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Acta Crystallogr Sect E Struct Rep Online. 2009 April 1; 65(Pt 4): o687.
Published online 2009 March 6. doi:  10.1107/S1600536809007375
PMCID: PMC2969006

tert-Butyl 2-borono-1H-pyrrole-1-carboxyl­ate

Abstract

In the crystal structure of the title compound, C9H14BNO4, the boronic acid group and carbamate groups are nearly co-planar with the pyrrole ring, making dihedral angles of 0.1 (2) and 2.2 (2)°, respectively. Intra­molecular and inter­molecular O—H(...)O hydrogen bonds help to stabilize the structure, the latter interaction leading to inversion dimers..

Related literature

For general background, see: Hall (2005 [triangle]); Kelly & Fuchs (1993 [triangle]).

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Object name is e-65-0o687-scheme1.jpg

Experimental

Crystal data

  • C9H14BNO4
  • M r = 211.02
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-65-0o687-efi1.jpg
  • a = 13.014 (3) Å
  • b = 9.940 (2) Å
  • c = 17.417 (4) Å
  • V = 2252.9 (9) Å3
  • Z = 8
  • Mo Kα radiation
  • μ = 0.10 mm−1
  • T = 293 K
  • 0.25 × 0.12 × 0.10 mm

Data collection

  • Bruker SMART 1000 CCD area-detector diffractometer
  • Absorption correction: none
  • 9542 measured reflections
  • 2213 independent reflections
  • 1208 reflections with I > 2σ(I)
  • R int = 0.065

Refinement

  • R[F 2 > 2σ(F 2)] = 0.042
  • wR(F 2) = 0.106
  • S = 0.85
  • 2213 reflections
  • 192 parameters
  • All H-atom parameters refined
  • Δρmax = 0.12 e Å−3
  • Δρmin = −0.21 e Å−3

Data collection: SMART (Bruker, 2001 [triangle]); cell refinement: SAINT (Bruker, 2001 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, New_Global_Publ_Block. DOI: 10.1107/S1600536809007375/xu2484sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809007375/xu2484Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

We thank Professor Lin-Hong Weng, Fudan University, for the X-ray analysis.

supplementary crystallographic information

Comment

Boronic acids are versatile compounds widely used in the synthesis of biaryls, as therapeutical agents, and as chemical sensors (Hall, 2005). The title compound is the key intermediate for the synthesis of (+)-pinanediol-L-boroproline (Kelly & Fuchs, 1993).

In the molecular structure of the title compound (Fig. 1), the pyrrole ring, the boronic acid group and the carboxyl groups are almost co-planar. The carbonyl links with the adjacent boronic acid group via O3—H3···O2 hydrogen bonding. Intermolecular hydrogen bond is also observed in the crystal structure (Table 1).

Experimental

All chemical reagents are commercial and used as received. Under -78°C and argon atmosphere, lithium diisopropylamide (1.0 M in THF, 5.0 ml, 5.0 mmol) was added dropwise to a solution of tert-butyl 1H-pyrrole-1-carboxylate (835 mg, 5.0 mmol) in dry THF (15 ml), and the solution was stirred at this temperature for 30 min. Trimethylborate (1.7 ml, 15 mmol) was added dropwise, and the mixture was allowed to warm to room temperature over 2 h and stirred overnight. After aqueous workup, the crude product was crystallized from hexanes. Single crystals suitable for X-ray analysis were obtained by recrystallization from a mixed solvent of ethyl acetate and hexane at ambient temperature (20–25°C).

Refinement

H atoms were located in a difference Fourier map and refined isotropically.

Figures

Fig. 1.
The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. H atoms are drawn as spheres of arbitrary radii.

Crystal data

C9H14BNO4F(000) = 896
Mr = 211.02Dx = 1.244 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 810 reflections
a = 13.014 (3) Åθ = 2.3–22.4°
b = 9.940 (2) ŵ = 0.10 mm1
c = 17.417 (4) ÅT = 293 K
V = 2252.9 (9) Å3Prism, colorless
Z = 80.25 × 0.12 × 0.10 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer1208 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.065
graphiteθmax = 26.0°, θmin = 2.3°
[var phi] and ω scansh = −16→13
9542 measured reflectionsk = −12→12
2213 independent reflectionsl = −21→19

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.106All H-atom parameters refined
S = 0.85w = 1/[σ2(Fo2) + (0.0588P)2] where P = (Fo2 + 2Fc2)/3
2213 reflections(Δ/σ)max < 0.001
192 parametersΔρmax = 0.12 e Å3
0 restraintsΔρmin = −0.20 e Å3

Special details

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)

xyzUiso*/Ueq
B11.03949 (15)0.6990 (2)0.51802 (11)0.0727 (6)
C11.09811 (14)1.0494 (2)0.59196 (12)0.0767 (5)
C21.17519 (16)1.0274 (3)0.54329 (13)0.0893 (7)
C31.16298 (14)0.8995 (3)0.51194 (12)0.0821 (6)
C41.07732 (12)0.83956 (18)0.54116 (8)0.0644 (5)
C50.94986 (12)0.92187 (19)0.63777 (9)0.0635 (4)
C60.85439 (15)1.03344 (19)0.74024 (10)0.0771 (5)
C70.75166 (18)1.0282 (3)0.70204 (16)0.0955 (7)
C80.8711 (3)0.9215 (3)0.79700 (14)0.1000 (7)
C90.8746 (3)1.1693 (3)0.7756 (2)0.1119 (9)
N11.03646 (9)0.93560 (14)0.59221 (7)0.0631 (4)
O10.93714 (8)1.02801 (13)0.68119 (7)0.0754 (4)
O20.89519 (9)0.82427 (13)0.63724 (7)0.0776 (4)
O30.95566 (10)0.63485 (15)0.54641 (8)0.0921 (5)
O41.09809 (10)0.6338 (2)0.46635 (8)0.0960 (5)
H31.2044 (14)0.8510 (17)0.4741 (10)0.083 (5)*
H7A0.7006 (17)1.040 (2)0.7397 (13)0.104 (7)*
H7B0.7430 (18)1.106 (3)0.6664 (14)0.131 (10)*
H8A0.8247 (16)0.934 (2)0.8403 (14)0.109 (7)*
H11.0760 (14)1.126 (2)0.6241 (11)0.089 (6)*
H9A0.8259 (16)1.184 (2)0.8132 (14)0.122 (8)*
H9B0.8706 (15)1.236 (2)0.7359 (14)0.109 (9)*
H7C0.7384 (15)0.942 (2)0.6764 (13)0.104 (7)*
H21.2262 (17)1.090 (2)0.5323 (11)0.104 (7)*
H8B0.941 (2)0.928 (2)0.8167 (14)0.130 (9)*
H9C0.949 (2)1.169 (3)0.7937 (16)0.169 (12)*
H8C0.8565 (17)0.826 (3)0.7735 (14)0.135 (9)*
H3A0.9265 (14)0.6888 (19)0.5791 (11)0.087 (6)*
H41.080 (2)0.548 (3)0.4581 (16)0.145 (12)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
B10.0572 (11)0.1046 (17)0.0563 (11)0.0146 (11)−0.0040 (9)−0.0053 (11)
C10.0616 (11)0.0916 (15)0.0767 (12)−0.0077 (11)−0.0134 (10)0.0135 (12)
C20.0590 (12)0.120 (2)0.0888 (15)−0.0117 (12)−0.0074 (11)0.0335 (14)
C30.0565 (11)0.1260 (19)0.0638 (11)0.0091 (12)0.0003 (9)0.0161 (13)
C40.0524 (9)0.0915 (13)0.0492 (8)0.0113 (9)−0.0034 (7)0.0069 (9)
C50.0586 (10)0.0744 (12)0.0576 (9)0.0032 (9)−0.0030 (8)0.0004 (9)
C60.0834 (13)0.0832 (13)0.0647 (11)0.0110 (10)0.0065 (9)−0.0149 (10)
C70.0793 (15)0.116 (2)0.0913 (17)0.0166 (14)0.0054 (13)−0.0170 (17)
C80.119 (2)0.115 (2)0.0655 (13)0.0172 (16)0.0126 (14)0.0019 (14)
C90.129 (2)0.103 (2)0.103 (2)0.0076 (16)0.0117 (18)−0.0376 (18)
N10.0494 (7)0.0814 (10)0.0585 (8)−0.0007 (7)−0.0031 (6)0.0075 (7)
O10.0787 (8)0.0766 (8)0.0708 (7)−0.0010 (6)0.0069 (6)−0.0128 (7)
O20.0698 (7)0.0786 (9)0.0844 (8)−0.0067 (6)0.0214 (6)−0.0166 (7)
O30.0730 (8)0.1037 (11)0.0996 (10)−0.0004 (7)0.0200 (7)−0.0384 (8)
O40.0799 (9)0.1217 (14)0.0863 (9)0.0147 (8)0.0190 (7)−0.0238 (9)

Geometric parameters (Å, °)

B1—O41.346 (2)C6—C71.494 (3)
B1—O31.357 (2)C6—C81.504 (3)
B1—C41.535 (3)C6—C91.507 (3)
C1—C21.331 (3)C7—H7A0.94 (2)
C1—N11.387 (2)C7—H7B0.99 (3)
C1—H10.99 (2)C7—H7C0.98 (2)
C2—C31.393 (3)C8—H8A0.97 (2)
C2—H20.93 (2)C8—H8B0.98 (3)
C3—C41.363 (3)C8—H8C1.05 (3)
C3—H30.978 (18)C9—H9A0.92 (2)
C4—N11.409 (2)C9—H9B0.96 (2)
C5—O21.2030 (19)C9—H9C1.02 (3)
C5—O11.309 (2)O3—H3A0.87 (2)
C5—N11.385 (2)O4—H40.89 (3)
C6—O11.490 (2)
O4—B1—O3118.2 (2)C6—C7—H7A108.5 (13)
O4—B1—C4115.60 (19)C6—C7—H7B110.6 (14)
O3—B1—C4126.14 (17)H7A—C7—H7B105.0 (18)
C2—C1—N1107.7 (2)C6—C7—H7C112.9 (12)
C2—C1—H1135.0 (12)H7A—C7—H7C107.4 (18)
N1—C1—H1117.2 (11)H7B—C7—H7C112 (2)
C1—C2—C3108.3 (2)C6—C8—H8A109.2 (12)
C1—C2—H2123.9 (13)C6—C8—H8B108.4 (15)
C3—C2—H2127.8 (13)H8A—C8—H8B107 (2)
C4—C3—C2110.3 (2)C6—C8—H8C112.7 (13)
C4—C3—H3119.1 (11)H8A—C8—H8C107.5 (18)
C2—C3—H3130.7 (10)H8B—C8—H8C111 (2)
C3—C4—N1104.36 (18)C6—C9—H9A107.9 (16)
C3—C4—B1124.22 (18)C6—C9—H9B108.3 (13)
N1—C4—B1131.40 (15)H9A—C9—H9B112 (2)
O2—C5—O1125.44 (15)C6—C9—H9C107.0 (17)
O2—C5—N1123.79 (16)H9A—C9—H9C116 (2)
O1—C5—N1110.77 (15)H9B—C9—H9C106 (2)
O1—C6—C7109.75 (16)C5—N1—C1123.57 (16)
O1—C6—C8108.80 (16)C5—N1—C4127.01 (15)
C7—C6—C8113.4 (2)C1—N1—C4109.41 (16)
O1—C6—C9100.86 (18)C5—O1—C6121.30 (13)
C7—C6—C9111.6 (2)B1—O3—H3A107.4 (12)
C8—C6—C9111.6 (2)B1—O4—H4114.5 (18)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O4—H4···O3i0.89 (3)1.88 (3)2.769 (3)173 (3)
O3—H3A···O20.87 (2)1.73 (2)2.5819 (18)164.7 (18)

Symmetry codes: (i) −x+2, −y+1, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: XU2484).

References

  • Bruker (2001). SAINT and SMART Bruker AXS Inc., Madison, Wisconsin, USA.
  • Hall, D. G. (2005). Editor. Boronic Acids, Weinheim: Wiley-VCH.
  • Kelly, T. A. & Fuchs, V. U. (1993). Tetrahedron49, 1009–1016.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography