5-Fluoro-1,3-dihydro-2,1-benzoxaborol-1-ol

Madura, I.D.; Adamczyk-Woźniak, A.; Jakubczyk, M.; Sporzyński, A.

doi:10.1107/S1600536811001632

organic compounds

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ISSN: 2056-9890

Volume 67| Part 2| February 2011| Pages o414-o415

doi:10.1107/S1600536811001632

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5-Fluoro-1,3-dihydro-2,1-benzoxaborol-1-ol

Izabela D. Madura,^a ^* Agnieszka Adamczyk-Woźniak,^a Michał Jakubczyk ^a and Andrzej Sporzyński ^a

^aWarsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664 Warszawa, Poland
^*Correspondence e-mail: izabela@ch.pw.edu.pl

(Received 23 December 2010; accepted 11 January 2011; online 15 January 2011)

In the crystal structure of the title compound, C₇H₆BFO₂, a broad-spectrum antifungal drug (AN2690), the planar [maximum deviation 0.035 (1) Å] molecules form centrosymmetric R₂²(8) dimers via strong O—H⋯O hydrogen bonds. The dimers are arranged into layers by weak intermolecular C—H⋯O and C—H⋯F hydrogen bonds. The symmetry of this two-dimensional supramolecular assembly can be described by the layer group p $[\overline{1}]$ and topologically classified as a simple uninodal four-connected two-dimensional network of a (4.4.4.4.6.6) topology. Further weak C—H⋯O interactions build up the three-dimensional structure.

Related literature

For the review of the synthesis, properties and applications of benzoxaboroles, see: Adamczyk-Woźniak et al. (2009 ). For the biological activity of the title compound, see: Baker et al. (2005 , 2006 ); Hui et al. (2007 ); Rock et al. (2007 ). For the synthesis see: Baker et al. (2006), Gunasekera et al. (2007 ). For related structures, see: Adamczyk-Woźniak et al. (2010 ); Tan et al. (2001 ); Yamamoto et al. (2005 ); Zhdankin et al. (1999 ). For hydrogen-bond graph-set descriptors and layer symmetry groups, see: Etter (1990 ) and International Tables for Crystallography (2006 ), respectively.

Experimental

Crystal data

C₇H₆BFO₂
M_r = 151.93
Triclinic, $[P \overline 1]$
a = 3.8799 (3) Å
b = 6.3077 (5) Å
c = 14.0735 (12) Å
α = 98.068 (7)°
β = 91.564 (7)°
γ = 100.473 (7)°
V = 334.84 (5) Å³
Z = 2
Cu Kα radiation
μ = 1.06 mm⁻¹
T = 100 K
0.60 × 0.35 × 0.20 mm

Data collection

Oxford Diffraction Gemini A Ultra diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis PRO. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.]$ ) T_min = 0.731, T_max = 1.000
3451 measured reflections
1193 independent reflections
1147 reflections with I > 2σ(I)
R_int = 0.016

Refinement

R[F² > 2σ(F²)] = 0.032
wR(F²) = 0.088
S = 1.07
1193 reflections
105 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O1ⁱ	0.83 (2)	1.93 (2)	2.7614 (13)	175 (2)
C7—H7B⋯O2ⁱⁱ	0.99	2.55	3.5325 (15)	172
C5—H5⋯F1ⁱⁱⁱ	0.95	2.58	3.4779 (14)	157
C7—H7A⋯O2^iv	0.99	2.66	3.2172 (14)	116
C3—H3⋯O2^iv	0.95	2.70	3.4276 (14)	134
Symmetry codes: (i) -x+2, -y+2, -z+1; (ii) x, y-1, z; (iii) -x, -y+2, -z+2; (iv) x-1, y-1, z.

Data collection: CrysAlis PRO (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis PRO. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.]$ ); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009 ), PLATON (Spek, 2009 ) and publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811001632/fj2381sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811001632/fj2381Isup2.hkl

checkCIF report

Related literature top

For the review of the synthesis, properties and applications of benzoxaboroles, see: Adamczyk-Woźniak et al. (2009). For the biological activity of the title compound, a broad-spectrum antifungal drug (AN2690), see: Baker et al. (2005, 2006); Hui et al. (2007); Rock et al. (2007). For the synthesis see: Baker et al. (2006), Gunasekera et al. (2007). For related structures, see: Adamczyk-Woźniak et al. (2010); Tan et al. (2001); Yamamoto et al. (2005); Zhdankin et al. (1999). For hydrogen-bond graph-set descriptors and layer symmetry groups, see: Etter (1990) and International Tables for Crystallography (2006), respectively.

Experimental top

5-Fluoro-1,3-dihydro-1-hydroxy-2,1-benzoxaborole (I) was synthesized according to Fig. 3.

2-Bromo-5-fluorobenzaldehyde was purchased from Sigma-Aldrich and used as received. 2-Bromo-5-fluorobenzaldehyde (5.00 g, 0.025 mol) and 2.69 g (0.025 mol) of trimethoxymethane was dissolved in 100 ml of methanol in a two-necked vessel. 0.4 ml of concentrated H₂SO₄ was added. The solution was refluxed for one hour and left to cool down. Then the solution was brought to pH≈11 with a concentrated solution of NaOMe in methanol. The reaction mixture was distilled under vacuum to give 5.90 g of 1-Bromo-2-(dimethoxymethyl)-4-fluorobenzene as a colorless liquid (yield 96%; ¹H NMR (CDCl₃, 400 MHz): 7.49 (dd, 1H), 7.34 (dd, 1H), 6.91 (td, 1H), 5.49 (s, 1H), 3.37 (s, 6H) p.p.m.). The product was dissolved in 100 ml of dry Et₂O in a three-necked vessel under argon flow. The solution was cooled down to -78°C using dry ice/acetone bath. n-Butyllithium in hexane (2.5 M, 11 ml) was added dropwise to keep the temperature under -70°C. The solution was stirred for one hour, then 3.80 g (0.026 mol, 4.4 ml) of triethyl borate was added slowly, keeping the temperature under -70°C. The dry ice/acetone bath was removed and the solution was stirred for one hour. The solution was brought to pH≈3 with 3 M aq. HCl. The aqueous layer was separated and extracted with Et₂O (2 × 100 ml). The organic layers were combined and the solvent was partially removed under vacuum. The remaining thick solution was dissolved in hot water. Yellowish crystals of 4-fluoro-2-formylphenylboronic acid were filtered after a few hours. Recrystallization from water gave 1.79 g of the product (yield 49%; ¹H NMR (CDCl₃, 400 MHz): 9.89 (s, 1H), 8.31 (dd, 1H), 7.62 (dd, 1H), 7.40 (td, 1H) p.p.m.). The product (1.79 g, 0.011 mol) was dissolved in 100 ml of methanol in a one-necked vessel. 0.44 g (0.012 mol) of NaBH₄ was added in small portions. The solution was mixed for 12 h. Another portion of 0.22 g of NaBH₄ was added and the solution was mixed for 3 days. The solvent was removed under vacuum. The crude product was dissolved in water. Crystallization gave 0.82 g of 5-Fluoro-1,3-dihydro-1-hydroxy-2,1-benzoxaborole (I) as yellowish crystals (yield 51%; ¹H NMR (CDCl₃, 400 MHz): 7.72 (dd, 1H), 7.06 (m, 2H), 5.08 (s, 2H) p.p.m.; ¹⁹F NMR (CDCl₃, 376.3 MHz): -113.51 (q) p.p.m.; ¹¹B NMR ((CdD₃)₂CO, 64.1 MHz): 32.0 p.p.m.; m.p. 135–136°C).

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2006); cell refinement: CrysAlis PRO (Oxford Diffraction, 2006); data reduction: CrysAlis PRO (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Figures top

ORTEP plot of the hydrogen bonded dimer of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.

Projection on (1 0 2) plane showing layers of molecules linked by O—H···O (dashed lines), C—H···O and C—H···F (dotted lines) H-bonds.

Synthesis of 5-fluoro-1,3-dihydro-1-hydroxy-2,1-benzoxaborole (I).

5-Fluoro-1,3-dihydro-2,1-benzoxaborol-1-ol top

Crystal data top

C₇H₆BFO₂	Z = 2
M_r = 151.93	F(000) = 156
Triclinic, P1	D_x = 1.507 Mg m⁻³
Hall symbol: -P 1	Melting point: 408 K
a = 3.8799 (3) Å	Cu Kα radiation, λ = 1.5418 Å
b = 6.3077 (5) Å	Cell parameters from 3116 reflections
c = 14.0735 (12) Å	θ = 3.2–67.1°
α = 98.068 (7)°	µ = 1.06 mm⁻¹
β = 91.564 (7)°	T = 100 K
γ = 100.473 (7)°	Prism, light yellow
V = 334.84 (5) Å³	0.60 × 0.35 × 0.20 mm

Data collection top

Oxford Diffraction Gemini A Ultra diffractometer	1193 independent reflections
Radiation source: Enhance Ultra (Cu) X-ray Source	1147 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.016
Detector resolution: 10.3347 pixels mm^-1	θ_max = 67.1°, θ_min = 3.2°
ω scans	h = −4→4
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2006)	k = −7→7
T_min = 0.731, T_max = 1.000	l = −16→14
3451 measured reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.032	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.088	w = 1/[σ²(F_o²) + (0.0511P)² + 0.1152P] where P = (F_o² + 2F_c²)/3
S = 1.07	(Δ/σ)_max < 0.001
1193 reflections	Δρ_max = 0.33 e Å⁻³
105 parameters	Δρ_min = −0.18 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.046 (5)

Crystal data top

C₇H₆BFO₂	γ = 100.473 (7)°
M_r = 151.93	V = 334.84 (5) Å³
Triclinic, P1	Z = 2
a = 3.8799 (3) Å	Cu Kα radiation
b = 6.3077 (5) Å	µ = 1.06 mm⁻¹
c = 14.0735 (12) Å	T = 100 K
α = 98.068 (7)°	0.60 × 0.35 × 0.20 mm
β = 91.564 (7)°

Data collection top

Oxford Diffraction Gemini A Ultra diffractometer	1193 independent reflections
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2006)	1147 reflections with I > 2σ(I)
T_min = 0.731, T_max = 1.000	R_int = 0.016
3451 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.032	0 restraints
wR(F²) = 0.088	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	Δρ_max = 0.33 e Å⁻³
1193 reflections	Δρ_min = −0.18 e Å⁻³
105 parameters

Special details top

Experimental. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. (Oxford Diffraction, 2006)

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.

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

	x	y	z	U_iso*/U_eq
O2	0.9636 (2)	1.22613 (14)	0.60638 (7)	0.0189 (3)
F1	0.0385 (2)	0.70856 (13)	0.93059 (5)	0.0282 (3)
O1	0.7364 (2)	0.84381 (13)	0.56821 (6)	0.0171 (3)
C3	0.2566 (3)	0.6725 (2)	0.77652 (9)	0.0185 (3)
H3	0.1624	0.5207	0.7660	0.022*
C4	0.2168 (3)	0.8036 (2)	0.86129 (9)	0.0200 (3)
C2	0.4422 (3)	0.7757 (2)	0.70750 (9)	0.0162 (3)
C1	0.5825 (3)	0.9983 (2)	0.72234 (9)	0.0167 (3)
C5	0.3485 (3)	1.0251 (2)	0.87950 (9)	0.0207 (3)
H5	0.3121	1.1083	0.9388	0.025*
C6	0.5346 (3)	1.1237 (2)	0.80968 (9)	0.0186 (3)
H6	0.6291	1.2754	0.8210	0.022*
B1	0.7783 (3)	1.0404 (2)	0.63011 (10)	0.0164 (3)
C7	0.5248 (3)	0.6711 (2)	0.61026 (9)	0.0170 (3)
H7B	0.6562	0.5526	0.6164	0.020*
H7A	0.3064	0.6096	0.5701	0.020*
H2	1.061 (5)	1.212 (3)	0.5545 (15)	0.040 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O2	0.0245 (5)	0.0147 (5)	0.0169 (5)	0.0025 (4)	0.0053 (4)	0.0011 (3)
F1	0.0329 (5)	0.0323 (5)	0.0196 (4)	0.0035 (4)	0.0106 (3)	0.0065 (3)
O1	0.0208 (5)	0.0145 (5)	0.0154 (5)	0.0019 (3)	0.0046 (3)	0.0017 (3)
C3	0.0178 (6)	0.0188 (6)	0.0193 (7)	0.0037 (5)	0.0009 (5)	0.0033 (5)
C4	0.0181 (6)	0.0273 (7)	0.0160 (6)	0.0052 (5)	0.0038 (5)	0.0061 (5)
C2	0.0149 (6)	0.0174 (6)	0.0168 (6)	0.0055 (5)	−0.0004 (4)	0.0014 (5)
C1	0.0154 (6)	0.0174 (6)	0.0178 (7)	0.0051 (5)	−0.0011 (5)	0.0021 (5)
C5	0.0212 (6)	0.0256 (7)	0.0155 (6)	0.0083 (5)	0.0008 (5)	−0.0016 (5)
C6	0.0187 (6)	0.0179 (6)	0.0188 (6)	0.0049 (5)	−0.0001 (5)	−0.0007 (5)
B1	0.0162 (6)	0.0162 (7)	0.0172 (7)	0.0055 (5)	−0.0011 (5)	0.0009 (5)
C7	0.0197 (6)	0.0135 (6)	0.0174 (6)	0.0017 (5)	0.0036 (5)	0.0021 (5)

Geometric parameters (Å, º) top

O2—B1	1.3483 (18)	C2—C1	1.3948 (18)
O2—H2	0.83 (2)	C2—C7	1.5025 (17)
F1—C4	1.3562 (15)	C1—C6	1.4013 (17)
O1—B1	1.3922 (17)	C1—B1	1.5522 (18)
O1—C7	1.4471 (15)	C5—H5	0.9500
C3—H3	0.9500	C5—C6	1.3856 (18)
C3—C4	1.3822 (19)	C6—H6	0.9500
C3—C2	1.3897 (18)	C7—H7B	0.9900
C4—C5	1.3829 (19)	C7—H7A	0.9900

O2—B1—O1	121.51 (12)	C2—C3—H3	121.9
O2—B1—C1	130.25 (12)	C2—C1—C6	119.16 (12)
F1—C4—C3	117.85 (12)	C2—C1—B1	104.93 (11)
F1—C4—C5	118.27 (12)	C2—C7—H7B	110.7
O1—B1—C1	108.24 (11)	C2—C7—H7A	110.7
O1—C7—C2	105.45 (9)	C1—C2—C7	110.88 (11)
O1—C7—H7B	110.7	C1—C6—H6	120.2
O1—C7—H7A	110.7	C5—C6—C1	119.66 (12)
C3—C4—C5	123.88 (12)	C5—C6—H6	120.2
C3—C2—C1	122.36 (12)	C6—C1—B1	135.86 (12)
C3—C2—C7	126.75 (11)	C6—C5—H5	120.6
C4—C3—H3	121.9	B1—O2—H2	115.3 (13)
C4—C3—C2	116.12 (12)	B1—O1—C7	110.46 (10)
C4—C5—H5	120.6	H7B—C7—H7A	108.8
C4—C5—C6	118.82 (12)

F1—C4—C5—C6	179.28 (10)	C2—C1—B1—O2	−179.25 (12)
C3—C4—C5—C6	−0.58 (19)	C2—C1—B1—O1	0.71 (13)
C3—C2—C1—C6	−0.23 (17)	C1—C2—C7—O1	2.08 (13)
C3—C2—C1—B1	177.60 (11)	C6—C1—B1—O2	−2.0 (2)
C3—C2—C7—O1	−177.19 (11)	C6—C1—B1—O1	178.00 (12)
C4—C3—C2—C1	0.24 (18)	B1—O1—C7—C2	−1.57 (13)
C4—C3—C2—C7	179.42 (11)	B1—C1—C6—C5	−177.18 (12)
C4—C5—C6—C1	0.57 (18)	C7—O1—B1—O2	−179.45 (10)
C2—C3—C4—F1	−179.69 (9)	C7—O1—B1—C1	0.59 (13)
C2—C3—C4—C5	0.17 (19)	C7—C2—C1—C6	−179.53 (10)
C2—C1—C6—C5	−0.19 (17)	C7—C2—C1—B1	−1.70 (13)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O1ⁱ	0.83 (2)	1.93 (2)	2.7614 (13)	175 (2)
C7—H7B···O2ⁱⁱ	0.99	2.55	3.5325 (15)	172
C5—H5···F1ⁱⁱⁱ	0.95	2.58	3.4779 (14)	157
C7—H7A···O2^iv	0.99	2.66	3.2172 (14)	116
C3—H3···O2^iv	0.95	2.70	3.4276 (14)	134

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

Experimental details

Crystal data
Chemical formula	C₇H₆BFO₂
M_r	151.93
Crystal system, space group	Triclinic, P1
Temperature (K)	100
a, b, c (Å)	3.8799 (3), 6.3077 (5), 14.0735 (12)
α, β, γ (°)	98.068 (7), 91.564 (7), 100.473 (7)
V (Å³)	334.84 (5)
Z	2
Radiation type	Cu Kα
µ (mm⁻¹)	1.06
Crystal size (mm)	0.60 × 0.35 × 0.20

Data collection
Diffractometer	Oxford Diffraction Gemini A Ultra diffractometer
Absorption correction	Multi-scan (CrysAlis PRO; Oxford Diffraction, 2006)
T_min, T_max	0.731, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	3451, 1193, 1147
R_int	0.016
(sin θ/λ)_max (Å⁻¹)	0.597

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.032, 0.088, 1.07
No. of reflections	1193
No. of parameters	105
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.33, −0.18

Computer programs: CrysAlis PRO (Oxford Diffraction, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEPIII (Burnett & Johnson, 1996), OLEX2 (Dolomanov et al., 2009), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O1ⁱ	0.83 (2)	1.93 (2)	2.7614 (13)	175 (2)
C7—H7B···O2ⁱⁱ	0.99	2.55	3.5325 (15)	172
C5—H5···F1ⁱⁱⁱ	0.95	2.58	3.4779 (14)	157
C7—H7A···O2^iv	0.99	2.66	3.2172 (14)	116
C3—H3···O2^iv	0.95	2.70	3.4276 (14)	134

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

Acknowledgements

The authors acknowledge financial support by the Ministry of Science and Higher Education (grant No. N204 127938).

References

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