diffraction analysis although the absolute configuration could not be reliably determined.
The conformation of this compound is stabilized by an intermolecular hydrogen bond between the hydroxyl O 2 -H 2 group and atom N 1 ( Table 1). The molecules are assembled by intermolecular O-H···N hydrogen bonds (Table 1

Extraction and isolation of the N-Methylisosalsoline from Hammada scoparia leaves:
Air-dried leaves of Hammada scoparia were extracted at room temperature during 48 h with a mixture (EtOH-H 2 O, 1-9, v-v). After filtration through folder filter paper Whatman N° 1, the ethanol was removed under reduced pressure and the remaining aqueous phase was acidified with HCl (pH = 3) and then defatted by extraction with CH 2 Cl 2 . The defatted mother liquor was made alkaline with an NH 4 OH solution (pH = 10) and immediately extracted with CH 2 Cl 2 to exhaustion.
The latter CH 2 Cl 2 extract was concentrated to yield a reddish-brown residue (total alkaloids).
supplementary materials sup-2 The total Alkaloids (5 g) were separated, on column chromatography over silica gel 60 (0.063-0.200 mm; 160 g), using a gradient of dichloromethane-methanol as eluents. Eleven fractions were isolated according to their similarity by thin layer chromatography analyses. Further purifications gave two major pure alkaloids; the first is oily: Carnegine (1050 mg; fraction 3 eluted with dichloromethane) and the second (white rosette crystals) is N-methylisosalsoline (545 mg; fraction 7 eluted with dichloromethane-methanol, 94-6, v-v). These alkaloids were previously isolated from Hammada scoparia (Carling & Sandberg, 1970;Benkrief et al., 1990;Jarraya & Damak, 2001;El-Shazly & Wink, 2003). Their structures were determined on the basis of their spectral data such as UV, MS, 1 H NMR and H-H COSY, 13  Suitable white X-ray quality crystals of this compound were obtained by recrystallization from methanol.
In the absence of significant anomalous scattering, the absolute configuration could not be reliably determined and then the Friedel pairs were merged and any references to the Flack parameter were removed.  1,2-dimethyl-6-methoxy-1,2,3,4-tetrahydroisoquinolin-7-ol Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.