(2R,4R)-4-(2-Eth­oxy-2-oxoeth­yl)-2,6,6-trimeth­yl–2-oxo-1,3,6,2λ5-dioxaza­phospho­can-6-ium iodide

Fulfer, B.W.; Fronczek, F.R.; Watkins, S.F.

doi:10.1107/S1600536812018466

organic compounds

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ISSN: 2056-9890

Volume 68| Part 6| June 2012| Page o1596

doi:10.1107/S1600536812018466

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(2R,4R)-4-(2-Ethoxy-2-oxoethyl)-2,6,6-trimethyl–2-oxo-1,3,6,2λ⁵-dioxazaphosphocan-6-ium iodide

Bradford W. Fulfer,^a Frank R. Fronczek ^a ^* and Steven F. Watkins ^a

^aDepartment of Chemistry, Louisiana State University, Baton Rouge, LA 70803-1804, USA
^*Correspondence e-mail: ffroncz@lsu.edu

(Received 20 April 2012; accepted 25 April 2012; online 2 May 2012)

The title compound, C₁₁H₂₃NO₅P⁺·I⁻, consists of an eight-membered cationic heterocyclic ring in a boat–chair conformation. The ring features a tetraalkylammonium N and a methylphosphonate P atom. A –CH₂(CO)OC₂H₅ ester side chain at the C adjacent to oxygen produces two chiral centers at that substituted C atom and the P atom, both of which were determined to have absolute R,R configurations. A previously determined racemic bromide analog has exactly the same ring but with a –C₁₅H₃₁ side chain. In that structure, both chiral centers show the same relative R/S,R/S configurations, but the ring in the bromide analog is in a boat conformation.

Related literature

For MM2 energy minimization, see Cambridgesoft (2010 ). For a description of the Cambridge Structural Database, see: Allen (2002 ). For the absolute configuration from Bijvoet pair analysis, see: Hooft et al. (2008 ). For the synthesis, see: Kumaravel et al. (1994 ); Hubieki et al. (1996 ). For a related structure, see: Kumaravel et al. (1995 ).

Experimental

Crystal data

C₁₁H₂₃NO₅P⁺·I⁻
M_r = 407.17
Orthorhombic, P 2₁ 2₁ 2₁
a = 7.4882 (2) Å
b = 11.7438 (2) Å
c = 18.0235 (4) Å
V = 1584.99 (6) Å³
Z = 4
Mo Kα radiation
μ = 2.14 mm⁻¹
T = 90 K
0.28 × 0.25 × 0.15 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997 ) T_min = 0.591, T_max = 0.740
26155 measured reflections
6304 independent reflections
6235 reflections with I > 2σ(I)
R_int = 0.042

Refinement

R[F² > 2σ(F²)] = 0.016
wR(F²) = 0.039
S = 1.05
6304 reflections
177 parameters
H-atom parameters constrained
Δρ_max = 0.39 e Å⁻³
Δρ_min = −0.66 e Å⁻³
Absolute structure: Flack (1983 ), 2741 Friedel pairs
Flack parameter: 0.006 (7)

Table 1
Selected torsion angles (°)

O2—P1—O1—C3	−68.45 (9)
P1—O1—C3—C4	77.51 (10)
O1—C3—C4—N1	−111.53 (11)
C3—C4—N1—C1	52.59 (13)
C4—N1—C1—C2	57.38 (13)
N1—C1—C2—O2	−64.93 (14)
C1—C2—O2—P1	−49.45 (14)
C2—O2—P1—O1	103.91 (10)

Data collection: COLLECT (Bruker 2004 ); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997), SCALEPACK and SORTAV (Blessing, 1987 , 1989 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812018466/pv2538sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812018466/pv2538Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812018466/pv2538Isup3.cml

checkCIF report

Comment top

The title compound (I) is an analog of 2,6,6-trimethyl-2-oxo-1,3-dioxa- 6-azonia-2-phosphocyclooctane bromide (compound II, CSD code YEVZUU, Allen, 2002), originally targeted for use as a reaction-intermediate inhibitor of carnitine acyltransferase (Kumaravel et al., 1994; Kumaravel et al., 1995). Both compounds contain the same 8-membered cationic heterocyclic ring (C₇H₁₆NO₃P) with two chiral centers at C3 and P1, but with different side chains at C3.

Compound I crystallizes as the R,R enantiomer, whereas II crystallizes as a racemate with R/S,R/S relative configurations. In I, the ring is in the boat-chair conformation, the lowest energy conformer of paradigmatic cyclooctane (Chem3DPro, Cambridgesoft, 2010), but surprisingly the ring in II is in the boat conformation, which in cyclooctane is a higher energy conformer.

Related literature top

For MM2 energy minimization, see Cambridgesoft (2010). For a description of the Cambridge Structural Database, see: Allen (2002). For the absolute configuration from Bijvoet pair analysis, see: Hooft et al. (2008). For the synthesis, see: Kumaravel et al. (1994); Hubieki et al. (1996). For a related structure, see: Kumaravel et al. (1995).

Experimental top

Synthesis of this class of compounds has been described (Kumaravel et al., 1994; Hubieki et al., 1996). A suitable single-crystal was kindly supplied by Dr. J. H. Rouden.

Computing details top

Data collection: COLLECT (Bruker 2004); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997), and SORTAV (Blessing, 1987, 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

Fig. 1. View of (I) (50% probability displacement ellipsoids)

(2R,4R)-4-(2-Ethoxy-2-oxoethyl)-2,6,6-trimethyl–2-oxo- 1,3,6,2λ⁵-dioxazaphosphocan-6-ium iodide top

Crystal data top

C₁₁H₂₃NO₅P⁺·I⁻	F(000) = 816
M_r = 407.17	D_x = 1.706 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 3522 reflections
a = 7.4882 (2) Å	θ = 2.5–33.7°
b = 11.7438 (2) Å	µ = 2.14 mm⁻¹
c = 18.0235 (4) Å	T = 90 K
V = 1584.99 (6) Å³	Prism, colourless
Z = 4	0.28 × 0.25 × 0.15 mm

Data collection top

Nonius KappaCCD diffractometer	6304 independent reflections
Radiation source: sealed tube	6235 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.042
Detector resolution: 9 pixels mm^-1	θ_max = 33.7°, θ_min = 2.9°
CCD rotation images, thick slices scans	h = −11→11
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997)	k = −18→18
T_min = 0.591, T_max = 0.740	l = −27→28
26155 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.016	w = 1/[σ²(F_o²) + (0.0158P)² + 0.6491P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.039	(Δ/σ)_max = 0.001
S = 1.05	Δρ_max = 0.39 e Å⁻³
6304 reflections	Δρ_min = −0.66 e Å⁻³
177 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0037 (2)
0 constraints	Absolute structure: Flack (1983), 2741 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.006 (7)
Secondary atom site location: difference Fourier map

Crystal data top

C₁₁H₂₃NO₅P⁺·I⁻	V = 1584.99 (6) Å³
M_r = 407.17	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 7.4882 (2) Å	µ = 2.14 mm⁻¹
b = 11.7438 (2) Å	T = 90 K
c = 18.0235 (4) Å	0.28 × 0.25 × 0.15 mm

Data collection top

Nonius KappaCCD diffractometer	6304 independent reflections
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997)	6235 reflections with I > 2σ(I)
T_min = 0.591, T_max = 0.740	R_int = 0.042
26155 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.016	H-atom parameters constrained
wR(F²) = 0.039	Δρ_max = 0.39 e Å⁻³
S = 1.05	Δρ_min = −0.66 e Å⁻³
6304 reflections	Absolute structure: Flack (1983), 2741 Friedel pairs
177 parameters	Absolute structure parameter: 0.006 (7)
0 restraints

Special details top

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 > 2σ(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) top

	x	y	z	U_iso*/U_eq
I1	0.043921 (11)	0.959574 (7)	0.228805 (4)	0.01449 (2)
C1	0.36047 (17)	0.73826 (11)	0.14505 (7)	0.0118 (2)
H1A	0.4184	0.762	0.0982	0.014*
H1B	0.3399	0.808	0.1747	0.014*
C2	0.17996 (17)	0.68738 (12)	0.12605 (7)	0.0127 (2)
H2A	0.122	0.662	0.1726	0.015*
H2B	0.1042	0.7478	0.1042	0.015*
C3	0.59764 (16)	0.56554 (10)	0.06758 (7)	0.0098 (2)
H3	0.6129	0.6486	0.0573	0.012*
C4	0.53465 (16)	0.55152 (10)	0.14844 (6)	0.01054 (18)
H4A	0.4272	0.5024	0.149	0.013*
H4B	0.6293	0.5121	0.1769	0.013*
C5	0.66050 (17)	0.73081 (11)	0.19789 (7)	0.0135 (2)
H5A	0.6346	0.7997	0.2266	0.02*
H5B	0.7092	0.7522	0.1494	0.02*
H5C	0.7479	0.6842	0.2246	0.02*
C6	0.41775 (17)	0.63424 (12)	0.26270 (7)	0.0157 (2)
H6A	0.5067	0.59	0.2903	0.024*
H6B	0.3084	0.5892	0.2572	0.024*
H6C	0.3908	0.7045	0.2898	0.024*
C7	0.17486 (17)	0.50423 (12)	−0.06268 (7)	0.0133 (2)
H7A	0.0611	0.54	−0.0761	0.02*
H7B	0.1518	0.431	−0.0385	0.02*
H7C	0.2462	0.4919	−0.1075	0.02*
C8	0.77289 (16)	0.50631 (11)	0.05177 (7)	0.0119 (2)
H8A	0.7942	0.5088	−0.0024	0.014*
H8B	0.8696	0.5504	0.0758	0.014*
C9	0.78769 (17)	0.38388 (11)	0.07689 (7)	0.0118 (2)
C10	1.00454 (18)	0.23653 (11)	0.09371 (9)	0.0171 (2)
H10A	0.964	0.1762	0.0592	0.021*
H10B	0.9495	0.223	0.1429	0.021*
C11	1.2050 (2)	0.23625 (13)	0.09977 (8)	0.0180 (2)
H11A	1.2573	0.2507	0.0508	0.027*
H11B	1.2453	0.162	0.118	0.027*
H11C	1.2429	0.2959	0.1344	0.027*
N1	0.49050 (13)	0.66341 (9)	0.18714 (6)	0.01052 (17)
O1	0.46590 (12)	0.52051 (7)	0.01612 (4)	0.01006 (14)
O2	0.18599 (12)	0.59216 (8)	0.07507 (5)	0.01138 (16)
O3	0.32941 (13)	0.71123 (8)	−0.02761 (5)	0.01296 (17)
O4	0.66875 (13)	0.32687 (9)	0.10299 (6)	0.01603 (18)
O5	0.95505 (14)	0.34845 (8)	0.06562 (5)	0.01394 (16)
P1	0.29315 (4)	0.59443 (3)	−0.001033 (16)	0.00900 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I1	0.01306 (3)	0.01533 (4)	0.01509 (4)	0.00285 (3)	−0.00355 (3)	−0.00370 (3)
C1	0.0108 (5)	0.0117 (5)	0.0129 (5)	0.0012 (4)	−0.0012 (4)	−0.0008 (4)
C2	0.0098 (5)	0.0163 (6)	0.0121 (5)	0.0020 (4)	0.0004 (4)	−0.0031 (4)
C3	0.0081 (4)	0.0108 (5)	0.0105 (4)	0.0001 (3)	0.0001 (3)	0.0006 (4)
C4	0.0108 (4)	0.0110 (5)	0.0098 (4)	0.0004 (4)	−0.0003 (4)	0.0010 (3)
C5	0.0111 (5)	0.0154 (5)	0.0141 (5)	−0.0038 (4)	−0.0010 (4)	−0.0012 (4)
C6	0.0158 (5)	0.0223 (6)	0.0090 (5)	−0.0027 (4)	0.0016 (4)	0.0004 (4)
C7	0.0119 (5)	0.0172 (5)	0.0109 (5)	−0.0009 (4)	−0.0015 (4)	−0.0015 (4)
C8	0.0077 (4)	0.0122 (5)	0.0159 (5)	0.0005 (4)	0.0013 (4)	0.0026 (4)
C9	0.0107 (5)	0.0121 (5)	0.0125 (5)	0.0016 (4)	−0.0011 (4)	−0.0001 (4)
C10	0.0149 (6)	0.0109 (5)	0.0256 (6)	0.0038 (4)	−0.0005 (5)	0.0033 (4)
C11	0.0147 (6)	0.0216 (6)	0.0179 (6)	0.0048 (5)	−0.0014 (5)	0.0021 (5)
N1	0.0093 (4)	0.0133 (4)	0.0089 (4)	−0.0003 (3)	0.0002 (3)	−0.0006 (3)
O1	0.0089 (3)	0.0120 (4)	0.0093 (3)	0.0011 (3)	−0.0009 (3)	−0.0004 (3)
O2	0.0102 (4)	0.0143 (4)	0.0096 (4)	−0.0010 (3)	0.0013 (3)	−0.0013 (3)
O3	0.0144 (4)	0.0123 (4)	0.0121 (4)	0.0011 (3)	0.0003 (3)	0.0031 (3)
O4	0.0118 (4)	0.0152 (4)	0.0211 (4)	−0.0009 (3)	0.0010 (3)	0.0039 (4)
O5	0.0107 (4)	0.0121 (4)	0.0191 (4)	0.0023 (3)	0.0016 (4)	0.0026 (3)
P1	0.00772 (12)	0.01135 (13)	0.00792 (11)	0.00067 (10)	−0.00033 (10)	0.00100 (10)

Geometric parameters (Å, º) top

C1—N1	1.5153 (16)	C6—H6C	0.98
C1—C2	1.5170 (18)	C7—P1	1.7723 (13)
C1—H1A	0.99	C7—H7A	0.98
C1—H1B	0.99	C7—H7B	0.98
C2—O2	1.4481 (16)	C7—H7C	0.98
C2—H2A	0.99	C8—C9	1.5115 (18)
C2—H2B	0.99	C8—H8A	0.99
C3—O1	1.4536 (15)	C8—H8B	0.99
C3—C8	1.5123 (17)	C9—O4	1.2095 (16)
C3—C4	1.5407 (16)	C9—O5	1.3361 (16)
C3—H3	1	C10—O5	1.4565 (16)
C4—N1	1.5239 (15)	C10—C11	1.505 (2)
C4—H4A	0.99	C10—H10A	0.99
C4—H4B	0.99	C10—H10B	0.99
C5—N1	1.5115 (16)	C11—H11A	0.98
C5—H5A	0.98	C11—H11B	0.98
C5—H5B	0.98	C11—H11C	0.98
C5—H5C	0.98	O1—P1	1.5883 (9)
C6—N1	1.5063 (16)	O2—P1	1.5893 (9)
C6—H6A	0.98	O3—P1	1.4780 (10)
C6—H6B	0.98

N1—C1—C2	117.20 (10)	P1—C7—H7C	109.5
N1—C1—H1A	108	H7A—C7—H7C	109.5
C2—C1—H1A	108	H7B—C7—H7C	109.5
N1—C1—H1B	108	C9—C8—C3	116.40 (10)
C2—C1—H1B	108	C9—C8—H8A	108.2
H1A—C1—H1B	107.2	C3—C8—H8A	108.2
O2—C2—C1	114.81 (10)	C9—C8—H8B	108.2
O2—C2—H2A	108.6	C3—C8—H8B	108.2
C1—C2—H2A	108.6	H8A—C8—H8B	107.3
O2—C2—H2B	108.6	O4—C9—O5	125.27 (12)
C1—C2—H2B	108.6	O4—C9—C8	126.10 (12)
H2A—C2—H2B	107.5	O5—C9—C8	108.63 (11)
O1—C3—C8	107.54 (10)	O5—C10—C11	106.31 (11)
O1—C3—C4	110.91 (9)	O5—C10—H10A	110.5
C8—C3—C4	113.25 (10)	C11—C10—H10A	110.5
O1—C3—H3	108.3	O5—C10—H10B	110.5
C8—C3—H3	108.3	C11—C10—H10B	110.5
C4—C3—H3	108.3	H10A—C10—H10B	108.7
N1—C4—C3	114.03 (9)	C10—C11—H11A	109.5
N1—C4—H4A	108.7	C10—C11—H11B	109.5
C3—C4—H4A	108.7	H11A—C11—H11B	109.5
N1—C4—H4B	108.7	C10—C11—H11C	109.5
C3—C4—H4B	108.7	H11A—C11—H11C	109.5
H4A—C4—H4B	107.6	H11B—C11—H11C	109.5
N1—C5—H5A	109.5	C6—N1—C5	107.93 (9)
N1—C5—H5B	109.5	C6—N1—C1	110.62 (10)
H5A—C5—H5B	109.5	C5—N1—C1	107.55 (10)
N1—C5—H5C	109.5	C6—N1—C4	107.23 (9)
H5A—C5—H5C	109.5	C5—N1—C4	109.11 (9)
H5B—C5—H5C	109.5	C1—N1—C4	114.23 (9)
N1—C6—H6A	109.5	C3—O1—P1	118.56 (7)
N1—C6—H6B	109.5	C2—O2—P1	123.39 (8)
H6A—C6—H6B	109.5	C9—O5—C10	117.83 (11)
N1—C6—H6C	109.5	O3—P1—O1	114.88 (5)
H6A—C6—H6C	109.5	O3—P1—O2	112.83 (5)
H6B—C6—H6C	109.5	O1—P1—O2	103.53 (5)
P1—C7—H7A	109.5	O3—P1—C7	116.32 (6)
P1—C7—H7B	109.5	O1—P1—C7	101.68 (6)
H7A—C7—H7B	109.5	O2—P1—C7	106.18 (6)

O2—P1—O1—C3	−68.45 (9)	C2—C1—N1—C6	−63.71 (13)
P1—O1—C3—C4	77.51 (10)	C2—C1—N1—C5	178.65 (10)
O1—C3—C4—N1	−111.53 (11)	C3—C4—N1—C6	175.54 (10)
C3—C4—N1—C1	52.59 (13)	C3—C4—N1—C5	−67.81 (12)
C4—N1—C1—C2	57.38 (13)	C8—C3—O1—P1	−158.16 (8)
N1—C1—C2—O2	−64.93 (14)	O4—C9—O5—C10	−6.70 (19)
C1—C2—O2—P1	−49.45 (14)	C8—C9—O5—C10	173.21 (11)
C2—O2—P1—O1	103.91 (10)	C11—C10—O5—C9	−159.32 (12)
C8—C3—C4—N1	127.45 (11)	C3—O1—P1—O3	55.03 (9)
O1—C3—C8—C9	−73.74 (13)	C3—O1—P1—C7	−178.47 (9)
C4—C3—C8—C9	49.16 (14)	C2—O2—P1—O3	−20.90 (11)
C3—C8—C9—O4	6.12 (19)	C2—O2—P1—C7	−149.44 (10)
C3—C8—C9—O5	−173.79 (11)

Experimental details

Crystal data
Chemical formula	C₁₁H₂₃NO₅P⁺·I⁻
M_r	407.17
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	90
a, b, c (Å)	7.4882 (2), 11.7438 (2), 18.0235 (4)
V (Å³)	1584.99 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	2.14
Crystal size (mm)	0.28 × 0.25 × 0.15

Data collection
Diffractometer	Nonius KappaCCD diffractometer
Absorption correction	Multi-scan (SCALEPACK; Otwinowski & Minor, 1997)
T_min, T_max	0.591, 0.740
No. of measured, independent and observed [I > 2σ(I)] reflections	26155, 6304, 6235
R_int	0.042
(sin θ/λ)_max (Å⁻¹)	0.781

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.016, 0.039, 1.05
No. of reflections	6304
No. of parameters	177
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.39, −0.66
Absolute structure	Flack (1983), 2741 Friedel pairs
Absolute structure parameter	0.006 (7)

Computer programs: COLLECT (Bruker 2004), DENZO and SCALEPACK (Otwinowski & Minor, 1997), and SORTAV (Blessing, 1987, 1989), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Selected torsion angles (º) top

O2—P1—O1—C3	−68.45 (9)	C4—N1—C1—C2	57.38 (13)
P1—O1—C3—C4	77.51 (10)	N1—C1—C2—O2	−64.93 (14)
O1—C3—C4—N1	−111.53 (11)	C1—C2—O2—P1	−49.45 (14)
C3—C4—N1—C1	52.59 (13)	C2—O2—P1—O1	103.91 (10)

Acknowledgements

The purchase of the diffractometer was made possible by grant No. LEQSF(1999–2000)-ENH-TR-13, administered by the Louisiana Board of Regents. We are grateful to Dr J. H. Rouden for providing the sample.

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