organic compounds
L-Tyrosine isopropyl ester
aUniversidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Química, Cra 30 No. 45-03, Bogotá, 4-72 Colombia, and bInstitute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
*Correspondence e-mail: arquevedop@unal.edu.co
The title compound, C12H17NO3, adopts a folded conformation with a C—C(NH2)—C(=O)—O torsion angle of −95.9 (2)°. In the crystal, molecules are linked by an O—H⋯N hydrogen bond, forming helical chains along the b-axis direction. Weak N—H⋯O and C—H⋯O hydrogen bonds are observed between the chains.
Related literature
For information about tyrosine alkyl L-tyrosine methyl ester compared to L-tyrosine and its ethyl and n-butyl see: Nicolaï et al. (2011). For the n-butyl analogue, see: Qian et al. (2006). For macrocyclization of tyrosine alkyl with formaldehyde, see: Quevedo & Moreno-Murillo (2009); Nuñez-Dallos et al. (2012). For a related structure of tyramine, see: Quevedo et al. (2012).
as prodrugs and the structure and intermolecular interactions ofExperimental
Crystal data
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Data collection
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Refinement
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Data collection: COLLECT (Nonius, 1998); cell SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536812042377/is5203sup1.cif
contains datablocks I, New_Global_Publ_Block. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812042377/is5203Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812042377/is5203Isup3.cml
Concentrated sulfuric acid (8 ml) was added to a suspension of L-tyrosine (10.00 g, 55.19 mmol) in isopropyl alcohol (40 ml). The mixture was heated at reflux and allowed to stir for 24 h. Then the reaction mixture was cooled to room temperature and placed into ice-cold water. The pH was brought to ~7 with concentrated ammonia, and isopropyl alcohol (40 ml) was added later to the reaction mixture. Precipitated ammonium sulfate was filtered off and washed with isopropyl alcohol (3×10 ml). The filtrate was concentrated under reduced pressure to a volume of 30 ml and single crystals were obtained by slow evaporation at room temperature. The title compound formed colorless prisms (5.50 g, 45%). m.p. 121–122 °C.
1H NMR (400 MHz, CDCl3) δ 7.03 (d, J = 8.4 Hz, 2H), 6.69 (d, J = 8.4 Hz, 2H), 5.03 (hept, J = 6.3 Hz, 1H), 3.65 (dd, J = 7.7, 5.4 Hz, 1H), 3.01 (dd, J = 13.7, 5.3 Hz, 1H), 2.79 (dd, J = 13.8, 7.7 Hz, 1H), 1.25 (d, J = 6.2 Hz, 3H), 1.22 (d, J = 6.3 Hz, 3H). 13C NMR (100 MHz, CD3OD) δ 21.9, 22.0, 41.1, 57.0, 69.7, 116.3, 128.9, 131.4, 157.4, 175.6. HRMS (ESI), m/z calcd for [C12H17NO3+H]+ 224.1281; found: 224.1279 [M+H]+, 246.1094 [M+Na]+, 222.1088 [M—H]-.
The H atoms on N1 and O3 were located in a difference map and refined isotropically [refined distances: N—H = 0.88 (2) and 0.89 (3) Å, and O—H = 0.97 (4) Å]. All H atoms bound to C atoms were refined using a riding model, with C—H = 0.94–0.98 Å and Uiso(H) = 1.2 or 1.5 times Ueq(C). In the absence of significant
effects, Friedel pairs have been merged in the final refinement.Data collection: COLLECT (Nonius, 1998); cell
SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C12H17NO3 | F(000) = 480 |
Mr = 223.27 | Dx = 1.172 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 13069 reflections |
a = 5.4539 (1) Å | θ = 1.0–25.0° |
b = 14.0521 (3) Å | µ = 0.08 mm−1 |
c = 16.5163 (4) Å | T = 233 K |
V = 1265.79 (5) Å3 | Prism, colorless |
Z = 4 | 0.4 × 0.3 × 0.2 mm |
Nonius KappaCCD diffractometer | 1271 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.020 |
Graphite monochromator | θmax = 25.0°, θmin = 2.5° |
Detector resolution: 9.1 pixels mm-1 | h = −6→6 |
ϕ and ω scans | k = −16→16 |
8375 measured reflections | l = −19→19 |
1318 independent reflections |
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)] = 0.036 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.099 | w = 1/[σ2(Fo2) + (0.054P)2 + 0.2704P] where P = (Fo2 + 2Fc2)/3 |
S = 1.07 | (Δ/σ)max < 0.001 |
1318 reflections | Δρmax = 0.17 e Å−3 |
158 parameters | Δρmin = −0.15 e Å−3 |
0 restraints | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.059 (14) |
C12H17NO3 | V = 1265.79 (5) Å3 |
Mr = 223.27 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 5.4539 (1) Å | µ = 0.08 mm−1 |
b = 14.0521 (3) Å | T = 233 K |
c = 16.5163 (4) Å | 0.4 × 0.3 × 0.2 mm |
Nonius KappaCCD diffractometer | 1271 reflections with I > 2σ(I) |
8375 measured reflections | Rint = 0.020 |
1318 independent reflections |
R[F2 > 2σ(F2)] = 0.036 | 0 restraints |
wR(F2) = 0.099 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.07 | Δρmax = 0.17 e Å−3 |
1318 reflections | Δρmin = −0.15 e Å−3 |
158 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 | ||
N1 | 0.2421 (4) | 0.74601 (12) | 0.07769 (10) | 0.0395 (4) | |
H1N | 0.241 (4) | 0.7383 (17) | 0.0246 (14) | 0.049 (6)* | |
H2N | 0.096 (6) | 0.7704 (18) | 0.0881 (16) | 0.056 (8)* | |
O1 | −0.1561 (3) | 0.61052 (12) | 0.07928 (14) | 0.0699 (6) | |
H3O | 0.483 (7) | 0.311 (2) | 0.404 (2) | 0.089 (10)* | |
O2 | 0.1284 (3) | 0.49667 (10) | 0.08581 (10) | 0.0539 (5) | |
O3 | 0.3192 (3) | 0.33815 (11) | 0.40495 (10) | 0.0528 (5) | |
C1 | 0.0508 (4) | 0.58592 (14) | 0.09087 (12) | 0.0392 (5) | |
C2 | 0.2565 (4) | 0.65246 (13) | 0.11620 (11) | 0.0364 (5) | |
H2 | 0.4156 | 0.6228 | 0.1023 | 0.044* | |
C3 | 0.2457 (5) | 0.66834 (15) | 0.20858 (12) | 0.0495 (6) | |
H3A | 0.3792 | 0.7114 | 0.2239 | 0.059* | |
H3B | 0.0910 | 0.7004 | 0.2216 | 0.059* | |
C4 | 0.2644 (4) | 0.57967 (14) | 0.25969 (11) | 0.0418 (5) | |
C5 | 0.4658 (5) | 0.52015 (17) | 0.25389 (15) | 0.0501 (6) | |
H5 | 0.5912 | 0.5351 | 0.2170 | 0.060* | |
C6 | 0.4873 (4) | 0.43895 (16) | 0.30120 (14) | 0.0469 (6) | |
H6 | 0.6246 | 0.3990 | 0.2955 | 0.056* | |
C7 | 0.3068 (4) | 0.41695 (14) | 0.35669 (12) | 0.0401 (5) | |
C8 | 0.1058 (4) | 0.47529 (16) | 0.36372 (14) | 0.0479 (6) | |
H8 | −0.0183 | 0.4607 | 0.4012 | 0.057* | |
C9 | 0.0861 (4) | 0.55580 (16) | 0.31541 (14) | 0.0475 (6) | |
H9 | −0.0524 | 0.5951 | 0.3208 | 0.057* | |
C10 | −0.0553 (6) | 0.42135 (18) | 0.07362 (19) | 0.0698 (8) | |
H10 | −0.2208 | 0.4471 | 0.0849 | 0.084* | |
C11 | 0.0012 (13) | 0.3444 (2) | 0.1322 (2) | 0.144 (2) | |
H11A | 0.0004 | 0.3701 | 0.1867 | 0.216* | |
H11B | 0.1617 | 0.3181 | 0.1203 | 0.216* | |
H11C | −0.1215 | 0.2947 | 0.1278 | 0.216* | |
C12 | −0.0438 (11) | 0.3886 (3) | −0.0106 (2) | 0.135 (2) | |
H12A | −0.0876 | 0.4405 | −0.0465 | 0.203* | |
H12B | −0.1574 | 0.3362 | −0.0182 | 0.203* | |
H12C | 0.1214 | 0.3673 | −0.0228 | 0.203* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0479 (11) | 0.0363 (9) | 0.0344 (9) | −0.0041 (8) | −0.0001 (8) | 0.0030 (7) |
O1 | 0.0357 (9) | 0.0493 (9) | 0.1246 (16) | −0.0022 (8) | 0.0005 (11) | 0.0016 (10) |
O2 | 0.0557 (9) | 0.0332 (7) | 0.0729 (11) | 0.0001 (7) | −0.0022 (9) | −0.0069 (7) |
O3 | 0.0521 (10) | 0.0499 (9) | 0.0564 (9) | 0.0071 (8) | 0.0075 (8) | 0.0213 (7) |
C1 | 0.0385 (11) | 0.0358 (10) | 0.0433 (10) | 0.0010 (9) | 0.0073 (9) | 0.0020 (9) |
C2 | 0.0382 (10) | 0.0325 (9) | 0.0385 (9) | 0.0019 (9) | 0.0011 (9) | −0.0007 (7) |
C3 | 0.0715 (15) | 0.0377 (10) | 0.0394 (10) | 0.0042 (12) | −0.0017 (11) | 0.0012 (8) |
C4 | 0.0503 (12) | 0.0400 (10) | 0.0351 (9) | −0.0007 (10) | −0.0045 (9) | 0.0012 (8) |
C5 | 0.0470 (12) | 0.0575 (13) | 0.0457 (11) | 0.0040 (11) | 0.0071 (10) | 0.0144 (11) |
C6 | 0.0420 (12) | 0.0513 (12) | 0.0474 (11) | 0.0083 (11) | 0.0019 (10) | 0.0103 (10) |
C7 | 0.0418 (11) | 0.0403 (10) | 0.0382 (10) | −0.0027 (10) | −0.0033 (9) | 0.0051 (9) |
C8 | 0.0439 (12) | 0.0503 (12) | 0.0495 (12) | 0.0010 (11) | 0.0075 (10) | 0.0089 (10) |
C9 | 0.0445 (12) | 0.0483 (12) | 0.0498 (12) | 0.0079 (10) | 0.0025 (10) | 0.0029 (10) |
C10 | 0.0762 (19) | 0.0401 (12) | 0.093 (2) | −0.0166 (13) | 0.0027 (17) | −0.0061 (13) |
C11 | 0.268 (7) | 0.081 (2) | 0.082 (2) | −0.073 (4) | −0.018 (4) | 0.0200 (19) |
C12 | 0.230 (6) | 0.109 (3) | 0.0674 (19) | −0.105 (4) | −0.022 (3) | 0.0063 (19) |
N1—C2 | 1.462 (2) | C5—H5 | 0.9400 |
N1—H1N | 0.88 (2) | C6—C7 | 1.380 (3) |
N1—H2N | 0.89 (3) | C6—H6 | 0.9400 |
O1—C1 | 1.196 (3) | C7—C8 | 1.374 (3) |
O2—C1 | 1.326 (2) | C8—C9 | 1.388 (3) |
O2—C10 | 1.471 (3) | C8—H8 | 0.9400 |
O3—C7 | 1.366 (2) | C9—H9 | 0.9400 |
O3—H3O | 0.97 (4) | C10—C12 | 1.467 (5) |
C1—C2 | 1.519 (3) | C10—C11 | 1.483 (5) |
C2—C3 | 1.543 (3) | C10—H10 | 0.9900 |
C2—H2 | 0.9900 | C11—H11A | 0.9700 |
C3—C4 | 1.508 (3) | C11—H11B | 0.9700 |
C3—H3A | 0.9800 | C11—H11C | 0.9700 |
C3—H3B | 0.9800 | C12—H12A | 0.9700 |
C4—C9 | 1.380 (3) | C12—H12B | 0.9700 |
C4—C5 | 1.384 (3) | C12—H12C | 0.9700 |
C5—C6 | 1.388 (3) | ||
C2—N1—H1N | 108.7 (15) | C5—C6—H6 | 120.1 |
C2—N1—H2N | 108.1 (17) | O3—C7—C8 | 118.29 (18) |
H1N—N1—H2N | 103 (2) | O3—C7—C6 | 122.25 (19) |
C1—O2—C10 | 118.1 (2) | C8—C7—C6 | 119.46 (18) |
C7—O3—H3O | 111 (2) | C7—C8—C9 | 120.0 (2) |
O1—C1—O2 | 124.4 (2) | C7—C8—H8 | 120.0 |
O1—C1—C2 | 124.3 (2) | C9—C8—H8 | 120.0 |
O2—C1—C2 | 111.33 (18) | C4—C9—C8 | 121.8 (2) |
N1—C2—C1 | 113.20 (17) | C4—C9—H9 | 119.1 |
N1—C2—C3 | 107.33 (15) | C8—C9—H9 | 119.1 |
C1—C2—C3 | 109.46 (17) | C12—C10—O2 | 109.0 (3) |
N1—C2—H2 | 108.9 | C12—C10—C11 | 112.4 (3) |
C1—C2—H2 | 108.9 | O2—C10—C11 | 107.1 (3) |
C3—C2—H2 | 108.9 | C12—C10—H10 | 109.4 |
C4—C3—C2 | 115.55 (17) | O2—C10—H10 | 109.4 |
C4—C3—H3A | 108.4 | C11—C10—H10 | 109.4 |
C2—C3—H3A | 108.4 | C10—C11—H11A | 109.5 |
C4—C3—H3B | 108.4 | C10—C11—H11B | 109.5 |
C2—C3—H3B | 108.4 | H11A—C11—H11B | 109.5 |
H3A—C3—H3B | 107.5 | C10—C11—H11C | 109.5 |
C9—C4—C5 | 117.29 (18) | H11A—C11—H11C | 109.5 |
C9—C4—C3 | 121.7 (2) | H11B—C11—H11C | 109.5 |
C5—C4—C3 | 121.0 (2) | C10—C12—H12A | 109.5 |
C4—C5—C6 | 121.7 (2) | C10—C12—H12B | 109.5 |
C4—C5—H5 | 119.2 | H12A—C12—H12B | 109.5 |
C6—C5—H5 | 119.2 | C10—C12—H12C | 109.5 |
C7—C6—C5 | 119.8 (2) | H12A—C12—H12C | 109.5 |
C7—C6—H6 | 120.1 | H12B—C12—H12C | 109.5 |
C10—O2—C1—O1 | −6.8 (3) | C3—C4—C5—C6 | 179.2 (2) |
C10—O2—C1—C2 | 171.22 (19) | C4—C5—C6—C7 | −1.1 (4) |
O1—C1—C2—N1 | −37.6 (3) | C5—C6—C7—O3 | −179.8 (2) |
O2—C1—C2—N1 | 144.43 (18) | C5—C6—C7—C8 | 0.8 (3) |
O1—C1—C2—C3 | 82.1 (3) | O3—C7—C8—C9 | −179.7 (2) |
O2—C1—C2—C3 | −95.9 (2) | C6—C7—C8—C9 | −0.2 (3) |
N1—C2—C3—C4 | −178.6 (2) | C5—C4—C9—C8 | −0.3 (3) |
C1—C2—C3—C4 | 58.2 (3) | C3—C4—C9—C8 | −178.6 (2) |
C2—C3—C4—C9 | −123.6 (2) | C7—C8—C9—C4 | 0.0 (3) |
C2—C3—C4—C5 | 58.2 (3) | C1—O2—C10—C12 | 105.1 (3) |
C9—C4—C5—C6 | 0.8 (3) | C1—O2—C10—C11 | −133.1 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3O···N1i | 0.97 (4) | 1.78 (4) | 2.736 (3) | 167 (3) |
N1—H1N···O3ii | 0.88 (2) | 2.27 (2) | 3.106 (2) | 157 (2) |
N1—H2N···O3iii | 0.89 (3) | 2.46 (3) | 3.336 (3) | 171 (2) |
C2—H2···O1iv | 0.99 | 2.37 | 3.314 (3) | 159 |
Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) −x+1/2, −y+1, z−1/2; (iii) −x, y+1/2, −z+1/2; (iv) x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C12H17NO3 |
Mr | 223.27 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 233 |
a, b, c (Å) | 5.4539 (1), 14.0521 (3), 16.5163 (4) |
V (Å3) | 1265.79 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.4 × 0.3 × 0.2 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8375, 1318, 1271 |
Rint | 0.020 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.099, 1.07 |
No. of reflections | 1318 |
No. of parameters | 158 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.17, −0.15 |
Computer programs: COLLECT (Nonius, 1998), DENZO and SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3O···N1i | 0.97 (4) | 1.78 (4) | 2.736 (3) | 167 (3) |
N1—H1N···O3ii | 0.88 (2) | 2.27 (2) | 3.106 (2) | 157 (2) |
N1—H2N···O3iii | 0.89 (3) | 2.46 (3) | 3.336 (3) | 171 (2) |
C2—H2···O1iv | 0.99 | 2.37 | 3.314 (3) | 159 |
Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) −x+1/2, −y+1, z−1/2; (iii) −x, y+1/2, −z+1/2; (iv) x+1, y, z. |
Acknowledgements
We thank the Universidad Nacional de Colombia for the financial support (DIB research project No. 14178).
References
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L-Tyrosine alkyl esters are used as prodrugs for L-tyrosine due to these esters are more lipophilic and absorbed faster than L-tyrosine. In addition, they are hydrolyzed under physiological conditions (Nicolaï et al., 2011). The crystal structures for a number of tyrosine esters have been determined: methyl, ethyl (Nicolaï et al., 2011) and n-butyl esters (Qian et al., 2006). Previous computational and spectroscopic studies of L-tyrosine isopropyl ester have suggested that the macrocyclization process with formaldehyde can be explained by the formation of a template in solution through intermolecular hydrogen bonds between the amino and the phenolic hydroxyl groups on adjacent molecules of L-tyrosine derivatives (Quevedo & Moreno-Murillo, 2009; Nuñez-Dallos et al., 2012). We report here for the first time the crystal structure of L-tyrosine isopropyl ester.
The molecular structure of the title compound is shown in Fig. 1. The molecule adopts a folded conformation called U-shaped or scorpion conformation, as evidenced in the C1—C2—C3—C4 torsion angle of 58.2 (3)°. Despite the adoption of this conformation, there is no evidence for significant intramolecular C—H···π interactions. In terms of overall conformation, the structure of the title compound resembles that of the n-butyl (Qian et al., 2006) and ethyl analogues (Nicolaï et al., 2011). The crystal packing is stabilized by strong hydrogen bonds between the hydroxyl of the phenol group and the N-atom of the amine group (Fig. 2). Furthermore, molecules are connected into a three-dimensional array via N1—H1N···O3, N1—H2N···O3 and C2—H2···O1 intermolecular hydrogen-bonding interactions; see Table 1 for geometric parameters and symmetry operations.