title: Structure of a chiral intermediate in the synthesis of (+)-19-epiajmalicine.
abstract: [2S*-(2 beta,3 alpha,6 alpha,12b beta)]-Methyl 3-acetyl-1,2,3,4,6,7,12,12b-octahydro-6-methoxycarbonyl-indolo+ ++[2,3-a] quinolizine-3-ethanoate, C22H26N2O5, M(r) = 398.46, orthorhombic, P2(1)2(1)2(1), a = 9.463 (2), b = 11.251 (3), c = 18.871 (6) A, V = 2009.2 (9) A3, Z = 4, Dx = 1.32 g cm-3 (178 K), lambda(Mo K alpha) = 0.7107 A, mu = 0.8762 cm-1, F(000) = 848, T = 178 K, R = 0.0536 for 1673 reflections [Fo > or = 6 sigma (Fo)]. Molecules are hydrogen bonded along the 2(1)-screw axis parallel to a. The hydrogen-bond geometric parameters for N12-H12...O19 (related by 0.5 + x, 1.5 - y, 1 - z) are N...O 2.986 (6), H...O 2.30 (5) A, N-H...O 161 (5) degrees. The C and D rings are trans fused with ring-junction torsion angles of -39.6 (5) and 63.8 (5) degrees for C12a-C12b-N5-C6 and C1-C12b-N5-C4, respectively. The conformation of the C ring is half chair with N5 and C6 -0.168 (4) and 0.552 (5) A, respectively, out of the plane defined by the remaining four atoms of the ring. The D ring is in the chair conformation.
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas, Austin 78712.
authors.forename: V M
authors.initials: VM
authors.lastname: Lynch
authors.forename: J W
authors.initials: JW
authors.lastname: Corbett
authors.forename: S F
authors.initials: SF
authors.lastname: Martin
authors.forename: B E
authors.initials: BE
authors.lastname: Davis
mesh_terms: D003460:Crystallization; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D015394:Molecular Structure; D046948:Secologanin Tryptamine Alkaloids; D014961:X-Ray Diffraction; D015016:Yohimbine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D046948:Secologanin Tryptamine Alkaloids; D015016:Yohimbine; C005709:raubasine