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Volume 62 
Part 8 
Pages o3348-o3350  
August 2006  

Received 6 July 2006
Accepted 7 July 2006
Online 14 July 2006

Key indicators
Single-crystal X-ray study
T = 294 K
Mean [sigma](C-C) = 0.005 Å
Disorder in main residue
R = 0.044
wR = 0.080
Data-to-parameter ratio = 7.4
Details

(2S)-4-Methyl-2-(1-oxo-1H-2,3-dihydroisoindol-2-yl)pentanoic acid

aSchool of Chemical Sciences, Dublin City University, Dublin 9, Ireland
Correspondence e-mail: john.gallagher@dcu.ie

The title compound, C14H17NO3, exhibits carboxylic acid group disorder about the C-CO2 axis, with site occupancies of 0.79 (5):0.21 (5). Molecules are linked by intermolecular O-H...O=Ciso, C-H...O=Ciso and C-H...[pi](arene) interactions (iso = isoindolinone).

Comment

The majority of structurally determined phthalimidine systems are either N-substituted or have a hydroxy substituent at the 3-position (McNab et al., 1997[McNab, H., Parsons, S. & Shannon, D. A. (1997). Acta Cryst. C53, 1098-1099.]; Mukherjee et al., 2000[Mukherjee, A. K., Guha, S., Khan, M. W., Kundu, N. G. & Helliwell, M. (2000). Acta Cryst. C56, 85-87.]). The title compound, (I)[link], synthesized from L-leucine and ortho-phthalaldehyde (Allin et al., 1996[Allin, S. M., Hodkinson, C. C. & Taj, N. (1996). Synlett, pp. 781-782.]), forms part of a structural study of phthalimidines (Brady et al., 1998[Brady, F., Gallagher, J. F. & Kenny, P. T. M. (1998). Acta Cryst. C54, 1523-1525.]; Gallagher et al., 2000[Gallagher, J. F., Brady, F. & Murphy, C. (2000). Acta Cryst. C56, 365-368.]; Gallagher & Brady, 2000[Gallagher, J. F. & Brady, F. (2000). Acta Cryst. C56, 619-622.]; Gallagher & Murphy, 2001[Gallagher, J. F. & Murphy, C. (2001). Acta Cryst. E57, o1227-o1229.]).

[Scheme 1]

The molecular structure of (I)[link] is depicted in Fig. 1[link] (S configuration) and selected dimensions are given in Table 1[link]. The geometric data are normal (McNab et al., 1997[McNab, H., Parsons, S. & Shannon, D. A. (1997). Acta Cryst. C53, 1098-1099.]) and in agreement with expected values (Allen, 2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]). The five- and six-membered rings of the isoindole group are coplanar [dihedral angle between rings = 1.0 (2)°], and the isoindolinone atom O3 is 0.022 (5) Å from the C4N ring plane; this ring is oriented at 82.5 (5)° to the major orientation of the CCO2 plane (O1A/O2A/C1/C2).

Molecules of (I)[link] exhibit CO2H group disorder about the C-CO2 axis with site occupancies of 0.79 (5):0.21 (5) for the major/minor sites, respectively. Conventional CO2H dimeric hydrogen bonding [R22(8) ring] is not present as a requirement of symmetry; rather, the primary hydrogen bonding as an (...O-H...O-H...)n chain along [010] involving O1A/B-H1A/B...O3i (Table 1[link]) is described by a C(7) motif (Grell et al., 1999[Grell, J., Bernstein, J. & Tinhofer, G. (1999). Acta Cryst. B55, 1030-1043.]). The closest H atoms to the carbonyl O2A/B are at contact distances, e.g. H7...O2Aiii is 2.71 Å, with C7-H7...O2Aiii = 136° (symmetry codes iii as in Table 2[link]). Disorder is facilitated on geometric grounds as O2 can rotate about the C1-C2 axis without greatly affecting the O1A/B-H1A/B...O3i interaction distance (Fig. 2[link]).

Combination of the O-H...O=Ciso C(7) motif with a C(5) motif (from C10-H10A...O3ii) generates a two-dimensional sheet comprising R43(20) rings as C(7)C(5)[R43(20)]; modest (arene)C-H...[pi](arene) interactions (Nishio, 2004[Nishio, M. (2004). CrystEngComm, 6, 130-158.]) link these sheets (Fig. 3[link] and Table 2[link]).

Compound (I)[link] and the L-norvaline derivative, (II), C13H15NO3, (2S)-2-(1-oxo-1H-2,3-dihydroisoindol-2-yl)pentanoic acid (Gallagher & Brady, 2000[Gallagher, J. F. & Brady, F. (2000). Acta Cryst. C56, 619-622.]), both crystallize in space group P212121 with similar cell dimensions. The corresponding atom coordinates and molecular conformations are comparable and hence the crystal structures are isomorphous. Molecules of (I)[link] and (II) differ in their respective alkyl chains with the (CH3)2CHCH2- group in (I)[link] occupying a similar volume as the disordered CH3CH2CH2- group in (II). The solid-state (KBr disk) C=O stretching vibrations are similar, 1736, 1638 cm-1 in (I)[link] and 1730, 1649 cm-1 in (II), highlighting the analogous environments of both C=O groups in (I)[link] and (II).

[Figure 1]
Figure 1
A view of (I)[link], with the atomic numbering scheme; displacement ellipsoids are drawn at the 30% probability level. Both disorder components are shown.
[Figure 2]
Figure 2
Two molecules of (I)[link], with atoms depicted as their van der Waals spheres, with C7 (C-H...Oiii contact) and C8 [C-H...[pi](arene)iii] labels.
[Figure 3]
Figure 3
A view of the C(7)C(5)[R43(20)] sheet in (I)[link] with the unit-cell outline (symmetry codes as in Table 2[link]); H atoms not involved in hydrogen bonding have been omitted for clarity.

Experimental

The title compound (I)[link] was prepared by the overnight reaction of L-leucine and o-phthalaldehyde in refluxing CH3CN under N2 (Allin et al., 1996[Allin, S. M., Hodkinson, C. C. & Taj, N. (1996). Synlett, pp. 781-782.]). Filtration of the hot solution and subsequent slow cooling of the filtrate allowed the isolation of block-like colourless crystals. M.p. 485-487 K (uncorrected).

Crystal data
  • C14H17NO3

  • Mr = 247.29

  • Orthorhombic, P 21 21 21

  • a = 5.8790 (5) Å

  • b = 12.5223 (16) Å

  • c = 18.029 (3) Å

  • V = 1327.3 (3) Å3

  • Z = 4

  • Dx = 1.237 Mg m-3

  • Mo K[alpha] radiation

  • [mu] = 0.09 mm-1

  • T = 294 (1) K

  • Block, colourless

  • 0.35 × 0.25 × 0.15 mm

Data collection
  • Enraf-Nonius CAD-4 diffractometer

  • [omega]-2[theta] scans

  • Absorption correction: none

  • 2394 measured reflections

  • 1373 independent reflections

  • 889 reflections with I > 2[sigma](I)

  • Rint = 0.053

  • [theta]max = 25.0°

  • 3 standard reflections frequency: 120 min intensity decay: 1%

Refinement
  • Refinement on F2

  • R[F2 > 2[sigma](F2)] = 0.044

  • wR(F2) = 0.080

  • S = 1.00

  • 1373 reflections

  • 185 parameters

  • H-atom parameters constrained

  • w = 1/[[sigma]2(Fo2) + (0.0312P)2] where P = (Fo2 + 2Fc2)/3

  • ([Delta]/[sigma])max < 0.001

  • [Delta][rho]max = 0.13 e Å-3

  • [Delta][rho]min = -0.13 e Å-3

  • Extinction correction: SHELXL97

  • Extinction coefficient: 0.013 (2)

Table 1
Selected torsion angles (°)

C3-N1-C2-C11 133.9 (3)
C3-N1-C2-C1 -97.4 (4)
O3-C3-N1-C2 -1.6 (5)
O1A-C1-C2-C11 -51.2 (9)

Table 2
Hydrogen-bond geometry (Å, °)

D-H...A D-H H...A D...A D-H...A
O1A-H1A...O3i 0.82 1.83 2.634 (9) 168
C10-H10A...O3ii 0.97 2.54 3.366 (4) 144
C8-H8...Cg1iii 0.93 2.74 3.473 (4) 137
C2-H2...O3 0.98 2.38 2.812 (4) 106
Symmetry codes: (i) [-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]; (ii) x+1, y, z; (iii) [x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1].

In the absence of significant anomalous dispersion effects, Friedel equivalents were merged prior to the final refinement cycles. The absolute configuration can be inferred from the known absolute configuration of the L-leucine starting material. H atoms were treated as riding atoms using the SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]) defaults [at 294 (1) K], with C-H distances from 0.93 to 0.98 Å and O-H = 0.82 Å, and with Uiso(H) from 1.2 to 1.5 times Ueq(C,O).

Data collection: CAD-4 (Enraf-Nonius, 1992[Enraf-Nonius (1992). CAD-4, SET4 and CELDIM. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: SET4 and CELDIM (Enraf-Nonius, 1992[Enraf-Nonius (1992). CAD-4, SET4 and CELDIM. Enraf-Nonius, Delft, The Netherlands.]); data reduction: DATRD2 in NRCVAX96 (Gabe et al., 1989[Gabe, E. J., Le Page, Y., Charland, J.-P., Lee, F. L. & White, P. S. (1989). J. Appl. Cryst. 22, 384-387.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); program(s) used to refine structure: NRCVAX96 and SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: ORTEPIII (Burnett & Johnson, 1996[Burnett, M. N. & Johnson, C. K. (1996). ORTEPIII. Report ORNL-6895. Oak Ridge National Laboratory, Tennessee, USA.]) and PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]); software used to prepare material for publication: SHELXL97 and WORDPERFECT macro PREP8 (Ferguson, 1998[Ferguson, G. (1998). PREP8. University of Guelph, Canada.]).

Acknowledgements

JFG thanks Dublin City University, Forbairt (International Collaboration Grants) and the Royal Irish Academy for funding research visits to the University of Guelph, Canada, from 1995 to 1998. Professor George Ferguson is thanked for use of his diffractometer and computer system.

References

Allen, F. H. (2002). Acta Cryst. B58, 380-388.  [ISI] [CrossRef] [details]
Allin, S. M., Hodkinson, C. C. & Taj, N. (1996). Synlett, pp. 781-782.  [CrossRef]
Brady, F., Gallagher, J. F. & Kenny, P. T. M. (1998). Acta Cryst. C54, 1523-1525.  [CrossRef] [details]
Burnett, M. N. & Johnson, C. K. (1996). ORTEPIII. Report ORNL-6895. Oak Ridge National Laboratory, Tennessee, USA.
Enraf-Nonius (1992). CAD-4, SET4 and CELDIM. Enraf-Nonius, Delft, The Netherlands.
Ferguson, G. (1998). PREP8. University of Guelph, Canada.
Gabe, E. J., Le Page, Y., Charland, J.-P., Lee, F. L. & White, P. S. (1989). J. Appl. Cryst. 22, 384-387.  [CrossRef] [ChemPort] [ISI] [details]
Gallagher, J. F. & Brady, F. (2000). Acta Cryst. C56, 619-622.  [CrossRef] [details]
Gallagher, J. F., Brady, F. & Murphy, C. (2000). Acta Cryst. C56, 365-368.  [CrossRef] [details]
Gallagher, J. F. & Murphy, C. (2001). Acta Cryst. E57, o1227-o1229.  [CrossRef] [details]
Grell, J., Bernstein, J. & Tinhofer, G. (1999). Acta Cryst. B55, 1030-1043.  [ISI] [CrossRef] [details]
McNab, H., Parsons, S. & Shannon, D. A. (1997). Acta Cryst. C53, 1098-1099.  [CrossRef] [details]
Mukherjee, A. K., Guha, S., Khan, M. W., Kundu, N. G. & Helliwell, M. (2000). Acta Cryst. C56, 85-87.  [CrossRef] [details]
Nishio, M. (2004). CrystEngComm, 6, 130-158.  [ISI] [CrossRef] [ChemPort]
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.
Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.  [ISI] [CrossRef] [ChemPort] [details]


Acta Cryst (2006). E62, o3348-o3350   [ doi:10.1107/S160053680602647X ]