organic compounds
(3R,4R,4aS,7aR,12bS)-3-Cyclopropylmethyl-4a,9-dihydroxy-3-methyl-7-oxo-2,3,4,4a,5,6,7,7a-octahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-3-ium bromide
aNanjing Haiguang Applied Chemistry Institute, Jiangsu Aosaikang Pharmaceutical Co. Ltd, Nanjing 211112, People's Republic of China, and bSchool of Pharmacy, China Pharmaceutical University, Nanjing 210009, People's Republic of China
*Correspondence e-mail: min.sun619@yahoo.com
The title compound, C21H26NO4+·Br−, also known as R-methylnaltrexone (MNTX) bromide, is a selective peripherally acting μ-opioid receptor antagonist with a oroxymorphone skeleton, synthesized by hydroxyl protection, N-methylation, deprotection and of naltrexone. It comprises a five-ring system A/B/C/D/E. Rings C and E adopt distorted chair conformations, whereas ring D is in half-chair conformation. The C/E ring junctions are trans fused. The dihedral angle between rings D and E is 82.3 (1)°, while the dihedral angles between the planes of rings C and A, and rings D and E are respectively 81.7 (1), 75.9 (1) and 12.2 (1)°. In the crystal, molecules are linked by O—H⋯Br hydrogen bonds.
Related literature
For general background to methylnaltrexone (MNTX) bromide, see: Garnock-Jones & McKeage (2010). For ring conformations, see: Cremer & Pople (1975). For synthesis of methylnaltrexone bromide via hydroxyl protection, N-methylation, deprotection and see: Doshan et al. (2010).
Experimental
Crystal data
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Data collection: SMART (Bruker, 2000); cell SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009).
Supporting information
10.1107/S1600536812000645/bg2437sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812000645/bg2437Isup2.hkl
To a solution of naltrexone (3.24 g, 9.5 mmol) in anhydrous tetrahydrofuran (THF) (200 mL) was added triethylamine (NEt3) (2.8 mL, 20 mmol) at 0 °C. After the reaction was stirred for 15 min at 0 °C, isobutyryl chloride (2.1 ml, 20 mmol) was added dropwise. Reaction mixture was stirred at 0 °C for 1 hr, then at room temperature for 18 hrs before being quenched with saturated sodium bicarbonate (NaHCO3) (aq) (140 ml) and 60 ml of H2O. The reaction was extracted with methylene chloride (CH2Cl2) (2×300 ml). The extracts were combined, washed with brine (200 ml), dried over sodium sulfate (Na2SO4) (50 g), filtered and concentrated in vacuo. The crude material was purified by flash
on silica gel to give 3-O-isobutyryl-naltrexone (2.8 g 71.6%) as a white solid.3-O-isobutyryl-naltrexone(1.4 g, 3.40 mmol) was transferred by spatula into a glass pressure vessel. The vessel was purged gently with nitrogen on the manifold for 5 minutes and was then evacuated under high vacuum. When the vacuum was constant, the lower part of the vessel was immersed in liquid nitrogen. Methyl iodide (2.0 g, 14.1 mmol) was dispensed into a separate flask on the manifold into a nitrogen atmosphere and frozen in liquid nitrogen. The frozen methyl iodide vessel was evacuated under high vacuum. The main manifold chamber was isolated from the high vacuum pump. The methyl iodide was allowed to warm to ambient temperature and sublime via the main chamber onto the liquid nitrogen cooled 3-O-isobutyryl-naltrexone. When
was complete, nitrogen was slowly allowed to leach into the glass pressure vessel. The vessel was then sealed tight, removed from the manifold and heated in an oil bath at 88–90 °C for 17 hrs. The vessel was allowed to cool to ambient temperature before allowing nitrogen to flow into the vessel. The vessel was then evacuated under high vacuum to remove residues of unreacted methyl iodide giving a white solid. The crude material was purified by flash on silica gel to give 3-O-isobutyryl-N-methylnaltrexone iodide salt (1.68 g, 89.3%) as a white solid.3-O-isobutyryl-N-methylnaltrexone iodide salt (1.68 g, 3.04 mmol) was dissolved in methanol (25 ml). To this mixture was added sterile water (23 ml) followed by 48% aqueous hydrobromic acid (3 ml). The resultant mixture was stirred under nitrogen and heated in an oil bath at 64–65 °C for 6.5 hrs. The mixture was concentrated on the rotary evaporator with the bath at 22–25 °C until approximately 1 ml of oily liquid remained. Acetonitrile (20 ml) was added and the mixture was reconcentrated. This was repeated a further three times, using 20 ml of acetonitrile, to give a ginger colored crisp foam (1.1 g, 83% crude yield).
The foam (1.1 g) was dispersed in water (12 ml)/methanol (4 ml). Some dark oil remained undissolved. The clear supernatant liquid was decanted and applied to the prepared
resin column. The residue was washed twice with methanol (0.4 mL)/water (6 ml). The supernatant liquors were applied to the column. The colunm was eluted with 4.2 L of sterile water and fractions of ~20 ml were collected. The yield of the white solid N-methylnaltrexone bromide 814.4 mg (64%).The H atom of the hydroxy groups were located from the difference map and refined isotropically. The remaining H atoms were placed in geometrical positions and constrained to ride on their parent atoms with C–H distances in the range 0.93–0.98 Å, and refined with Uiso(H) = 1.5Ueq(C) for methyl H and 1.2Ueq(C) for other H atoms.
Data collection: SMART (Bruker, 2000); cell
SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).Fig. 1. The molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. |
C21H26NO4+·Br− | F(000) = 452 |
Mr = 436.34 | Dx = 1.514 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 2706 reflections |
a = 7.708 (3) Å | θ = 2.3–24.6° |
b = 13.187 (5) Å | µ = 2.18 mm−1 |
c = 9.501 (3) Å | T = 291 K |
β = 97.679 (6)° | Block, colourless |
V = 957.1 (6) Å3 | 0.28 × 0.24 × 0.22 mm |
Z = 2 |
Bruker SMART APEX CCD diffractometer | 4179 independent reflections |
Radiation source: sealed tube | 3259 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.048 |
phi and ω scans | θmax = 28.5°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | h = −7→10 |
Tmin = 0.581, Tmax = 0.646 | k = −12→17 |
6955 measured reflections | l = −12→11 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.035 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.073 | w = 1/[σ2(Fo2) + (0.020P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.04 | (Δ/σ)max = 0.001 |
4179 reflections | Δρmax = 0.39 e Å−3 |
245 parameters | Δρmin = −0.44 e Å−3 |
2 restraints | Absolute structure: Flack (1983), 1636 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.006 (7) |
C21H26NO4+·Br− | V = 957.1 (6) Å3 |
Mr = 436.34 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 7.708 (3) Å | µ = 2.18 mm−1 |
b = 13.187 (5) Å | T = 291 K |
c = 9.501 (3) Å | 0.28 × 0.24 × 0.22 mm |
β = 97.679 (6)° |
Bruker SMART APEX CCD diffractometer | 4179 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | 3259 reflections with I > 2σ(I) |
Tmin = 0.581, Tmax = 0.646 | Rint = 0.048 |
6955 measured reflections |
R[F2 > 2σ(F2)] = 0.035 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.073 | Δρmax = 0.39 e Å−3 |
S = 1.04 | Δρmin = −0.44 e Å−3 |
4179 reflections | Absolute structure: Flack (1983), 1636 Friedel pairs |
245 parameters | Absolute structure parameter: −0.006 (7) |
2 restraints |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
Br1 | −0.27040 (4) | 0.31792 (5) | 0.03917 (3) | 0.05094 (11) | |
C1 | 0.5410 (4) | 0.4248 (3) | 0.5393 (4) | 0.0436 (9) | |
C2 | 0.5975 (4) | 0.4559 (3) | 0.6764 (4) | 0.0506 (10) | |
C3 | 0.4825 (5) | 0.5137 (3) | 0.7423 (4) | 0.0519 (10) | |
H3 | 0.5192 | 0.5375 | 0.8336 | 0.062* | |
C4 | 0.3139 (5) | 0.5383 (3) | 0.6787 (3) | 0.0464 (9) | |
H4 | 0.2389 | 0.5748 | 0.7287 | 0.056* | |
C5 | 0.2590 (4) | 0.5076 (3) | 0.5394 (3) | 0.0392 (8) | |
C6 | 0.3776 (4) | 0.4540 (3) | 0.4748 (3) | 0.0372 (8) | |
C7 | 0.3529 (4) | 0.4120 (3) | 0.3254 (3) | 0.0358 (8) | |
C8 | 0.1586 (4) | 0.3871 (3) | 0.2814 (3) | 0.0330 (7) | |
C9 | 0.0565 (4) | 0.4882 (3) | 0.3026 (3) | 0.0320 (7) | |
H9 | −0.0676 | 0.4745 | 0.2710 | 0.038* | |
C10 | 0.0725 (4) | 0.5145 (2) | 0.4634 (3) | 0.0405 (8) | |
H10A | 0.0292 | 0.5828 | 0.4737 | 0.049* | |
H10B | −0.0013 | 0.4687 | 0.5088 | 0.049* | |
C11 | 0.4099 (4) | 0.4890 (3) | 0.2210 (3) | 0.0425 (9) | |
H11A | 0.5342 | 0.5021 | 0.2444 | 0.051* | |
H11B | 0.3901 | 0.4611 | 0.1257 | 0.051* | |
C12 | 0.3096 (4) | 0.5877 (3) | 0.2249 (3) | 0.0398 (8) | |
H12A | 0.3397 | 0.6316 | 0.1499 | 0.048* | |
H12B | 0.3468 | 0.6213 | 0.3147 | 0.048* | |
C13 | 0.0381 (4) | 0.67932 (19) | 0.2407 (3) | 0.0406 (8) | |
H13A | 0.0929 | 0.7008 | 0.3338 | 0.049* | |
H13B | 0.0694 | 0.7280 | 0.1719 | 0.049* | |
C14 | −0.1571 (4) | 0.6804 (3) | 0.2385 (3) | 0.0432 (8) | |
H14 | −0.2058 | 0.6347 | 0.3045 | 0.052* | |
C15 | −0.2726 (5) | 0.7068 (3) | 0.1044 (4) | 0.0565 (11) | |
H15A | −0.2176 | 0.7162 | 0.0192 | 0.068* | |
H15B | −0.3881 | 0.6764 | 0.0887 | 0.068* | |
C16 | −0.2390 (5) | 0.7841 (3) | 0.2174 (4) | 0.058 | |
H16A | −0.3338 | 0.8006 | 0.2710 | 0.070* | |
H16B | −0.1632 | 0.8405 | 0.2015 | 0.070* | |
C17 | 0.0470 (4) | 0.5559 (3) | 0.0514 (3) | 0.0395 (8) | |
H17A | 0.0618 | 0.6163 | −0.0020 | 0.059* | |
H17B | −0.0747 | 0.5377 | 0.0404 | 0.059* | |
H17C | 0.1132 | 0.5016 | 0.0173 | 0.059* | |
C18 | 0.4825 (3) | 0.3216 (4) | 0.3524 (3) | 0.0451 (7) | |
H18 | 0.5266 | 0.3014 | 0.2645 | 0.054* | |
C19 | 0.3966 (5) | 0.2325 (3) | 0.4176 (4) | 0.0465 (9) | |
C20 | 0.2143 (5) | 0.2074 (3) | 0.3494 (4) | 0.0488 (9) | |
H20A | 0.1708 | 0.1484 | 0.3946 | 0.059* | |
H20B | 0.2141 | 0.1927 | 0.2494 | 0.059* | |
C21 | 0.0982 (4) | 0.2997 (3) | 0.3677 (3) | 0.0398 (9) | |
H21A | −0.0232 | 0.2836 | 0.3347 | 0.048* | |
H21B | 0.1078 | 0.3184 | 0.4671 | 0.048* | |
N1 | 0.1112 (3) | 0.5747 (2) | 0.2073 (3) | 0.0335 (6) | |
O1 | 0.7622 (3) | 0.4286 (3) | 0.7404 (3) | 0.0719 (10) | |
H1X | 0.762 (6) | 0.403 (4) | 0.817 (5) | 0.086* | |
O2 | 0.6235 (3) | 0.3609 (2) | 0.4553 (2) | 0.0548 (8) | |
O3 | 0.4644 (4) | 0.1902 (2) | 0.5242 (3) | 0.0638 (9) | |
O4 | 0.1381 (3) | 0.35700 (17) | 0.1374 (2) | 0.0393 (6) | |
H4X | 0.037 (4) | 0.344 (3) | 0.108 (3) | 0.047* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.04321 (15) | 0.0671 (2) | 0.04230 (17) | −0.0020 (2) | 0.00507 (11) | −0.0091 (2) |
C1 | 0.0374 (18) | 0.051 (3) | 0.040 (2) | 0.0021 (17) | −0.0021 (15) | 0.0060 (17) |
C2 | 0.0402 (18) | 0.064 (3) | 0.044 (2) | −0.0095 (18) | −0.0098 (15) | 0.0156 (18) |
C3 | 0.061 (2) | 0.061 (3) | 0.0297 (18) | −0.021 (2) | −0.0071 (16) | 0.0019 (17) |
C4 | 0.061 (2) | 0.046 (2) | 0.0322 (18) | −0.0040 (18) | 0.0057 (15) | 0.0002 (16) |
C5 | 0.0437 (18) | 0.044 (2) | 0.0299 (16) | −0.0031 (16) | 0.0036 (13) | 0.0046 (15) |
C6 | 0.0340 (17) | 0.048 (2) | 0.0286 (17) | −0.0016 (16) | 0.0022 (13) | 0.0085 (16) |
C7 | 0.0337 (16) | 0.046 (2) | 0.0284 (16) | 0.0083 (14) | 0.0059 (12) | 0.0059 (15) |
C8 | 0.0318 (15) | 0.041 (2) | 0.0260 (15) | 0.0057 (14) | 0.0041 (12) | 0.0001 (14) |
C9 | 0.0282 (14) | 0.040 (2) | 0.0283 (15) | 0.0008 (13) | 0.0045 (12) | 0.0048 (14) |
C10 | 0.0440 (18) | 0.048 (2) | 0.0305 (16) | 0.0079 (16) | 0.0079 (13) | −0.0009 (15) |
C11 | 0.0295 (15) | 0.058 (3) | 0.0409 (18) | 0.0000 (16) | 0.0082 (13) | 0.0117 (17) |
C12 | 0.0274 (15) | 0.050 (2) | 0.0413 (18) | −0.0081 (15) | 0.0020 (13) | 0.0094 (16) |
C13 | 0.0469 (18) | 0.033 (2) | 0.0417 (17) | 0.0000 (16) | 0.0036 (14) | −0.0012 (15) |
C14 | 0.0475 (19) | 0.042 (2) | 0.0420 (18) | 0.0075 (16) | 0.0127 (15) | 0.0091 (16) |
C15 | 0.050 (2) | 0.072 (3) | 0.047 (2) | 0.011 (2) | 0.0065 (16) | 0.022 (2) |
C16 | 0.062 | 0.052 | 0.066 | 0.029 | 0.031 | 0.019 |
C17 | 0.0460 (19) | 0.045 (2) | 0.0257 (16) | 0.0010 (16) | −0.0012 (13) | 0.0055 (15) |
C18 | 0.0359 (14) | 0.064 (2) | 0.0348 (14) | 0.016 (2) | 0.0037 (11) | 0.008 (2) |
C19 | 0.056 (2) | 0.048 (3) | 0.0360 (19) | 0.0243 (19) | 0.0088 (16) | 0.0002 (18) |
C20 | 0.062 (2) | 0.039 (2) | 0.047 (2) | 0.0038 (19) | 0.0162 (18) | 0.0040 (17) |
C21 | 0.0403 (15) | 0.042 (3) | 0.0380 (15) | 0.0039 (16) | 0.0074 (12) | 0.0049 (16) |
N1 | 0.0306 (12) | 0.0356 (17) | 0.0337 (14) | −0.0007 (12) | 0.0020 (10) | 0.0028 (12) |
O1 | 0.0516 (15) | 0.105 (3) | 0.0531 (16) | −0.0082 (16) | −0.0165 (13) | 0.0250 (17) |
O2 | 0.0337 (11) | 0.083 (2) | 0.0459 (13) | 0.0126 (12) | −0.0002 (10) | 0.0088 (12) |
O3 | 0.081 (2) | 0.059 (2) | 0.0489 (16) | 0.0221 (18) | −0.0009 (15) | 0.0115 (15) |
O4 | 0.0431 (11) | 0.0443 (17) | 0.0300 (11) | 0.0049 (10) | 0.0029 (9) | −0.0029 (9) |
C1—O2 | 1.374 (4) | C13—C14 | 1.502 (5) |
C1—C2 | 1.379 (5) | C13—N1 | 1.539 (4) |
C1—C6 | 1.380 (4) | C13—H13A | 0.9700 |
C2—O1 | 1.380 (4) | C13—H13B | 0.9700 |
C2—C3 | 1.381 (5) | C14—C15 | 1.495 (4) |
C3—C4 | 1.396 (5) | C14—C16 | 1.508 (5) |
C3—H3 | 0.9300 | C14—H14 | 0.9800 |
C4—C5 | 1.395 (4) | C15—C16 | 1.478 (6) |
C4—H4 | 0.9300 | C15—H15A | 0.9700 |
C5—C6 | 1.364 (5) | C15—H15B | 0.9700 |
C5—C10 | 1.524 (4) | C16—H16A | 0.9700 |
C6—C7 | 1.512 (4) | C16—H16B | 0.9700 |
C7—C11 | 1.524 (5) | C17—N1 | 1.518 (4) |
C7—C8 | 1.536 (4) | C17—H17A | 0.9600 |
C7—C18 | 1.555 (5) | C17—H17B | 0.9600 |
C8—O4 | 1.413 (3) | C17—H17C | 0.9600 |
C8—C21 | 1.523 (5) | C18—O2 | 1.457 (4) |
C8—C9 | 1.575 (4) | C18—C19 | 1.520 (6) |
C9—N1 | 1.549 (4) | C18—H18 | 0.9800 |
C9—C10 | 1.555 (4) | C19—O3 | 1.212 (4) |
C9—H9 | 0.9800 | C19—C20 | 1.504 (5) |
C10—H10A | 0.9700 | C20—C21 | 1.534 (5) |
C10—H10B | 0.9700 | C20—H20A | 0.9700 |
C11—C12 | 1.517 (5) | C20—H20B | 0.9700 |
C11—H11A | 0.9700 | C21—H21A | 0.9700 |
C11—H11B | 0.9700 | C21—H21B | 0.9700 |
C12—N1 | 1.526 (4) | O1—H1X | 0.80 (5) |
C12—H12A | 0.9700 | O4—H4X | 0.82 (3) |
C12—H12B | 0.9700 | ||
O2—C1—C2 | 128.2 (3) | C14—C13—H13B | 108.9 |
O2—C1—C6 | 112.3 (3) | N1—C13—H13B | 108.9 |
C2—C1—C6 | 119.4 (4) | H13A—C13—H13B | 107.7 |
C1—C2—O1 | 119.6 (4) | C15—C14—C13 | 119.7 (3) |
C1—C2—C3 | 116.8 (3) | C15—C14—C16 | 59.0 (2) |
O1—C2—C3 | 123.6 (3) | C13—C14—C16 | 114.3 (3) |
C2—C3—C4 | 123.3 (3) | C15—C14—H14 | 117.0 |
C2—C3—H3 | 118.4 | C13—C14—H14 | 117.0 |
C4—C3—H3 | 118.4 | C16—C14—H14 | 117.0 |
C5—C4—C3 | 119.3 (3) | C16—C15—C14 | 61.0 (2) |
C5—C4—H4 | 120.3 | C16—C15—H15A | 117.7 |
C3—C4—H4 | 120.3 | C14—C15—H15A | 117.7 |
C6—C5—C4 | 116.2 (3) | C16—C15—H15B | 117.7 |
C6—C5—C10 | 117.7 (3) | C14—C15—H15B | 117.7 |
C4—C5—C10 | 125.4 (3) | H15A—C15—H15B | 114.8 |
C5—C6—C1 | 124.8 (3) | C15—C16—C14 | 60.1 (2) |
C5—C6—C7 | 127.2 (3) | C15—C16—H16A | 117.8 |
C1—C6—C7 | 107.9 (3) | C14—C16—H16A | 117.8 |
C6—C7—C11 | 110.9 (3) | C15—C16—H16B | 117.8 |
C6—C7—C8 | 109.2 (2) | C14—C16—H16B | 117.8 |
C11—C7—C8 | 108.7 (2) | H16A—C16—H16B | 114.9 |
C6—C7—C18 | 97.4 (2) | N1—C17—H17A | 109.5 |
C11—C7—C18 | 112.5 (3) | N1—C17—H17B | 109.5 |
C8—C7—C18 | 117.5 (3) | H17A—C17—H17B | 109.5 |
O4—C8—C21 | 107.8 (3) | N1—C17—H17C | 109.5 |
O4—C8—C7 | 107.6 (2) | H17A—C17—H17C | 109.5 |
C21—C8—C7 | 111.9 (2) | H17B—C17—H17C | 109.5 |
O4—C8—C9 | 111.6 (2) | O2—C18—C19 | 109.1 (2) |
C21—C8—C9 | 112.2 (2) | O2—C18—C7 | 104.1 (4) |
C7—C8—C9 | 105.6 (3) | C19—C18—C7 | 110.8 (2) |
N1—C9—C10 | 114.7 (3) | O2—C18—H18 | 110.9 |
N1—C9—C8 | 111.7 (2) | C19—C18—H18 | 110.9 |
C10—C9—C8 | 109.8 (2) | C7—C18—H18 | 110.9 |
N1—C9—H9 | 106.7 | O3—C19—C20 | 122.1 (4) |
C10—C9—H9 | 106.7 | O3—C19—C18 | 122.3 (3) |
C8—C9—H9 | 106.7 | C20—C19—C18 | 115.3 (3) |
C5—C10—C9 | 113.5 (2) | C19—C20—C21 | 107.6 (3) |
C5—C10—H10A | 108.9 | C19—C20—H20A | 110.2 |
C9—C10—H10A | 108.9 | C21—C20—H20A | 110.2 |
C5—C10—H10B | 108.9 | C19—C20—H20B | 110.2 |
C9—C10—H10B | 108.9 | C21—C20—H20B | 110.2 |
H10A—C10—H10B | 107.7 | H20A—C20—H20B | 108.5 |
C12—C11—C7 | 111.3 (3) | C8—C21—C20 | 108.3 (3) |
C12—C11—H11A | 109.4 | C8—C21—H21A | 110.0 |
C7—C11—H11A | 109.4 | C20—C21—H21A | 110.0 |
C12—C11—H11B | 109.4 | C8—C21—H21B | 110.0 |
C7—C11—H11B | 109.4 | C20—C21—H21B | 110.0 |
H11A—C11—H11B | 108.0 | H21A—C21—H21B | 108.4 |
C11—C12—N1 | 114.0 (3) | C17—N1—C12 | 108.4 (2) |
C11—C12—H12A | 108.7 | C17—N1—C13 | 105.5 (2) |
N1—C12—H12A | 108.7 | C12—N1—C13 | 105.4 (2) |
C11—C12—H12B | 108.7 | C17—N1—C9 | 111.8 (2) |
N1—C12—H12B | 108.7 | C12—N1—C9 | 111.5 (2) |
H12A—C12—H12B | 107.6 | C13—N1—C9 | 113.8 (2) |
C14—C13—N1 | 113.5 (3) | C2—O1—H1X | 114 (3) |
C14—C13—H13A | 108.9 | C1—O2—C18 | 104.3 (2) |
N1—C13—H13A | 108.9 | C8—O4—H4X | 112 (2) |
O2—C1—C2—O1 | 5.5 (6) | C8—C9—C10—C5 | 47.6 (3) |
C6—C1—C2—O1 | −178.7 (4) | C6—C7—C11—C12 | −57.6 (3) |
O2—C1—C2—C3 | −174.4 (4) | C8—C7—C11—C12 | 62.5 (3) |
C6—C1—C2—C3 | 1.3 (6) | C18—C7—C11—C12 | −165.5 (3) |
C1—C2—C3—C4 | 2.1 (6) | C7—C11—C12—N1 | −52.0 (4) |
O1—C2—C3—C4 | −177.8 (4) | N1—C13—C14—C15 | −92.0 (4) |
C2—C3—C4—C5 | −3.0 (6) | N1—C13—C14—C16 | −158.8 (2) |
C3—C4—C5—C6 | 0.3 (5) | C13—C14—C15—C16 | −102.1 (4) |
C3—C4—C5—C10 | 170.4 (3) | C13—C14—C16—C15 | 111.3 (3) |
C4—C5—C6—C1 | 3.3 (6) | C6—C7—C18—O2 | −35.8 (3) |
C10—C5—C6—C1 | −167.6 (4) | C11—C7—C18—O2 | 80.5 (3) |
C4—C5—C6—C7 | −179.8 (3) | C8—C7—C18—O2 | −152.0 (2) |
C10—C5—C6—C7 | 9.3 (5) | C6—C7—C18—C19 | 81.4 (3) |
O2—C1—C6—C5 | 172.2 (4) | C11—C7—C18—C19 | −162.3 (3) |
C2—C1—C6—C5 | −4.2 (6) | C8—C7—C18—C19 | −34.8 (4) |
O2—C1—C6—C7 | −5.2 (4) | O2—C18—C19—O3 | −14.9 (5) |
C2—C1—C6—C7 | 178.4 (3) | C7—C18—C19—O3 | −129.0 (3) |
C5—C6—C7—C11 | 90.1 (4) | O2—C18—C19—C20 | 159.1 (3) |
C1—C6—C7—C11 | −92.6 (4) | C7—C18—C19—C20 | 45.1 (4) |
C5—C6—C7—C8 | −29.7 (5) | O3—C19—C20—C21 | 112.0 (4) |
C1—C6—C7—C8 | 147.6 (3) | C18—C19—C20—C21 | −62.0 (4) |
C5—C6—C7—C18 | −152.3 (4) | O4—C8—C21—C20 | 61.1 (3) |
C1—C6—C7—C18 | 25.1 (4) | C7—C8—C21—C20 | −57.1 (3) |
C6—C7—C8—O4 | 174.7 (3) | C9—C8—C21—C20 | −175.6 (2) |
C11—C7—C8—O4 | 53.6 (4) | C19—C20—C21—C8 | 66.2 (3) |
C18—C7—C8—O4 | −75.7 (3) | C11—C12—N1—C17 | −77.1 (3) |
C6—C7—C8—C21 | −67.0 (4) | C11—C12—N1—C13 | 170.2 (2) |
C11—C7—C8—C21 | 171.8 (3) | C11—C12—N1—C9 | 46.3 (3) |
C18—C7—C8—C21 | 42.6 (3) | C14—C13—N1—C17 | 69.2 (3) |
C6—C7—C8—C9 | 55.4 (3) | C14—C13—N1—C12 | −176.2 (2) |
C11—C7—C8—C9 | −65.7 (3) | C14—C13—N1—C9 | −53.7 (3) |
C18—C7—C8—C9 | 165.0 (2) | C10—C9—N1—C17 | −164.4 (2) |
O4—C8—C9—N1 | −55.3 (3) | C8—C9—N1—C17 | 69.9 (3) |
C21—C8—C9—N1 | −176.5 (2) | C10—C9—N1—C12 | 74.1 (3) |
C7—C8—C9—N1 | 61.3 (3) | C8—C9—N1—C12 | −51.7 (3) |
O4—C8—C9—C10 | 176.3 (2) | C10—C9—N1—C13 | −45.0 (3) |
C21—C8—C9—C10 | 55.1 (3) | C8—C9—N1—C13 | −170.7 (2) |
C7—C8—C9—C10 | −67.1 (3) | C2—C1—O2—C18 | 156.9 (4) |
C6—C5—C10—C9 | −18.0 (4) | C6—C1—O2—C18 | −19.2 (4) |
C4—C5—C10—C9 | 172.1 (3) | C19—C18—O2—C1 | −83.5 (3) |
N1—C9—C10—C5 | −79.1 (3) | C7—C18—O2—C1 | 34.8 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1X···Br1i | 0.80 (5) | 2.43 (5) | 3.231 (3) | 174 (5) |
O4—H4X···Br1 | 0.81 (3) | 2.40 (3) | 3.204 (3) | 174 (2) |
Symmetry code: (i) x+1, y, z+1. |
Experimental details
Crystal data | |
Chemical formula | C21H26NO4+·Br− |
Mr | 436.34 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 291 |
a, b, c (Å) | 7.708 (3), 13.187 (5), 9.501 (3) |
β (°) | 97.679 (6) |
V (Å3) | 957.1 (6) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 2.18 |
Crystal size (mm) | 0.28 × 0.24 × 0.22 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2000) |
Tmin, Tmax | 0.581, 0.646 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6955, 4179, 3259 |
Rint | 0.048 |
(sin θ/λ)max (Å−1) | 0.672 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.035, 0.073, 1.04 |
No. of reflections | 4179 |
No. of parameters | 245 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.39, −0.44 |
Absolute structure | Flack (1983), 1636 Friedel pairs |
Absolute structure parameter | −0.006 (7) |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1X···Br1i | 0.80 (5) | 2.43 (5) | 3.231 (3) | 174 (5) |
O4—H4X···Br1 | 0.81 (3) | 2.40 (3) | 3.204 (3) | 174 (2) |
Symmetry code: (i) x+1, y, z+1. |
References
Bruker (2000). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358. CrossRef CAS Web of Science Google Scholar
Doshan, H. D. & Perez, J. (2010). US Patent No. 7674904. Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Garnock-Jones, K. P. & McKeage, K. (2010). Drugs, 70, 919–928. Web of Science CAS PubMed Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Methylnaltrexone bromide is a selective µ-opioid receptor antagonist that has restricted ability to cross the blood-brain barrier, thus enabling reversal of opioid induced peripheral effects, such as constipation, without affecting the central effects, such as pain relief (Garnock-Jones et al., 2010).
The title compound was obtained by hydroxyl protection, N-methylation, deprotection and anion exchange of naltrexone. The molecule structure of (I) contains a five-ring system A/B/C/D/E (Fig. 1). Ring A is defined by atoms C1—C6, ring B by atoms C1/C6/C7/C18/O2, ring C by atoms C7/C8/C21/C20/C19/C18, ring D by atoms C5—C10, and ring E by atoms C9/C8/C7/C11/C12/N1. Ring C and E adopt a distorted chair conformation (Puckering parameters as defined by Cremer & Pople, 1975: Q = 0.558 (4)/ 0.604 (4) Å, θ= 158.7 (4)/ 13.4 (3) ° and ϕ= 334.6 (11)/ 145.3 (14) °, respectively), whereas ring D is in half chair conformation with puckering amplitude Q = 0.556 (4) Å, θ= 135.5 (4) ° ϕ=18.4 (5) °. The stereochemistry of the C/E ring junctions are trans fused. The dihedral angle between ring D and E is 82.3 (1)°, while the dihedral angles between the planes of ring C and the ring A, ring D and ring E are respectively 81.7 (1), 75.9 (1) and 12.2 (1)°. In the crystal structure, the molecules are linked by O—H···Br hydrogen bonds (Table 1).