rac-Ethyl rel-(2R,3R,4S)-4-hy­droxy-1,2-dimethyl-5-oxopyrrolidine-3-carboxyl­ate

Abdul Rashid, F.N.A.; Bacho, M.Z.; Hamali, M.A.; Slawin, A.M.Z.; Mohammat, M.F.; Shamsujunaidi, R.; Abdul Manan, M.A.F.

doi:10.1107/S2414314623000755

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 8| Part 2| February 2023| x230075

https://doi.org/10.1107/S2414314623000755

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rac-Ethyl rel-(2R,3R,4S)-4-hydroxy-1,2-dimethyl-5-oxopyrrolidine-3-carboxylate

Fatin Nur Ain Abdul Rashid,^a Muhamad Zulfaqar Bacho,^a Muhamad Azwan Hamali,^b Alexandra M. Z. Slawin,^c Mohd Fazli Mohammat,^a Ruwaida Shamsujunaidi ^b and Mohd Abdul Fatah Abdul Manan ^b ^*

^aOrganic Synthesis Research Laboratory, Institute of Science, Universiti Teknologi MARA, 42300 Bandar Puncak Alam, Selangor, Malaysia, ^bFaculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia, and ^cEaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, United Kingdom
^*Correspondence e-mail: abdfatah@uitm.edu.my

Edited by S. Bernès, Benemérita Universidad Autónoma de Puebla, México (Received 4 January 2023; accepted 28 January 2023; online 9 February 2023)

The asymmetric unit of the title compound, C₉H₁₅NO₄, consists of a functionalized pyrrolidine ring having an envelope conformation, synthesized as an ethyl ester. The molecule has three chiral centres and crystallized as a racemic mixture. In the crystal, molecules are linked by pairwise O—H⋯O bonds, generating dimers with twofold rotational symmetry.

Keywords: crystal structure; oxopyrrolidine; ring conformation; hydrogen bonds.

CCDC reference: 2238498

Structure description

The heterocyclic compound 2-oxopyrrolidine and its derivatives have generated a lot of interest because of their practical significance (Pandya & Desai, 2020 ). These compounds have shown to be effective analgesics, anti-inflammatory (Salgın-Gökşen et al., 2007 ), antiviral (Tian et al., 2009 ), antimicrobial (Özkay et al., 2010 ; Salgın-Gökşen et al., 2007), antitumor (Abdel-Aziz et al., 2021 ), anticonvulsant (Angelova et al., 2016 ), antidepressant (Kulandasamy et al., 2009 ), cardioprotective (Ghazouani et al., 2019 ) and antiplatelet agents (Mashayekhi et al., 2013 ; Ghazouani et al., 2019).

During the course of our study towards pyrrolidine-based iminosugars, we have synthesized the title compound by reduction of 2,3-dioxopyrrolidine (Bacho et al., 2020 ; Abdul Rashid et al., 2020 ). The starting material, 2,3-dioxopyrrolidine, was initially prepared via a multicomponent reaction, according to a previously reported procedure (Mohammat et al., 2009 , 2011 ).

The title compound crystallizes in the monoclinic crystal system, space group C2/c, with one molecule in the asymmetric unit (Fig. 1). The pyrrolidine ring (C1–C4/N1) adopts an envelope conformation, with atom C4 deviating by 0.180 (1) Å from the mean plane. There are three chiral centres within the ring, at C4, with a C1—C4—C5—O4 torsion angle of −94.04 (11)°. The methyl and hydroxyl groups, attached to C1 and C3, respectively, are orientated awayfrom the mean plane with C2—N1—C1—C8 and N1—C2—C3—O2 torsion angles of 142.07 (10) and −135.48 (10)°, respectively. Meanwhile, the ethyl ester group (O3/C5/O4/C6/C7) occupies the equatorial position on the pyrrolidine ring at C1, C3, and C4, . All bond lengths (Allen et al., 1987 ) and angles in the molecule show normal values.

Figure 1
Crystal structure of the title compound, showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.

In the crystal, the molecules are linked by pairwise O—H⋯O hydrogen bonds, involving the carbonyl and hydroxy groups, forming centrosymmetric R₂²(10) ring motifs (Table 1, entry 1; Fig. 2). The packing also features C—H⋯O hydrogen bonds (Table 1), forming zigzag motifs propagating along the c-axis direction (Fig. 3).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O1ⁱ	0.97 (1)	1.78 (1)	2.7405 (12)	170 (2)
C1—H1⋯O1ⁱⁱ	1.00	2.62	3.3953 (14)	134
C9—H9A⋯O1ⁱⁱ	0.98	2.51	3.3355 (16)	142
C9—H9C⋯O3ⁱⁱⁱ	0.98	2.54	3.5086 (15)	169
C7—H7C⋯O1^iv	0.98	2.58	3.5134 (17)	160
Symmetry codes: (i) $[-x+1, y, -z+{\script{1\over 2}}]$ ; (ii) $[-x+{\script{3\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) $[x+{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ ; (iv) $[x, -y+1, z+{\script{1\over 2}}]$ .

Figure 2
The O—H⋯O hydrogen bonds, indicated by green dashed bonds, forming R₂²(10) motifs in the crystal.

Figure 3
The molecular packing of title compound, viewed down the a axis. Intermolecular hydrogen bonds are indicated by green dashed lines.

Synthesis and crystallization

A solution of 2,3-dioxopyrrolidine (2.00 g, 10.04 mmol) together with Pd—C (10% wt; 1.39 g, 1.31 mmol) and acetic acid (4.59 ml, 80.32 mmol) was stirred in ethanol. The reaction was stirred vigorously under a hydrogen atmosphere to completion (24 h) and then filtered through Celite. After removal of the solvent, the crude product was purified by flash column chromatography on silica gel using ethyl acetate/petroleum ether (9/1), to afford two compounds; trans-hydroxyester 1 as a white solid and cis-hydroxyester 2 as a colourless oil. The white solid of trans-hydroxyester 1 was recrystallized from methanol solution to give single crystals of the title compound 1 (0.24 g, 12%).

trans-hydroxyester 1: ¹H NMR (400 MHz, CDCl₃): δ 4.57 (d, J = 8.5 Hz, 1H), 4.22 (q, J = 6.9 Hz, 2H), 3.63 (s, 1H), 2.82 (s, 3H), 2.67 (t, J = 8.4 Hz, 1H), 1.37 (d, J = 3.7 Hz, 3H), 1.29 (t, J = 6.9 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃): δ 173.00 (C=O), 171.54 (C=O), 72.26 (CHOH), 61.71 (OCH₂), 54.35 (CH), 31.23 (CHCH₃), 27.33 (CH₃N), 19.31 (CH₃), 14.27 (CH₃); GCMS m/z (EI, +ve): found: 201.10 ([M]⁺), calculated for C₉H₁₅NO₄: 201.10.

cis-hydroxyester 2: (0.50 g, 25%). ¹H NMR (400 MHz, CDCl₃): δ 4.44 (d, J = 7.3 Hz, 1H), 4.19 (td, J = 7.2, 4.9 Hz, 2H), 3.74 (t, J = 6.6 Hz, 1H), 3.38 (t, J = 6.6 Hz, 1H), 2.82 (s, 3H), 1.32–1.23 (m, 6H); ¹³C NMR (100 MHz, CDCl₃): δ 172.82 (C=O), 169.59 (C=O), 70.88 (CHOH), 61.11 (OCH₂), 53.06 (CH), 49.21 (CHCH₃), 27.13 (CH₃N), 15.28 (CH₃), 14.37 (CH₃); GCMS m/z (EI, +ve): found: 201.10 ([M]⁺), calculated for C₉H₁₅NO₄: 201.10.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₉H₁₅NO₄
M_r	201.22
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	173
a, b, c (Å)	12.1599 (15), 8.6065 (8), 20.217 (2)
β (°)	101.960 (3)
V (Å³)	2069.9 (4)
Z	8
Radiation type	Mo Kα
μ (mm⁻¹)	0.10
Crystal size (mm)	0.2 × 0.2 × 0.1

Data collection
Diffractometer	Rigaku XtaLAB P200
Absorption correction	Multi-scan (REQAB; Rigaku, 1998 )
T_min, T_max	0.879, 0.990
No. of measured, independent and observed [I > 2σ(I)] reflections	11140, 1874, 1769
R_int	0.019
(sin θ/λ)_max (Å⁻¹)	0.603

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.033, 0.088, 1.04
No. of reflections	1874
No. of parameters	134
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.24, −0.18
Computer programs: CrystalClear-SM Expert (Rigaku, 2015 ), SHELXT2018/2 (Sheldrick, 2015a ), SHELXL2018/3 (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 2238498

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314623000755/bh4072sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314623000755/bh4072Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314623000755/bh4072Isup3.mol

Supporting information file. DOI: https://doi.org/10.1107/S2414314623000755/bh4072Isup4.cml

checkCIF report

Computing details top

Data collection: CrystalClear-SM Expert (Rigaku, 2015); cell refinement: CrystalClear-SM Expert (Rigaku, 2015); data reduction: CrystalClear-SM Expert (Rigaku, 2015); program(s) used to solve structure: SHELXT2018/2 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: Olex2 (Dolomanov et al., 2009); software used to prepare material for publication: Olex2 (Dolomanov et al., 2009).

rac-Ethyl rel-(2R,3R,4S)-4-hydroxy-1,2-dimethyl-5-oxopyrrolidine-3-carboxylate top

Crystal data top

C₉H₁₅NO₄	F(000) = 864
M_r = 201.22	D_x = 1.291 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71075 Å
a = 12.1599 (15) Å	Cell parameters from 3484 reflections
b = 8.6065 (8) Å	θ = 2.1–27.5°
c = 20.217 (2) Å	µ = 0.10 mm⁻¹
β = 101.960 (3)°	T = 173 K
V = 2069.9 (4) Å³	Prism, colorless
Z = 8	0.2 × 0.2 × 0.1 mm

Data collection top

Rigaku XtaLAB P200 diffractometer	1769 reflections with I > 2σ(I)
Detector resolution: 5.814 pixels mm^-1	R_int = 0.019
ω scans	θ_max = 25.4°, θ_min = 2.1°
Absorption correction: multi-scan (REQAB; Rigaku, 1998)	h = −14→14
T_min = 0.879, T_max = 0.990	k = −10→10
11140 measured reflections	l = −24→24
1874 independent reflections

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.033	Hydrogen site location: mixed
wR(F²) = 0.088	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0452P)² + 1.1669P] where P = (F_o² + 2F_c²)/3
1874 reflections	(Δ/σ)_max < 0.001
134 parameters	Δρ_max = 0.24 e Å⁻³
1 restraint	Δρ_min = −0.18 e Å⁻³

Special details top

Refinement. The hydroxyl H atom (H2) was refined with free coordinates and isotropic displacement parameter.

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

	x	y	z	U_iso*/U_eq
O1	0.65691 (7)	0.16087 (10)	0.24315 (4)	0.0360 (2)
O2	0.53577 (7)	0.18679 (11)	0.35435 (4)	0.0388 (2)
O3	0.58426 (9)	0.59491 (13)	0.40623 (5)	0.0556 (3)
O4	0.68278 (7)	0.49308 (10)	0.50163 (4)	0.0348 (2)
N1	0.78865 (8)	0.29976 (11)	0.31723 (5)	0.0282 (2)
C2	0.68560 (9)	0.24451 (13)	0.29333 (5)	0.0275 (3)
C3	0.60731 (9)	0.30292 (13)	0.33799 (5)	0.0278 (3)
H3	0.561557	0.391982	0.315420	0.033*
C4	0.68834 (9)	0.35965 (13)	0.40091 (5)	0.0259 (3)
H4	0.706096	0.271938	0.433837	0.031*
C1	0.79582 (9)	0.40440 (13)	0.37550 (5)	0.0275 (3)
H1	0.789576	0.514521	0.359380	0.033*
C9	0.88156 (10)	0.28015 (15)	0.28261 (6)	0.0359 (3)
H9A	0.902826	0.381524	0.267070	0.043*
H9B	0.858357	0.211119	0.243670	0.043*
H9C	0.946000	0.234634	0.313807	0.043*
C5	0.64421 (9)	0.49526 (13)	0.43501 (6)	0.0294 (3)
C6	0.64892 (11)	0.62159 (15)	0.54030 (6)	0.0364 (3)
H6A	0.566573	0.619870	0.537083	0.044*
H6B	0.669524	0.722225	0.522480	0.044*
C7	0.70872 (15)	0.60126 (19)	0.61170 (7)	0.0567 (4)
H7A	0.790035	0.600863	0.614059	0.068*
H7B	0.686220	0.502495	0.629065	0.068*
H7C	0.689349	0.687011	0.639073	0.068*
C8	0.90310 (10)	0.38489 (16)	0.42851 (6)	0.0374 (3)
H8A	0.967321	0.419643	0.410005	0.045*
H8B	0.912839	0.275194	0.441383	0.045*
H8C	0.898462	0.447241	0.468402	0.045*
H2	0.4729 (10)	0.174 (2)	0.3162 (6)	0.063 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0353 (5)	0.0407 (5)	0.0292 (4)	0.0041 (4)	0.0005 (3)	−0.0061 (4)
O2	0.0307 (4)	0.0512 (5)	0.0333 (5)	−0.0129 (4)	0.0038 (4)	0.0043 (4)
O3	0.0666 (7)	0.0579 (7)	0.0377 (5)	0.0363 (5)	0.0007 (5)	−0.0005 (4)
O4	0.0418 (5)	0.0345 (5)	0.0271 (4)	0.0084 (4)	0.0048 (3)	−0.0033 (3)
N1	0.0256 (5)	0.0321 (5)	0.0274 (5)	0.0024 (4)	0.0067 (4)	0.0004 (4)
C2	0.0280 (5)	0.0283 (6)	0.0247 (5)	0.0033 (4)	0.0022 (4)	0.0041 (4)
C3	0.0239 (5)	0.0324 (6)	0.0262 (6)	0.0001 (4)	0.0031 (4)	0.0030 (4)
C4	0.0238 (5)	0.0286 (6)	0.0247 (5)	0.0024 (4)	0.0034 (4)	0.0025 (4)
C1	0.0257 (5)	0.0273 (5)	0.0296 (6)	0.0003 (4)	0.0061 (4)	−0.0003 (4)
C9	0.0297 (6)	0.0449 (7)	0.0353 (6)	0.0061 (5)	0.0118 (5)	0.0014 (5)
C5	0.0248 (5)	0.0342 (6)	0.0291 (6)	0.0029 (5)	0.0054 (4)	0.0014 (5)
C6	0.0399 (7)	0.0341 (6)	0.0370 (7)	0.0036 (5)	0.0126 (5)	−0.0060 (5)
C7	0.0757 (10)	0.0528 (9)	0.0374 (7)	0.0168 (8)	0.0023 (7)	−0.0136 (6)
C8	0.0252 (6)	0.0478 (7)	0.0372 (6)	−0.0010 (5)	0.0021 (5)	−0.0065 (5)

Geometric parameters (Å, º) top

O1—C2	1.2340 (14)	C1—H1	1.0000
O2—C3	1.4087 (14)	C1—C8	1.5162 (16)
O2—H2	0.973 (5)	C9—H9A	0.9800
O3—C5	1.1957 (14)	C9—H9B	0.9800
O4—C5	1.3313 (14)	C9—H9C	0.9800
O4—C6	1.4620 (14)	C6—H6A	0.9900
N1—C2	1.3337 (15)	C6—H6B	0.9900
N1—C1	1.4709 (14)	C6—C7	1.4860 (19)
N1—C9	1.4569 (14)	C7—H7A	0.9800
C2—C3	1.5266 (15)	C7—H7B	0.9800
C3—H3	1.0000	C7—H7C	0.9800
C3—C4	1.5192 (15)	C8—H8A	0.9800
C4—H4	1.0000	C8—H8B	0.9800
C4—C1	1.5488 (14)	C8—H8C	0.9800
C4—C5	1.5095 (15)

C3—O2—H2	108.5 (10)	N1—C9—H9B	109.5
C5—O4—C6	116.81 (9)	N1—C9—H9C	109.5
C2—N1—C1	113.81 (9)	H9A—C9—H9B	109.5
C2—N1—C9	123.27 (10)	H9A—C9—H9C	109.5
C9—N1—C1	122.17 (9)	H9B—C9—H9C	109.5
O1—C2—N1	126.17 (10)	O3—C5—O4	123.63 (11)
O1—C2—C3	125.01 (10)	O3—C5—C4	124.81 (10)
N1—C2—C3	108.82 (9)	O4—C5—C4	111.53 (9)
O2—C3—C2	113.35 (10)	O4—C6—H6A	110.3
O2—C3—H3	109.8	O4—C6—H6B	110.3
O2—C3—C4	110.88 (9)	O4—C6—C7	107.16 (10)
C2—C3—H3	109.8	H6A—C6—H6B	108.5
C4—C3—C2	103.02 (8)	C7—C6—H6A	110.3
C4—C3—H3	109.8	C7—C6—H6B	110.3
C3—C4—H4	109.1	C6—C7—H7A	109.5
C3—C4—C1	104.33 (8)	C6—C7—H7B	109.5
C1—C4—H4	109.1	C6—C7—H7C	109.5
C5—C4—C3	113.62 (9)	H7A—C7—H7B	109.5
C5—C4—H4	109.1	H7A—C7—H7C	109.5
C5—C4—C1	111.32 (9)	H7B—C7—H7C	109.5
N1—C1—C4	101.50 (8)	C1—C8—H8A	109.5
N1—C1—H1	109.4	C1—C8—H8B	109.5
N1—C1—C8	113.44 (9)	C1—C8—H8C	109.5
C4—C1—H1	109.4	H8A—C8—H8B	109.5
C8—C1—C4	113.55 (9)	H8A—C8—H8C	109.5
C8—C1—H1	109.4	H8B—C8—H8C	109.5
N1—C9—H9A	109.5

O1—C2—C3—O2	45.04 (15)	C1—N1—C2—O1	176.42 (11)
O1—C2—C3—C4	164.92 (11)	C1—N1—C2—C3	−3.06 (12)
O2—C3—C4—C1	148.36 (9)	C1—C4—C5—O3	84.29 (14)
O2—C3—C4—C5	−90.22 (11)	C1—C4—C5—O4	−94.04 (11)
N1—C2—C3—O2	−135.48 (10)	C9—N1—C2—O1	6.15 (18)
N1—C2—C3—C4	−15.60 (12)	C9—N1—C2—C3	−173.33 (10)
C2—N1—C1—C4	19.89 (12)	C9—N1—C1—C4	−169.72 (9)
C2—N1—C1—C8	142.07 (10)	C9—N1—C1—C8	−47.54 (14)
C2—C3—C4—C1	26.79 (11)	C5—O4—C6—C7	−175.57 (11)
C2—C3—C4—C5	148.21 (9)	C5—C4—C1—N1	−151.06 (9)
C3—C4—C1—N1	−28.13 (10)	C5—C4—C1—C8	86.83 (11)
C3—C4—C1—C8	−150.24 (10)	C6—O4—C5—O3	−0.29 (17)
C3—C4—C5—O3	−33.14 (16)	C6—O4—C5—C4	178.06 (9)
C3—C4—C5—O4	148.53 (9)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O1ⁱ	0.97 (1)	1.78 (1)	2.7405 (12)	170 (2)
C1—H1···O1ⁱⁱ	1.00	2.62	3.3953 (14)	134
C9—H9A···O1ⁱⁱ	0.98	2.51	3.3355 (16)	142
C9—H9C···O3ⁱⁱⁱ	0.98	2.54	3.5086 (15)	169
C7—H7C···O1^iv	0.98	2.58	3.5134 (17)	160

Symmetry codes: (i) −x+1, y, −z+1/2; (ii) −x+3/2, y+1/2, −z+1/2; (iii) x+1/2, y−1/2, z; (iv) x, −y+1, z+1/2.

Funding information

The authors thank Universiti Teknologi MARA and the Malaysian Government (MOHE) for financial support [grant No. 600-RMC/SRC/5/3 (043/2020)].

References

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