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Acta Cryst. (2008). E64, o550    [ doi:10.1107/S1600536808003279 ]

tert-Butyl N-[(S)-3-isopropyl-2-oxooxetan-3-yl]carbamate

L. Sieron, A. Kudaj, A. Olma and J. Karolak-Wojciechowska

Abstract top

The structure of the title compound, C11H19NO4, contains two crystallographically independent molecules in the asymmetric unit. Both adopt the same conformation and they form pseudosymmetric R22(8) dimers via two N-H...O hydrogen bonds. The dimers are linked by weak C-H...O interactions and are stacked in columns along the a axis.

Comment top

Over the last 20 years, much attention has been focused on β-lactones, because their occurrence in many natural biologically active compounds (Lowe & Vederas, 1995). N-Cbz-serine and threonine β-lactones have been found as a new class of hepatitis A virus 3 C cysteine proteinase inhibitors (Lall et al., 2002).

The crystal structure of the title compound, (I), is related to this area of interest. The title compound - useful and versatile intermediate in the synthesis of β-substituted α-alkyl alanines was prepared according to standard procedure (Olma & Kudaj, 2005).

The asymmetric unit in the crystal structure of (I) contains two molecules. Both molecules in (I) are practically identical. The pairs of the molecules are connected into the same motif as observed in the structures of other N-protected-α-amino-β-lactones (Sieroń, et al., 2008; Smith & Goodman, 2003). Therefore the molecules are connected in pesudocentrosymmetric dimers via N–H···O hydrogen bonds, forming eight-membered rings described by the R22(8) graph-set motif (Etter et al., 1990) (Fig. 1). In the crystal of (I) dimers are stacked down the α-axis in columns.

Related literature top

For related literature, see: Etter et al. (1990); Lall et al. (2002); Lowe & Vederas (1995); Olma & Kudaj (2005); Sieroń et al. (2008); Smith & Goodman (2003).

Experimental top

The title compound was synthesized by treating complex of triphenylphosphine (525 mg, 2 mmol) and diethyldiazadicarboxylate in dry tetrahydrofurane with solution of Boc-(S)-iso-propylserine (N-Boc-(S)-hydroxymethylvaline) in dry THF (670 mg, 2 mmol) at 0°C. After stirring 1 h at 0°C and then 16 h at room temperature, THF was removed in vacuo and the crude product was purified by flash chromatography on silica gel 60 (230–400 mesh) using ethyl acetate-n-hexane (1:1) aseluent.The N-Boc-(S)-α-benzylserine lactone was obtained in 92% yield. White crystals of N-Boc-(S)-α-iso-propylserine lactone suitable for X-ray investigation were grown from chloroform, m.p. 403–404 K.

Refinement top

In the absence of significant anomalous scattering effects, Friedel pairs were merged. The absolute configuration was assigned consistent with the starting material. All H atoms were included in calculated positions and treated as riding, C–H = 0.96–0.98 and N–H = 0.86 Å with Uiso(H) = 1.2 or 1.5Ueq(C) and 1.2Ueq(N).

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2007); cell refinement: CrysAlis RED (Oxford Diffraction, 2007); data reduction: CrysAlis RED (Oxford Diffraction, 2007); 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: PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The structure of (I), showing 30% probability displacement ellipsoids and the atom-numbering scheme. Dotted lines indicate hydrogen bonds.
tert-Butyl N-[(S)-3-isopropyl-2-oxooxetan-3-yl]carbamate top
Crystal data top
C11H19NO4F000 = 496
Mr = 229.27Dx = 1.175 Mg m−3
Monoclinic, P21Mo Kα radiation
λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 11196 reflections
a = 6.0475 (2) Åθ = 1.9–28.0º
b = 20.8957 (6) ŵ = 0.09 mm−1
c = 10.2928 (3) ÅT = 298 K
β = 94.675 (3)ºRectangular plate, colourless
V = 1296.34 (7) Å30.4 × 0.3 × 0.3 mm
Z = 4
Data collection top
Kuma KM-4-CCD
diffractometer		2118 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.026
Detector resolution: 8.2356 pixels mm-1θmax = 26.0º
T = 298 Kθmin = 2.2º
ω scansh = −7→7
Absorption correction: nonek = −23→25
19342 measured reflectionsl = −12→12
2615 independent reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.035H-atom parameters constrained
wR(F2) = 0.103  w = 1/[σ2(Fo2) + (0.0757P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
2615 reflectionsΔρmax = 0.14 e Å−3
299 parametersΔρmin = −0.15 e Å−3
1 restraintExtinction correction: SHELXTL (Bruker, 2000), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.023 (5)
Crystal data top
C11H19NO4V = 1296.34 (7) Å3
Mr = 229.27Z = 4
Monoclinic, P21Mo Kα
a = 6.0475 (2) ŵ = 0.09 mm−1
b = 20.8957 (6) ÅT = 298 K
c = 10.2928 (3) Å0.4 × 0.3 × 0.3 mm
β = 94.675 (3)º
Data collection top
Kuma KM-4-CCD
diffractometer		2615 independent reflections
Absorption correction: none2118 reflections with I > 2σ(I)
19342 measured reflectionsRint = 0.026
Refinement top
R[F2 > 2σ(F2)] = 0.035H-atom parameters constrained
wR(F2) = 0.103Δρmax = 0.14 e Å−3
S = 1.03Δρmin = −0.15 e Å−3
2615 reflectionsAbsolute structure: ?
299 parametersFlack parameter: ?
1 restraintRogers parameter: ?
Special details top

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 on F2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs 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
xyzUiso*/Ueq
O10.6494 (4)0.23045 (10)0.63037 (19)0.0829 (8)
O20.8994 (4)0.25263 (14)0.4835 (3)0.1062 (10)
O90.2398 (3)0.27971 (8)0.20705 (16)0.0622 (6)
O100.4114 (3)0.21360 (7)0.35786 (15)0.0564 (5)
N80.4182 (3)0.31805 (8)0.39179 (17)0.0497 (6)
C20.7305 (5)0.26212 (14)0.5292 (3)0.0688 (10)
C30.5404 (4)0.31069 (10)0.5160 (2)0.0468 (6)
C40.4449 (5)0.26711 (14)0.6194 (2)0.0664 (9)
C50.6185 (5)0.37608 (11)0.5715 (2)0.0595 (8)
C60.4225 (6)0.41648 (14)0.6078 (3)0.0806 (13)
C70.7639 (6)0.41090 (18)0.4834 (3)0.0893 (11)
C90.3479 (4)0.27053 (10)0.3106 (2)0.0489 (7)
C110.3517 (4)0.15329 (10)0.2879 (2)0.0535 (7)
C120.4526 (5)0.15184 (14)0.1587 (3)0.0698 (10)
C130.4626 (7)0.10416 (14)0.3800 (4)0.0905 (13)
C140.1059 (5)0.14520 (14)0.2731 (3)0.0751 (10)
O21−0.3083 (4)0.48529 (11)−0.0728 (2)0.1029 (10)
O220.0293 (6)0.47727 (12)−0.1507 (2)0.1157 (12)
O290.2623 (3)0.44185 (7)0.28415 (17)0.0670 (6)
O300.0350 (3)0.50520 (7)0.15453 (15)0.0591 (5)
N280.0285 (3)0.40040 (9)0.12378 (16)0.0503 (6)
C22−0.1048 (6)0.45988 (14)−0.0824 (3)0.0744 (10)
C23−0.1359 (4)0.40626 (11)0.01507 (19)0.0490 (7)
C24−0.3549 (5)0.44115 (16)0.0314 (3)0.0809 (11)
C25−0.1695 (4)0.34178 (12)−0.0555 (2)0.0544 (7)
C260.0390 (6)0.31841 (15)−0.1124 (3)0.0732 (10)
C27−0.2654 (5)0.29098 (14)0.0287 (3)0.0730 (10)
C290.1192 (4)0.44917 (10)0.1946 (2)0.0497 (7)
C310.1104 (4)0.56660 (10)0.2160 (2)0.0541 (7)
C320.0453 (6)0.56815 (15)0.3535 (3)0.0784 (10)
C33−0.0211 (6)0.61481 (14)0.1317 (3)0.0854 (11)
C340.3547 (5)0.57527 (15)0.2071 (3)0.0800 (10)
H4A0.415700.289400.698900.0800*
H4B0.316500.242600.586100.0800*
H50.709700.367500.652700.0710*
H6A0.476200.453000.657400.1210*
H6B0.329200.391300.658900.1210*
H6C0.338600.430600.529800.1210*
H7A0.677000.424100.405800.1340*
H7B0.880800.383000.460500.1340*
H7C0.827000.447900.527600.1340*
H80.386800.356500.366800.0600*
H12A0.380100.182900.101100.1050*
H12B0.434100.110000.120900.1050*
H12C0.607800.161700.171800.1050*
H13A0.619000.112600.391400.1360*
H13B0.438400.062100.344000.1360*
H13C0.400500.106600.462700.1360*
H14A0.046600.152000.355800.1130*
H14B0.070300.102700.242900.1130*
H14C0.042500.175700.211100.1130*
H24A−0.485300.414800.010900.0970*
H24B−0.360600.461600.115600.0970*
H25−0.279500.34910−0.129300.0650*
H26A0.148500.30770−0.043000.1100*
H26B0.095500.35150−0.165300.1100*
H26C0.005100.28120−0.165000.1100*
H27A−0.297100.25310−0.022300.1100*
H27B−0.399800.306600.061000.1100*
H27C−0.160200.281000.100700.1100*
H280.072400.362400.145200.0600*
H32A−0.111100.560400.353700.1180*
H32B0.080100.609300.391000.1180*
H32C0.125300.535600.403700.1180*
H33A0.015000.610400.043100.1280*
H33B0.015500.657300.162000.1280*
H33C−0.176900.607400.136500.1280*
H34A0.434400.544300.261700.1200*
H34B0.397200.617600.235500.1200*
H34C0.389100.569400.118500.1200*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.1125 (17)0.0604 (12)0.0703 (11)0.0111 (11)−0.0261 (11)0.0139 (9)
O20.0701 (14)0.121 (2)0.1255 (19)0.0289 (13)−0.0045 (13)−0.0300 (16)
O90.0816 (12)0.0452 (9)0.0549 (9)0.0060 (8)−0.0242 (8)−0.0014 (7)
O100.0752 (11)0.0329 (8)0.0572 (9)0.0017 (7)−0.0190 (7)−0.0017 (6)
N80.0650 (11)0.0329 (9)0.0479 (9)0.0014 (8)−0.0148 (8)0.0006 (7)
C20.0660 (18)0.0677 (17)0.0690 (16)0.0119 (13)−0.0178 (13)−0.0129 (13)
C30.0549 (12)0.0401 (11)0.0437 (10)0.0011 (9)−0.0062 (9)−0.0013 (8)
C40.0836 (18)0.0597 (16)0.0548 (13)−0.0038 (14)−0.0004 (12)0.0062 (11)
C50.0801 (17)0.0483 (13)0.0465 (12)−0.0082 (12)−0.0174 (11)−0.0019 (10)
C60.120 (3)0.0534 (16)0.0676 (16)0.0097 (16)0.0025 (16)−0.0139 (12)
C70.092 (2)0.084 (2)0.0889 (19)−0.0388 (19)−0.0102 (17)0.0089 (17)
C90.0569 (12)0.0393 (11)0.0480 (11)0.0018 (10)−0.0107 (9)0.0003 (9)
C110.0625 (14)0.0343 (11)0.0623 (13)−0.0004 (10)−0.0025 (11)−0.0064 (9)
C120.0778 (17)0.0534 (15)0.0787 (18)−0.0049 (13)0.0103 (13)−0.0123 (12)
C130.126 (3)0.0419 (15)0.099 (2)0.0051 (16)−0.0194 (19)0.0095 (13)
C140.0700 (17)0.0581 (17)0.097 (2)−0.0114 (13)0.0063 (14)−0.0184 (14)
O210.124 (2)0.0657 (13)0.1089 (16)0.0282 (13)−0.0526 (14)0.0013 (12)
O220.191 (3)0.0772 (16)0.0807 (14)−0.0227 (18)0.0218 (16)0.0257 (13)
O290.0875 (12)0.0407 (9)0.0661 (10)0.0031 (8)−0.0337 (9)−0.0037 (7)
O300.0761 (11)0.0358 (8)0.0608 (9)0.0037 (7)−0.0226 (8)−0.0020 (7)
N280.0638 (11)0.0355 (9)0.0490 (9)0.0023 (8)−0.0119 (8)−0.0014 (8)
C220.110 (2)0.0510 (15)0.0580 (15)−0.0025 (16)−0.0194 (15)0.0069 (11)
C230.0553 (12)0.0462 (12)0.0433 (10)0.0034 (10)−0.0088 (9)−0.0020 (9)
C240.0643 (16)0.079 (2)0.096 (2)0.0137 (14)−0.0133 (14)−0.0235 (16)
C250.0652 (14)0.0490 (12)0.0464 (11)−0.0050 (11)−0.0111 (10)−0.0019 (10)
C260.093 (2)0.0652 (16)0.0618 (15)0.0043 (14)0.0082 (14)−0.0139 (12)
C270.0766 (18)0.0601 (16)0.0800 (17)−0.0185 (13)−0.0084 (14)0.0069 (13)
C290.0621 (13)0.0382 (11)0.0470 (11)0.0006 (10)−0.0069 (10)−0.0006 (9)
C310.0646 (14)0.0326 (11)0.0634 (13)0.0001 (10)−0.0048 (11)−0.0014 (9)
C320.097 (2)0.0627 (17)0.0760 (17)−0.0035 (16)0.0099 (15)−0.0136 (14)
C330.108 (2)0.0432 (14)0.101 (2)0.0107 (15)−0.0159 (18)0.0070 (14)
C340.0734 (19)0.0540 (15)0.114 (2)−0.0037 (14)0.0167 (16)−0.0104 (15)
Geometric parameters (Å, °) top
O1—C21.359 (4)C12—H12C0.96
O1—C41.451 (4)C12—H12B0.96
O2—C21.176 (4)C12—H12A0.96
O9—C91.219 (3)C13—H13C0.96
O10—C91.330 (3)C13—H13A0.96
O10—C111.481 (3)C13—H13B0.96
O21—C241.459 (4)C14—H14B0.96
O21—C221.351 (4)C14—H14A0.96
O22—C221.173 (5)C14—H14C0.96
O29—C291.221 (3)C22—C231.526 (4)
O30—C311.486 (3)C23—C251.536 (3)
O30—C291.329 (3)C23—C241.533 (4)
N8—C31.432 (3)C25—C261.514 (4)
N8—C91.344 (3)C25—C271.515 (4)
N8—H80.86C31—C331.513 (4)
N28—C231.440 (3)C31—C341.499 (4)
N28—C291.344 (3)C31—C321.500 (4)
N28—H280.86C24—H24A0.97
C2—C31.531 (4)C24—H24B0.97
C3—C51.540 (3)C25—H250.98
C3—C41.548 (3)C26—H26A0.96
C5—C71.502 (4)C26—H26B0.96
C5—C61.526 (4)C26—H26C0.96
C11—C141.492 (4)C27—H27A0.96
C11—C121.508 (4)C27—H27B0.96
C11—C131.516 (4)C27—H27C0.96
C4—H4A0.97C32—H32A0.96
C4—H4B0.97C32—H32B0.96
C5—H50.98C32—H32C0.96
C6—H6B0.96C33—H33A0.96
C6—H6C0.96C33—H33B0.96
C6—H6A0.96C33—H33C0.96
C7—H7B0.96C34—H34A0.96
C7—H7C0.96C34—H34B0.96
C7—H7A0.96C34—H34C0.96
C2—O1—C492.4 (2)H14A—C14—H14B109
C9—O10—C11122.10 (17)H14A—C14—H14C109
C22—O21—C2492.1 (2)H14B—C14—H14C109
C29—O30—C31122.15 (17)C11—C14—H14A109
C3—N8—C9126.14 (17)C11—C14—H14B109
C9—N8—H8117O22—C22—C23138.6 (3)
C3—N8—H8117O21—C22—O22126.9 (3)
C23—N28—C29125.62 (19)O21—C22—C2394.5 (2)
C29—N28—H28117N28—C23—C22117.3 (2)
C23—N28—H28117C22—C23—C2482.9 (2)
O1—C2—C394.3 (2)N28—C23—C24120.21 (19)
O1—C2—O2127.2 (3)N28—C23—C25110.43 (18)
O2—C2—C3138.3 (3)C24—C23—C25112.8 (2)
C2—C3—C482.45 (19)C22—C23—C25110.60 (18)
N8—C3—C5110.87 (17)O21—C24—C2390.0 (2)
C2—C3—C5110.5 (2)C23—C25—C27112.71 (19)
N8—C3—C4118.9 (2)C23—C25—C26112.6 (2)
N8—C3—C2118.66 (19)C26—C25—C27111.4 (2)
C4—C3—C5112.78 (18)O29—C29—N28123.2 (2)
O1—C4—C390.0 (2)O29—C29—O30125.1 (2)
C3—C5—C6111.1 (2)O30—C29—N28111.76 (19)
C6—C5—C7112.6 (2)O30—C31—C33101.66 (19)
C3—C5—C7112.5 (2)O30—C31—C34110.4 (2)
O9—C9—O10125.4 (2)C32—C31—C34113.0 (2)
O9—C9—N8123.2 (2)C33—C31—C34111.1 (2)
O10—C9—N8111.47 (18)C32—C31—C33111.2 (2)
C12—C11—C14112.3 (2)O30—C31—C32108.99 (19)
C13—C11—C14111.9 (2)O21—C24—H24A114
C12—C11—C13110.3 (2)O21—C24—H24B114
O10—C11—C14110.3 (2)C23—C24—H24A114
O10—C11—C12110.22 (19)C23—C24—H24B114
O10—C11—C13101.20 (19)H24A—C24—H24B111
C3—C4—H4B114C23—C25—H25107
C3—C4—H4A114C26—C25—H25107
H4A—C4—H4B111C27—C25—H25107
O1—C4—H4B114C25—C26—H26A109
O1—C4—H4A114C25—C26—H26B109
C6—C5—H5107C25—C26—H26C109
C3—C5—H5107H26A—C26—H26B110
C7—C5—H5107H26A—C26—H26C109
H6A—C6—H6C109H26B—C26—H26C109
C5—C6—H6C109C25—C27—H27A109
H6A—C6—H6B109C25—C27—H27B110
H6B—C6—H6C109C25—C27—H27C109
C5—C6—H6A110H27A—C27—H27B109
C5—C6—H6B110H27A—C27—H27C109
C5—C7—H7A110H27B—C27—H27C109
C5—C7—H7C109C31—C32—H32A109
C5—C7—H7B109C31—C32—H32B109
H7B—C7—H7C109C31—C32—H32C109
H7A—C7—H7C109H32A—C32—H32B110
H7A—C7—H7B110H32A—C32—H32C109
C11—C12—H12B109H32B—C32—H32C110
C11—C12—H12C109C31—C33—H33A109
H12B—C12—H12C109C31—C33—H33B109
H12A—C12—H12B109C31—C33—H33C110
C11—C12—H12A109H33A—C33—H33B109
H12A—C12—H12C109H33A—C33—H33C109
C11—C13—H13C109H33B—C33—H33C109
H13A—C13—H13B109C31—C34—H34A109
C11—C13—H13B109C31—C34—H34B109
C11—C13—H13A109C31—C34—H34C109
H13B—C13—H13C109H34A—C34—H34B109
H13A—C13—H13C110H34A—C34—H34C109
C11—C14—H14C109H34B—C34—H34C109
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N8—H8···O290.862.092.939 (2)169
N28—H28···O90.862.082.924 (3)168
C6—H6C···O290.962.543.434 (4)154
C27—H27C···O90.962.573.442 (4)151
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N8—H8···O290.862.092.939 (2)169
N28—H28···O90.862.082.924 (3)168
C6—H6C···O290.962.543.434 (4)154
C27—H27C···O90.962.573.442 (4)151
Acknowledgements top

This work was supported partly by the Ministry of Scientific Research and Information Technology (grant No. T09A 167 22).

references
References top

Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256–262.

Lall, M. S., Ramtohul, Y. K., James, M. N. G. & Vederas, J. C. (2002). J. Org. Chem. 67, 1536–1547.

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