5-Hydroxy­alkyl derivatives of tert-butyl 2-oxo-2,5-dihydro-1H-pyrrole-1-carboxyl­ate: diastereoselectivity of the Mukaiyama crossed-aldol-type reaction

The title compounds, rac-(1′R,2R)-tert-butyl 2-(1′-hydroxy­ethyl)-3-(2-nitro­phen­yl)-5-oxo-2,5-dihydro-1H-pyrrole-1-car­box­yl­ate, C₁₇H₂₀N₂O₆, (I), rac-(1′S,2R)-tert-butyl 2-[1′-hy­droxy-3′-(methoxy­carbon­yl)prop­yl]-3-(2-nitro­phen­yl)-5-oxo-2,5-di­hydro-1H-pyrrole-1-carboxyl­ate, C₂₀H₂₄N₂O₈, (II), and rac-(1′S,2R)-tert-butyl 2-(4′-bromo-1′-hydroxy­butyl)-5-oxo-2,5-di­hydro-1H-pyrrole-1-carboxyl­ate, C₁₃H₂₀BrNO₄, (III), are 5-hy­droxy­alkyl derivatives of tert-butyl 2-oxo-2,5-dihydro­pyrrole-1-carboxyl­ate. In all three compounds, the tert-butoxy­carbonyl (Boc) unit is orientated in the same manner with respect to the mean plane through the 2-oxo-2,5-dihydro-1H-pyrrole ring. The hydroxyl substituent at one of the newly created chiral centres, which have relative R,R stereochemistry, is trans with respect to the oxo group of the pyrrole ring in (I), synthesized using acetaldehyde. When a larger aldehyde was used, as in compounds (II) and (III), the hydroxyl substituent was found to be cis with respect to the oxo group of the pyrrole ring. Here, the relative stereochemistry of the newly created chiral centres is R,S. In compound (I), O—H...O hydrogen bonding leads to an inter­esting hexa­gonal arrangement of symmetry-related mol­ecules. In (II) and (III), the hydroxyl groups are involved in bifurcated O—H...O hydrogen bonds, and centrosymmetric hydrogen-bonded dimers are formed. The Mukaiyama crossed-aldol-type reaction was successful when using the 2-nitro­phenyl-substituted hydroxy­pyrrole, or the unsubstituted hydroxy­pyrrole, and boron trifluoride diethyl ether as catalyst. The synthetic procedure leads to a syn configuration of the two newly created chiral centres in all three compounds.

S1. Comment

The natural product (-)-rhazinilam was first isolated by Linde in 1965 from Melodinus australis (Baudoin et al., 2004). The tetracyclic structure was determined by a combination of X-ray analysis and chemical studies 7 years later (De Silva et al., 1972). Screening experiments have shown that (-)-rhazinilam has interesting pharmacological properties, due to its interference in the tubuline–microtubule equilibrium during mitosis. It has also been shown to have significant in vitro cytotoxicity, but no activity in vivo (Baudoin et al., 2004). Several groups have reported their studies on the synthesis of this natural product and its analogues (Decor et al., 2006; Baudoin et al., 2002; Ghosez et al., 2001; Rubio et al., 2001; Dupont et al., 2000; Alazard et al., 1996). Our synthetic strategy was to replace the pyrrole ring by a corresponding pyrrol-2(5H)-one ring or its protected 2-hydroxypyrrole tautomer (Vallat et al., 2009).

In order to introduce the missing side chain needed for the formation of ring B of rhazinilam, we tested the known Mukaiyama crossed-aldol-type reaction (Mukaiyama et al., 1974) of the protected 2-hydroxypyrrole with different aldehydes. This reaction was successful when using the 2-nitrophenyl-substituted hydroxypyrrole (1), or the unsubstituted hydroxypyrrole (2), and boron trifluoride diethyl ether as catalyst. The relative configuration at the two newly formed chiral centres could not be determined unequivocally using NMR methods. A literature search showed that the Boc-protected (Boc is tert-butoxycarbonyl) TBS-silyloxy-pyrrole (2) had been used in a series of very elegant natural product syntheses (Battistini et al., 2004; Rassu et al., 2002, 2003; Barnes et al., 2002; Casiraghi et al., 1992; DeGoey et al., 2002). The diastereoselectivity of the reaction with a series of chiral aldehydes and imines has been carefully studied and was shown, for most of the reported processes, to be syn. However, the reaction using the imine has been reported to be anti selective (Barnes et al., 2002; DeGoey et al., 2002). The diastereoselectivity of the crossed-aldol-type reaction using a phenyl-substituted pyrrole has not been reported previously, to our knowledge. We report here the crystal structures of tert-butyl 2-(1-hydroxyethyl)-3-(2-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate, (I), tert-butyl 2-[1-hydroxy-3-(methoxycarbonyl)propyl]-3-(2-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate, (II), and tert-butyl 2-(4-bromo-1-hydroxybutyl)-5-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate, (III), which were studied to determine the diastereoselectivity of the Mukaiyama crossed-aldol-type reaction.

The molecular structures of compounds (I), (II) and (III) are illustrated in Figs. 1, 3 and 5, respectively. The crystal packing in compounds (I), (II) and (III), also showing the hydrogen bonding, are illustrated in Figs. 2, 4 and 6, respectively. The bond lengths and angles in all three compounds are in normal ranges (Allen et al., 1987). Details of the hydrogen bonding are given in Tables 1, 2 and 3, respectively.

All three compounds contain a 2-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate unit that has a very similar geometry. In compounds (I) and (II), the 2-nitrophenyl substituent at C3 is inclined to the best plane through the 2,5-dihydro-1H-pyrrole ring by 52.47 (6) and 71.25 (11)°, respectively. The orientation of the hydroxyl substituent at C10 in compound (I) (Fig. 1) is different to that in compounds (II) (Fig. 3) and (III) (Fig. 5). In (I), it lies trans with respect to the 2,5-dihydro-1H-pyrrole ring, and the C10—O4 bond makes an angle of 1.16 (9)° with the mean plane of the pyrrole ring. In compounds (II) and (III), however, it is cis with respect to the pyrrole ring, and here the C10—O4 bond is inclined to the pyrrole ring mean plane by 55.22 (11)° in (II), and 56.08 (11)° in (III).

In all three compounds, O—H···O hydrogen bonds play an important role. In the crystal structure of compound (I), a hexagonal arrangement of symmetry-related molecules is formed (Fig. 2 and Table 1). In compounds (II) and (III), the hydroxyl group is involved in bifurcated O—H···O hydrogen bonds, and in both crystal structures centrosymmetric hydrogen-bonded dimers are formed (Figs. 4 and 6, and Tables 2 and 3, respectively).

The relative stereochemistry of the newly created chiral centres in compound (I), at C4 and C10, is R,R. When a larger aldehyde was used, as in the case of compounds (II) and (III), the relative stereochemistry of the newly created chiral centres is R,S. The synthetic procedure used led to a syn configuration of the two newly created chiral centres in all three compounds, in close analogy to reports in the literature (Battistini et al., 2004; Rassu et al., 2002, 2003; Casiraghi et al., 1992). Changing the Lewis acid, that is using BF₃ instead of SnCl₄, and introducing an aryl substituent at the carbon next to the nucleophilic centre, does not influence the diastereoselectivity of the process. An extended transition state respecting the Bürgi–Dunitz angle (Bürgi & Dunitz, 1974) is compatible with these results.

Related literature

For related literature, see: Alazard et al. (1996); Allen et al. (1987); Bürgi & Dunitz (1974); Barnes et al. (2002); Battistini et al. (2004); Baudoin et al. (2004); Casiraghi et al. (1992); De Silva, Ratcliffe, Smith & Smith (1972); DeGoey, Chen, Flosi, Grampovnik, Yeung, Klein & Kempf (2002); Decor et al. (2006); Dupont et al. (2000); Ghosez et al. (2001); Mukaiyama et al. (1974); Rassu et al. (2002, 2003); Rubio & Bornmann (2001).

S2. Experimental

For the preparation of compound (I), acetaldehyde (0.18 ml, 3.20 mmol) and BF₃.OEt₂ (0.47 ml, 3.78 mmol) were added dropwise to a solution of tert-butyl 2-(tert-butyldimethylsilyloxy)-4-(2-nitrophenyl)-1H-pyrrole-1-carboxylate (1.22 g, 2.91 mmol) in dry CH₂Cl₂ (30 ml) at 195 K under argon. The colour of the solution changed from yellow to light yellow. The mixture was stirred at 195 K for 1 h. The reaction mixture was quenched at 195 K with a saturated aqueous solution of NaHCO₃ (20 ml) and the aqueous layer was extracted with CH₂Cl₂. The combined organic layers were washed with brine, dried over MgSO₄ and concentrated. Purification of the residue by flash chromatography (silica gel, ethyl acetate–dichloromethane 4:6 v/v) afforded the aldol product (3) as a white solid (yield 0.53 g, 52%). Crystals suitable for X-ray analysis were otained by slow evaporation of an ether–hexane (1:1) solution.

For the preparation of compound (II), methyl 4-oxobutanoate (348 mg, 3.0 mmol) and BF₃.OEt₂ (0.38 ml, 2.3 mmol) were added dropwise to a solution of tert-butyl 2-(tert-butyldimethylsilyloxy)-4-(2-nitrophenyl)-1H-pyrrole-1-carboxylate (966 mg, 2.3 mmol) in dry CH₂Cl₂ (20 ml) at 195 K under argon. The colour of the solution changed from yellow to light yellow. The mixture was stirred at 195 K for 1 h. The reaction mixture was quenched at 195 K with a saturated aqueous solution of NaHCO₃ (15 ml) and the aqueous layer was extracted with CH₂Cl₂. The combined organic layers were washed with brine, dried over MgSO₄ and concentrated. Purification of the residue by flash chromatography (silica gel, ethyl acetate–diethyl ether 3:7 v/v) afforded the aldol product (4) as a white solid (yield 815 mg, 93%). Crystals suitable for X-ray analysis were otained by slow evaporation of an ether–hexane (1:1) solution.

For the preparation of compound (III), 4-bromobutanal (0.35 g, 2.31 mmol) and BF₃.OEt₂ (0.29 ml, 2.31 mmol) were added dropwise to a solution of tert-butyl 2-(tert-butyldimethylsilyloxy)-1H-pyrrole-1-carboxylate (0.68 g, 2.31 mmol) in dry CH₂Cl₂ (20 ml) at 195 K under argon. The colour of the solution changed from yellow to light yellow. The mixture was stirred at 195 K for 1 h. The reaction mixture was quenched at 195 K with a saturated aqueous solution of NaHCO₃ (15 ml) and the aqueous layer was extracted with CH₂Cl₂. The combined organic layers were washed with brine, dried over MgSO₄ and concentrated. Purification of the residue by flash chromatography (silica gel, ethyl acetate–dichloromethane 3:7 v/v) afforded the aldol product (5) as a white solid (yield 0.30 g, 39%). Crystals suitable for X-ray analysis were otained by slow evaporation of an ether–hexane (1:1) solution.

S3. Refinement

In compound (I), the hydroxyl H atom was located from a difference Fourier map and freely refined [O—H = 0.852 (18) Å]. For compounds (II) and (III), the hydroxyl H atoms were included in calculated positions and treated as riding [O—H = 0.84 Å and U_iso(H) = 1.5U_eq(O)]. The C-bound H atoms in all three compounds were included in calculated positions and treated as riding atoms [C—H = 0.95–1.00Å and U_iso(H) = 1.2 or 1.5U_eq(C)]. A small cusp of data is missing for structure (II): this problem is related to the image-plate diffractometer using only one azimuthal scan. A fraction of the reciprocal lattice points never intersect the Ewald sphere and so a small cusp of data is missing. This has a small effect on the precision of the structure analysis, which can be seen when comparing the s.u. values of structure (II) with those of structures (I) and (III); for example, on average, the bond distances differ by 5 s.u., whereas for structures (I) and (III) they differ by only 2 s.u.

Computing details

For all compounds, data collection: X-AREA (Stoe & Cie, 2006); cell refinement: X-AREA (Stoe & Cie, 2006); data reduction: X-RED32 (Stoe & Cie, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of compound (I), showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.
	Fig. 2. A partial cell view along the c axis of the crystal packing of compound (I), showing the formation of the hexagonal arrangement of symmetry-related hydrogen-bonded molecules (see Table 1 for details). Hydrogen bonds are shown as dotted lines and H atoms not involved in hydrogen bonding have been omitted for clarity.
	Fig. 3. The molecular structure of compound (II), showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.
	Fig. 4. A view along the a axis of the crystal packing of compound (II), showing the bifurcated hydrogen bonds and the formation of the centrosymmetric hydrogen-bonded dimers (see Table 2 for details). Hydrogen bonds are shown as dotted lines and H atoms not involved in hydrogen bonding have been omitted for clarity.
	Fig. 5. The molecular structure of compound (III), showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.
	Fig. 6. A cell view along the a axis of compound (III), showing the bifurcated hydrogen bonds and the formation of the centrosymmetric hydrogen-bonded dimers (see Table 3 for details). Hydrogen bonds are shown as dotted lines and H atoms not involved in hydrogen bonding have been omitted for clarity.

(I) tert-butyl 2-(1-hydroxyethyl)-3-(2-nitrophenyl)-5-oxo-2,5-dihydro- 1H-pyrrole-1-carboxylate

Crystal data

C17H20N2O6	Dx = 1.327 Mg m^−3
Mr = 348.35	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3	Cell parameters from 37232 reflections
Hall symbol: -R 3	θ = 1.9–29.6°
a = 21.1117 (8) Å	µ = 0.10 mm^−1
c = 20.3244 (9) Å	T = 173 K
V = 7845.0 (5) Å^3	Block, pale violet
Z = 18	0.45 × 0.45 × 0.45 mm
F(000) = 3312

Data collection

Stoe IPDS-2 diffractometer	4041 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.089
Graphite monochromator	θmax = 29.3°, θmin = 1.9°
ϕ and ω scans	h = −28→29
39673 measured reflections	k = −28→28
4718 independent reflections	l = −25→27

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.039	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.098	w = 1/[σ^2(Fo^2) + (0.0345P)^2 + 5.9651P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max < 0.001
4718 reflections	Δρmax = 0.27 e Å^−3
235 parameters	Δρmin = −0.17 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00059 (14)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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	0.29424 (5)	0.41562 (5)	0.00122 (5)	0.0391 (3)
O2	0.21212 (5)	0.28894 (5)	0.07457 (5)	0.0480 (3)
O3	0.25771 (5)	0.21244 (4)	0.06812 (4)	0.0371 (3)
O4	0.41816 (5)	0.23954 (4)	−0.06199 (5)	0.0372 (3)
O5	0.50360 (5)	0.38580 (5)	0.09835 (4)	0.0417 (3)
O6	0.56788 (6)	0.33232 (5)	0.09317 (5)	0.0447 (3)
N1	0.31770 (5)	0.32006 (5)	0.01879 (5)	0.0294 (3)
N2	0.54177 (5)	0.36699 (5)	0.06844 (4)	0.0295 (2)
C1	0.33427 (6)	0.39007 (6)	−0.00134 (5)	0.0287 (3)
C2	0.40944 (6)	0.42536 (5)	−0.02579 (5)	0.0278 (3)
C3	0.43615 (5)	0.38024 (5)	−0.02026 (5)	0.0244 (2)
C4	0.37748 (5)	0.30600 (5)	0.00296 (6)	0.0270 (3)
C5	0.25675 (6)	0.27380 (6)	0.05644 (6)	0.0320 (3)
C6	0.20133 (6)	0.15371 (6)	0.10954 (6)	0.0353 (3)
C7	0.20589 (10)	0.18259 (9)	0.17826 (7)	0.0559 (5)
C8	0.12653 (8)	0.12481 (9)	0.07984 (9)	0.0595 (5)
C9	0.22464 (9)	0.09680 (8)	0.10738 (8)	0.0513 (5)
C10	0.35612 (6)	0.24733 (6)	−0.05118 (6)	0.0342 (3)
C11	0.33351 (8)	0.26656 (8)	−0.11510 (8)	0.0489 (4)
C12	0.51070 (5)	0.39876 (5)	−0.03979 (5)	0.0234 (3)
C13	0.53620 (6)	0.42848 (5)	−0.10190 (5)	0.0273 (3)
C14	0.60600 (6)	0.44736 (6)	−0.12258 (5)	0.0305 (3)
C15	0.65207 (6)	0.43617 (6)	−0.08213 (6)	0.0322 (3)
C16	0.62888 (6)	0.40740 (6)	−0.02006 (5)	0.0286 (3)
C17	0.55966 (5)	0.39000 (5)	−0.00005 (5)	0.0243 (3)
H2	0.43550	0.47360	−0.04310	0.0330*
H4	0.39390	0.29140	0.04350	0.0320*
H4O	0.4094 (9)	0.1984 (10)	−0.0466 (8)	0.050 (4)*
H7A	0.19070	0.21950	0.17780	0.0840*
H7B	0.25630	0.20470	0.19420	0.0840*
H7C	0.17350	0.14230	0.20740	0.0840*
H8A	0.12740	0.11170	0.03370	0.0890*
H8B	0.11250	0.16250	0.08220	0.0890*
H8C	0.09100	0.08140	0.10420	0.0890*
H9A	0.22470	0.08200	0.06170	0.0770*
H9B	0.27390	0.11730	0.12580	0.0770*
H9C	0.19040	0.05410	0.13320	0.0770*
H10	0.31500	0.19980	−0.03470	0.0410*
H11A	0.37550	0.30970	−0.13440	0.0730*
H11B	0.31630	0.22530	−0.14570	0.0730*
H11C	0.29400	0.27720	−0.10680	0.0730*
H13	0.50510	0.43600	−0.13070	0.0330*
H14	0.62230	0.46820	−0.16500	0.0370*
H15	0.69950	0.44820	−0.09700	0.0390*
H16	0.66010	0.39970	0.00840	0.0340*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0436 (5)	0.0381 (4)	0.0497 (5)	0.0309 (4)	0.0099 (4)	0.0058 (4)
O2	0.0417 (5)	0.0501 (5)	0.0662 (6)	0.0334 (5)	0.0241 (4)	0.0187 (5)
O3	0.0361 (4)	0.0315 (4)	0.0479 (5)	0.0200 (3)	0.0182 (4)	0.0127 (3)
O4	0.0361 (4)	0.0246 (4)	0.0577 (5)	0.0203 (3)	0.0199 (4)	0.0106 (4)
O5	0.0480 (5)	0.0603 (6)	0.0284 (4)	0.0358 (5)	0.0067 (3)	−0.0001 (4)
O6	0.0559 (6)	0.0532 (5)	0.0383 (5)	0.0373 (5)	0.0082 (4)	0.0166 (4)
N1	0.0285 (4)	0.0258 (4)	0.0390 (5)	0.0174 (4)	0.0083 (4)	0.0037 (4)
N2	0.0314 (4)	0.0307 (4)	0.0272 (4)	0.0162 (4)	0.0024 (3)	0.0024 (3)
C1	0.0328 (5)	0.0266 (5)	0.0321 (5)	0.0190 (4)	0.0024 (4)	−0.0009 (4)
C2	0.0307 (5)	0.0217 (4)	0.0323 (5)	0.0140 (4)	0.0007 (4)	−0.0005 (4)
C3	0.0256 (4)	0.0212 (4)	0.0262 (4)	0.0115 (4)	−0.0001 (4)	−0.0016 (3)
C4	0.0238 (4)	0.0229 (4)	0.0370 (5)	0.0138 (4)	0.0064 (4)	0.0030 (4)
C5	0.0299 (5)	0.0327 (5)	0.0377 (6)	0.0189 (4)	0.0068 (4)	0.0047 (4)
C6	0.0348 (6)	0.0319 (5)	0.0363 (6)	0.0144 (5)	0.0112 (4)	0.0085 (4)
C7	0.0747 (11)	0.0519 (8)	0.0388 (7)	0.0299 (8)	0.0134 (7)	0.0043 (6)
C8	0.0397 (7)	0.0500 (8)	0.0744 (11)	0.0117 (6)	−0.0006 (7)	0.0060 (7)
C9	0.0609 (9)	0.0384 (7)	0.0585 (9)	0.0278 (6)	0.0215 (7)	0.0177 (6)
C10	0.0249 (5)	0.0208 (5)	0.0546 (7)	0.0098 (4)	0.0100 (4)	−0.0040 (4)
C11	0.0381 (6)	0.0556 (8)	0.0576 (8)	0.0269 (6)	−0.0162 (6)	−0.0285 (7)
C12	0.0242 (4)	0.0170 (4)	0.0269 (5)	0.0088 (3)	0.0010 (3)	−0.0014 (3)
C13	0.0293 (5)	0.0218 (4)	0.0263 (5)	0.0095 (4)	−0.0017 (4)	0.0001 (4)
C14	0.0314 (5)	0.0245 (5)	0.0266 (5)	0.0072 (4)	0.0046 (4)	0.0009 (4)
C15	0.0248 (5)	0.0310 (5)	0.0344 (5)	0.0091 (4)	0.0061 (4)	0.0006 (4)
C16	0.0257 (5)	0.0272 (5)	0.0320 (5)	0.0126 (4)	0.0007 (4)	−0.0002 (4)
C17	0.0265 (5)	0.0204 (4)	0.0249 (4)	0.0109 (4)	0.0024 (3)	0.0003 (3)

Geometric parameters (Å, º)

O1—C1	1.2098 (18)	C13—C14	1.3855 (19)
O2—C5	1.1945 (18)	C14—C15	1.3811 (19)
O3—C5	1.3271 (15)	C15—C16	1.3794 (16)
O3—C6	1.4788 (15)	C16—C17	1.3781 (18)
O4—C10	1.4164 (18)	C2—H2	0.9500
O5—N2	1.2234 (15)	C4—H4	1.0000
O6—N2	1.2230 (16)	C7—H7A	0.9800
O4—H4O	0.852 (18)	C7—H7B	0.9800
N1—C1	1.3990 (15)	C7—H7C	0.9800
N1—C5	1.3923 (16)	C8—H8A	0.9800
N1—C4	1.4694 (17)	C8—H8B	0.9800
N2—C17	1.4604 (13)	C8—H8C	0.9800
C1—C2	1.4622 (18)	C9—H9A	0.9800
C2—C3	1.3323 (16)	C9—H9B	0.9800
C3—C12	1.4738 (16)	C9—H9C	0.9800
C3—C4	1.5074 (14)	C10—H10	1.0000
C4—C10	1.5459 (16)	C11—H11A	0.9800
C6—C8	1.506 (2)	C11—H11B	0.9800
C6—C9	1.510 (2)	C11—H11C	0.9800
C6—C7	1.5077 (19)	C13—H13	0.9500
C10—C11	1.508 (2)	C14—H14	0.9500
C12—C17	1.3950 (16)	C15—H15	0.9500
C12—C13	1.3926 (14)	C16—H16	0.9500
C5—O3—C6	121.44 (11)	C1—C2—H2	125.00
C10—O4—H4O	108.6 (14)	C3—C2—H2	125.00
C1—N1—C5	123.85 (11)	N1—C4—H4	110.00
C4—N1—C5	124.37 (10)	C3—C4—H4	110.00
C1—N1—C4	111.29 (10)	C10—C4—H4	110.00
O5—N2—O6	123.86 (10)	C6—C7—H7A	109.00
O6—N2—C17	118.15 (10)	C6—C7—H7B	109.00
O5—N2—C17	117.93 (10)	C6—C7—H7C	109.00
O1—C1—N1	126.66 (12)	H7A—C7—H7B	110.00
N1—C1—C2	105.79 (11)	H7A—C7—H7C	109.00
O1—C1—C2	127.56 (10)	H7B—C7—H7C	110.00
C1—C2—C3	110.28 (9)	C6—C8—H8A	110.00
C2—C3—C12	124.42 (9)	C6—C8—H8B	109.00
C4—C3—C12	124.99 (9)	C6—C8—H8C	109.00
C2—C3—C4	110.39 (10)	H8A—C8—H8B	109.00
N1—C4—C10	112.45 (10)	H8A—C8—H8C	109.00
C3—C4—C10	111.66 (10)	H8B—C8—H8C	110.00
N1—C4—C3	101.58 (8)	C6—C9—H9A	110.00
O2—C5—N1	123.91 (11)	C6—C9—H9B	110.00
O3—C5—N1	108.86 (11)	C6—C9—H9C	109.00
O2—C5—O3	127.24 (12)	H9A—C9—H9B	109.00
O3—C6—C7	109.05 (10)	H9A—C9—H9C	109.00
O3—C6—C9	101.81 (11)	H9B—C9—H9C	110.00
C7—C6—C8	112.16 (14)	O4—C10—H10	109.00
O3—C6—C8	110.67 (11)	C4—C10—H10	109.00
C8—C6—C9	111.04 (12)	C11—C10—H10	109.00
C7—C6—C9	111.62 (13)	C10—C11—H11A	109.00
O4—C10—C11	109.46 (11)	C10—C11—H11B	110.00
C4—C10—C11	113.72 (10)	C10—C11—H11C	109.00
O4—C10—C4	106.69 (10)	H11A—C11—H11B	109.00
C3—C12—C17	124.93 (9)	H11A—C11—H11C	109.00
C13—C12—C17	116.07 (11)	H11B—C11—H11C	109.00
C3—C12—C13	118.99 (10)	C12—C13—H13	119.00
C12—C13—C14	121.37 (11)	C14—C13—H13	119.00
C13—C14—C15	120.59 (10)	C13—C14—H14	120.00
C14—C15—C16	119.64 (13)	C15—C14—H14	120.00
C15—C16—C17	118.87 (12)	C14—C15—H15	120.00
N2—C17—C16	115.68 (10)	C16—C15—H15	120.00
C12—C17—C16	123.44 (10)	C15—C16—H16	121.00
N2—C17—C12	120.69 (10)	C17—C16—H16	121.00
C6—O3—C5—O2	−2.40 (19)	C1—C2—C3—C12	−179.43 (9)
C6—O3—C5—N1	177.35 (10)	C2—C3—C4—N1	−8.07 (12)
C5—O3—C6—C7	−62.67 (16)	C2—C3—C4—C10	111.98 (11)
C5—O3—C6—C8	61.16 (14)	C12—C3—C4—N1	176.97 (10)
C5—O3—C6—C9	179.26 (11)	C12—C3—C4—C10	−62.99 (14)
C4—N1—C1—O1	175.08 (11)	C2—C3—C12—C13	−49.77 (14)
C4—N1—C1—C2	−4.97 (12)	C2—C3—C12—C17	129.10 (11)
C5—N1—C1—O1	−12.66 (19)	C4—C3—C12—C13	124.51 (11)
C5—N1—C1—C2	167.29 (10)	C4—C3—C12—C17	−56.63 (15)
C1—N1—C4—C3	7.80 (12)	N1—C4—C10—O4	179.54 (9)
C1—N1—C4—C10	−111.70 (10)	N1—C4—C10—C11	58.76 (14)
C5—N1—C4—C3	−164.42 (10)	C3—C4—C10—O4	66.10 (12)
C5—N1—C4—C10	76.09 (14)	C3—C4—C10—C11	−54.68 (15)
C1—N1—C5—O2	0.98 (19)	C3—C12—C13—C14	179.54 (9)
C1—N1—C5—O3	−178.78 (10)	C17—C12—C13—C14	0.57 (14)
C4—N1—C5—O2	172.23 (12)	C3—C12—C17—N2	−5.69 (14)
C4—N1—C5—O3	−7.52 (16)	C3—C12—C17—C16	179.51 (10)
O5—N2—C17—C12	−31.70 (14)	C13—C12—C17—N2	173.20 (9)
O5—N2—C17—C16	143.49 (11)	C13—C12—C17—C16	−1.60 (14)
O6—N2—C17—C12	150.83 (10)	C12—C13—C14—C15	0.89 (16)
O6—N2—C17—C16	−33.99 (14)	C13—C14—C15—C16	−1.41 (17)
O1—C1—C2—C3	179.47 (11)	C14—C15—C16—C17	0.42 (16)
N1—C1—C2—C3	−0.48 (12)	C15—C16—C17—N2	−173.92 (9)
C1—C2—C3—C4	5.58 (12)	C15—C16—C17—C12	1.12 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4O···O1^i	0.852 (18)	1.930 (19)	2.7600 (15)	164.3 (19)

Symmetry code: (i) y, −x+y, −z.

(II) tert-butyl 2-[1-hydroxy-3-(methoxycarbonyl)propyl]-3-(2-nitrophenyl)-5-oxo-2,5-dihydro- 1H-pyrrole-1-carboxylate

Crystal data

C20H24N2O8	F(000) = 1776
Mr = 420.41	Dx = 1.365 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 14223 reflections
a = 9.1439 (7) Å	θ = 1.4–26.0°
b = 20.7113 (18) Å	µ = 0.11 mm^−1
c = 21.598 (2) Å	T = 153 K
V = 4090.3 (6) Å^3	Plate, colourless
Z = 8	0.50 × 0.45 × 0.10 mm

Data collection

Stoe IPDS-2 diffractometer	2605 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.078
Graphite monochromator	θmax = 26.0°, θmin = 1.9°
rotation method scans	h = −8→11
16666 measured reflections	k = −17→25
3856 independent reflections	l = −26→26

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.044	H-atom parameters constrained
wR(F^2) = 0.110	w = 1/[σ^2(Fo^2) + (0.0615P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.95	(Δ/σ)max = 0.001
3856 reflections	Δρmax = 0.18 e Å^−3
277 parameters	Δρmin = −0.22 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0048 (6)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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	0.82338 (16)	1.04916 (7)	1.03743 (5)	0.0398 (4)
O2	0.98587 (16)	1.10030 (7)	0.94111 (5)	0.0377 (4)
O3	0.95859 (15)	1.04336 (7)	0.85188 (5)	0.0355 (4)
O4	0.94241 (16)	0.86269 (7)	0.92957 (5)	0.0381 (4)
O5	1.0951 (2)	0.73288 (9)	0.85235 (9)	0.0652 (7)
O6	0.85174 (18)	0.72804 (8)	0.85811 (7)	0.0503 (5)
O7	0.46800 (17)	0.97641 (8)	0.87432 (6)	0.0426 (5)
O8	0.3128 (2)	0.91739 (10)	0.82448 (6)	0.0618 (7)
N1	0.84959 (18)	1.00760 (8)	0.93705 (6)	0.0314 (5)
N2	0.40953 (19)	0.92421 (10)	0.86356 (7)	0.0405 (6)
C1	0.7897 (2)	1.01036 (10)	0.99720 (7)	0.0330 (6)
C2	0.6820 (2)	0.95899 (10)	1.00009 (7)	0.0345 (6)
C3	0.6746 (2)	0.92758 (10)	0.94629 (7)	0.0321 (6)
C4	0.7851 (2)	0.95408 (9)	0.90103 (7)	0.0309 (5)
C5	0.9383 (2)	1.05520 (10)	0.91219 (7)	0.0308 (6)
C6	1.0587 (2)	1.08406 (10)	0.81389 (7)	0.0354 (6)
C7	0.9866 (3)	1.14807 (11)	0.80216 (9)	0.0455 (7)
C8	1.2068 (2)	1.08975 (12)	0.84463 (9)	0.0428 (7)
C9	1.0704 (3)	1.04371 (12)	0.75502 (8)	0.0459 (7)
C10	0.9001 (2)	0.90391 (10)	0.88007 (7)	0.0343 (6)
C11	0.8398 (3)	0.86263 (11)	0.82758 (8)	0.0404 (7)
C12	0.9515 (3)	0.81462 (11)	0.80205 (9)	0.0460 (7)
C13	0.9772 (3)	0.75551 (12)	0.84067 (10)	0.0459 (7)
C14	0.8654 (3)	0.67016 (13)	0.89480 (11)	0.0604 (9)
C15	0.5813 (2)	0.87049 (10)	0.93627 (7)	0.0347 (6)
C16	0.6175 (3)	0.81437 (11)	0.96806 (9)	0.0439 (7)
C17	0.5335 (3)	0.75894 (12)	0.96383 (10)	0.0541 (8)
C18	0.4101 (3)	0.75838 (13)	0.92703 (10)	0.0546 (8)
C19	0.3711 (3)	0.81283 (12)	0.89444 (9)	0.0483 (7)
C20	0.4561 (2)	0.86762 (10)	0.89889 (8)	0.0367 (6)
H2	0.62450	0.94910	1.03550	0.0410*
H4	0.73330	0.97180	0.86400	0.0370*
H4O	1.00180	0.88220	0.95260	0.0570*
H7A	0.89070	1.14110	0.78300	0.0680*
H7B	1.04790	1.17380	0.77430	0.0680*
H7C	0.97420	1.17110	0.84150	0.0680*
H8A	1.19770	1.11540	0.88250	0.0640*
H8B	1.27540	1.11090	0.81630	0.0640*
H8C	1.24320	1.04660	0.85500	0.0640*
H9A	1.11600	1.00210	0.76470	0.0690*
H9B	1.13020	1.06670	0.72450	0.0690*
H9C	0.97240	1.03640	0.73800	0.0690*
H10	0.98860	0.92740	0.86480	0.0410*
H11A	0.80700	0.89130	0.79360	0.0480*
H11B	0.75340	0.83860	0.84280	0.0480*
H12A	0.91880	0.80070	0.76040	0.0550*
H12B	1.04600	0.83730	0.79680	0.0550*
H14A	0.91600	0.63690	0.87070	0.0910*
H14B	0.76790	0.65460	0.90630	0.0910*
H14C	0.92170	0.67960	0.93230	0.0910*
H16	0.70240	0.81400	0.99340	0.0530*
H17	0.56080	0.72130	0.98620	0.0650*
H18	0.35210	0.72040	0.92420	0.0650*
H19	0.28620	0.81270	0.86910	0.0580*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0431 (8)	0.0422 (8)	0.0341 (6)	−0.0070 (8)	0.0024 (5)	−0.0091 (6)
O2	0.0461 (8)	0.0322 (8)	0.0348 (6)	−0.0067 (7)	−0.0004 (5)	−0.0041 (5)
O3	0.0435 (8)	0.0348 (8)	0.0283 (5)	−0.0078 (7)	0.0027 (5)	−0.0013 (5)
O4	0.0429 (9)	0.0323 (8)	0.0390 (6)	0.0015 (7)	−0.0080 (5)	−0.0012 (5)
O5	0.0419 (10)	0.0490 (12)	0.1047 (13)	0.0032 (9)	−0.0081 (9)	−0.0138 (9)
O6	0.0428 (9)	0.0463 (10)	0.0618 (9)	−0.0045 (8)	−0.0055 (7)	−0.0016 (7)
O7	0.0392 (9)	0.0437 (10)	0.0448 (7)	0.0001 (8)	−0.0008 (6)	0.0071 (6)
O8	0.0570 (11)	0.0812 (14)	0.0473 (8)	0.0047 (10)	−0.0222 (7)	−0.0111 (8)
N1	0.0341 (9)	0.0306 (9)	0.0295 (7)	−0.0022 (8)	0.0010 (6)	−0.0024 (6)
N2	0.0369 (10)	0.0516 (12)	0.0330 (7)	0.0008 (10)	−0.0002 (7)	−0.0043 (7)
C1	0.0338 (11)	0.0356 (11)	0.0295 (8)	0.0016 (9)	−0.0003 (7)	−0.0011 (7)
C2	0.0376 (11)	0.0352 (11)	0.0307 (8)	−0.0043 (10)	0.0017 (7)	−0.0001 (7)
C3	0.0339 (11)	0.0298 (11)	0.0325 (8)	0.0007 (9)	−0.0026 (7)	0.0024 (7)
C4	0.0360 (11)	0.0273 (10)	0.0294 (7)	−0.0012 (9)	−0.0018 (7)	−0.0014 (7)
C5	0.0318 (10)	0.0298 (11)	0.0309 (8)	−0.0002 (9)	−0.0009 (7)	−0.0004 (7)
C6	0.0401 (12)	0.0348 (12)	0.0314 (8)	−0.0047 (10)	0.0033 (7)	0.0026 (7)
C7	0.0577 (14)	0.0386 (13)	0.0402 (9)	−0.0028 (11)	−0.0070 (9)	0.0063 (8)
C8	0.0375 (12)	0.0491 (14)	0.0419 (9)	−0.0042 (11)	0.0032 (8)	0.0002 (9)
C9	0.0576 (14)	0.0474 (14)	0.0327 (8)	−0.0067 (12)	0.0063 (9)	−0.0035 (8)
C10	0.0366 (11)	0.0326 (11)	0.0336 (8)	0.0006 (10)	−0.0007 (7)	−0.0004 (7)
C11	0.0462 (13)	0.0401 (13)	0.0348 (8)	0.0002 (11)	−0.0010 (8)	−0.0077 (8)
C12	0.0509 (14)	0.0398 (13)	0.0474 (10)	−0.0016 (11)	0.0075 (9)	−0.0140 (9)
C13	0.0433 (13)	0.0411 (13)	0.0534 (11)	−0.0016 (12)	−0.0026 (9)	−0.0195 (9)
C14	0.0652 (18)	0.0479 (16)	0.0682 (14)	−0.0051 (14)	−0.0135 (12)	0.0034 (11)
C15	0.0385 (11)	0.0339 (11)	0.0317 (8)	−0.0052 (10)	0.0045 (7)	−0.0005 (7)
C16	0.0511 (13)	0.0362 (12)	0.0445 (10)	−0.0023 (11)	0.0026 (9)	0.0039 (8)
C17	0.0759 (18)	0.0324 (12)	0.0540 (11)	−0.0052 (13)	0.0191 (12)	0.0040 (9)
C18	0.0618 (16)	0.0425 (14)	0.0594 (12)	−0.0201 (13)	0.0246 (12)	−0.0144 (11)
C19	0.0454 (13)	0.0522 (15)	0.0473 (10)	−0.0157 (12)	0.0101 (9)	−0.0156 (10)
C20	0.0408 (12)	0.0350 (12)	0.0342 (8)	−0.0029 (10)	0.0039 (8)	−0.0051 (8)

Geometric parameters (Å, º)

O1—C1	1.223 (2)	C16—C17	1.384 (4)
O2—C5	1.205 (2)	C17—C18	1.380 (4)
O3—C5	1.3384 (19)	C18—C19	1.376 (3)
O3—C6	1.491 (2)	C19—C20	1.379 (3)
O4—C10	1.422 (2)	C2—H2	0.9500
O5—C13	1.202 (3)	C4—H4	1.0000
O6—C13	1.335 (3)	C7—H7A	0.9800
O6—C14	1.442 (3)	C7—H7B	0.9800
O7—N2	1.228 (3)	C7—H7C	0.9800
O8—N2	1.231 (2)	C8—H8A	0.9800
O4—H4O	0.8400	C8—H8B	0.9800
N1—C4	1.477 (2)	C8—H8C	0.9800
N1—C5	1.385 (3)	C9—H9A	0.9800
N1—C1	1.411 (2)	C9—H9B	0.9800
N2—C20	1.462 (3)	C9—H9C	0.9800
C1—C2	1.451 (3)	C10—H10	1.0000
C2—C3	1.333 (2)	C11—H11A	0.9900
C3—C15	1.474 (3)	C11—H11B	0.9900
C3—C4	1.509 (2)	C12—H12A	0.9900
C4—C10	1.546 (3)	C12—H12B	0.9900
C6—C7	1.502 (3)	C14—H14A	0.9800
C6—C8	1.513 (3)	C14—H14B	0.9800
C6—C9	1.525 (3)	C14—H14C	0.9800
C10—C11	1.523 (3)	C16—H16	0.9500
C11—C12	1.528 (3)	C17—H17	0.9500
C12—C13	1.500 (3)	C18—H18	0.9500
C15—C20	1.402 (2)	C19—H19	0.9500
C15—C16	1.390 (3)
C5—O3—C6	121.15 (14)	N1—C4—H4	110.00
C13—O6—C14	115.78 (19)	C3—C4—H4	110.00
C10—O4—H4O	109.00	C10—C4—H4	110.00
C1—N1—C4	111.13 (15)	C6—C7—H7A	110.00
C1—N1—C5	123.74 (16)	C6—C7—H7B	109.00
C4—N1—C5	124.32 (13)	C6—C7—H7C	109.00
O7—N2—O8	122.9 (2)	H7A—C7—H7B	109.00
O7—N2—C20	118.69 (16)	H7A—C7—H7C	110.00
O8—N2—C20	118.38 (19)	H7B—C7—H7C	109.00
O1—C1—C2	128.47 (15)	C6—C8—H8A	109.00
N1—C1—C2	105.86 (15)	C6—C8—H8B	110.00
O1—C1—N1	125.67 (17)	C6—C8—H8C	109.00
C1—C2—C3	110.77 (15)	H8A—C8—H8B	109.00
C2—C3—C4	110.67 (17)	H8A—C8—H8C	109.00
C2—C3—C15	123.28 (16)	H8B—C8—H8C	109.00
C4—C3—C15	125.74 (14)	C6—C9—H9A	110.00
N1—C4—C10	112.77 (15)	C6—C9—H9B	109.00
C3—C4—C10	113.62 (15)	C6—C9—H9C	109.00
N1—C4—C3	101.48 (13)	H9A—C9—H9B	109.00
O2—C5—O3	126.62 (17)	H9A—C9—H9C	109.00
O2—C5—N1	124.21 (15)	H9B—C9—H9C	109.00
O3—C5—N1	109.15 (16)	O4—C10—H10	109.00
O3—C6—C7	108.81 (16)	C4—C10—H10	109.00
O3—C6—C8	110.62 (14)	C11—C10—H10	109.00
C7—C6—C8	113.46 (19)	C10—C11—H11A	109.00
C7—C6—C9	111.95 (15)	C10—C11—H11B	109.00
C8—C6—C9	110.23 (17)	C12—C11—H11A	109.00
O3—C6—C9	101.08 (16)	C12—C11—H11B	109.00
O4—C10—C11	108.73 (16)	H11A—C11—H11B	108.00
C4—C10—C11	110.42 (16)	C11—C12—H12A	108.00
O4—C10—C4	111.62 (13)	C11—C12—H12B	108.00
C10—C11—C12	113.1 (2)	C13—C12—H12A	108.00
C11—C12—C13	115.79 (18)	C13—C12—H12B	108.00
O5—C13—C12	125.1 (2)	H12A—C12—H12B	107.00
O6—C13—C12	111.7 (2)	O6—C14—H14A	109.00
O5—C13—O6	123.0 (2)	O6—C14—H14B	109.00
C3—C15—C20	126.24 (18)	O6—C14—H14C	110.00
C16—C15—C20	116.32 (19)	H14A—C14—H14B	109.00
C3—C15—C16	117.42 (17)	H14A—C14—H14C	109.00
C15—C16—C17	121.9 (2)	H14B—C14—H14C	110.00
C16—C17—C18	119.9 (2)	C15—C16—H16	119.00
C17—C18—C19	120.0 (2)	C17—C16—H16	119.00
C18—C19—C20	119.5 (2)	C16—C17—H17	120.00
N2—C20—C19	117.34 (17)	C18—C17—H17	120.00
C15—C20—C19	122.36 (19)	C17—C18—H18	120.00
N2—C20—C15	120.29 (18)	C19—C18—H18	120.00
C1—C2—H2	125.00	C18—C19—H19	120.00
C3—C2—H2	125.00	C20—C19—H19	120.00
C6—O3—C5—O2	5.9 (3)	C2—C3—C4—C10	118.35 (18)
C6—O3—C5—N1	−175.48 (15)	C15—C3—C4—N1	−176.71 (17)
C5—O3—C6—C7	−73.9 (2)	C15—C3—C4—C10	−55.4 (2)
C5—O3—C6—C8	51.4 (2)	C2—C3—C15—C16	−67.2 (3)
C5—O3—C6—C9	168.17 (17)	C2—C3—C15—C20	110.8 (2)
C14—O6—C13—O5	2.7 (3)	C4—C3—C15—C16	105.8 (2)
C14—O6—C13—C12	179.15 (18)	C4—C3—C15—C20	−76.2 (3)
C4—N1—C1—O1	179.15 (18)	N1—C4—C10—O4	76.74 (18)
C4—N1—C1—C2	−1.4 (2)	N1—C4—C10—C11	−162.19 (15)
C5—N1—C1—O1	−10.8 (3)	C3—C4—C10—O4	−38.0 (2)
C5—N1—C1—C2	168.65 (17)	C3—C4—C10—C11	83.03 (18)
C1—N1—C4—C3	2.58 (19)	O4—C10—C11—C12	−60.7 (2)
C1—N1—C4—C10	−119.33 (16)	C4—C10—C11—C12	176.57 (16)
C5—N1—C4—C3	−167.39 (17)	C10—C11—C12—C13	77.2 (3)
C5—N1—C4—C10	70.7 (2)	C11—C12—C13—O5	−135.7 (3)
C1—N1—C5—O2	8.1 (3)	C11—C12—C13—O6	48.0 (3)
C1—N1—C5—O3	−170.64 (16)	C3—C15—C16—C17	177.31 (19)
C4—N1—C5—O2	176.79 (18)	C20—C15—C16—C17	−0.9 (3)
C4—N1—C5—O3	−1.9 (2)	C3—C15—C20—N2	2.1 (3)
O7—N2—C20—C15	−10.9 (3)	C3—C15—C20—C19	−176.86 (18)
O7—N2—C20—C19	168.10 (18)	C16—C15—C20—N2	−179.86 (17)
O8—N2—C20—C15	169.43 (17)	C16—C15—C20—C19	1.2 (3)
O8—N2—C20—C19	−11.6 (3)	C15—C16—C17—C18	0.2 (3)
O1—C1—C2—C3	178.8 (2)	C16—C17—C18—C19	0.2 (4)
N1—C1—C2—C3	−0.6 (2)	C17—C18—C19—C20	0.0 (3)
C1—C2—C3—C4	2.3 (2)	C18—C19—C20—N2	−179.74 (19)
C1—C2—C3—C15	176.26 (17)	C18—C19—C20—C15	−0.8 (3)
C2—C3—C4—N1	−3.0 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4O···O1^i	0.84	2.15	2.903 (2)	149
O4—H4O···O2^i	0.84	2.33	2.9696 (16)	134

Symmetry code: (i) −x+2, −y+2, −z+2.

(III) tert-butyl 2-(4-bromo-1-hydroxybutyl)-5-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate

Crystal data

C13H20BrNO4	Z = 2
Mr = 334.21	F(000) = 344
Triclinic, P1	Dx = 1.543 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.8340 (9) Å	Cell parameters from 12982 reflections
b = 9.0750 (9) Å	θ = 2.2–29.7°
c = 10.7283 (10) Å	µ = 2.87 mm^−1
α = 104.176 (7)°	T = 173 K
β = 113.759 (7)°	Block, colourless
γ = 101.367 (8)°	0.50 × 0.50 × 0.50 mm
V = 719.57 (12) Å^3

Data collection

Stoe IPDS-2 diffractometer	3862 independent reflections
Radiation source: fine-focus sealed tube	3587 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
Detector resolution: 0.81Å pixels mm^-1	θmax = 29.2°, θmin = 2.2°
ϕ and ω scans	h = −12→12
Absorption correction: multi-scan (MULscanABS in PLATON; Spek, 2009)	k = −10→12
Tmin = 0.307, Tmax = 0.472	l = −14→14
9956 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.027	H-atom parameters constrained
wR(F^2) = 0.066	w = 1/[σ^2(Fo^2) + (0.0236P)^2 + 0.4857P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.003
3862 reflections	Δρmax = 0.43 e Å^−3
177 parameters	Δρmin = −0.78 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.012 (2)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
Br1	1.47778 (2)	0.30287 (2)	1.13729 (2)	0.0329 (1)
O1	0.31030 (14)	−0.11093 (15)	0.53882 (12)	0.0262 (3)
O2	0.52777 (14)	−0.25263 (14)	0.45870 (12)	0.0245 (3)
O3	0.80224 (14)	−0.16522 (13)	0.64932 (12)	0.0231 (3)
O4	0.82532 (15)	0.30771 (13)	0.76664 (12)	0.0245 (3)
N1	0.61400 (16)	−0.04621 (15)	0.67145 (13)	0.0192 (3)
C1	0.44905 (19)	−0.03668 (18)	0.64902 (16)	0.0211 (4)
C2	0.4806 (2)	0.0789 (2)	0.78665 (18)	0.0247 (4)
C3	0.6499 (2)	0.13381 (19)	0.88148 (17)	0.0236 (4)
C4	0.75282 (19)	0.06297 (18)	0.81779 (15)	0.0201 (3)
C5	0.63877 (19)	−0.16534 (17)	0.58003 (16)	0.0200 (3)
C6	0.8667 (2)	−0.28116 (19)	0.57988 (17)	0.0230 (4)
C7	0.7644 (3)	−0.4500 (2)	0.5536 (2)	0.0342 (5)
C8	0.8571 (3)	−0.2594 (2)	0.4414 (2)	0.0336 (5)
C9	1.0554 (2)	−0.2308 (3)	0.6973 (2)	0.0385 (6)
C10	0.89225 (19)	0.19009 (18)	0.81204 (16)	0.0200 (3)
C11	1.05272 (19)	0.27493 (19)	0.96104 (16)	0.0229 (4)
C12	1.1980 (2)	0.39234 (19)	0.95675 (17)	0.0240 (4)
C13	1.3675 (2)	0.46521 (19)	1.09855 (17)	0.0244 (4)
H4	0.81030	−0.00080	0.87430	0.0240*
H2	0.39270	0.10970	0.80500	0.0300*
H3	0.69970	0.20910	0.97810	0.0280*
H4O	0.75420	0.26750	0.67690	0.0370*
H7A	0.76700	−0.45500	0.64460	0.0510*
H7B	0.64260	−0.47870	0.47880	0.0510*
H7C	0.81720	−0.52580	0.52020	0.0510*
H8A	0.91190	−0.14520	0.46220	0.0500*
H8B	0.73400	−0.29600	0.36660	0.0500*
H8C	0.91910	−0.32290	0.40610	0.0500*
H9A	1.05770	−0.24010	0.78710	0.0580*
H9B	1.11690	−0.11880	0.71640	0.0580*
H9C	1.11350	−0.30100	0.66420	0.0580*
H10	0.92810	0.13480	0.74120	0.0240*
H11A	1.09730	0.19350	0.99690	0.0270*
H11B	1.01900	0.33430	1.03060	0.0270*
H12A	1.22070	0.33530	0.87830	0.0290*
H12B	1.15710	0.48030	0.93160	0.0290*
H13A	1.34380	0.51190	1.17960	0.0290*
H13B	1.44870	0.55330	1.09370	0.0290*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0263 (1)	0.0349 (1)	0.0359 (1)	0.0131 (1)	0.0108 (1)	0.0149 (1)
O1	0.0180 (5)	0.0296 (6)	0.0238 (5)	0.0047 (4)	0.0064 (4)	0.0070 (4)
O2	0.0204 (5)	0.0215 (5)	0.0212 (5)	0.0046 (4)	0.0046 (4)	0.0024 (4)
O3	0.0186 (5)	0.0209 (5)	0.0226 (5)	0.0066 (4)	0.0059 (4)	0.0032 (4)
O4	0.0232 (5)	0.0194 (5)	0.0223 (5)	0.0052 (4)	0.0036 (4)	0.0080 (4)
N1	0.0166 (5)	0.0175 (6)	0.0187 (5)	0.0038 (4)	0.0058 (5)	0.0049 (4)
C1	0.0195 (6)	0.0202 (7)	0.0233 (7)	0.0056 (5)	0.0095 (6)	0.0096 (5)
C2	0.0230 (7)	0.0248 (7)	0.0267 (7)	0.0071 (6)	0.0130 (6)	0.0086 (6)
C3	0.0248 (7)	0.0225 (7)	0.0211 (7)	0.0061 (6)	0.0104 (6)	0.0062 (6)
C4	0.0186 (6)	0.0184 (6)	0.0174 (6)	0.0037 (5)	0.0050 (5)	0.0050 (5)
C5	0.0196 (6)	0.0166 (6)	0.0220 (6)	0.0047 (5)	0.0088 (5)	0.0073 (5)
C6	0.0227 (7)	0.0252 (7)	0.0238 (7)	0.0106 (6)	0.0122 (6)	0.0091 (6)
C7	0.0444 (10)	0.0237 (8)	0.0413 (10)	0.0149 (7)	0.0235 (8)	0.0141 (7)
C8	0.0353 (9)	0.0419 (10)	0.0295 (8)	0.0121 (8)	0.0191 (7)	0.0164 (7)
C9	0.0250 (8)	0.0576 (13)	0.0313 (9)	0.0190 (8)	0.0114 (7)	0.0128 (8)
C10	0.0192 (6)	0.0176 (6)	0.0195 (6)	0.0044 (5)	0.0069 (5)	0.0060 (5)
C11	0.0185 (6)	0.0232 (7)	0.0209 (7)	0.0033 (5)	0.0057 (5)	0.0076 (6)
C12	0.0198 (7)	0.0222 (7)	0.0244 (7)	0.0035 (6)	0.0067 (6)	0.0087 (6)
C13	0.0207 (7)	0.0193 (7)	0.0265 (7)	0.0053 (5)	0.0081 (6)	0.0042 (6)

Geometric parameters (Å, º)

Br1—C13	1.9575 (19)	C2—H2	0.9500
O1—C1	1.213 (2)	C3—H3	0.9500
O2—C5	1.2015 (19)	C4—H4	1.0000
O3—C5	1.331 (2)	C7—H7A	0.9800
O3—C6	1.477 (2)	C7—H7B	0.9800
O4—C10	1.413 (2)	C7—H7C	0.9800
O4—H4O	0.8400	C8—H8A	0.9800
N1—C4	1.4691 (19)	C8—H8B	0.9800
N1—C5	1.388 (2)	C8—H8C	0.9800
N1—C1	1.402 (2)	C9—H9A	0.9800
C1—C2	1.467 (2)	C9—H9B	0.9800
C2—C3	1.324 (3)	C9—H9C	0.9800
C3—C4	1.491 (3)	C10—H10	1.0000
C4—C10	1.545 (2)	C11—H11A	0.9900
C6—C8	1.517 (3)	C11—H11B	0.9900
C6—C9	1.517 (3)	C12—H12A	0.9900
C6—C7	1.510 (3)	C12—H12B	0.9900
C10—C11	1.516 (2)	C13—H13A	0.9900
C11—C12	1.522 (3)	C13—H13B	0.9900
C12—C13	1.508 (2)
C5—O3—C6	121.31 (12)	C6—C7—H7B	109.00
C10—O4—H4O	109.00	C6—C7—H7C	109.00
C1—N1—C4	111.34 (13)	H7A—C7—H7B	110.00
C4—N1—C5	123.47 (14)	H7A—C7—H7C	109.00
C1—N1—C5	124.00 (13)	H7B—C7—H7C	109.00
O1—C1—N1	126.53 (15)	C6—C8—H8A	109.00
N1—C1—C2	105.51 (14)	C6—C8—H8B	109.00
O1—C1—C2	127.96 (17)	C6—C8—H8C	109.00
C1—C2—C3	109.86 (17)	H8A—C8—H8B	109.00
C2—C3—C4	111.62 (15)	H8A—C8—H8C	110.00
N1—C4—C10	112.27 (12)	H8B—C8—H8C	110.00
C3—C4—C10	113.40 (14)	C6—C9—H9A	109.00
N1—C4—C3	101.63 (14)	C6—C9—H9B	109.00
O2—C5—N1	124.16 (17)	C6—C9—H9C	109.00
O3—C5—N1	108.81 (13)	H9A—C9—H9B	109.00
O2—C5—O3	127.03 (16)	H9A—C9—H9C	109.00
O3—C6—C7	109.20 (16)	H9B—C9—H9C	109.00
O3—C6—C8	110.36 (15)	O4—C10—H10	109.00
C7—C6—C8	112.91 (14)	C4—C10—H10	109.00
C7—C6—C9	111.11 (17)	C11—C10—H10	109.00
O3—C6—C9	101.43 (14)	C10—C11—H11A	109.00
C8—C6—C9	111.24 (18)	C10—C11—H11B	109.00
O4—C10—C11	108.24 (13)	C12—C11—H11A	109.00
C4—C10—C11	110.71 (13)	C12—C11—H11B	109.00
O4—C10—C4	111.18 (15)	H11A—C11—H11B	108.00
C10—C11—C12	112.01 (13)	C11—C12—H12A	109.00
C11—C12—C13	113.79 (14)	C11—C12—H12B	109.00
Br1—C13—C12	111.00 (12)	C13—C12—H12A	109.00
C1—C2—H2	125.00	C13—C12—H12B	109.00
C3—C2—H2	125.00	H12A—C12—H12B	108.00
C2—C3—H3	124.00	Br1—C13—H13A	109.00
C4—C3—H3	124.00	Br1—C13—H13B	109.00
N1—C4—H4	110.00	C12—C13—H13A	109.00
C3—C4—H4	110.00	C12—C13—H13B	109.00
C10—C4—H4	110.00	H13A—C13—H13B	108.00
C6—C7—H7A	109.00
C6—O3—C5—O2	−0.7 (3)	C4—N1—C5—O2	−177.97 (16)
C6—O3—C5—N1	179.11 (13)	C4—N1—C5—O3	2.2 (2)
C5—O3—C6—C7	−64.05 (19)	O1—C1—C2—C3	179.65 (18)
C5—O3—C6—C8	60.6 (2)	N1—C1—C2—C3	0.5 (2)
C5—O3—C6—C9	178.60 (16)	C1—C2—C3—C4	0.8 (2)
C4—N1—C1—O1	179.21 (17)	C2—C3—C4—N1	−1.68 (19)
C4—N1—C1—C2	−1.66 (18)	C2—C3—C4—C10	119.01 (16)
C5—N1—C1—O1	−12.9 (3)	N1—C4—C10—O4	72.57 (17)
C5—N1—C1—C2	166.25 (15)	N1—C4—C10—C11	−167.08 (14)
C1—N1—C4—C3	2.02 (17)	C3—C4—C10—O4	−41.91 (17)
C1—N1—C4—C10	−119.46 (16)	C3—C4—C10—C11	78.44 (17)
C5—N1—C4—C3	−165.97 (15)	O4—C10—C11—C12	−62.07 (19)
C5—N1—C4—C10	72.6 (2)	C4—C10—C11—C12	175.84 (14)
C1—N1—C5—O2	15.6 (3)	C10—C11—C12—C13	−173.35 (15)
C1—N1—C5—O3	−164.30 (14)	C11—C12—C13—Br1	68.73 (17)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4O···O1^i	0.84	2.17	2.9138 (16)	148
O4—H4O···O2^i	0.84	2.28	2.9225 (18)	134

Symmetry code: (i) −x+1, −y, −z+1.