(S)-Methyl 3-(3,4-dimeth­oxy­phen­yl)-2-[2-(diphenyl­phosphan­yl)benzamido]­propano­ate

Tricia Naicker; Thavendran Govender; Hendrick G Kruger; Glenn E M Maguire

doi:10.1107/S1600536811047179

. 2011 Nov 12;67(Pt 12):o3285. doi: 10.1107/S1600536811047179

(S)-Methyl 3-(3,4-dimethoxyphenyl)-2-[2-(diphenylphosphanyl)benzamido]propanoate

Tricia Naicker ^a, Thavendran Govender ^a, Hendrick G Kruger ^b, Glenn E M Maguire ^b,^*

PMCID: PMC3238941 PMID: 22199790

Abstract

Molecules of the title compound, C₃₁H₃₀NO₅P, show a sttagered conformation about the C—C bond joining the dimethoxybenzene group to the chiral centre, with the dimethoxybenzene ring gauche to the amide group and anti to the ester group. In the crystal, weak intermolecular N—H⋯O and C—H⋯O hydrogen bonds form layers parallel to (110).

Related literature

For related structures, see: Clegg & Elsegood, (2003 ▶). For organocatalysts prepared from a related precursor, see: Naicker et al. (2010 ▶, 2011 ▶). For analogous precusors to several biologically active compounds, see: Zalán et al. (2006 ▶).

Experimental

Crystal data

C₃₁H₃₀NO₅P
M _r = 527.53
Monoclinic,
a = 10.2218 (3) Å
b = 8.4535 (2) Å
c = 15.7633 (4) Å
β = 100.300 (2)°
V = 1340.16 (6) Å³
Z = 2
Mo Kα radiation
μ = 0.14 mm⁻¹
T = 173 K
0.18 × 0.15 × 0.14 mm

Data collection

Nonius KappaCCD diffractometer
6654 measured reflections
6654 independent reflections
5550 reflections with I > 2σ(I)

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.079
S = 1.04
6654 reflections
350 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.25 e Å⁻³
Absolute structure: Flack (1983 ▶), 3108 Friedel pairs
Flack parameter: −0.08 (6)

Data collection: COLLECT (Nonius, 2000 ▶); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997 ▶); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: OLEX2 (Dolomanov et al., 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811047179/lr2034sup1.cif

e-67-o3285-sup1.cif^{(25.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811047179/lr2034Isup2.hkl

e-67-o3285-Isup2.hkl^{(325.6KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811047179/lr2034Isup3.cml

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯O2ⁱ	0.816 (17)	2.345 (17)	3.1428 (17)	166 (15)
C10—H10A⋯O3ⁱ	0.98	2.56	3.371 (2)	140
C21—H21⋯O4ⁱⁱ	0.95	2.58	3.279 (2)	131

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors wish to thank Dr Hong Su of the Chemistry Department of the University of Cape Town for her assistance with the crystallographic data collection.

supplementary crystallographic information

Comment

The title compound is being used as a precusor to novel chiral organocatalysts (Naicker et al. 2010 and 2011). Analogous structures are well known precusors to several biologically active compounds (Zalán et al., 2006).

There is an analogous X-ray crystal structure reported (Clegg and Elsegood, 2003), which has a tert-butoxy group at the ester carboxyl carbon and a (9-H-Fluoren-9-yl)-methoxy group attached to the amide carboxyl carbon. The title compound has a methoxy and a 2-diphenylphoshinobenzene group at the these positions respectively.

The title compound exists in a well ordered staggered conformation about the C7—C8 bond (Fig. 1). As in the analogous X-ray structure, the dimethoxybenzene ring is gauche to the amide group and anti to the ester group. The configuration at C8 was confirmed to be S, on the basis of anomalous scaterring effects, Flack x parameter = -0.08 (6).

The molecules in the crystal are connected by relatively weak hydrogen bond interactions (Fig. 2) in which the N1—H1···O2 and the C10—H10A···O3 interactions give chains along the b axis. These chains are interconnected via the C21—H21···O4 interaction giving a layered packing system.

Experimental

2-(diphenylphosphanyl)benzoic acid (1.3 g, 4.2 mmol) was dissolved was dissolved in DMF (15 ml) and THF (5 ml) followed by addition of HBTU (4.6 mmol), DIPEA (8.4 mmol) and (S)-methyl 2-amino-3-(3,4-dimethoxyphenyl)propanoate (1.0 g, 4.2 mmol). The reaction mixture was then stirred at room temperature until no more starting material could be detected by TLC analysis. The reaction mixture was poured into 30 volumes of chilled water; the mixture was then extracted thrice with ethyl acetate (20 ml). The combined extracts were dried over anhydrous sodium sulfate and then concentrated to dryness affording the crude product. This crude product was purified by column chromatography (50:50 EtOAc/Hexane, R_f = 0.6) to afford the product 2.20 g (98%) as a white solid. M.p. = 420 K.

Recrystallization from ethyl acetate at room temperature afforded crystals suitable for X-ray analysis.