(3R,4S)-3,4-Isopropyl­idenedioxy-3,4-dihydro-2H-pyrrole 1-oxide

Flores, M.F.; Garcia, P.; Garrido, N.M.; Sanz, F.; Diez, D.

doi:10.1107/S1600536811013055

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 67| Part 5| May 2011| Pages o1116-o1117

doi:10.1107/S1600536811013055

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(3R,4S)-3,4-Isopropylidenedioxy-3,4-dihydro-2H-pyrrole 1-oxide

Mari Fe Flores,^a Pilar Garcia,^a Narciso M. Garrido,^a Francisca Sanz ^b and David Diez ^a ^*

^aDepartamento de Quimica Organica, Universidad de Salamanca, Plaza de los Caidos, 37008-Salamanca, Spain, and ^bServicio General de Rayos X, Universidad de Salamanca, Plaza de los Caidos, 37008-Salamanca, Spain
^*Correspondence e-mail: ddm@usal.es

(Received 31 March 2011; accepted 7 April 2011; online 13 April 2011)

The title compound C₇H₁₁NO₃ was prepared by intramolecular nucleophilic displacement of 2,3-O-iso-propylidene-D-erythronolactol. There are two molecules in the asymmetric unit, which are related by a pseudo-inversion centre. The crystal structure determination confirms unequivocally the configuration of the chiral centres as 3S,4R. In the crystal structure, intermolecular C—H⋯O interactions link the molecules (into infinite zigzag chains along the a axis.

Related literature

Nitrones play a useful role in the synthesis of complex molecular frameworks, undergoing several synthetically useful reactions such as 1,3-dipolar cycloadditions (Tufariello, 1984 ) and nucleophilic addition (Merino et al., 2000 ; Lombardo & Trombini, 2002 ). They also allow direct access to nitrones by simple reactions, see: Döpp & Döpp (1990 ); Hamer & Macaluso (1964 ). For the use of the title compound as a starting material in the sythesis of potential therapeutic (antibiotic, antiviral, antitumoral) agents, see: Hall et al. (1997 ); Closa & Wightman (1998 ); McCaig et al. (1998 ); Cicchi et al. (2002 ); Revuelta et al. (2007 ). For a related structure, see: Keleşoğlu et al. (2010 ). For the preparation of the title compound, see: Flores et al. (2010 ); Cicchi et al. (2006 ).

Experimental

Crystal data

C₇H₁₁NO₃
M_r = 157.17
Monoclinic, C 2
a = 11.335 (2) Å
b = 5.4467 (11) Å
c = 26.508 (5) Å
β = 101.40 (3)°
V = 1604.2 (6) Å³
Z = 8
Cu Kα radiation
μ = 0.86 mm⁻¹
T = 298 K
0.15 × 0.10 × 0.08 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2006 ) T_min = 0.902, T_max = 0.934
4369 measured reflections
2365 independent reflections
2261 reflections with I > 2σ(I)
R_int = 0.022

Refinement

R[F² > 2σ(F²)] = 0.033
wR(F²) = 0.091
S = 1.05
2365 reflections
204 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.11 e Å⁻³
Absolute structure: Flack (1983 ), 761 Friedel pairs
Flack parameter: 0.0 (2)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O1ⁱ	0.93	2.44	3.366 (3)	171
C1—H1⋯O3ⁱⁱ	0.98	2.38	3.355 (3)	171
C2—H2A⋯O3ⁱⁱⁱ	0.97	2.70	3.441 (3)	134
C2—H2B⋯O3^iv	0.97	2.41	3.120 (3)	130
C2′—H2′1⋯O2′^v	0.97	2.49	3.247 (2)	135
C4′—H4′⋯O3′^vi	0.98	2.48	3.375 (3)	152
C2′—H2′2⋯O3′^vii	0.97	2.61	3.254 (2)	124
C3′—H3′⋯O3′^viii	0.93	2.48	3.345 (3)	156
Symmetry codes: (i) $[x+{\script{1\over 2}}, y+{\script{1\over 2}}, z]$ ; (ii) $[x-{\script{1\over 2}}, y+{\script{1\over 2}}, z]$ ; (iii) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+1]$ ; (iv) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+1]$ ; (v) $[x-{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ ; (vi) $[x+{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ ; (vii) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+2]$ ; (viii) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+2]$ .

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811013055/bt5507sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811013055/bt5507Isup2.hkl

checkCIF report

Comment top

Nitrones have been the subject of intense research efforts, because of the wide role played in the synthesis of complex molecular frameworks. They undergo several synthetically useful reactions such as 1,3-dipolar cycloadditions, (Tufariello et al., 1984) nucleophilic additions, (Merino et al., 2000; Lombardo et al., 2002). Both the reactions give rise to the formation of new carbon-carbon bonds, often with a high degree of stereocontrol. These features, together with the direct access to nitrones by simple reactions (Hamer et al., 1964; Döpp et al., 1990), and their stability which permits isolation and long storage, make nitrones ideal tools for application in organic syntheses, particularly in the field of alkaloids, nitrogen containing natural products or bioactive analogues. The construction of highly functionalized nitrogen heterocycles in a stereoselective manner is an important focus of medicinal and natural product chemistry. Although, in the last few years, the title compound has been reported more and more in the literature as a starting material due to its biological relevance in the synthesis of polyhydroxypyrrolidines or polyhydroxypyrrolizidines, both interesting compounds as potential glycosidase inhibitors and consequently as potential therapeutic (antibiotic, antiviral, antitumoral) agents (Hall et al., 1997; Closa et al., 1998; McCaig et al., 1998; Cicchi et al., 2002; Revuelta et al., 2007) there was not any crystallographic data.

Following our special interest in nitrogen compounds such as isoxazolidines, we prepared the title N-oxide, and its crystal structure is reported here.

The asymmetric unit contains two symmetrically independent molecules. The title molecule consists of a pyrroline-N-oxide ring with an isopropylidenedioxy as substituent. All the bond lengths and angles are within the normal ranges. The carbonyl group at N1 is coplanar with the pyrroline ring being the O3—N1=C3—C4 and O3'-N1'=C3'-C4' torsion angles of 179.1 (4)° and 179.2 (7)°, respectively. These results are in good agreement with the literature (Keleşoğlu et al., 2010).

In the crystal structure, intermolecular C—H···O interactions (Table 1) link the molecules (Fig. 2) into infinite zigzag chains along the a axis.

Related literature top

Nitrones play a useful role in the synthesis of complex molecular frameworks, undergoing several synthetically useful reactions such as 1,3-dipolar cycloadditions (Tufariello, 1984) and nucleophilic addition (Merino et al., 2000; Lombardo & Trombini, 2002). They also allow direct access to nitrones by simple reactions, see: Döpp & Döpp (1990); Hamer & Macaluso (1964). For the use of the title compound as a starting material in the sythesis of potential therapeutic (antibiotic, antiviral, antitumoral) agents, see: Hall et al. (1997); Closa & Wightman (1998); McCaig et al. (1998); Cicchi et al. (2002); Revuelta et al. (2007). For a related structure, see: Keleşoğlu et al. (2010). For the preparation of the title compound, see: Flores et al. (2010); Cicchi et al. (2006).

Experimental top

The title N-oxide was obtained by intramolecular nucleophilic displacement, which is based on a simple one-pot procedure employing NH₂OSiMe₂t-Bu, methanesulfonyl chloride, and 2,3-O-iso-propylidene-D-erythronolactol, according to the methodology described by Cicchi et al. (2006) and by us (Flores et al., 2010). Well shaped colourless single crystals were obtained by crystallization from CH₂Cl₂/MeOH.

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. Molecular structure of C₇H₁₁NO₃.
	Fig. 2. Crystal packing of C₇H₁₁NO₃ view along b axis, showing intermolecular hydrogen bonding.

(3R,4S)-3,4-Isopropylidenedioxy-3,4-dihydro-2H-pyrrole 1-oxide top

Crystal data top

C₇H₁₁NO₃	F(000) = 672
M_r = 157.17	D_x = 1.302 Mg m⁻³
Monoclinic, C2	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: C 2y	Cell parameters from 2365 reflections
a = 11.335 (2) Å	θ = 1.7–66.9°
b = 5.4467 (11) Å	µ = 0.86 mm⁻¹
c = 26.508 (5) Å	T = 298 K
β = 101.40 (3)°	Prismatic, colourless
V = 1604.2 (6) Å³	0.15 × 0.10 × 0.08 mm
Z = 8

Data collection top

Bruker APEXII CCD area-detector diffractometer	2365 independent reflections
Radiation source: fine-focus sealed tube	2261 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.022
phi and ω scans	θ_max = 66.9°, θ_min = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 2006)	h = −13→11
T_min = 0.902, T_max = 0.934	k = −6→5
4369 measured reflections	l = −28→31

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.033	w = 1/[σ²(F_o²) + (0.0479P)² + 0.4187P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.091	(Δ/σ)_max = 0.001
S = 1.05	Δρ_max = 0.16 e Å⁻³
2365 reflections	Δρ_min = −0.11 e Å⁻³
204 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.00105 (18)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 761 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.0 (2)

Crystal data top

C₇H₁₁NO₃	V = 1604.2 (6) Å³
M_r = 157.17	Z = 8
Monoclinic, C2	Cu Kα radiation
a = 11.335 (2) Å	µ = 0.86 mm⁻¹
b = 5.4467 (11) Å	T = 298 K
c = 26.508 (5) Å	0.15 × 0.10 × 0.08 mm
β = 101.40 (3)°

Data collection top

Bruker APEXII CCD area-detector diffractometer	2365 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2006)	2261 reflections with I > 2σ(I)
T_min = 0.902, T_max = 0.934	R_int = 0.022
4369 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.033	H-atom parameters constrained
wR(F²) = 0.091	Δρ_max = 0.16 e Å⁻³
S = 1.05	Δρ_min = −0.11 e Å⁻³
2365 reflections	Absolute structure: Flack (1983), 761 Friedel pairs
204 parameters	Absolute structure parameter: 0.0 (2)
1 restraint

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
O1'	0.30975 (12)	0.5460 (3)	0.84350 (5)	0.0571 (4)
O2'	0.44334 (11)	0.8279 (3)	0.88116 (5)	0.0566 (4)
O3'	0.14788 (12)	0.7976 (4)	0.96810 (6)	0.0693 (5)
N1'	0.23631 (12)	0.7223 (3)	0.94785 (5)	0.0481 (4)
C1'	0.33483 (16)	0.4762 (4)	0.89604 (7)	0.0476 (4)
H1'	0.3729	0.3142	0.9013	0.057*
C3'	0.34095 (15)	0.8196 (4)	0.95186 (6)	0.0464 (4)
H3'	0.3657	0.9601	0.9709	0.056*
C4'	0.41764 (14)	0.6811 (4)	0.92243 (6)	0.0463 (4)
H4'	0.4907	0.6168	0.9445	0.056*
C5'	0.40764 (17)	0.6940 (4)	0.83486 (7)	0.0525 (5)
C6'	0.3627 (3)	0.8714 (6)	0.79227 (9)	0.0866 (8)
H6'1	0.2985	0.9674	0.8009	0.130*
H6'2	0.3337	0.7826	0.7610	0.130*
H6'3	0.4271	0.9780	0.7876	0.130*
C7'	0.5109 (3)	0.5377 (6)	0.82529 (12)	0.0928 (9)
H7'1	0.4860	0.4458	0.7941	0.139*
H7'2	0.5349	0.4266	0.8536	0.139*
H7'3	0.5776	0.6413	0.8221	0.139*
C2'	0.22244 (16)	0.4919 (4)	0.91839 (8)	0.0553 (5)
H2'1	0.1510	0.4965	0.8913	0.066*
H2'2	0.2168	0.3528	0.9406	0.066*
O1	0.09613 (11)	0.3663 (3)	0.62016 (5)	0.0557 (4)
O2	0.21761 (13)	0.6589 (3)	0.66182 (5)	0.0666 (5)
O3	0.36792 (14)	0.3733 (4)	0.52993 (7)	0.0861 (6)
N1	0.29356 (13)	0.4731 (4)	0.55436 (6)	0.0544 (4)
C1	0.10961 (15)	0.5348 (4)	0.58059 (7)	0.0514 (5)
H1	0.0341	0.6186	0.5659	0.062*
C2	0.16439 (16)	0.4088 (4)	0.54033 (7)	0.0556 (5)
H2A	0.1530	0.2325	0.5413	0.067*
H2B	0.1293	0.4687	0.5062	0.067*
C3	0.31507 (17)	0.6385 (4)	0.58935 (8)	0.0586 (5)
H3	0.3910	0.7049	0.6014	0.070*
C4	0.20620 (17)	0.7127 (4)	0.60855 (7)	0.0522 (5)
H4	0.1847	0.8848	0.6007	0.063*
C5	0.12362 (18)	0.4967 (4)	0.66756 (7)	0.0558 (5)
C6	0.0151 (3)	0.6365 (7)	0.67681 (11)	0.0971 (10)
H6A	−0.0464	0.5228	0.6816	0.146*
H6B	−0.0148	0.7394	0.6477	0.146*
H6C	0.0374	0.7365	0.7070	0.146*
C7	0.1714 (3)	0.3142 (6)	0.70956 (9)	0.0882 (8)
H7A	0.2404	0.2320	0.7016	0.132*
H7B	0.1101	0.1958	0.7120	0.132*
H7C	0.1942	0.3990	0.7418	0.132*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1'	0.0642 (8)	0.0626 (10)	0.0440 (7)	−0.0248 (7)	0.0098 (6)	−0.0060 (6)
O2'	0.0573 (7)	0.0637 (9)	0.0517 (7)	−0.0225 (7)	0.0178 (6)	−0.0098 (7)
O3'	0.0556 (7)	0.0876 (12)	0.0713 (9)	0.0236 (8)	0.0283 (7)	0.0071 (9)
N1'	0.0431 (7)	0.0554 (10)	0.0467 (8)	0.0091 (7)	0.0108 (6)	0.0067 (7)
C1'	0.0541 (9)	0.0433 (10)	0.0471 (9)	0.0010 (9)	0.0142 (8)	0.0032 (8)
C3'	0.0484 (9)	0.0476 (10)	0.0420 (9)	−0.0002 (8)	0.0061 (7)	0.0000 (8)
C4'	0.0374 (8)	0.0565 (12)	0.0434 (9)	0.0022 (8)	0.0042 (7)	0.0000 (9)
C5'	0.0612 (11)	0.0527 (12)	0.0467 (10)	−0.0157 (9)	0.0176 (8)	−0.0056 (9)
C6'	0.115 (2)	0.0827 (19)	0.0616 (13)	−0.0206 (17)	0.0163 (13)	0.0152 (14)
C7'	0.1036 (19)	0.084 (2)	0.108 (2)	0.0040 (17)	0.0634 (17)	−0.0118 (18)
C2'	0.0509 (10)	0.0578 (12)	0.0581 (11)	−0.0114 (10)	0.0127 (8)	−0.0032 (10)
O1	0.0564 (7)	0.0588 (9)	0.0530 (7)	−0.0180 (7)	0.0137 (6)	−0.0052 (7)
O2	0.0758 (9)	0.0742 (12)	0.0499 (8)	−0.0306 (9)	0.0126 (6)	−0.0074 (8)
O3	0.0679 (9)	0.1030 (15)	0.0940 (11)	0.0252 (10)	0.0316 (8)	−0.0034 (12)
N1	0.0472 (8)	0.0598 (10)	0.0560 (9)	0.0068 (8)	0.0098 (7)	0.0045 (9)
C1	0.0395 (8)	0.0617 (14)	0.0502 (10)	0.0022 (9)	0.0022 (7)	0.0044 (9)
C2	0.0511 (10)	0.0646 (14)	0.0488 (10)	−0.0048 (9)	0.0045 (8)	−0.0025 (10)
C3	0.0465 (9)	0.0662 (14)	0.0612 (11)	−0.0129 (9)	0.0061 (8)	0.0058 (11)
C4	0.0600 (11)	0.0397 (10)	0.0572 (11)	−0.0048 (9)	0.0127 (9)	0.0008 (9)
C5	0.0627 (11)	0.0549 (12)	0.0523 (10)	−0.0128 (10)	0.0179 (8)	−0.0059 (10)
C6	0.0920 (19)	0.112 (3)	0.098 (2)	0.0096 (19)	0.0441 (16)	−0.018 (2)
C7	0.127 (2)	0.0758 (18)	0.0603 (13)	−0.0100 (18)	0.0159 (13)	0.0090 (14)

Geometric parameters (Å, º) top

O1'—C1'	1.417 (2)	O1—C5	1.423 (2)
O1'—C5'	1.426 (2)	O1—C1	1.425 (2)
O2'—C5'	1.416 (2)	O2—C5	1.415 (2)
O2'—C4'	1.431 (2)	O2—C4	1.423 (2)
O3'—N1'	1.2937 (19)	O3—N1	1.281 (2)
N1'—C3'	1.284 (2)	N1—C3	1.282 (3)
N1'—C2'	1.470 (3)	N1—C2	1.480 (2)
C1'—C2'	1.510 (2)	C1—C2	1.502 (3)
C1'—C4'	1.535 (3)	C1—C4	1.538 (3)
C1'—H1'	0.9800	C1—H1	0.9800
C3'—C4'	1.484 (3)	C2—H2A	0.9700
C3'—H3'	0.9300	C2—H2B	0.9700
C4'—H4'	0.9800	C3—C4	1.481 (3)
C5'—C6'	1.497 (3)	C3—H3	0.9300
C5'—C7'	1.509 (4)	C4—H4	0.9800
C6'—H6'1	0.9600	C5—C6	1.507 (3)
C6'—H6'2	0.9600	C5—C7	1.511 (4)
C6'—H6'3	0.9600	C6—H6A	0.9600
C7'—H7'1	0.9600	C6—H6B	0.9600
C7'—H7'2	0.9600	C6—H6C	0.9600
C7'—H7'3	0.9600	C7—H7A	0.9600
C2'—H2'1	0.9700	C7—H7B	0.9600
C2'—H2'2	0.9700	C7—H7C	0.9600

C1'—O1'—C5'	107.35 (14)	C5—O1—C1	106.97 (16)
C5'—O2'—C4'	107.96 (15)	C5—O2—C4	108.22 (15)
C3'—N1'—O3'	127.85 (19)	O3—N1—C3	127.89 (18)
C3'—N1'—C2'	113.34 (15)	O3—N1—C2	119.33 (19)
O3'—N1'—C2'	118.74 (16)	C3—N1—C2	112.67 (16)
O1'—C1'—C2'	110.46 (15)	O1—C1—C2	110.37 (18)
O1'—C1'—C4'	103.80 (15)	O1—C1—C4	102.75 (14)
C2'—C1'—C4'	105.50 (15)	C2—C1—C4	105.98 (15)
O1'—C1'—H1'	112.2	O1—C1—H1	112.4
C2'—C1'—H1'	112.2	C2—C1—H1	112.4
C4'—C1'—H1'	112.2	C4—C1—H1	112.4
N1'—C3'—C4'	111.98 (18)	N1—C2—C1	103.94 (16)
N1'—C3'—H3'	124.0	N1—C2—H2A	111.0
C4'—C3'—H3'	124.0	C1—C2—H2A	111.0
O2'—C4'—C3'	110.31 (17)	N1—C2—H2B	111.0
O2'—C4'—C1'	104.86 (13)	C1—C2—H2B	111.0
C3'—C4'—C1'	103.90 (14)	H2A—C2—H2B	109.0
O2'—C4'—H4'	112.4	N1—C3—C4	112.86 (17)
C3'—C4'—H4'	112.4	N1—C3—H3	123.6
C1'—C4'—H4'	112.4	C4—C3—H3	123.6
O2'—C5'—O1'	104.48 (13)	O2—C4—C3	111.49 (17)
O2'—C5'—C6'	108.5 (2)	O2—C4—C1	105.37 (15)
O1'—C5'—C6'	109.05 (19)	C3—C4—C1	102.97 (17)
O2'—C5'—C7'	109.8 (2)	O2—C4—H4	112.2
O1'—C5'—C7'	111.2 (2)	C3—C4—H4	112.2
C6'—C5'—C7'	113.4 (2)	C1—C4—H4	112.2
C5'—C6'—H6'1	109.5	O2—C5—O1	104.75 (13)
C5'—C6'—H6'2	109.5	O2—C5—C6	111.0 (2)
H6'1—C6'—H6'2	109.5	O1—C5—C6	110.64 (19)
C5'—C6'—H6'3	109.5	O2—C5—C7	108.8 (2)
H6'1—C6'—H6'3	109.5	O1—C5—C7	107.8 (2)
H6'2—C6'—H6'3	109.5	C6—C5—C7	113.4 (2)
C5'—C7'—H7'1	109.5	C5—C6—H6A	109.5
C5'—C7'—H7'2	109.5	C5—C6—H6B	109.5
H7'1—C7'—H7'2	109.5	H6A—C6—H6B	109.5
C5'—C7'—H7'3	109.5	C5—C6—H6C	109.5
H7'1—C7'—H7'3	109.5	H6A—C6—H6C	109.5
H7'2—C7'—H7'3	109.5	H6B—C6—H6C	109.5
N1'—C2'—C1'	104.30 (16)	C5—C7—H7A	109.5
N1'—C2'—H2'1	110.9	C5—C7—H7B	109.5
C1'—C2'—H2'1	110.9	H7A—C7—H7B	109.5
N1'—C2'—H2'2	110.9	C5—C7—H7C	109.5
C1'—C2'—H2'2	110.9	H7A—C7—H7C	109.5
H2'1—C2'—H2'2	108.9	H7B—C7—H7C	109.5

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O1ⁱ	0.93	2.44	3.366 (3)	171
C1—H1···O3ⁱⁱ	0.98	2.38	3.355 (3)	171
C2—H2A···O3ⁱⁱⁱ	0.97	2.70	3.441 (3)	134
C2—H2B···O3^iv	0.97	2.41	3.120 (3)	130
C2′—H2′1···O2′^v	0.97	2.49	3.247 (2)	135
C4′—H4′···O3′^vi	0.98	2.48	3.375 (3)	152
C2′—H2′2···O3′^vii	0.97	2.61	3.254 (2)	124
C3′—H3′···O3′^viii	0.93	2.48	3.345 (3)	156

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

Experimental details

Crystal data
Chemical formula	C₇H₁₁NO₃
M_r	157.17
Crystal system, space group	Monoclinic, C2
Temperature (K)	298
a, b, c (Å)	11.335 (2), 5.4467 (11), 26.508 (5)
β (°)	101.40 (3)
V (Å³)	1604.2 (6)
Z	8
Radiation type	Cu Kα
µ (mm⁻¹)	0.86
Crystal size (mm)	0.15 × 0.10 × 0.08

Data collection
Diffractometer	Bruker APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2006)
T_min, T_max	0.902, 0.934
No. of measured, independent and observed [I > 2σ(I)] reflections	4369, 2365, 2261
R_int	0.022
(sin θ/λ)_max (Å⁻¹)	0.596

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.033, 0.091, 1.05
No. of reflections	2365
No. of parameters	204
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.16, −0.11
Absolute structure	Flack (1983), 761 Friedel pairs
Absolute structure parameter	0.0 (2)

Computer programs: APEX2 (Bruker, 2006), SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2006).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O1ⁱ	0.93	2.44	3.366 (3)	171
C1—H1···O3ⁱⁱ	0.98	2.38	3.355 (3)	171
C2—H2A···O3ⁱⁱⁱ	0.97	2.70	3.441 (3)	134
C2—H2B···O3^iv	0.97	2.41	3.120 (3)	130
C2'—H2'1···O2'^v	0.97	2.49	3.247 (2)	135
C4'—H4'···O3'^vi	0.98	2.48	3.375 (3)	152
C2'—H2'2···O3'^vii	0.97	2.61	3.254 (2)	124
C3'—H3'···O3'^viii	0.93	2.48	3.345 (3)	156

Acknowledgements

The authors are grateful to the MICINN (CTQ2009–11172), Junta de Castilla y Leon, for financial support (GR178 and SA001A09) and for the doctoral fellowships awarded to MFF.

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