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Acta Crystallogr Sect E Struct Rep Online. 2009 December 1; 65(Pt 12): o3252–o3253.
Published online 2009 November 28. doi:  10.1107/S1600536809050351
PMCID: PMC2972137

Methyl­ergometrine maleate from synchrotron powder diffraction data


The title compound {systematic name: 9,10-didehydro-N-[1-(hydroxy­meth­yl)prop­yl]-d-lysergamide maleate}, C20H26N3O2 +·C4H3O4 , contains a large rigid ergolene group. This group consists of an indole plane connected to a six-membered carbon ring adopting an envelope conformation and N-methyl­tetra­hydro­pyridine where the methyl group is in an equatorial position. In the crystal, inter­molecular N—H(...)O, O—H(...)N and O—H(...)O hydrogen bonds form an extensive three-dimensional hydrogen-bonding network, which holds the cations and anions together.

Related literature

For background to ergometrine, see: Dudley & Moir (1935 [triangle]); Kharasch & Legault (1935 [triangle]). Formethyl­ergometrine, see Stoll & Hofmann (1943 [triangle]). For crystal structure determinations of ergometrine, see: Čejka et al. (1996 [triangle]); Hušák et al. (1998 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o3252-scheme1.jpg


Crystal data

  • C20H26N3O2 +·C4H3O4
  • M r = 455.51
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-65-o3252-efi1.jpg
  • a = 5.71027 (5) Å
  • b = 12.76978 (17) Å
  • c = 33.1455 (4) Å
  • V = 2416.93 (5) Å3
  • Z = 4
  • Synchrotron radiation
  • λ = 0.6996 Å
  • T = 293 K
  • Specimen shape: cylinder
  • 40 × 1 × 1 mm
  • Specimen prepared at 101 kPa
  • Specimen prepared at 293 K
  • Particle morphology: needle, white

Data collection

  • BM01B, ESRF, Grenoble
  • Specimen mounting: 1.0 mm borosilicate glass capillary
  • Specimen mounted in transmission mode
  • Scan method: step
  • Absorption correction: none
  • min = 0.5, 2θmax = 29.5°
  • Increment in 2θ = 0.003°


  • R p = 0.060
  • R wp = 0.080
  • R exp = 0.021
  • R B = 0.088
  • S = 3.76
  • Wavelength of incident radiation: 0.6996 Å
  • Excluded region(s): none
  • Profile function: pseudo-Voigt profile coefficients as parameterized in Thompson et al. (1987 [triangle]), asymmetry correction according to Finger et al. (1994 [triangle])
  • 617 reflections
  • 100 parameters
  • 96 restraints
  • H-atom parameters not refined
  • Preferred orientation correction: March–Dollase (Dollase, 1986 [triangle]); direction of preferred orientation - 011, MD = 1.26

Data collection: ESRF SPEC package (Certified Scientific Software, 2003 [triangle]); cell refinement: GSAS (Larson & Von Dreele, 1994 [triangle]); data reduction: CRYSFIRE (Shirley, 2000 [triangle]); program(s) used to solve structure: FOX (Favre-Nicolin & Černý, 2002 [triangle]); program(s) used to refine structure: GSAS; molecular graphics: Mercury (Macrae et al., 2006 [triangle]) and PLATON (Spek, 2003 [triangle]); software used to prepare material for publication: enCIFer (Allen et al., 2004 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809050351/cv2630sup1.cif

Rietveld powder data: contains datablocks I. DOI: 10.1107/S1600536809050351/cv2630Isup2.rtv

Additional supplementary materials: crystallographic information; 3D view; checkCIF report


This study was supported by the grant of the Czech Grant Agency (GAČR 203/07/0040) and by the research programs MSM6046137302 and NPV II 2B08021of the Ministry of Education, Youth and Sports of the Czech Republic. We acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities and we thank Denis Testemale for assistance in using beamline BM01B.

supplementary crystallographic information


Methylergometrine is a semisynthetic ergot alkaloid derived from (+)-lysergic acid and (S)-(+)-2-amino-1-butanol (Stoll & Hofmann, 1943). It is nearly isostructural with natural ergot alkaloid ergometrine maleate (Čejka et al., 1996). Previous attempts to solve this structure by molecular modeling using ergometrine maleate as the starting model were successful, but the result was not very precise (Čejka et al., 1996). Hence the crystal structure was not published. In this paper we report crystal structure determination of the title compound (I) from synchrotron powder diffraction data.

The asymmetric unit of (I) contains a methylergometrinium cation and one molecule of maleate (Fig. 1). All bond lengths and angles in (I) are comparable with reported structure of ergometrine maleate (Čejka et al., 1996). The molecule of maleate is situated in the same position and the hydrogen bonding system is practically the same. Intermolecular N—H···O, O—H···N and O—H···O hydrogen bonds (Table 1) form an extensive three-dimensional hydrogen-bonding network which held cations and anions together.


Crystallization of methylergometrine maleate from various solvents (alcohols, acetic acid esters, acetone, dioxane, dimethyl sulphoxide) provided hair-like long needle crystals in all cases. One crystalline form with distinct powder patterns was found.


The powder diffraction data measurement was done on BM01B beamline (Swiss-Norwegian Beamlines) at the ESRF, Grenoble. Before the measurement the diffractometer was calibrated by using LaB6 standard sample and the value of wavelength was checked (0.6996 Å). The powder sample was placed in a 1 mm capillary. The measurement was done at room temperature. The capillary was rotating during the data collection. The diffractogram was measured from 0.515° to 29.49° 2θ with 0.0025° step scan and the sample was irradiated for 1 s per step. The data from all six detectors were finally binned.

The indexation confirmed unit-cell parameters and space group obtained from previous measurement (Čejka et al., 1996): a =5.71 Å, b=12.77 Å, c =33.15 Å, Z = 4, V = 2 417 Å3, P212121. Molecule of ergometrine (Čejka et al., 1996) was used as a starting model for structure solution. This model was transferred to the z-matrix and the missing methyl group was added in the standard C—C distance (1.52 Å). This way changed z-matrix was loaded into the program FOX (Favre-Nicolin & Černý, 2002) and structure was solved by using parallel tempering algorithm. The structure solution result confirmed similarity with ergometrine maleate, see Fig.2. Refinement of this result was carried out in GSAS (Larson & Von Dreele, 1994). Hydrogen atoms were placed in their theoretical positions and structure was refined with bonds, angles and planar groups restraints (N1—C10,C9/C10/C12/C16, C17/C18/O19/N20, C6s/C5s/O1s/O2s, C7s/C8s/O3s/O4s andC5s/C6s/C7s/C8s). All atomic coordinates and Uiso parameters of non-hydrogen atoms were refined. Hydrogen atoms were not refined, it was necessary to relocate H atoms into the correct positions after few cycles. Hydrogen atom H202 was manually placed between oxygen atoms O2s and O4s. At the final stage of the refinement, only atomic coordinates of non-hydrogen atoms were refined to the final agreement factors Rp = 0.0631 and Rwp = 0.0831. The diffraction profiles and differences between the measured and calculated profiles are shown in Fig. 3.


Fig. 1.
The molecular structure of methylergometrine maleate showing the atomic numbering. Displacement spheres are drawn at the 30% probability level.
Fig. 2.
Overlaid asymmetric parts of unit cells of methylergometrine maleate (blue) and ergometrine maleate (red)
Fig. 3.
The final Rietveld plot showing the measured data (black thin-plus), calculated data (red line) and difference curve (blue line). Calculated positions of the reflection are shown by vertical bars.

Crystal data

C20H26N3O2+·C4H3O4F(000) = 960.0
Mr = 455.51Dx = 1.246 Mg m3
Orthorhombic, P212121Synchrotron radiation, λ = 0.6996 Å
a = 5.71027 (5) ÅT = 293 K
b = 12.76978 (17) ÅParticle morphology: needle
c = 33.1455 (4) Åwhite
V = 2416.93 (5) Å3cylinder, 40 × 1 mm
Z = 4Specimen preparation: Prepared at 293 K and 101 kPa

Data collection

ID31 diffractometerData collection mode: transmission
Radiation source: X-RayScan method: step
Si(111)min = 0.52°, 2θmax = 29.49°, 2θstep = 0.003°
Specimen mounting: 1.0 mm borosilicate glass capillary


Least-squares matrix: fullProfile function: Pseudo-Voigt profile coefficients as parameterized in Thompson et al. (1987), asymmetry correction according to Finger et al. (1994)
Rp = 0.060100 parameters
Rwp = 0.08096 restraints
Rexp = 0.0210 constraints
RBragg = 0.088H-atom parameters not refined
R(F2) = 0.08232Weighting scheme based on measured s.u.'s w = 1/σ(Yobs)2
χ2 = 14.138(Δ/σ)max = 0.03
11591 data pointsBackground function: Shifted Chebyschev
Excluded region(s): noPreferred orientation correction: March–Dollase (Dollase, 1986); direction of preferred orientation - 011, MD = 1.26

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

N1−0.2972 (5)0.6888 (3)0.29856 (7)0.07305*
C2−0.1311 (5)0.6344 (2)0.27627 (8)0.04511*
C3−0.0706 (4)0.6910 (2)0.24331 (7)0.03699*
C4−0.2019 (3)0.7843 (2)0.24509 (6)0.03942*
C5−0.3442 (4)0.7819 (3)0.27994 (6)0.05116*
C6−0.4884 (4)0.8647 (3)0.28782 (7)0.04053*
C7−0.4901 (4)0.9470 (3)0.26187 (8)0.03292*
C8−0.3485 (4)0.9500 (2)0.22692 (7)0.02676*
C9−0.2006 (3)0.86750 (18)0.21789 (6)0.04409*
C10−0.0383 (3)0.85683 (16)0.18355 (6)0.05585*
C110.0703 (5)0.66917 (18)0.20642 (8)0.01406*
C120.1520 (3)0.77235 (18)0.18765 (6)0.02621*
N130.2572 (4)0.7525 (2)0.14658 (7)0.02834*
C140.4543 (6)0.6780 (3)0.14769 (10)0.04728*
C150.3333 (4)0.8518 (2)0.12743 (7)0.0149*
C16−0.0506 (3)0.9178 (3)0.15108 (8)0.01827*
C170.1276 (3)0.9217 (2)0.11776 (6)0.05457*
C180.2054 (3)1.0353 (2)0.11406 (5)0.01555*
O190.3842 (5)1.0675 (3)0.13078 (10)0.03564*
N200.0695 (5)1.0956 (2)0.09146 (10)0.0567*
C210.0846 (6)1.2096 (2)0.08735 (7)0.12048*
C22−0.1555 (8)1.2575 (4)0.09008 (13)0.13815*
O23−0.2828 (7)1.2409 (7)0.12481 (15)0.18992*
C240.1859 (9)1.2439 (4)0.04775 (12)0.16384*
C250.254 (2)1.3598 (5)0.0502 (2)0.24862*
O1s0.1598 (8)0.5073 (3)−0.05735 (10)0.05346*
O2s0.3200 (5)0.6095 (3)−0.01229 (11)0.09409*
O3s−0.0518 (7)0.6674 (3)0.09751 (9)0.05776*
O4s0.2452 (6)0.6788 (3)0.05636 (10)0.06078*
C5s0.1379 (6)0.56141 (17)−0.02617 (8)0.06152*
C6s−0.0894 (5)0.57248 (19)−0.00445 (9)0.0169*
C7s−0.1334 (5)0.61043 (19)0.03209 (9)0.05644*
C8s0.0294 (5)0.65414 (14)0.06283 (8)0.01622*

Geometric parameters (Å, °)

N13—C141.474 (4)N13—H1310.86
N13—C151.483 (4)N20—H2010.87
N20—C181.325 (4)C2—H210.98
N20—C211.465 (4)C6—H610.96
C2—C31.355 (4)C7—H710.92
C3—C41.409 (3)C8—H810.91
C3—C111.490 (4)C11—H1110.98
C4—C51.413 (3)C11—H1120.95
C4—C91.393 (3)C12—H1210.95
C5—C61.365 (5)C14—H1410.94
C6—C71.358 (5)C14—H1420.94
C7—C81.413 (3)C14—H1430.99
C8—C91.383 (3)C15—H1510.94
C9—C101.474 (3)C15—H1520.95
C10—C121.538 (3)C16—H1610.92
C10—C161.330 (4)C17—H1710.95
C11—C121.530 (3)C21—H2110.95
C15—C171.510 (3)C22—H2210.96
C16—C171.503 (3)C22—H2220.90
C17—C181.522 (4)C24—H2410.99
C21—C221.504 (6)C24—H2420.99
C21—C241.500 (5)C25—H2511.00
C24—C251.532 (9)C25—H2520.90
C2—N1—C5109.2 (2)C3—C2—H21126
C12—N13—C14112.9 (2)C5—C6—H61119
C12—N13—C15111.0 (2)C7—C6—H61122
C14—N13—C15109.8 (2)C6—C7—H71117
C18—N20—C21126.6 (3)C8—C7—H71120
N1—C2—C3109.7 (2)C7—C8—H81121
C2—C3—C4106.4 (2)C9—C8—H81119
C2—C3—C11134.4 (2)C3—C11—H111108
C4—C3—C11118.7 (2)C3—C11—H112109
C3—C4—C5108.8 (2)C12—C11—H111111
C3—C4—C9127.96 (19)C12—C11—H112112
C5—C4—C9123.3 (2)H111—C11—H112107
N1—C5—C4106.0 (3)N13—C12—H121108
N1—C5—C6134.9 (2)C10—C12—H121110
C4—C5—C6119.1 (3)C11—C12—H121105
C5—C6—C7118.8 (2)N13—C14—H141111
C6—C7—C8122.4 (3)N13—C14—H142112
C7—C8—C9120.4 (2)N13—C14—H143110
C4—C9—C8115.97 (19)H141—C14—H142111
C4—C9—C10115.61 (18)H141—C14—H143106
C8—C9—C10128.4 (2)H142—C14—H143106
C9—C10—C12116.18 (17)N13—C15—H151106
C9—C10—C16122.53 (19)N13—C15—H152106
C12—C10—C16121.28 (18)C17—C15—H151111
C3—C11—C12109.71 (19)C17—C15—H152111
N13—C12—C10108.63 (17)H151—C15—H152110
N13—C12—C11110.09 (19)C10—C16—H161116
C10—C12—C11115.12 (17)C17—C16—H161119
N13—C15—C17111.62 (19)C15—C17—H171108
C10—C16—C17125.4 (2)C16—C17—H171109
C15—C17—C16110.6 (2)C18—C17—H171112
C15—C17—C18110.70 (16)N20—C21—H211107
C16—C17—C18106.8 (2)C22—C21—H211112
O19—C18—N20123.1 (3)C24—C21—H211108
O19—C18—C17121.6 (2)O23—C22—H221104
N20—C18—C17115.37 (19)O23—C22—H222110
N20—C21—C22110.2 (3)C21—C22—H221104
N20—C21—C24113.2 (3)C21—C22—H222108
C22—C21—C24106.6 (3)H221—C22—H222113
O23—C22—C21117.9 (4)C21—C24—H241106
C21—C24—C25109.5 (4)C21—C24—H242107

Hydrogen-bond geometry (Å, °)

O2s—H202···O4s1.201.282.479 (5)179
N13—H131···O3s0.861.772.634 (4)173
O23—H232···O19i0.832.122.925 (8)160
N20—H201···O1sii0.872.042.912 (5)177
N1—H11···O19iii0.882.032.852 (4)154

Symmetry codes: (i) x−1, y, z; (ii) x−1/2, −y+3/2, −z; (iii) −x, y−1/2, −z+1/2.


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CV2630).


  • Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst. 37, 335–338.
  • Čejka, J., Hušák, M., Kratochvíl, B., Jegorov, A. & Cvak, L. (1996). Coll. Czech. Chem. Commun. 61 1396–1404.
  • Certified Scientific Software (2003). SPEC. Certified Scientific Software, Cambridge, MA, USA.
  • Dollase, W. A. (1986). J. Appl. Cryst. 19, 267–272.
  • Dudley, H. W. & Moir, C. (1935). Br. Med. J 1, 520–523. [PMC free article] [PubMed]
  • Favre-Nicolin, V. & Černý, R. (2002). J. Appl. Cryst. 35, 734–743.
  • Finger, L. W., Cox, D. E. & Jephcoat, A. P. (1994). J. Appl. Cryst. 27, 892–900.
  • Hušák, M., Kratochvíl, B. & Jegorov, A. (1998). Z. Kristallogr. 213, 195–196.
  • Kharasch, M. S. & Legault, R. R. (1935). Science, 81, 388. [PubMed]
  • Larson, A. C. & Von Dreele, R. B. (1994). GSAS. Report LAUR 86-748. Los Alamos National Laboratory, New Mexico, USA.
  • Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.
  • Shirley, R. (2000). CRYSFIRE User’s Manual. Guildford, England: The Lattice Press.
  • Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13.
  • Stoll, A. & Hofmann, A. (1943). Helv. Chim. Acta, 26, 944–965.
  • Thompson, P., Cox, D. E. & Hastings, J. B. (1987). J. Appl. Cryst. 20, 79–83.

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