organic compounds
2-(4-Methyl-2-phenylpiperazin-4-ium-1-yl)pyridine-3-carboxylate dihydrate
aCollege of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, People's Republic of China, bDepartment of Chemical and Environmental Engineering, Hebei Chemical and Pharmaceutical College, Shijiazhuang 050026, People's Republic of China, and cSchool of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
*Correspondence e-mail: liaj@yeah.net
The title compound, C17H19N3O2·2H2O, is particularly useful in the preparation of mirtazapine, which is the active agent in a new class of antidepressants. It crystallized as a zwitterion with two molecules of water in the The is dominated by a system of hydrogen bonds involving the positively charged N atom and both water molecules.
Related literature
For details of the synthesis see: Eiichi et al. (2002a,b); Metzger et al. (2004). For related literature, see: Singer et al. (2004).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 2002); cell SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536808011288/fl2184sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536808011288/fl2184Isup2.hkl
To 162 g of 1-butanol were added 2-(4-methyl-2-phenylpiperazine-1-yl)pyridine-3-carbonitrile(54 g, 0.2 mol) and 60.93 g of potassium hydroxide. The mixture was heated to 125 - 135 centigrade degree. (Eiichi, et al., 2002a; Eiichi, et al., 2002b; Metzger, et al., 2004) After 7 h, the reaction mixture was cooled and the butanol removed from the mixture by vacuum distilation after which fresh water and toluene were added and the two phases were separated. The water solution was neutralized with hydrochloric acid to pH=6.5–7. The water was evaporated and toluene was added. The inorganic salt were filtered and toluene solution was evaporated to dryness. Yield:52 g(90%). (Singer et al., 2004) Colourless crystals suitable for X-ray analysis were obtained by slow evaporation of an methanol-toluene solution at room temperature over 30 days.
All H atoms were positioned geometrically and refined as riding, with C—H = 0.93–0.98 Å and N—H=0.949 Å Uiso(H) = 1.2 Ueq(C).
Data collection: SMART (Bruker, 2002); cell
SMART (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).Fig. 1. The molecular structure of the title compound, drawn with 30% probability ellipsoids. | |
Fig. 2. The crystal structure of (I), viewed along a axis |
C17H19N3O2·2H2O | F(000) = 712 |
Mr = 333.38 | Dx = 1.271 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 12.730 (7) Å | Cell parameters from 1949 reflections |
b = 8.157 (4) Å | θ = 3.0–22.9° |
c = 16.814 (9) Å | µ = 0.09 mm−1 |
β = 94.031 (10)° | T = 294 K |
V = 1741.6 (16) Å3 | Block, colorless |
Z = 4 | 0.24 × 0.20 × 0.18 mm |
Bruker SMART CCD area-detector diffractometer | 3550 independent reflections |
Radiation source: fine-focus sealed tube | 2039 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.051 |
ϕ and ω scans | θmax = 26.5°, θmin = 1.9° |
Absorption correction: multi-scan (SADABS; Bruker, 2002) | h = −14→15 |
Tmin = 0.978, Tmax = 0.984 | k = −10→9 |
9611 measured reflections | l = −21→18 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.044 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.117 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0459P)2 + 0.2854P] where P = (Fo2 + 2Fc2)/3 |
3550 reflections | (Δ/σ)max = 0.001 |
218 parameters | Δρmax = 0.18 e Å−3 |
7 restraints | Δρmin = −0.20 e Å−3 |
C17H19N3O2·2H2O | V = 1741.6 (16) Å3 |
Mr = 333.38 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 12.730 (7) Å | µ = 0.09 mm−1 |
b = 8.157 (4) Å | T = 294 K |
c = 16.814 (9) Å | 0.24 × 0.20 × 0.18 mm |
β = 94.031 (10)° |
Bruker SMART CCD area-detector diffractometer | 3550 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2002) | 2039 reflections with I > 2σ(I) |
Tmin = 0.978, Tmax = 0.984 | Rint = 0.051 |
9611 measured reflections |
R[F2 > 2σ(F2)] = 0.044 | 7 restraints |
wR(F2) = 0.117 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.18 e Å−3 |
3550 reflections | Δρmin = −0.20 e Å−3 |
218 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 | ||
O1 | 0.23746 (11) | −0.07865 (17) | 0.91677 (8) | 0.0468 (4) | |
O2 | 0.09369 (12) | −0.19110 (17) | 0.85735 (9) | 0.0523 (4) | |
N1 | 0.01524 (12) | 0.33067 (19) | 0.81432 (9) | 0.0336 (4) | |
N2 | 0.09094 (11) | 0.12896 (18) | 0.73567 (8) | 0.0276 (4) | |
N3 | 0.18394 (12) | 0.11644 (19) | 0.58307 (8) | 0.0317 (4) | |
H3A | 0.2110 | 0.2203 | 0.5847 | 0.038* | |
C1 | 0.14487 (17) | −0.0721 (2) | 0.88370 (10) | 0.0326 (5) | |
C2 | 0.09270 (14) | 0.0949 (2) | 0.88117 (10) | 0.0284 (4) | |
C3 | 0.06312 (16) | 0.1573 (2) | 0.95305 (11) | 0.0377 (5) | |
H3 | 0.0816 | 0.1015 | 1.0002 | 0.045* | |
C4 | 0.00669 (17) | 0.3009 (3) | 0.95524 (12) | 0.0433 (5) | |
H4 | −0.0156 | 0.3411 | 1.0030 | 0.052* | |
C5 | −0.01572 (17) | 0.3828 (3) | 0.88490 (12) | 0.0412 (5) | |
H5 | −0.0543 | 0.4795 | 0.8860 | 0.049* | |
C6 | 0.06542 (14) | 0.1873 (2) | 0.81196 (10) | 0.0276 (4) | |
C7 | 0.20574 (14) | 0.1119 (2) | 0.72897 (10) | 0.0322 (5) | |
H7A | 0.2362 | 0.0515 | 0.7746 | 0.039* | |
H7B | 0.2377 | 0.2198 | 0.7296 | 0.039* | |
C8 | 0.23032 (16) | 0.0240 (2) | 0.65354 (10) | 0.0345 (5) | |
H8A | 0.3060 | 0.0155 | 0.6509 | 0.041* | |
H8B | 0.2013 | −0.0860 | 0.6535 | 0.041* | |
C9 | 0.06793 (15) | 0.1316 (2) | 0.58939 (10) | 0.0333 (5) | |
H9A | 0.0367 | 0.0231 | 0.5880 | 0.040* | |
H9B | 0.0375 | 0.1924 | 0.5439 | 0.040* | |
C10 | 0.04152 (14) | 0.2186 (2) | 0.66603 (10) | 0.0278 (4) | |
H10 | 0.0702 | 0.3300 | 0.6658 | 0.033* | |
C11 | −0.07784 (15) | 0.2284 (2) | 0.66480 (10) | 0.0302 (5) | |
C12 | −0.12829 (16) | 0.3603 (3) | 0.62727 (11) | 0.0396 (5) | |
H12 | −0.0887 | 0.4409 | 0.6042 | 0.048* | |
C13 | −0.23716 (18) | 0.3743 (3) | 0.62352 (13) | 0.0502 (6) | |
H13 | −0.2699 | 0.4638 | 0.5981 | 0.060* | |
C14 | −0.29645 (18) | 0.2561 (3) | 0.65735 (13) | 0.0530 (6) | |
H14 | −0.3693 | 0.2660 | 0.6556 | 0.064* | |
C15 | −0.24739 (17) | 0.1225 (3) | 0.69391 (13) | 0.0530 (6) | |
H15 | −0.2875 | 0.0418 | 0.7164 | 0.064* | |
C16 | −0.13856 (16) | 0.1075 (3) | 0.69733 (11) | 0.0419 (5) | |
H16 | −0.1062 | 0.0162 | 0.7215 | 0.050* | |
C17 | 0.20966 (18) | 0.0401 (3) | 0.50601 (11) | 0.0486 (6) | |
H17A | 0.1818 | −0.0693 | 0.5028 | 0.073* | |
H17B | 0.2847 | 0.0364 | 0.5033 | 0.073* | |
H17C | 0.1790 | 0.1040 | 0.4624 | 0.073* | |
O3 | 0.40776 (15) | 0.1829 (2) | 0.92970 (9) | 0.0746 (5) | |
H3B | 0.3615 | 0.1080 | 0.9385 | 0.112* | |
H3C | 0.4310 | 0.1736 | 0.8827 | 0.112* | |
O4 | 0.01683 (14) | 0.6489 (2) | 0.72071 (9) | 0.0695 (5) | |
H4A | 0.0391 | 0.7172 | 0.7563 | 0.104* | |
H4B | 0.0095 | 0.5500 | 0.7353 | 0.104* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0447 (10) | 0.0401 (9) | 0.0542 (9) | 0.0108 (7) | −0.0058 (7) | −0.0023 (7) |
O2 | 0.0587 (11) | 0.0337 (9) | 0.0632 (10) | −0.0008 (8) | −0.0061 (8) | −0.0103 (8) |
N1 | 0.0378 (10) | 0.0320 (10) | 0.0306 (9) | 0.0057 (8) | 0.0001 (7) | −0.0031 (7) |
N2 | 0.0271 (9) | 0.0327 (9) | 0.0230 (8) | 0.0018 (7) | 0.0017 (6) | −0.0002 (7) |
N3 | 0.0354 (10) | 0.0322 (9) | 0.0282 (8) | −0.0069 (7) | 0.0073 (7) | −0.0036 (7) |
C1 | 0.0419 (13) | 0.0324 (12) | 0.0242 (10) | 0.0035 (10) | 0.0065 (9) | 0.0006 (9) |
C2 | 0.0286 (11) | 0.0301 (11) | 0.0264 (10) | 0.0013 (8) | 0.0006 (8) | −0.0015 (8) |
C3 | 0.0480 (13) | 0.0394 (12) | 0.0258 (10) | 0.0048 (10) | 0.0033 (9) | 0.0010 (9) |
C4 | 0.0550 (15) | 0.0448 (13) | 0.0307 (11) | 0.0100 (11) | 0.0075 (10) | −0.0093 (10) |
C5 | 0.0489 (14) | 0.0374 (12) | 0.0373 (12) | 0.0131 (10) | 0.0026 (10) | −0.0088 (10) |
C6 | 0.0261 (10) | 0.0290 (11) | 0.0275 (10) | −0.0016 (9) | 0.0000 (8) | −0.0032 (8) |
C7 | 0.0297 (11) | 0.0376 (12) | 0.0294 (10) | 0.0010 (9) | 0.0037 (8) | 0.0016 (9) |
C8 | 0.0356 (12) | 0.0325 (11) | 0.0359 (11) | 0.0026 (9) | 0.0066 (9) | 0.0000 (9) |
C9 | 0.0321 (11) | 0.0389 (12) | 0.0288 (10) | −0.0060 (9) | 0.0027 (8) | −0.0013 (9) |
C10 | 0.0297 (11) | 0.0288 (10) | 0.0248 (10) | −0.0026 (8) | 0.0009 (8) | 0.0010 (8) |
C11 | 0.0313 (12) | 0.0376 (12) | 0.0215 (9) | −0.0016 (9) | −0.0004 (8) | −0.0035 (9) |
C12 | 0.0370 (13) | 0.0410 (12) | 0.0401 (12) | −0.0013 (10) | −0.0026 (9) | −0.0009 (10) |
C13 | 0.0420 (14) | 0.0486 (14) | 0.0579 (14) | 0.0055 (11) | −0.0114 (11) | −0.0019 (12) |
C14 | 0.0327 (13) | 0.0750 (18) | 0.0506 (14) | 0.0020 (13) | −0.0014 (11) | −0.0101 (13) |
C15 | 0.0366 (14) | 0.0773 (18) | 0.0455 (13) | −0.0175 (13) | 0.0051 (10) | 0.0070 (13) |
C16 | 0.0383 (13) | 0.0498 (14) | 0.0373 (12) | −0.0060 (11) | −0.0002 (9) | 0.0063 (10) |
C17 | 0.0517 (14) | 0.0610 (15) | 0.0350 (12) | −0.0073 (12) | 0.0166 (10) | −0.0150 (11) |
O3 | 0.1035 (15) | 0.0632 (12) | 0.0586 (10) | −0.0064 (11) | 0.0167 (9) | −0.0125 (9) |
O4 | 0.0919 (14) | 0.0659 (11) | 0.0516 (10) | −0.0169 (10) | 0.0098 (9) | −0.0118 (9) |
O1—C1 | 1.269 (2) | C9—C10 | 1.529 (2) |
O2—C1 | 1.234 (2) | C9—H9A | 0.9700 |
N1—C6 | 1.335 (2) | C9—H9B | 0.9700 |
N1—C5 | 1.346 (2) | C10—C11 | 1.520 (3) |
N2—C6 | 1.427 (2) | C10—H10 | 0.9800 |
N2—C7 | 1.480 (2) | C11—C12 | 1.382 (3) |
N2—C10 | 1.482 (2) | C11—C16 | 1.389 (3) |
N3—C8 | 1.491 (2) | C12—C13 | 1.388 (3) |
N3—C9 | 1.493 (2) | C12—H12 | 0.9300 |
N3—C17 | 1.495 (2) | C13—C14 | 1.373 (3) |
N3—H3A | 0.9140 | C13—H13 | 0.9300 |
C1—C2 | 1.514 (3) | C14—C15 | 1.379 (3) |
C2—C3 | 1.388 (2) | C14—H14 | 0.9300 |
C2—C6 | 1.409 (2) | C15—C16 | 1.388 (3) |
C3—C4 | 1.376 (3) | C15—H15 | 0.9300 |
C3—H3 | 0.9300 | C16—H16 | 0.9300 |
C4—C5 | 1.371 (3) | C17—H17A | 0.9600 |
C4—H4 | 0.9300 | C17—H17B | 0.9600 |
C5—H5 | 0.9300 | C17—H17C | 0.9600 |
C7—C8 | 1.509 (2) | O3—H3B | 0.8682 |
C7—H7A | 0.9700 | O3—H3C | 0.8664 |
C7—H7B | 0.9700 | O4—H4A | 0.8512 |
C8—H8A | 0.9700 | O4—H4B | 0.8504 |
C8—H8B | 0.9700 | ||
C6—N1—C5 | 118.28 (16) | H8A—C8—H8B | 108.2 |
C6—N2—C7 | 112.85 (13) | N3—C9—C10 | 112.07 (14) |
C6—N2—C10 | 115.78 (14) | N3—C9—H9A | 109.2 |
C7—N2—C10 | 110.66 (13) | C10—C9—H9A | 109.2 |
C8—N3—C9 | 108.89 (14) | N3—C9—H9B | 109.2 |
C8—N3—C17 | 112.30 (16) | C10—C9—H9B | 109.2 |
C9—N3—C17 | 111.98 (14) | H9A—C9—H9B | 107.9 |
C8—N3—H3A | 108.5 | N2—C10—C11 | 113.90 (14) |
C9—N3—H3A | 107.1 | N2—C10—C9 | 109.32 (15) |
C17—N3—H3A | 107.9 | C11—C10—C9 | 106.98 (14) |
O2—C1—O1 | 125.09 (19) | N2—C10—H10 | 108.8 |
O2—C1—C2 | 118.56 (18) | C11—C10—H10 | 108.8 |
O1—C1—C2 | 116.26 (18) | C9—C10—H10 | 108.8 |
C3—C2—C6 | 117.18 (17) | C12—C11—C16 | 118.62 (19) |
C3—C2—C1 | 116.78 (16) | C12—C11—C10 | 118.64 (17) |
C6—C2—C1 | 125.90 (16) | C16—C11—C10 | 122.70 (18) |
C4—C3—C2 | 120.64 (18) | C11—C12—C13 | 121.0 (2) |
C4—C3—H3 | 119.7 | C11—C12—H12 | 119.5 |
C2—C3—H3 | 119.7 | C13—C12—H12 | 119.5 |
C5—C4—C3 | 118.00 (18) | C14—C13—C12 | 120.0 (2) |
C5—C4—H4 | 121.0 | C14—C13—H13 | 120.0 |
C3—C4—H4 | 121.0 | C12—C13—H13 | 120.0 |
N1—C5—C4 | 123.40 (19) | C13—C14—C15 | 119.7 (2) |
N1—C5—H5 | 118.3 | C13—C14—H14 | 120.2 |
C4—C5—H5 | 118.3 | C15—C14—H14 | 120.2 |
N1—C6—C2 | 122.34 (16) | C14—C15—C16 | 120.5 (2) |
N1—C6—N2 | 117.30 (15) | C14—C15—H15 | 119.8 |
C2—C6—N2 | 120.36 (16) | C16—C15—H15 | 119.8 |
N2—C7—C8 | 111.90 (14) | C15—C16—C11 | 120.2 (2) |
N2—C7—H7A | 109.2 | C15—C16—H16 | 119.9 |
C8—C7—H7A | 109.2 | C11—C16—H16 | 119.9 |
N2—C7—H7B | 109.2 | N3—C17—H17A | 109.5 |
C8—C7—H7B | 109.2 | N3—C17—H17B | 109.5 |
H7A—C7—H7B | 107.9 | H17A—C17—H17B | 109.5 |
N3—C8—C7 | 109.50 (16) | N3—C17—H17C | 109.5 |
N3—C8—H8A | 109.8 | H17A—C17—H17C | 109.5 |
C7—C8—H8A | 109.8 | H17B—C17—H17C | 109.5 |
N3—C8—H8B | 109.8 | H3B—O3—H3C | 111.9 |
C7—C8—H8B | 109.8 | H4A—O4—H4B | 117.0 |
O2—C1—C2—C3 | 106.1 (2) | C17—N3—C8—C7 | 177.34 (15) |
O1—C1—C2—C3 | −70.7 (2) | N2—C7—C8—N3 | 59.1 (2) |
O2—C1—C2—C6 | −69.5 (3) | C8—N3—C9—C10 | 58.5 (2) |
O1—C1—C2—C6 | 113.8 (2) | C17—N3—C9—C10 | −176.74 (16) |
C6—C2—C3—C4 | 2.0 (3) | C6—N2—C10—C11 | −55.0 (2) |
C1—C2—C3—C4 | −174.01 (19) | C7—N2—C10—C11 | 175.00 (15) |
C2—C3—C4—C5 | −2.4 (3) | C6—N2—C10—C9 | −174.59 (14) |
C6—N1—C5—C4 | 3.7 (3) | C7—N2—C10—C9 | 55.40 (18) |
C3—C4—C5—N1 | −0.5 (3) | N3—C9—C10—N2 | −57.03 (19) |
C5—N1—C6—C2 | −4.1 (3) | N3—C9—C10—C11 | 179.19 (15) |
C5—N1—C6—N2 | 175.71 (16) | N2—C10—C11—C12 | 151.89 (16) |
C3—C2—C6—N1 | 1.4 (3) | C9—C10—C11—C12 | −87.2 (2) |
C1—C2—C6—N1 | 176.95 (18) | N2—C10—C11—C16 | −30.5 (2) |
C3—C2—C6—N2 | −178.48 (16) | C9—C10—C11—C16 | 90.4 (2) |
C1—C2—C6—N2 | −2.9 (3) | C16—C11—C12—C13 | 1.4 (3) |
C7—N2—C6—N1 | 117.95 (18) | C10—C11—C12—C13 | 179.18 (17) |
C10—N2—C6—N1 | −11.0 (2) | C11—C12—C13—C14 | 0.0 (3) |
C7—N2—C6—C2 | −62.2 (2) | C12—C13—C14—C15 | −1.0 (3) |
C10—N2—C6—C2 | 168.87 (15) | C13—C14—C15—C16 | 0.6 (3) |
C6—N2—C7—C8 | 170.43 (15) | C14—C15—C16—C11 | 0.8 (3) |
C10—N2—C7—C8 | −58.0 (2) | C12—C11—C16—C15 | −1.8 (3) |
C9—N3—C8—C7 | −58.05 (19) | C10—C11—C16—C15 | −179.48 (18) |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3A···O1i | 0.91 | 1.77 | 2.681 (2) | 178 |
O3—H3C···O4ii | 0.87 | 1.92 | 2.781 (3) | 179 |
O4—H4A···O2iii | 0.85 | 1.94 | 2.761 (2) | 162 |
O3—H3B···O1 | 0.87 | 2.21 | 3.038 (3) | 161 |
O4—H4B···N1 | 0.85 | 2.23 | 3.037 (3) | 159 |
Symmetry codes: (i) −x+1/2, y+1/2, −z+3/2; (ii) −x+1/2, y−1/2, −z+3/2; (iii) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | C17H19N3O2·2H2O |
Mr | 333.38 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 294 |
a, b, c (Å) | 12.730 (7), 8.157 (4), 16.814 (9) |
β (°) | 94.031 (10) |
V (Å3) | 1741.6 (16) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.24 × 0.20 × 0.18 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2002) |
Tmin, Tmax | 0.978, 0.984 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9611, 3550, 2039 |
Rint | 0.051 |
(sin θ/λ)max (Å−1) | 0.627 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.044, 0.117, 1.00 |
No. of reflections | 3550 |
No. of parameters | 218 |
No. of restraints | 7 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.18, −0.20 |
Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3A···O1i | 0.91 | 1.77 | 2.681 (2) | 177.5 |
O3—H3C···O4ii | 0.87 | 1.92 | 2.781 (3) | 178.9 |
O4—H4A···O2iii | 0.85 | 1.94 | 2.761 (2) | 161.7 |
O3—H3B···O1 | 0.87 | 2.21 | 3.038 (3) | 160.7 |
O4—H4B···N1 | 0.85 | 2.23 | 3.037 (3) | 159.3 |
Symmetry codes: (i) −x+1/2, y+1/2, −z+3/2; (ii) −x+1/2, y−1/2, −z+3/2; (iii) x, y+1, z. |
References
Bruker (2002). SADABS, SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Eiichi, I. & Kanami, Y. (2002a). US patent 6 376 668. Google Scholar
Eiichi, I. & Kanami, Y. (2002b). US patent 6 437 120. Google Scholar
Metzger, L.. & Wizel, S. (2004). US patent 6 774 230. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Singer, C., Liberman, A. & Finkelstein, N. (2004). US patent 20 040 176 591. Google Scholar
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The title compound, C17H19N3O2.2H2O, is particularly useful in the preparation of mirtazapine which is the active agent in a new class of antidepressants. It crystallized as a zwitterion with two molecues of water in the asymmetric unit (Fig 1). The central piperazine ring has a normal chair conformation. In the molecule, the dihedral angle is 81.20 between plane 1(C7 C8 C9 C10) and plane 2(C11 C12 C13 C14 C15 C16), the dihedral angle is 68.40 between plane 2(C11 C12 C13 C14 C15 C16) and plane 3(N1 C2 C3 C4 C5 C6)and the the dihedral angle is 36.90 between plane 1 and plane 3. Packing is dominated by a system of hydrogen bonds involving the positively charged nitrogen and both water molecules (Table 1, Fig. 2)