2-Methyl-1,3-benzoxazol-4-yl diphenyl­phosphinate

Kleinhans, D.J.

doi:10.1107/S1600536811000420

organic compounds

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Volume 67| Part 2| February 2011| Page o339

doi:10.1107/S1600536811000420

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2-Methyl-1,3-benzoxazol-4-yl diphenylphosphinate

Dewald J. Kleinhans ^a ^*

^aDepartment of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
^*Correspondence e-mail: dewaldk@sun.ac.za

(Received 8 December 2010; accepted 5 January 2011; online 12 January 2011)

The title compound, C₂₀H₁₆NO₃P, was synthesized by the addition of diphenylphosphine chloride to a tetrahydrofuran solution of Et₃N and 2-methyl-1,3-benzoxazol-4-ol at 233 K. In the molecule, the almost planar (r.m.s. deviation = 0.010 Å) benzoxazole moiety is attached to the slightly distorted tetrahedral P atom [C—P—C—C torsion angle = 132.20 (18)°]. The crystal structure does not exhibit any significant intermolecular interactions.

Related literature

For reference structural data, see: Bruno et al. (2004 ). For related benzoxazole structures, see: Dreher et al. (1982 ); Mrozek et al. (1999 ); Qu et al. (2008 ).

Experimental

Crystal data

C₂₀H₁₆NO₃P
M_r = 349.31
Orthorhombic, P b c a
a = 9.4239 (4) Å
b = 15.7574 (6) Å
c = 23.5398 (8) Å
V = 3495.6 (2) Å³
Z = 8
Mo Kα radiation
μ = 0.18 mm⁻¹
T = 294 K
0.39 × 0.28 × 0.19 mm

Data collection

Bruker APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ) T_min = 0.934, T_max = 0.968
17406 measured reflections
4323 independent reflections
2395 reflections with I > 2sI)
R_int = 0.048

Refinement

R[F² > 2σ(F²)] = 0.047
wR(F²) = 0.119
S = 1.01
4323 reflections
229 parameters
H-atom parameters constrained
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

P12—C13	1.785 (2)
P12—C19	1.786 (2)
P12—O11	1.6075 (14)
P12—O25	1.4665 (15)

C13—P12—C19	109.59 (9)
O11—P12—C13	99.36 (8)
O25—P12—C13	113.91 (9)
O11—P12—C19	104.76 (8)
O25—P12—C19	112.73 (9)
O25—P12—O11	115.37 (8)

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001 ; Atwood & Barbour, 2003 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811000420/bh2332sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811000420/bh2332Isup2.hkl

checkCIF report

Comment top

In an attempt to synthesize phosphinite derivatives of benzoxazole ligands the title compound, 2-methyl-1,3-benzoxazol-4-yl diphenylphosphinate, was formed as the major product (Fig. 1).

All bond lengths are within normal values (Bruno et al., 2004) and compare well with related benzoxazole structures (Dreher et al., 1982; Mrozek et al., 1999; Qu et al., 2008). In the molecular structure, the planar benzoxazole moiety is attached to the slightly distorted tetrahedral P12 atom [O25—P12—O11 115.37 (8)°, O25—P12—C13 113.91 (9)°, O11—P12—C19 104.76 (8)°] through O11. No significant intermolecular interactions are observed in the orthorhombic crystal structure (Fig. 2).

Related literature top

For reference structural data, see: Bruno et al. (2004). For related benzoxazole structures, see: Dreher et al. (1982); Mrozek et al. (1999); Qu et al. (2008).

Experimental top

To a flask containing 2-methyl-1,3-benzoxazol-4-ol (50 mg, 0.34 mmol), was added dry tetrahydrofuran (6 ml) and the mixture was cooled to 233 K (-40 °C). To this solution was added triethylamine (0.071 ml, 0.51 mmol) and the reaction mixture was left stirring for 15 min. Diphenylphosphine chloride (0.070 ml, 0.37 mmol) in dry tetrahydrofuran (1 ml) was added dropwise to the reaction solution and on completion of addition was left to stir for a further 10 min. at -40 °C. The reaction mixture was warmed to room temperature and left to stir overnight. The mixture was filtered through Celite and the solvent removed under vacuum to leave a whitish oil. Column chromatography (SiO₂, eluting with 1:3 ethyl acetate/petroleum ether followed by 1:1 ethyl acetate/petroleum ether) furnished the title compound as a white solid (71 mg, 60% yield). X-ray quality crystals were formed by slow diffusion of petroleum ether into a dichloromethane solution of the title compound.

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001; Atwood & Barbour, 2003); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

	Fig. 1. The molecular structure of the title compound with 50% probability ellipsoids.
	Fig. 2. Molecular packing of the title compound (viewed along the a axis).

2-Methyl-1,3-benzoxazol-4-yl diphenylphosphinate top

Crystal data top

C₂₀H₁₆NO₃P	F(000) = 1456
M_r = 349.31	D_x = 1.327 Mg m⁻³
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 2232 reflections
a = 9.4239 (4) Å	θ = 2.6–21.4°
b = 15.7574 (6) Å	µ = 0.18 mm⁻¹
c = 23.5398 (8) Å	T = 294 K
V = 3495.6 (2) Å³	Shard, colourless
Z = 8	0.39 × 0.28 × 0.19 mm

Data collection top

Bruker APEX CCD area-detector diffractometer	4323 independent reflections
Radiation source: fine-focus sealed tube	2395 reflections with I > 2s˘I)
Graphite monochromator	R_int = 0.048
ω scans	θ_max = 28.3°, θ_min = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −9→12
T_min = 0.934, T_max = 0.968	k = −20→20
17406 measured reflections	l = −31→27

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.119	H-atom parameters constrained
S = 1.01	w = 1/[σ²(F_o²) + (0.0424P)² + 0.590P] where P = (F_o² + 2F_c²)/3
4323 reflections	(Δ/σ)_max = 0.001
229 parameters	Δρ_max = 0.17 e Å⁻³
0 restraints	Δρ_min = −0.26 e Å⁻³
0 constraints

Crystal data top

C₂₀H₁₆NO₃P	V = 3495.6 (2) Å³
M_r = 349.31	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 9.4239 (4) Å	µ = 0.18 mm⁻¹
b = 15.7574 (6) Å	T = 294 K
c = 23.5398 (8) Å	0.39 × 0.28 × 0.19 mm

Data collection top

Bruker APEX CCD area-detector diffractometer	4323 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	2395 reflections with I > 2s˘I)
T_min = 0.934, T_max = 0.968	R_int = 0.048
17406 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.047	0 restraints
wR(F²) = 0.119	H-atom parameters constrained
S = 1.01	Δρ_max = 0.17 e Å⁻³
4323 reflections	Δρ_min = −0.26 e Å⁻³
229 parameters

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

	x	y	z	U_iso*/U_eq
C1	1.0692 (3)	0.38155 (17)	0.26208 (12)	0.0919 (9)
H1A	1.0661	0.4112	0.2977	0.138*
H1B	1.0397	0.4190	0.2321	0.138*
H1C	1.1643	0.3625	0.2549	0.138*
C2	0.9726 (2)	0.30737 (14)	0.26439 (10)	0.0637 (6)
O3	0.95849 (15)	0.26057 (10)	0.21540 (6)	0.0675 (5)
C4	0.8664 (2)	0.19615 (14)	0.22996 (9)	0.0542 (5)
C5	0.8185 (2)	0.13016 (16)	0.19692 (9)	0.0648 (6)
H5	0.8464	0.1232	0.1593	0.078*
C6	0.7269 (2)	0.07556 (15)	0.22317 (10)	0.0665 (6)
H6	0.6905	0.0301	0.2026	0.080*
C7	0.6858 (2)	0.08550 (14)	0.28007 (9)	0.0599 (6)
H7	0.6227	0.0472	0.2964	0.072*
C8	0.7383 (2)	0.15153 (13)	0.31183 (8)	0.0505 (5)
C9	0.8305 (2)	0.20841 (12)	0.28635 (8)	0.0477 (5)
N10	0.89952 (18)	0.28056 (11)	0.30715 (7)	0.0575 (5)
O11	0.70042 (15)	0.16648 (8)	0.36812 (5)	0.0582 (4)
P12	0.66708 (6)	0.09284 (4)	0.41346 (2)	0.0517 (2)
C13	0.6671 (2)	0.15461 (13)	0.47700 (8)	0.0502 (5)
C14	0.5843 (2)	0.12659 (15)	0.52184 (9)	0.0617 (6)
H14	0.5311	0.0772	0.5180	0.074*
C15	0.5800 (2)	0.17110 (17)	0.57194 (9)	0.0698 (7)
H15	0.5233	0.1519	0.6016	0.084*
C16	0.6584 (2)	0.24348 (16)	0.57858 (10)	0.0678 (7)
H16	0.6545	0.2735	0.6126	0.081*
C17	0.7424 (3)	0.27171 (15)	0.53511 (11)	0.0726 (7)
H17	0.7968	0.3205	0.5398	0.087*
C18	0.7468 (3)	0.22806 (13)	0.48430 (9)	0.0639 (6)
H18	0.8035	0.2479	0.4548	0.077*
C19	0.8204 (2)	0.02618 (12)	0.41212 (8)	0.0505 (5)
C20	0.8072 (3)	−0.05892 (14)	0.39910 (10)	0.0702 (7)
H20	0.7181	−0.0814	0.3913	0.084*
C21	0.9249 (3)	−0.11072 (16)	0.39760 (12)	0.0866 (8)
H21	0.9150	−0.1678	0.3885	0.104*
C22	1.0558 (3)	−0.07849 (18)	0.40944 (11)	0.0839 (8)
H22	1.1348	−0.1139	0.4088	0.101*
C23	1.0718 (3)	0.00536 (19)	0.42221 (11)	0.0834 (8)
H23	1.1616	0.0272	0.4297	0.100*
C24	0.9548 (3)	0.05755 (15)	0.42402 (10)	0.0709 (7)
H24	0.9659	0.1145	0.4333	0.085*
O25	0.53499 (15)	0.04578 (9)	0.40384 (6)	0.0670 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0868 (19)	0.0779 (18)	0.111 (2)	−0.0161 (15)	0.0206 (16)	0.0018 (16)
C2	0.0600 (13)	0.0646 (14)	0.0665 (16)	0.0027 (12)	0.0041 (12)	0.0027 (13)
O3	0.0706 (10)	0.0740 (11)	0.0577 (10)	0.0022 (8)	0.0158 (8)	0.0062 (8)
C4	0.0541 (12)	0.0603 (13)	0.0482 (12)	0.0089 (10)	0.0040 (10)	0.0085 (11)
C5	0.0728 (15)	0.0778 (16)	0.0439 (12)	0.0118 (13)	0.0024 (11)	−0.0043 (12)
C6	0.0727 (15)	0.0687 (15)	0.0582 (14)	0.0022 (12)	−0.0032 (12)	−0.0118 (12)
C7	0.0651 (14)	0.0592 (14)	0.0555 (13)	−0.0002 (11)	0.0025 (10)	0.0012 (11)
C8	0.0595 (12)	0.0517 (12)	0.0403 (11)	0.0081 (10)	0.0028 (9)	0.0025 (10)
C9	0.0501 (11)	0.0517 (12)	0.0413 (11)	0.0090 (9)	−0.0010 (9)	0.0041 (9)
N10	0.0582 (11)	0.0588 (11)	0.0555 (11)	0.0024 (9)	0.0006 (9)	0.0028 (9)
O11	0.0817 (10)	0.0508 (8)	0.0422 (8)	0.0052 (7)	0.0118 (7)	0.0046 (6)
P12	0.0586 (4)	0.0516 (4)	0.0449 (4)	−0.0010 (3)	0.0046 (2)	0.0041 (2)
C13	0.0532 (11)	0.0504 (12)	0.0470 (12)	0.0049 (10)	0.0059 (9)	0.0031 (10)
C14	0.0590 (13)	0.0721 (15)	0.0538 (14)	−0.0065 (11)	0.0063 (10)	−0.0019 (12)
C15	0.0622 (14)	0.0961 (19)	0.0512 (14)	0.0002 (13)	0.0122 (11)	−0.0042 (13)
C16	0.0688 (15)	0.0790 (17)	0.0555 (14)	0.0165 (13)	0.0034 (11)	−0.0161 (12)
C17	0.0850 (17)	0.0587 (14)	0.0740 (17)	−0.0007 (13)	0.0058 (14)	−0.0115 (13)
C18	0.0788 (15)	0.0540 (13)	0.0589 (14)	−0.0003 (12)	0.0163 (11)	0.0014 (11)
C19	0.0635 (13)	0.0450 (11)	0.0432 (11)	−0.0031 (10)	0.0061 (9)	0.0025 (9)
C20	0.0791 (16)	0.0538 (14)	0.0777 (16)	−0.0058 (12)	0.0103 (12)	−0.0039 (12)
C21	0.109 (2)	0.0509 (15)	0.100 (2)	0.0125 (15)	0.0238 (17)	−0.0060 (14)
C22	0.091 (2)	0.080 (2)	0.0803 (18)	0.0298 (16)	0.0098 (15)	0.0116 (15)
C23	0.0668 (16)	0.088 (2)	0.095 (2)	0.0125 (15)	−0.0068 (14)	−0.0001 (16)
C24	0.0698 (15)	0.0566 (14)	0.0864 (18)	0.0029 (12)	−0.0041 (13)	−0.0074 (13)
O25	0.0622 (9)	0.0766 (11)	0.0620 (10)	−0.0109 (8)	−0.0011 (7)	0.0023 (8)

Geometric parameters (Å, º) top

P12—C13	1.785 (2)	C5—C6	1.366 (3)
P12—C19	1.786 (2)	C5—H5	0.9300
P12—O11	1.6075 (14)	C24—C23	1.377 (3)
P12—O25	1.4665 (15)	C24—H24	0.9300
C19—C20	1.381 (3)	C18—C17	1.380 (3)
C19—C24	1.388 (3)	C18—H18	0.9300
O11—C8	1.392 (2)	C15—C14	1.373 (3)
C13—C14	1.385 (3)	C15—H15	0.9300
C13—C18	1.390 (3)	C14—H14	0.9300
C9—C4	1.383 (3)	C20—C21	1.378 (3)
C9—C8	1.385 (3)	C20—H20	0.9300
C9—N10	1.398 (2)	C6—H6	0.9300
O3—C2	1.375 (3)	C2—C1	1.483 (3)
O3—C4	1.379 (2)	C17—H17	0.9300
N10—C2	1.291 (3)	C21—C22	1.363 (4)
C8—C7	1.373 (3)	C21—H21	0.9300
C7—C6	1.403 (3)	C22—C23	1.363 (4)
C7—H7	0.9300	C22—H22	0.9300
C4—C5	1.375 (3)	C23—H23	0.9300
C16—C15	1.368 (3)	C1—H1A	0.9600
C16—C17	1.368 (3)	C1—H1B	0.9600
C16—H16	0.9300	C1—H1C	0.9600

C13—P12—C19	109.59 (9)	C17—C18—C13	120.4 (2)
O11—P12—C13	99.36 (8)	C17—C18—H18	119.8
O25—P12—C13	113.91 (9)	C13—C18—H18	119.8
O11—P12—C19	104.76 (8)	C16—C15—C14	120.6 (2)
O25—P12—C19	112.73 (9)	C16—C15—H15	119.7
O25—P12—O11	115.37 (8)	C14—C15—H15	119.7
C20—C19—C24	118.2 (2)	C15—C14—C13	120.5 (2)
C20—C19—P12	120.14 (17)	C15—C14—H14	119.7
C24—C19—P12	121.66 (16)	C13—C14—H14	119.7
C8—O11—P12	124.04 (13)	C21—C20—C19	120.6 (2)
C14—C13—C18	118.41 (19)	C21—C20—H20	119.7
C14—C13—P12	117.69 (16)	C19—C20—H20	119.7
C18—C13—P12	123.90 (15)	C5—C6—C7	122.4 (2)
C4—C9—C8	118.61 (19)	C5—C6—H6	118.8
C4—C9—N10	109.61 (18)	C7—C6—H6	118.8
C8—C9—N10	131.78 (18)	N10—C2—O3	115.3 (2)
C2—O3—C4	104.30 (16)	N10—C2—C1	127.9 (2)
C2—N10—C9	103.96 (18)	O3—C2—C1	116.8 (2)
C7—C8—C9	118.71 (18)	C16—C17—C18	120.2 (2)
C7—C8—O11	123.65 (19)	C16—C17—H17	119.9
C9—C8—O11	117.61 (18)	C18—C17—H17	119.9
C8—C7—C6	120.3 (2)	C22—C21—C20	120.2 (2)
C8—C7—H7	119.8	C22—C21—H21	119.9
C6—C7—H7	119.8	C20—C21—H21	119.9
C5—C4—O3	128.53 (19)	C21—C22—C23	120.4 (3)
C5—C4—C9	124.6 (2)	C21—C22—H22	119.8
O3—C4—C9	106.86 (19)	C23—C22—H22	119.8
C15—C16—C17	119.9 (2)	C22—C23—C24	119.8 (3)
C15—C16—H16	120.1	C22—C23—H23	120.1
C17—C16—H16	120.1	C24—C23—H23	120.1
C6—C5—C4	115.3 (2)	C2—C1—H1A	109.5
C6—C5—H5	122.3	C2—C1—H1B	109.5
C4—C5—H5	122.3	H1A—C1—H1B	109.5
C23—C24—C19	120.8 (2)	C2—C1—H1C	109.5
C23—C24—H24	119.6	H1A—C1—H1C	109.5
C19—C24—H24	119.6	H1B—C1—H1C	109.5

O25—P12—C19—C20	4.2 (2)	N10—C9—C4—C5	179.05 (19)
O11—P12—C19—C20	−122.00 (18)	C8—C9—C4—O3	−179.84 (16)
C13—P12—C19—C20	132.20 (18)	N10—C9—C4—O3	0.2 (2)
O25—P12—C19—C24	−175.71 (17)	O3—C4—C5—C6	−179.98 (19)
O11—P12—C19—C24	58.08 (19)	C9—C4—C5—C6	1.4 (3)
C13—P12—C19—C24	−47.7 (2)	C20—C19—C24—C23	0.7 (3)
O25—P12—O11—C8	−70.10 (17)	P12—C19—C24—C23	−179.33 (18)
C13—P12—O11—C8	167.71 (15)	C14—C13—C18—C17	−0.2 (3)
C19—P12—O11—C8	54.45 (17)	P12—C13—C18—C17	−179.16 (17)
O25—P12—C13—C14	28.64 (19)	C17—C16—C15—C14	−0.3 (4)
O11—P12—C13—C14	151.88 (16)	C16—C15—C14—C13	−0.5 (3)
C19—P12—C13—C14	−98.69 (17)	C18—C13—C14—C15	0.8 (3)
O25—P12—C13—C18	−152.41 (17)	P12—C13—C14—C15	179.80 (17)
O11—P12—C13—C18	−29.17 (19)	C24—C19—C20—C21	−0.5 (3)
C19—P12—C13—C18	80.26 (19)	P12—C19—C20—C21	179.57 (19)
C4—C9—N10—C2	−0.6 (2)	C4—C5—C6—C7	−0.7 (3)
C8—C9—N10—C2	179.4 (2)	C8—C7—C6—C5	−0.4 (3)
C4—C9—C8—C7	−0.2 (3)	C9—N10—C2—O3	0.9 (2)
N10—C9—C8—C7	179.73 (19)	C9—N10—C2—C1	−178.8 (2)
C4—C9—C8—O11	−178.21 (17)	C4—O3—C2—N10	−0.8 (2)
N10—C9—C8—O11	1.8 (3)	C4—O3—C2—C1	178.93 (19)
P12—O11—C8—C7	34.9 (3)	C15—C16—C17—C18	0.9 (4)
P12—O11—C8—C9	−147.28 (15)	C13—C18—C17—C16	−0.6 (3)
C9—C8—C7—C6	0.9 (3)	C19—C20—C21—C22	0.5 (4)
O11—C8—C7—C6	178.74 (19)	C20—C21—C22—C23	−0.8 (4)
C2—O3—C4—C5	−178.5 (2)	C21—C22—C23—C24	1.0 (4)
C2—O3—C4—C9	0.3 (2)	C19—C24—C23—C22	−1.0 (4)
C8—C9—C4—C5	−1.0 (3)

Experimental details

Crystal data
Chemical formula	C₂₀H₁₆NO₃P
M_r	349.31
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	294
a, b, c (Å)	9.4239 (4), 15.7574 (6), 23.5398 (8)
V (Å³)	3495.6 (2)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.18
Crystal size (mm)	0.39 × 0.28 × 0.19

Data collection
Diffractometer	Bruker APEX CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.934, 0.968
No. of measured, independent and observed [I > 2s˘I)] reflections	17406, 4323, 2395
R_int	0.048
(sin θ/λ)_max (Å⁻¹)	0.667

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.047, 0.119, 1.01
No. of reflections	4323
No. of parameters	229
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.26

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001; Atwood & Barbour, 2003), publCIF (Westrip, 2010).

Selected geometric parameters (Å, º) top

P12—C13	1.785 (2)	P12—O11	1.6075 (14)
P12—C19	1.786 (2)	P12—O25	1.4665 (15)

C13—P12—C19	109.59 (9)	O11—P12—C19	104.76 (8)
O11—P12—C13	99.36 (8)	O25—P12—C19	112.73 (9)
O25—P12—C13	113.91 (9)	O25—P12—O11	115.37 (8)

Acknowledgements

The author thanks Dr JA Gertenbach at the Central Analytical Facility (CAF) of the University of Stellenbosch for the data collection. He would also like to thank SASOL and the University of Stellenbosch for financial assistance.

References

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