Structure of sinoacutine

Abstract

In the title alkaloid, (9a,13a)-5,6,8,14-tetradehydro-4-hydroxy-3,6-dimethoxy-17-methylmorphinan-7-one, the mean value of three C--N--C angles is 111.0 (4) ° indicating sp 3 hybridization of the N atom.The interplanar angle between the aromatic ring A and planar ring D [maximum deviation 0.051 (5)/~ at C14] is 53.8 (1)°. The absolute configuration has been assigned to agree with the known chirality at C3 (S) [Southon & Buckingham, (1989). Dictionary of Alkaloids, p. 974. London: Chapman and Hall]. CommentSinoacutine is an enantiomer of salutaridine. In nature it occurs both in optically active and racemic © 1993 International Union of Crystallography REGULAR STRUCTURAL PAPERS 979 forms (Stuart, 1971). Sinoacutine contains a sequence isosteric with y-aminobutyric acid (GABA) and according to in vitro measurements (Kardos, Blask6, Simonyi & Szfintay, 1984) it can be considered as a partial agonist of the GABA/ benzodiazepine receptor complex. Sinoacutine plays an important role as biosynthetic intermediate in the formation of morphine (Barton & Cohen, 1957).The title alkaloid of morphinandienone-type was isolated from the aerial parts of the species Corydalis ochroleuca. The extraction of dried plant material was carried out according to Preininger, Vesely, Ga~i6, ~imanek & Dolej~ (1975) and it was isolated as described by Gagi6, Popovi6 & Dragutinovi6 (1985). Total synthesis of sinoacutine has been described by Ludwig & Schaefer (1986).From the puckering parameters (Cremer & Pople, 1975) of ring B [Q = 0.530 (6) .~, ~o = 18.2 (8) °, 0 = 52.6 (6) °] it can be seen that it is a transition form between half-chair and envelope shape, whereas ring C [Q = 0.556 (6) .,~, ~p = 305 (4) °, 0 = 8.6 (6)°], forming a bridge between C ll and the chiral atom C3, adopts an almost perfect chair conformation. HY participates in a symmetrical three-centered hydrogen-bond interaction (Jeffrey, 1978). 1.514 (7) C12--C13 1.328 (6) C3--N 1.475 (7) C13--C14 1.479 (7) C4--C5 1.520 (7) C13--O4 1.371 (6) C5--C61.387 (7) C14--O1 1.214 (6) C5--C101.408 (7) C15--C16 1.521 (7) C6--C71.361 (8) C15--N 1.471 (7) C7--C81.372 (8) C17--O2 1.403 (7) C8--C91.402 (7) C18--O4 1.399 (7) C8--O21.363 (6) C19--N 1.469 (7) C9--C101.387 (6)Data were corrected for Lorentz and polarization factors. A value for Rint is missing since a unique data set was collected. The structure was solved by direct methods using SHELXS86 (Sheldrick, 1985) and refined using SHELX76 (Sheldrick, 1976). The positions of H atoms were generated from assumed geometry except that of H3' which was calculated using the program MMX (Allinger, Scb_~fer, Siam, Klimkowski & van Alsenoy, 1985) and refined isotropically. The positions of H atoms in CH3 groups were checked on a Ap map. Non-H atoms were refined anisotropicaUy. Several weighting schemes were tested and the best results were obtained with the unit weight. The overall isotropic temperature factor for H atoms was U1 = 0.0575 (50) A 2 and for the methyl H atoms U2 = 0.0868 (73) ,~2. Software used to prepare material for...

Refinement of the crystal structure of sinoacutine, C19H21NO4

“…It has been isolated from Sinomenium acutum and several other plant species and identified by spectral methods [6][7][8][9][10]. The crystal structure of sinoacutine isolated from Corydalis ochro-leuca was already reported [9]. The present refinement reveals a higher accuracy.…”

“…In the course of our systematic search for bioactive substances from Chinese traditional herb medicines, we have studied the roots of S. acutum and obtained several compounds, including the title compound. It has been isolated from Sinomenium acutum and several other plant species and identified by spectral methods [6][7][8][9][10]. The crystal structure of sinoacutine isolated from Corydalis ochro-leuca was already reported [9].…”

β-Phenylethylamines and the isoquinoline alkaloids

“…An X-ray crystallographic study of nudaurine has led to a revision of the C-7 stereochemistry of this alkaloid to that shown in (157), which is the reverse of that previously deduced from the results of oxidation.200 An X-ray study of sinoacutine has confirmed the accepted structure of this alkaloid. 201 The treatment of codeine with chloroiodomethane has yielded the quaternary N-chloromethyl iodide,202 and the bromination of dihydrocodeinone in bright sunlight has given 1 -bromodihydrocodinone and 1 -bromo-1 0-hydroxydihydrocodeinone (1 58). 203 Mannich reaction of dihydrocodeinone and of 14hydroxydihydrocodeinone with dimethylamine and formaldehyde has afforded the bimolecular compounds (1 59a) and (1 59b), which presumably arise from the loss of dimethylamine from the initially formed Mannich base, followed by Diels-Alder addition of the resulting olefinic lactone to itself, as in the part structures (160).…”