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

Brady, F.; Gallagher, J.F.

doi:10.1107/S160053680602647X

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 62| Part 8| August 2006| Pages o3348-o3350

https://doi.org/10.1107/S160053680602647X

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

Fiona Brady ^a and John F. Gallagher ^a ^*

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

(Received 6 July 2006; accepted 7 July 2006; online 14 July 2006)

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=C_iso, C—H⋯O=C_iso and C—H⋯π(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 ; Mukherjee et al., 2000 ). The title compound, (I), synthesized from L-leucine and ortho-phthalaldehyde (Allin et al., 1996 ), forms part of a structural study of phthalimidines (Brady et al., 1998 ; Gallagher et al., 2000 ; Gallagher & Brady, 2000 ; Gallagher & Murphy, 2001 ).

The molecular structure of (I) is depicted in Fig. 1 (S configuration) and selected dimensions are given in Table 1. The geometric data are normal (McNab et al., 1997) and in agreement with expected values (Allen, 2002 ). 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) 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) is described by a C(7) motif (Grell et al., 1999 ). 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). 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).

Combination of the O—H⋯O=C_iso 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⋯π(arene) interactions (Nishio, 2004 ) link these sheets (Fig. 3 and Table 2).

Compound (I) and the L-norvaline derivative, (II), C₁₃H₁₅NO₃, (2S)-2-(1-oxo-1H-2,3-dihydroisoindol-2-yl)pentanoic acid (Gallagher & Brady, 2000), 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) and (II) differ in their respective alkyl chains with the (CH₃)₂CHCH₂– group in (I) 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) and 1730, 1649 cm⁻¹ in (II), highlighting the analogous environments of both C=O groups in (I) and (II).

Figure 1
A view of (I)

, with the atomic numbering scheme; displacement ellipsoids are drawn at the 30% probability level. Both disorder components are shown.

Figure 2
Two molecules of (I)

, with atoms depicted as their van der Waals spheres, with C7 (C—H⋯Oⁱⁱⁱ contact) and C8 [C—H⋯π(arene)ⁱⁱⁱ] labels.

Figure 3
A view of the C(7)C(5)[R₄³(20)] sheet in (I)

with the unit-cell outline (symmetry codes as in Table 2

); H atoms not involved in hydrogen bonding have been omitted for clarity.

Experimental

The title compound (I) was prepared by the overnight reaction of L-leucine and o-phthalaldehyde in refluxing CH₃CN under N₂ (Allin et al., 1996). 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
M_r = 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
D_x = 1.237 Mg m⁻³
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 294 (1) K
Block, colourless
0.35 × 0.25 × 0.15 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
ω–2θ scans
Absorption correction: none
2394 measured reflections
1373 independent reflections
889 reflections with I > 2σ(I)
R_int = 0.053
θ_max = 25.0°
3 standard reflections frequency: 120 min intensity decay: 1%

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.080
S = 1.00
1373 reflections
185 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.0312P)²] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.13 e Å⁻³
Δρ_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 ) defaults [at 294 (1) K], with C—H distances from 0.93 to 0.98 Å and O—H = 0.82 Å, and with U_iso(H) from 1.2 to 1.5 times U_eq(C,O).

Data collection: CAD-4 (Enraf–Nonius, 1992 ); cell refinement: SET4 and CELDIM (Enraf–Nonius, 1992); data reduction: DATRD2 in NRCVAX96 (Gabe et al., 1989 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: NRCVAX96 and SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ) and PLATON (Spek, 2003 ); software used to prepare material for publication: SHELXL97 and WORDPERFECT macro PREP8 (Ferguson, 1998 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S160053680602647X/lh2126sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053680602647X/lh2126Isup2.hkl

Computing details top

Data collection: CAD-4 (Enraf–Nonius, 1992); cell refinement: SET4 and CELDIM (Enraf–Nonius, 1992); data reduction: DATRD2 in NRCVAX96 (Gabe et al., 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: NRCVAX96 and SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and WORDPERFECT macro PREP8 (Ferguson, 1998).

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

Crystal data top

C₁₄H₁₇NO₃	IR (ν_C_═_O, cm^-1): 1736, 1638 (KBr).
M_r = 247.29	D_x = 1.237 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Melting point: 486 K
Hall symbol: P 2ac 2ab	Mo Kα radiation, λ = 0.71073 Å
a = 5.8790 (5) Å	Cell parameters from 25 reflections
b = 12.5223 (16) Å	θ = 15.0–25.0°
c = 18.029 (3) Å	µ = 0.09 mm⁻¹
V = 1327.3 (3) Å³	T = 294 K
Z = 4	Block, colourless
F(000) = 528	0.35 × 0.25 × 0.15 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.053
Radiation source: X-ray tube	θ_max = 25.0°, θ_min = 2.3°
Graphite monochromator	h = −6→6
ω–2θ scans	k = −14→14
2394 measured reflections	l = −21→21
1373 independent reflections	3 standard reflections every 120 min
889 reflections with I > 2σ(I)	intensity decay: 1%

Refinement top

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)] = 0.044	H-atom parameters constrained
wR(F²) = 0.080	w = 1/[σ²(F_o²) + (0.0312P)²] where P = (F_o² + 2F_c²)/3
S = 1.00	(Δ/σ)_max < 0.001
1373 reflections	Δρ_max = 0.13 e Å⁻³
185 parameters	Δρ_min = −0.13 e Å⁻³
36 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.013 (2)

Special details top

Experimental. ? #Insert any special details here.

Geometry. Mean plane data ex-SHELXL97 for molecule (I) ############################################

As detailed in the comment text section.

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
O1A	0.648 (3)	0.4641 (5)	0.8185 (5)	0.059 (3)	0.79 (5)
O2A	0.667 (4)	0.4445 (9)	0.6954 (4)	0.074 (3)	0.79 (5)
O1B	0.582 (8)	0.459 (3)	0.807 (2)	0.059 (10)	0.21 (5)
O2B	0.752 (8)	0.458 (3)	0.7002 (18)	0.066 (10)	0.21 (5)
O3	0.5705 (4)	0.14460 (18)	0.70543 (13)	0.0517 (8)
N1	0.8834 (5)	0.2520 (2)	0.70881 (13)	0.0380 (7)
C1	0.7067 (7)	0.4140 (3)	0.75684 (19)	0.0457 (10)
C2	0.8176 (6)	0.3080 (2)	0.77582 (16)	0.0392 (9)
C3	0.7532 (6)	0.1753 (2)	0.67839 (18)	0.0371 (9)
C4	0.8679 (6)	0.1403 (2)	0.61054 (17)	0.0370 (9)
C5	0.8039 (7)	0.0641 (3)	0.55912 (18)	0.0527 (11)
C6	0.9450 (8)	0.0476 (3)	0.4992 (2)	0.0605 (12)
C7	1.1438 (8)	0.1045 (3)	0.4917 (2)	0.0593 (11)
C8	1.2086 (6)	0.1802 (3)	0.54341 (18)	0.0495 (10)
C9	1.0656 (6)	0.1982 (3)	0.60280 (17)	0.0387 (9)
C10	1.0864 (6)	0.2761 (2)	0.66548 (17)	0.0432 (9)
C11	1.0083 (7)	0.3177 (3)	0.83211 (19)	0.0481 (10)
C12	1.1179 (8)	0.2129 (3)	0.8559 (2)	0.0552 (11)
C13	1.2949 (8)	0.2351 (4)	0.9156 (2)	0.0842 (15)
C14	0.9461 (8)	0.1313 (3)	0.8821 (2)	0.0753 (13)
H1A	0.5976	0.5234	0.8082	0.071*	0.79 (5)
H2A	0.4770	0.4909	0.7871	0.071*	0.21 (5)
H2	0.6993	0.2643	0.7993	0.047*
H5	0.6701	0.0253	0.5648	0.063*
H6	0.9054	−0.0026	0.4635	0.073*
H7	1.2367	0.0917	0.4509	0.071*
H8	1.3442	0.2178	0.5383	0.059*
H10A	1.2239	0.2640	0.6940	0.052*
H10B	1.0850	0.3492	0.6477	0.052*
H11A	0.9490	0.3530	0.8759	0.058*
H11B	1.1256	0.3634	0.8114	0.058*
H12	1.1970	0.1830	0.8128	0.066*
H13A	1.4020	0.2869	0.8977	0.126*
H13B	1.3735	0.1702	0.9276	0.126*
H13C	1.2209	0.2622	0.9592	0.126*
H14A	0.8369	0.1185	0.8436	0.113*
H14B	0.8697	0.1578	0.9254	0.113*
H14C	1.0228	0.0658	0.8940	0.113*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1A	0.079 (6)	0.047 (3)	0.051 (3)	0.035 (3)	−0.012 (4)	−0.008 (3)
O2A	0.103 (8)	0.075 (4)	0.044 (3)	0.039 (4)	−0.002 (3)	0.006 (3)
O1B	0.045 (16)	0.102 (17)	0.031 (11)	0.004 (12)	0.013 (12)	0.028 (11)
O2B	0.076 (16)	0.061 (11)	0.062 (13)	0.013 (11)	0.025 (10)	0.027 (10)
O3	0.0407 (17)	0.0489 (15)	0.0655 (17)	−0.0112 (14)	0.0112 (15)	−0.0048 (13)
N1	0.0326 (17)	0.0406 (15)	0.0408 (16)	−0.0046 (16)	0.0052 (15)	−0.0090 (14)
C1	0.049 (3)	0.045 (2)	0.043 (2)	0.001 (2)	0.002 (2)	−0.003 (2)
C2	0.039 (2)	0.0374 (19)	0.0408 (18)	0.000 (2)	0.0040 (19)	−0.0032 (17)
C3	0.035 (2)	0.0294 (18)	0.047 (2)	−0.0018 (19)	−0.0004 (19)	0.0021 (16)
C4	0.040 (2)	0.0315 (17)	0.0400 (18)	0.005 (2)	0.002 (2)	−0.0026 (16)
C5	0.059 (3)	0.040 (2)	0.059 (2)	−0.001 (2)	0.001 (2)	−0.0060 (19)
C6	0.074 (3)	0.052 (2)	0.055 (3)	0.007 (3)	0.002 (3)	−0.020 (2)
C7	0.067 (3)	0.060 (2)	0.051 (2)	0.015 (3)	0.011 (2)	−0.010 (2)
C8	0.041 (2)	0.056 (2)	0.051 (2)	0.003 (2)	0.008 (2)	−0.001 (2)
C9	0.037 (2)	0.0373 (19)	0.0418 (19)	0.003 (2)	0.0011 (19)	−0.0009 (17)
C10	0.038 (2)	0.044 (2)	0.0479 (19)	−0.007 (2)	−0.002 (2)	−0.0012 (16)
C11	0.051 (3)	0.045 (2)	0.048 (2)	0.009 (2)	−0.002 (2)	−0.0040 (18)
C12	0.059 (3)	0.054 (2)	0.053 (2)	0.019 (3)	0.005 (2)	0.0045 (19)
C13	0.062 (3)	0.117 (4)	0.073 (3)	0.021 (3)	−0.019 (3)	0.015 (3)
C14	0.083 (3)	0.062 (3)	0.081 (3)	0.011 (3)	0.006 (3)	0.018 (2)

Geometric parameters (Å, º) top

O1A—C1	1.323 (7)	O2B—C1	1.193 (19)
O2A—C1	1.194 (7)	O1A—H1A	0.8200
O3—C3	1.241 (4)	O1B—H2A	0.8200
N1—C2	1.449 (4)	C2—H2	0.9800
N1—C3	1.345 (4)	C5—H5	0.9300
N1—C10	1.458 (4)	C6—H6	0.9300
C1—C2	1.518 (4)	C7—H7	0.9300
C2—C11	1.517 (4)	C8—H8	0.9300
C3—C4	1.464 (4)	C10—H10A	0.9700
C4—C9	1.377 (5)	C10—H10B	0.9700
C4—C5	1.383 (4)	C11—H11A	0.9700
C5—C6	1.377 (5)	C11—H11B	0.9700
C6—C7	1.375 (5)	C12—H12	0.9800
C7—C8	1.384 (4)	C13—H13A	0.9600
C8—C9	1.380 (4)	C13—H13B	0.9600
C9—C10	1.498 (4)	C13—H13C	0.9600
C11—C12	1.524 (4)	C14—H14A	0.9600
C12—C14	1.513 (5)	C14—H14B	0.9600
C12—C13	1.523 (5)	C14—H14C	0.9600
O1B—C1	1.292 (19)

C2—N1—C3	122.2 (3)	C1—C2—H2	106.3
C2—N1—C10	124.4 (3)	C6—C5—H5	121.1
C3—N1—C10	113.3 (3)	C4—C5—H5	121.1
O1A—C1—O2A	125.2 (6)	C7—C6—H6	119.6
O1B—C1—O2B	121.6 (18)	C5—C6—H6	119.6
O2A—C1—C2	124.9 (5)	C6—C7—H7	119.3
O2B—C1—C2	120.2 (16)	C8—C7—H7	119.3
O1A—C1—C2	109.8 (5)	C9—C8—H8	121.1
O1B—C1—C2	117.8 (13)	C7—C8—H8	121.1
N1—C2—C1	110.5 (3)	N1—C10—H10A	111.4
N1—C2—C11	113.5 (3)	C9—C10—H10A	111.4
C1—C2—C11	113.4 (3)	N1—C10—H10B	111.4
O3—C3—N1	123.6 (3)	C9—C10—H10B	111.4
O3—C3—C4	129.4 (3)	H10A—C10—H10B	109.3
N1—C3—C4	107.0 (3)	C2—C11—H11A	108.4
C3—C4—C5	129.9 (3)	C12—C11—H11A	108.4
C3—C4—C9	108.4 (3)	C2—C11—H11B	108.4
C5—C4—C9	121.7 (3)	C12—C11—H11B	108.4
C4—C5—C6	117.7 (4)	H11A—C11—H11B	107.5
C5—C6—C7	120.8 (4)	C14—C12—H12	107.8
C6—C7—C8	121.5 (4)	C13—C12—H12	107.8
C7—C8—C9	117.8 (3)	C11—C12—H12	107.8
C4—C9—C8	120.5 (3)	C12—C13—H13A	109.5
C4—C9—C10	109.6 (3)	C12—C13—H13B	109.5
C8—C9—C10	129.9 (3)	H13A—C13—H13B	109.5
N1—C10—C9	101.7 (3)	C12—C13—H13C	109.5
C2—C11—C12	115.6 (3)	H13A—C13—H13C	109.5
C11—C12—C13	109.3 (3)	H13B—C13—H13C	109.5
C11—C12—C14	112.8 (3)	C12—C14—H14A	109.5
C13—C12—C14	111.0 (3)	C12—C14—H14B	109.5
C1—O1A—H1A	109.5	H14A—C14—H14B	109.5
C1—O1B—H2A	109.5	C12—C14—H14C	109.5
N1—C2—H2	106.3	H14A—C14—H14C	109.5
C11—C2—H2	106.3	H14B—C14—H14C	109.5

C3—N1—C2—C11	133.9 (3)	C9—C4—C5—C6	0.0 (5)
C3—N1—C2—C1	−97.4 (4)	C3—C4—C5—C6	179.5 (3)
O3—C3—N1—C2	−1.6 (5)	C4—C5—C6—C7	0.7 (5)
O1A—C1—C2—C11	−51.2 (9)	C5—C6—C7—C8	−0.3 (6)
C10—N1—C2—C11	−49.7 (4)	C6—C7—C8—C9	−0.8 (5)
C10—N1—C2—C1	79.0 (4)	C5—C4—C9—C8	−1.1 (5)
O2B—C1—C2—N1	−26 (3)	C3—C4—C9—C8	179.3 (3)
O2A—C1—C2—N1	4.0 (14)	C5—C4—C9—C10	178.5 (3)
O1B—C1—C2—N1	161 (3)	C3—C4—C9—C10	−1.1 (4)
O1A—C1—C2—N1	−179.9 (8)	C7—C8—C9—C4	1.4 (5)
O2B—C1—C2—C11	102 (3)	C7—C8—C9—C10	−178.0 (3)
O2A—C1—C2—C11	132.8 (13)	C3—N1—C10—C9	−1.7 (3)
O1B—C1—C2—C11	−71 (3)	C2—N1—C10—C9	−178.3 (3)
C10—N1—C3—O3	−178.3 (3)	C4—C9—C10—N1	1.6 (3)
C2—N1—C3—C4	177.8 (3)	C8—C9—C10—N1	−178.9 (3)
C10—N1—C3—C4	1.1 (3)	N1—C2—C11—C12	−55.7 (4)
O3—C3—C4—C9	179.4 (3)	C1—C2—C11—C12	177.2 (3)
N1—C3—C4—C9	0.0 (3)	C2—C11—C12—C14	−52.5 (4)
O3—C3—C4—C5	−0.2 (6)	C2—C11—C12—C13	−176.5 (3)
N1—C3—C4—C5	−179.5 (3)

Hydrogen-bond geometry (Å, º) top

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

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.

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