1-Benzyl-5-ethyl-5-hy­droxy-1H-pyrrol-2(5H)-one

The title compound, C₁₃H₁₅NO₂, was obtained as a by-product in the Grignard reaction of malimide. The dihedral angle between the five-memebred ring (r.m.s. deviation = 0.005 Å) and the benzene ring is 67.20 (14)°. The benzene ring and the ethyl chain lie to the same side of the five-membered ring. In the crystal, mol­ecules are linked by O—H...O hydrogen bonds, generating C(6) chains propagating in [010].

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.044
• wR factor = 0.145
• Data-to-parameter ratio = 13.4

checkCIF/PLATON results

No syntax errors found



Alert level B
            Crystal system given = monoclinic
PLAT934_ALERT_3_B Number of (Iobs-Icalc)/SigmaW > 10 Outliers ....          3

Alert level C
CHEMW01_ALERT_1_C  The difference between the given and expected weight for
            compound is greater 1 mass unit. Check that all hydrogen
            atoms have been taken into account.
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......      0.964
PLAT068_ALERT_1_C Reported F000 Differs from Calcd (or Missing)...          ? Check
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          1
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          5
PLAT915_ALERT_3_C Low Friedel Pair Coverage ......................         53 %
PLAT918_ALERT_3_C Reflection(s) # with I(obs) much smaller I(calc)          1
PLAT939_ALERT_3_C Large Value of Not (SHELXL) Weight Optimized S .      13.19

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF          ? Do !
PLAT007_ALERT_5_G Note: Number of Unrefined Donor-H Atoms ........          1
PLAT093_ALERT_1_G No su's on H-positions, refinement reported as .      mixed
PLAT791_ALERT_4_G Note: The Model has Chirality at C7     (Verify)          S
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600         42

   0 ALERT level A = Most likely a serious problem - resolve or explain
   1 ALERT level B = A potentially serious problem, consider carefully
   8 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   5 ALERT level G = General information/check it is not something unexpected

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   7 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

---

S1. Comment

Using Grignard reagents as the nucleophiles allows a flexible introduction of diverse side chains at the C-2 carbonyl of malimides (Huang, 2006). In addition, Grignard reagents are essentially strong bases, so the addition of a Grignard reagent to a malimide provided an unexpected 3-alkoxy group elimination product rac-1-benzyl-5-methyl-1H-pyrrol-2(5H)-one (He et al., 2003). Recently a new addition-elimination product, rac-1-benzyl-5-ethyl-5-hydroxy-1H-pyrrol-2(5H)-one, was found in the Grignard addition reaction. Here we report the structure of the title compound.

In γ-lactam ring the vinyl carbon atoms remain almost coplanar with the amide moiety [r.m.s. 0.0006 Å], which are agreement with the similar compounds (Goh et al., 2007; Ma & Xie, 2002). In the crystal, the molecules are linked by O—H···O hydrogen bonds between the hydroxyl group and the oxygen atom of the carbonyl group.

Related literature

For background to Grignard reagents, see: Huang (2006); He et al. (2003). For related structures, see: Goh et al. (2007); Ma & Xie (2002).

S2. Experimental

To a stirred solution of (S)-N,O-benzyl-malimide ((S)-1-benzyl-3-(benzyloxy)pyrrolidine-2,5-dione) (2 mmol) in anhydrous CH₂Cl₂ (20 ml) was added dropwise EtMgBr (4 mmol) in diethyl ether at -20 °C under nitrogen atmosphere. The mixture was stirred at -20 °C for 1 h and then quenched by adding a saturated aqueous solution of NH₄Cl. The mixture was extracted with CH₂Cl₂ (4 × 10 ml). The combined extracts were washed with brine, dried over Na₂SO4, concentrated under reduced pressure. The residue was purified by flash chromatography (eluent: EtOAc/PE = 1: 2; then 2: 1), provided a mixture of diastereomers (4S)-1-benzyl-4-(benzyloxy)-5-ethyl-5-hydroxypyrrolidin-2-one as major products (white crystals, yield 85%) and the title compound as minor product (colourless crystals, yield 10%). Colourless pillars of the tiltle compound were obtained by slow evaporation of a mixture of n-hexane/ethyl acetate solution.

S3. Refinement

The hydrogen atoms were positioned geometrically, with C—H = 0.93, 0.98, 0.97 and 0.96 Å for phenyl, methine, methylene and methyl H atoms, respectively, and were included in the refinement in the riding model approximation. The displacement parameters of methyl H atoms were set to 1.5U_eq(C), while those of other H atoms were set to 1.2U_eq(C). In the absence of significant anomalous scattering effects the absolute structure of the chosen crystal was indeterminate.

Computing details

Data collection: CrysAlis PRO (Oxford Diffraction, 2010); cell refinement: CrysAlis PRO (Oxford Diffraction, 2010); data reduction: CrysAlis PRO (Oxford Diffraction, 2010); 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).

Figures

	Fig. 1. The molecular structure of the title compound showing 50% probability displacement ellipsoids.
	Fig. 2. The packing of the molecules, viewed down the a axis. O—H···O hydrogen bond interactions are shown as dashed lines.

1-Benzyl-5-ethyl-5-hydroxy-1H-pyrrol-2(5H)-one

Crystal data

C13H15NO2	F(000) = 230
Mr = 215.27	Dx = 1.227 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
a = 7.0399 (14) Å	Cell parameters from 2119 reflections
b = 7.1795 (14) Å	θ = 3.0–27.0°
c = 11.817 (2) Å	µ = 0.08 mm^−1
β = 102.72 (3)°	T = 173 K
V = 582.6 (2) Å^3	Pillar, colourless
Z = 2	0.3 × 0.2 × 0.2 mm

Data collection

Oxford Diffraction Xcalibur (Sapphire3, Gemini ultra) diffractometer	1947 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1811 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.054
Detector resolution: 16.1903 pixels mm^-1	θmax = 27.0°, θmin = 3.0°
phi and ω scans	h = −8→8
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010)	k = −9→9
Tmin = 0.980, Tmax = 0.983	l = −14→15
3363 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.145	H-atom parameters constrained
S = 1.13	w = 1/[σ^2(Fo^2) + (0.0893P)^2 + 0.0423P] where P = (Fo^2 + 2Fc^2)/3
1947 reflections	(Δ/σ)max < 0.001
145 parameters	Δρmax = 0.25 e Å^−3
1 restraint	Δρmin = −0.32 e Å^−3

Special details

Experimental. Absorption correction: CrysAlisPro, Oxford Diffraction Ltd., Version 1.171.34.44. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	−0.2177 (3)	0.6481 (3)	0.96950 (15)	0.0294 (4)
N1	−0.0106 (3)	0.7331 (3)	0.85306 (15)	0.0214 (4)
C1	−0.2478 (4)	0.4825 (5)	0.4747 (2)	0.0383 (7)
H1A	−0.2359	0.4924	0.3981	0.046*
O2	0.2472 (3)	0.9389 (2)	0.83792 (15)	0.0294 (4)
H2A	0.2397	1.0049	0.8934	0.044*
C2	−0.3230 (4)	0.3208 (5)	0.5114 (2)	0.0403 (7)
H2B	−0.36	0.2222	0.4602	0.048*
C3	−0.3426 (4)	0.3079 (5)	0.6254 (2)	0.0352 (6)
H3A	−0.3927	0.2	0.6511	0.042*
C4	0.2774 (4)	0.6967 (4)	0.9869 (2)	0.0291 (6)
H4A	0.4086	0.6937	1.0235	0.035*
C5	−0.1894 (4)	0.6312 (4)	0.5507 (2)	0.0325 (6)
H5A	−0.1362	0.738	0.5255	0.039*
C6	−0.1548 (4)	0.7814 (4)	0.74846 (19)	0.0254 (5)
H6A	−0.1033	0.8808	0.7084	0.03*
H6B	−0.2707	0.8281	0.7706	0.03*
C7	0.2009 (4)	0.7521 (3)	0.8611 (2)	0.0241 (5)
C8	−0.2875 (4)	0.4557 (4)	0.7009 (2)	0.0283 (6)
H8A	−0.3016	0.4459	0.7771	0.034*
C9	−0.0541 (3)	0.6758 (3)	0.95313 (19)	0.0225 (5)
C10	−0.2118 (3)	0.6177 (4)	0.66498 (19)	0.0252 (5)
C11	0.1357 (4)	0.6535 (4)	1.0372 (2)	0.0300 (6)
H11A	0.151	0.6149	1.1138	0.036*
C12	0.2726 (4)	0.6284 (4)	0.7756 (2)	0.0286 (6)
H12A	0.4104	0.652	0.7826	0.034*
H12B	0.2061	0.6643	0.6978	0.034*
C13	0.2442 (4)	0.4196 (4)	0.7893 (2)	0.0335 (6)
H13A	0.2931	0.3535	0.7311	0.05*
H13B	0.1081	0.3932	0.7807	0.05*
H13C	0.3136	0.3806	0.8649	0.05*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0328 (9)	0.0290 (11)	0.0303 (9)	−0.0023 (8)	0.0153 (7)	−0.0011 (8)
N1	0.0209 (9)	0.0227 (10)	0.0203 (8)	0.0000 (8)	0.0035 (7)	−0.0002 (8)
C1	0.0360 (14)	0.053 (2)	0.0254 (12)	0.0033 (15)	0.0061 (10)	−0.0087 (13)
O2	0.0358 (10)	0.0214 (10)	0.0325 (9)	−0.0076 (8)	0.0104 (7)	0.0009 (7)
C2	0.0317 (14)	0.052 (2)	0.0370 (14)	−0.0020 (14)	0.0067 (11)	−0.0215 (14)
C3	0.0295 (14)	0.0360 (16)	0.0398 (14)	−0.0060 (12)	0.0068 (11)	−0.0067 (12)
C4	0.0289 (12)	0.0263 (14)	0.0283 (11)	−0.0024 (11)	−0.0020 (9)	0.0022 (10)
C5	0.0311 (13)	0.0398 (16)	0.0260 (12)	0.0042 (12)	0.0049 (10)	0.0011 (12)
C6	0.0249 (12)	0.0254 (13)	0.0242 (11)	0.0054 (10)	0.0017 (9)	0.0016 (10)
C7	0.0224 (11)	0.0218 (13)	0.0274 (11)	−0.0005 (10)	0.0039 (8)	0.0017 (10)
C8	0.0237 (11)	0.0339 (16)	0.0268 (11)	0.0028 (11)	0.0047 (8)	−0.0044 (11)
C9	0.0300 (12)	0.0150 (11)	0.0230 (10)	−0.0016 (10)	0.0069 (8)	−0.0021 (9)
C10	0.0196 (10)	0.0320 (14)	0.0222 (10)	0.0058 (11)	0.0004 (8)	−0.0033 (10)
C11	0.0363 (13)	0.0278 (14)	0.0225 (11)	−0.0053 (12)	−0.0008 (9)	0.0013 (10)
C12	0.0244 (12)	0.0275 (14)	0.0362 (13)	0.0000 (10)	0.0118 (9)	0.0008 (11)
C13	0.0310 (14)	0.0260 (13)	0.0449 (14)	0.0059 (12)	0.0114 (11)	−0.0022 (12)

Geometric parameters (Å, º)

O1—C9	1.225 (3)	C5—C10	1.397 (3)
N1—C9	1.349 (3)	C5—H5A	0.93
N1—C6	1.458 (3)	C6—C10	1.530 (3)
N1—C7	1.477 (3)	C6—H6A	0.97
C1—C2	1.385 (5)	C6—H6B	0.97
C1—C5	1.397 (4)	C7—C12	1.513 (4)
C1—H1A	0.93	C8—C10	1.384 (4)
O2—C7	1.421 (3)	C8—H8A	0.93
O2—H2A	0.82	C9—C11	1.488 (3)
C2—C3	1.387 (4)	C11—H11A	0.93
C2—H2B	0.93	C12—C13	1.526 (4)
C3—C8	1.386 (4)	C12—H12A	0.97
C3—H3A	0.93	C12—H12B	0.97
C4—C11	1.306 (4)	C13—H13A	0.96
C4—C7	1.518 (3)	C13—H13B	0.96
C4—H4A	0.93	C13—H13C	0.96
C9—N1—C6	124.4 (2)	O2—C7—C4	112.9 (2)
C9—N1—C7	113.05 (18)	N1—C7—C4	100.05 (19)
C6—N1—C7	122.47 (19)	C12—C7—C4	113.7 (2)
C2—C1—C5	121.2 (2)	C10—C8—C3	121.2 (2)
C2—C1—H1A	119.4	C10—C8—H8A	119.4
C5—C1—H1A	119.4	C3—C8—H8A	119.4
C7—O2—H2A	109.5	O1—C9—N1	126.2 (2)
C1—C2—C3	119.1 (3)	O1—C9—C11	127.9 (2)
C1—C2—H2B	120.4	N1—C9—C11	105.9 (2)
C3—C2—H2B	120.4	C8—C10—C5	119.2 (2)
C8—C3—C2	120.0 (3)	C8—C10—C6	120.7 (2)
C8—C3—H3A	120	C5—C10—C6	120.0 (2)
C2—C3—H3A	120	C4—C11—C9	109.5 (2)
C11—C4—C7	111.5 (2)	C4—C11—H11A	125.3
C11—C4—H4A	124.3	C9—C11—H11A	125.3
C7—C4—H4A	124.3	C7—C12—C13	115.8 (2)
C10—C5—C1	119.2 (3)	C7—C12—H12A	108.3
C10—C5—H5A	120.4	C13—C12—H12A	108.3
C1—C5—H5A	120.4	C7—C12—H12B	108.3
N1—C6—C10	113.5 (2)	C13—C12—H12B	108.3
N1—C6—H6A	108.9	H12A—C12—H12B	107.4
C10—C6—H6A	108.9	C12—C13—H13A	109.5
N1—C6—H6B	108.9	C12—C13—H13B	109.5
C10—C6—H6B	108.9	H13A—C13—H13B	109.5
H6A—C6—H6B	107.7	C12—C13—H13C	109.5
O2—C7—N1	110.21 (19)	H13A—C13—H13C	109.5
O2—C7—C12	107.48 (19)	H13B—C13—H13C	109.5
N1—C7—C12	112.5 (2)
C5—C1—C2—C3	0.8 (4)	C7—N1—C9—O1	−179.5 (2)
C1—C2—C3—C8	0.1 (4)	C6—N1—C9—C11	−176.7 (2)
C2—C1—C5—C10	−1.5 (4)	C7—N1—C9—C11	0.3 (3)
C9—N1—C6—C10	−92.1 (3)	C3—C8—C10—C5	−0.5 (4)
C7—N1—C6—C10	91.2 (3)	C3—C8—C10—C6	178.9 (2)
C9—N1—C7—O2	−119.7 (2)	C1—C5—C10—C8	1.4 (4)
C6—N1—C7—O2	57.4 (3)	C1—C5—C10—C6	−178.0 (2)
C9—N1—C7—C12	120.4 (2)	N1—C6—C10—C8	57.8 (3)
C6—N1—C7—C12	−62.5 (3)	N1—C6—C10—C5	−122.8 (2)
C9—N1—C7—C4	−0.6 (3)	C7—C4—C11—C9	−0.6 (3)
C6—N1—C7—C4	176.5 (2)	O1—C9—C11—C4	180.0 (3)
C11—C4—C7—O2	117.8 (3)	N1—C9—C11—C4	0.2 (3)
C11—C4—C7—N1	0.7 (3)	O2—C7—C12—C13	177.5 (2)
C11—C4—C7—C12	−119.4 (3)	N1—C7—C12—C13	−61.0 (3)
C2—C3—C8—C10	−0.2 (4)	C4—C7—C12—C13	51.8 (3)
C6—N1—C9—O1	3.5 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O1^i	0.82	1.95	2.772 (3)	176

Symmetry code: (i) −x, y+1/2, −z+2.