Conformational switching caused by bi­phenyl substitution at the C^α position: ethyl 2-benzyl-2-(formyl­amino)-3-phenyl­propionate and ethyl 3-(1,1′-bi­phenyl-4-yl)-2-(formyl­amino)-2-(4-phenyl­benzyl)­propionate

The title compounds, C₁₉H₂₁NO₃ and C₃₁H₂₉NO₃, are derivatives of α-amino­isobutyric acid, with benzyl and di­benzyl substitution. The pseudo-peptide formed by the N-formyl and ethyl ester substitution at the C^α position switches from a trans–trans to a trans–cis configuration as a result of bi­phenyl substitution. The packing of the compounds is stabilized by N—H...O and C—H...O hydrogen bonds.

S1. Comment

α-Aminoisobutyric acid (Aib), which is achiral, has well established structural impacts [features?] (Karle et al., 1994; Ramesh & Balaram, 1999; Formaggio et al., 2000). Similarly, benzyl substitution at the C^α position provides rigidity to the peptide backbone and this conformational restriction is useful in peptide motif design (Studer & Seebach, 1995; Damodharan et al., 2002; Karle & Balaram, 1990; Polese et al., 1996; Kotha & Brahmachary, 2000). The effect of benzyl and phenyl substitution at the C^α position of Aib has been studied via crystal structure analyses. Both of the title compounds, C₁₉H₂₁NO₃, (I), and C₃₁H₂₉NO₃, (II), crystallize in the same P21/c space group from 1:1 n-propanol–methanol and 2-propanol solution, respectively.

The crystal structures of the title compounds are shown in Fig. 1. Terminal atoms C18 and C17 of the ethyl ester side chains of (I) exhibit disorder. The bond angles at atoms C2 and C9 of (I), and at C2 and C15 of (II), are significantly larger than normal tetrahedral values because of the presence of the bulky substitutions [115.4 (2)° at C2 and 115.8 (3)° at C9 in (I), and 115.9 (2)° at C2 and 116.4 (2)° at C15 in (II)]. The angles between benzene rings A and B are 61.4 (2) and 61.8 (1)° in (I) and (II), respectively. The angle between rings A and C in (II) is 18.1 (1)°, and that between rings B and D in (II) is 39.8 (2)°. Additional phenyl substitution causes the molecules to be arranged along the longest axis (viz. the a axis) in (II), and a herringbone packing arrangement is seen in both structures.

The N-formyl and ethyl ester chains form a pseudo-peptide. The backbone of this pseudo-peptide adopts a trans–trans conformation [C16—C1—N1—C19 (ϕ) = −178.8 (3)°, O17A—C16—C1—N1 (ψ) = 170.5 (5)° and O17B—C16—C1—N1 (ψ) = −169.8 (7)°; as a result of disorder, ψ adopt two values] in (I), while the pseudo-peptide adopts a trans–cis conformation in (II) [C28—C1—N31—C32 (ϕ) = 178.4 (2)° and N31—C1—C28—O29 (ψ) = −5.4 (3)°; Fig. 2]. This conformational switching may be due to the additional phenyl ring substitutions on either side of the C^α atom.

The N-formyl side chain is planar and is in a folded conformation in both compounds [C1—N1—C19—-O19 = −4.4 (5)° and C1—N31—C32—O33 = 0.7 (4)° for (I) and (II), respectively]. The ethyl ester side chains adopt different conformations in the two compounds, viz. -ap (antiperiplanar) and +sc (syn-clinal) in (I), and +ac (anticlinal) in (II) [C16—O17A—C17A—C18A = −171.9 (10)° (-ap) and C16—O17B—C17B—C18B = 82 (2)° (+sc) in (I) (two conformations as a result of the disorder), and C28—O29—C29—C30 = 93.8 (4)° (+ac) in (II)]. The switch from -ap/+sc to +ap can be attributed to the biphenyl substitutions (Fig. 3).

N—H···O and C—H···O intramolecular hydrogen bonds are present in both structures. The N1—C1—C16 (τ) angle is 105.0 (2)°, which may be due to the intramolecular N1—H···O16 hydrogen bond, whereas the corresponding angle [N31—C1—C28 (τ)] in (II) is 110.2 (2)° (Fig. 4). The bifurcated N31—H31···O29(x,y,z)/O33(x,3/2 − y,z − 1/2) hydrogen bond may be the reason for the widening of this bond angle.

The packing of both structures is stabilized by C—H···O and N—H···O interactions. Atom O19 of the N-formyl group in (I) forms an intermolecular C5—H5···O19 hydrogen bond, which is replaced by an N31—H31···O33 hydrogen bond in (II) (Tables 1 and 2, and Figs. 3 and 4).

S2. Experimental

Reaction of benzyl bromide, 1, with ethyl isocyanoacetate in the presence of a phase-transfer catalyst, such as tetrabutylammonium sulfate in acetonitrile/potassium carbonate, gave a coupling product. Hydrolysis of the coupling product with concentrated HCl in the presence of diethyl ether gave the formyl derivative 2(I).

Similarly, compound 4 was prepared from p-iodobenzyl bromide, 3. A Suzuki–Miyaura coupling reaction (Kotha et al., 2002) of 4 with benzene boronic acid in the presence of Pd(0) as catalyst gave the cross-coupling product 5(II).

S3. Refinement

H atoms were positioned geometrically and treated as riding, with C—H distances of 0.93–0.97 Å.

Computing details

For both compounds, data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997). Molecular graphics: ORTEP-3 (Farrugia, 1997) for (I); ORTEP-3 (Farrugia,1997) for (II). For both compounds, software used to prepare material for publication: reference?.

Figures

	Fig. 1. The crystal structure of the title compounds, (a) (I) and (b) (II), with 50% probability displacement ellipsoids, showing the atomic numbering scheme.
	Fig. 2. A stereoview of the superposition of (I) (black) and (II) (grey), showing the conformational switching from trans–trans in (I) to cis–trans in (II) of the ethyl ester chain.
	Fig. 3. A stereoview of the packing of (I), showing N—H···O intramolecular interactions and C—H···O intermolecular interactions.
	Fig. 4. A stereoview of the packing of (II), showing N—H···O, C—H···π and π···π interactions.

(I) ethyl 2-benzyl-2-(formylamino)-3-phenylpropionate

Crystal data

C19H21NO3	F(000) = 664
Mr = 311.37	Dx = 1.203 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.980 (2) Å	Cell parameters from 3802 reflections
b = 11.853 (3) Å	θ = 2.1–27.9°
c = 14.575 (4) Å	µ = 0.08 mm^−1
β = 94.147 (4)°	T = 293 K
V = 1719.6 (7) Å^3	Rectangle, colorless
Z = 4	0.52 × 0.43 × 0.42 mm

Data collection

Bruker SMART CCD area-detector diffractometer	2295 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.023
Graphite monochromator	θmax = 27.9°, θmin = 2.1°
ω scans	h = −12→12
13797 measured reflections	k = −13→15
3802 independent reflections	l = −18→19

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.062	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.161	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0598P)^2 + 0.3098P] where P = (Fo^2 + 2Fc^2)/3
3802 reflections	(Δ/σ)max < 0.001
245 parameters	Δρmax = 0.22 e Å^−3
75 restraints	Δρmin = −0.11 e Å^−3

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
N1	0.94081 (17)	0.02619 (13)	0.11843 (11)	0.0687 (4)
H1	0.9129	−0.0023	0.0662	0.082*
C1	0.8930 (2)	0.13885 (16)	0.13822 (13)	0.0694 (5)
C2	1.0089 (2)	0.22513 (17)	0.15058 (13)	0.0762 (6)
H2A	0.9721	0.2967	0.1690	0.091*
H2B	1.0713	0.1997	0.2004	0.091*
C3	1.0855 (2)	0.24453 (17)	0.06752 (13)	0.0726 (6)
C4	1.0566 (3)	0.3356 (2)	0.00986 (17)	0.0964 (7)
H4	0.9883	0.3851	0.0231	0.116*
C5	1.1266 (4)	0.3546 (3)	−0.0662 (2)	0.1171 (10)
H5	1.1055	0.4165	−0.1037	0.141*
C6	1.2266 (4)	0.2836 (3)	−0.0871 (2)	0.1218 (11)
H6	1.2735	0.2964	−0.1389	0.146*
C7	1.2583 (3)	0.1924 (3)	−0.0311 (2)	0.1095 (9)
H7	1.3269	0.1435	−0.0450	0.131*
C8	1.1881 (2)	0.1737 (2)	0.04559 (17)	0.0846 (6)
H8	1.2104	0.1122	0.0833	0.102*
C9	0.8149 (2)	0.1401 (2)	0.22613 (14)	0.0833 (6)
H9A	0.8782	0.1267	0.2787	0.100*
H9B	0.7777	0.2149	0.2331	0.100*
C10	0.7033 (2)	0.0559 (2)	0.22873 (15)	0.0822 (6)
C11	0.5783 (3)	0.0752 (3)	0.1857 (2)	0.1253 (11)
H11	0.5613	0.1421	0.1537	0.150*
C12	0.4777 (3)	−0.0045 (4)	0.1897 (3)	0.1571 (15)
H12	0.3939	0.0089	0.1595	0.189*
C13	0.4997 (4)	−0.1021 (3)	0.2372 (3)	0.1368 (12)
H13	0.4312	−0.1549	0.2402	0.164*
C14	0.6208 (3)	−0.1216 (3)	0.2795 (2)	0.1155 (9)
H14	0.6363	−0.1882	0.3123	0.139*
C15	0.7218 (3)	−0.0449 (2)	0.27529 (16)	0.0951 (7)
H15	0.8055	−0.0610	0.3046	0.114*
C19	1.0230 (2)	−0.03744 (18)	0.17235 (16)	0.0771 (6)
H19	1.0396	−0.1100	0.1518	0.092*
O19	1.07822 (18)	−0.01026 (14)	0.24543 (11)	0.0981 (5)
O16A	0.7888 (15)	0.1211 (13)	−0.0176 (10)	0.093 (3)	0.600 (10)
O17A	0.7356 (13)	0.2660 (7)	0.0722 (6)	0.099 (3)	0.600 (10)
C17A	0.6556 (9)	0.3017 (6)	−0.0170 (6)	0.129 (3)	0.600 (10)
H17A	0.7139	0.3037	−0.0674	0.155*	0.600 (10)
H17B	0.5839	0.2482	−0.0323	0.155*	0.600 (10)
C18A	0.6015 (9)	0.4100 (6)	−0.0029 (5)	0.157 (3)	0.600 (10)
H18A	0.5524	0.4349	−0.0583	0.236*	0.600 (10)
H18B	0.6732	0.4621	0.0131	0.236*	0.600 (10)
H18C	0.5424	0.4068	0.0461	0.236*	0.600 (10)
O16B	0.768 (2)	0.102 (2)	−0.0034 (16)	0.109 (6)	0.400 (10)
O17B	0.764 (2)	0.2805 (11)	0.0540 (9)	0.095 (4)	0.400 (10)
C17B	0.7013 (10)	0.3533 (10)	−0.0286 (8)	0.121 (4)	0.400 (10)
H17C	0.7094	0.4339	−0.0182	0.145*	0.400 (10)
H17D	0.7345	0.3330	−0.0873	0.145*	0.400 (10)
C18B	0.5724 (12)	0.3114 (14)	−0.0168 (13)	0.181 (6)	0.400 (10)
H18D	0.5096	0.3434	−0.0626	0.272*	0.400 (10)
H18E	0.5467	0.3315	0.0433	0.272*	0.400 (10)
H18F	0.5726	0.2308	−0.0229	0.272*	0.400 (10)
C16	0.8006 (3)	0.1710 (2)	0.05443 (16)	0.0856 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0823 (11)	0.0583 (10)	0.0642 (9)	0.0016 (8)	−0.0033 (8)	−0.0096 (7)
C1	0.0820 (13)	0.0596 (12)	0.0649 (11)	0.0089 (10)	−0.0068 (10)	−0.0094 (9)
C2	0.1028 (16)	0.0564 (12)	0.0666 (12)	0.0025 (11)	−0.0125 (11)	−0.0096 (9)
C3	0.0919 (15)	0.0547 (11)	0.0679 (12)	−0.0077 (11)	−0.0155 (11)	−0.0071 (9)
C4	0.124 (2)	0.0728 (15)	0.0894 (16)	−0.0034 (14)	−0.0121 (15)	0.0065 (12)
C5	0.158 (3)	0.104 (2)	0.0858 (18)	−0.032 (2)	−0.0193 (19)	0.0191 (16)
C6	0.148 (3)	0.128 (3)	0.0898 (19)	−0.054 (2)	0.0136 (19)	−0.014 (2)
C7	0.1014 (19)	0.103 (2)	0.125 (2)	−0.0274 (17)	0.0171 (18)	−0.0279 (19)
C8	0.0876 (15)	0.0701 (14)	0.0940 (16)	−0.0099 (13)	−0.0084 (13)	−0.0072 (12)
C9	0.0920 (15)	0.0839 (15)	0.0735 (13)	0.0174 (13)	0.0013 (11)	−0.0122 (11)
C10	0.0761 (14)	0.0919 (16)	0.0784 (13)	0.0168 (13)	0.0045 (11)	−0.0017 (12)
C11	0.091 (2)	0.124 (2)	0.158 (3)	0.0212 (18)	−0.0131 (18)	0.038 (2)
C12	0.077 (2)	0.180 (4)	0.209 (4)	−0.003 (2)	−0.029 (2)	0.058 (3)
C13	0.103 (2)	0.149 (3)	0.158 (3)	−0.018 (2)	0.000 (2)	0.043 (2)
C14	0.097 (2)	0.129 (2)	0.121 (2)	0.0028 (19)	0.0157 (17)	0.0367 (18)
C15	0.0809 (16)	0.118 (2)	0.0870 (15)	0.0158 (15)	0.0069 (12)	0.0233 (14)
C19	0.0913 (15)	0.0596 (12)	0.0805 (14)	0.0052 (11)	0.0078 (12)	0.0004 (11)
O19	0.1191 (14)	0.0879 (11)	0.0836 (10)	0.0134 (9)	−0.0189 (10)	0.0019 (8)
O16A	0.107 (4)	0.104 (7)	0.066 (3)	0.021 (5)	−0.012 (2)	−0.017 (4)
O17A	0.109 (5)	0.083 (3)	0.099 (5)	0.031 (3)	−0.021 (4)	0.003 (3)
C17A	0.111 (6)	0.100 (5)	0.170 (7)	0.018 (5)	−0.047 (6)	0.020 (4)
C18A	0.166 (7)	0.120 (5)	0.181 (6)	0.041 (5)	−0.022 (5)	0.035 (5)
O16B	0.144 (11)	0.085 (5)	0.089 (10)	−0.010 (5)	−0.048 (8)	−0.003 (5)
O17B	0.126 (9)	0.094 (5)	0.064 (3)	0.037 (5)	0.006 (4)	0.011 (3)
C17B	0.138 (8)	0.093 (7)	0.136 (6)	0.010 (6)	0.043 (6)	−0.004 (5)
C18B	0.124 (8)	0.157 (14)	0.265 (15)	−0.003 (9)	0.023 (11)	−0.045 (10)
C16	0.0939 (16)	0.0827 (16)	0.0776 (15)	0.0151 (14)	−0.0125 (12)	−0.0067 (12)

Geometric parameters (Å, º)

N1—C19	1.329 (3)	C12—C13	1.357 (5)
N1—C1	1.454 (2)	C12—H12	0.9300
N1—H1	0.8600	C13—C14	1.337 (4)
C1—C16	1.524 (3)	C13—H13	0.9300
C1—C2	1.545 (3)	C14—C15	1.362 (4)
C1—C9	1.547 (3)	C14—H14	0.9300
C2—C3	1.495 (3)	C15—H15	0.9300
C2—H2A	0.9700	C19—O19	1.207 (2)
C2—H2B	0.9700	C19—H19	0.9300
C3—C8	1.379 (3)	O16A—C16	1.203 (14)
C3—C4	1.386 (3)	O17A—C16	1.334 (7)
C4—C5	1.371 (4)	O17A—C17A	1.535 (9)
C4—H4	0.9300	C17A—C18A	1.414 (9)
C5—C6	1.356 (4)	C17A—H17A	0.9700
C5—H5	0.9300	C17A—H17B	0.9700
C6—C7	1.377 (4)	C18A—H18A	0.9600
C6—H6	0.9300	C18A—H18B	0.9600
C7—C8	1.379 (4)	C18A—H18C	0.9600
C7—H7	0.9300	O16B—C16	1.21 (2)
C8—H8	0.9300	O17B—C16	1.350 (10)
C9—C10	1.498 (3)	O17B—C17B	1.572 (11)
C9—H9A	0.9700	C17B—C18B	1.401 (11)
C9—H9B	0.9700	C17B—H17C	0.9700
C10—C11	1.375 (3)	C17B—H17D	0.9700
C10—C15	1.381 (3)	C18B—H18D	0.9600
C11—C12	1.383 (5)	C18B—H18E	0.9600
C11—H11	0.9300	C18B—H18F	0.9600
C19—N1—C1	126.96 (17)	C14—C13—C12	119.3 (3)
C19—N1—H1	116.5	C14—C13—H13	120.3
C1—N1—H1	116.5	C12—C13—H13	120.3
N1—C1—C16	104.98 (16)	C13—C14—C15	120.7 (3)
N1—C1—C2	112.18 (16)	C13—C14—H14	119.6
C16—C1—C2	109.42 (18)	C15—C14—H14	119.6
N1—C1—C9	111.41 (17)	C14—C15—C10	121.8 (2)
C16—C1—C9	110.46 (18)	C14—C15—H15	119.1
C2—C1—C9	108.36 (16)	C10—C15—H15	119.1
C3—C2—C1	115.45 (15)	O19—C19—N1	126.4 (2)
C3—C2—H2A	108.4	O19—C19—H19	116.8
C1—C2—H2A	108.4	N1—C19—H19	116.8
C3—C2—H2B	108.4	C16—O17A—C17A	107.4 (7)
C1—C2—H2B	108.4	C18A—C17A—O17A	107.9 (6)
H2A—C2—H2B	107.5	C18A—C17A—H17A	110.1
C8—C3—C4	117.3 (2)	O17A—C17A—H17A	110.1
C8—C3—C2	121.7 (2)	C18A—C17A—H17B	110.1
C4—C3—C2	121.0 (2)	O17A—C17A—H17B	110.1
C5—C4—C3	121.5 (3)	H17A—C17A—H17B	108.4
C5—C4—H4	119.2	C17A—C18A—H18A	109.5
C3—C4—H4	119.2	C17A—C18A—H18B	109.5
C6—C5—C4	120.4 (3)	H18A—C18A—H18B	109.5
C6—C5—H5	119.8	C17A—C18A—H18C	109.5
C4—C5—H5	119.8	H18A—C18A—H18C	109.5
C5—C6—C7	119.7 (3)	H18B—C18A—H18C	109.5
C5—C6—H6	120.1	C16—O17B—C17B	128.7 (12)
C7—C6—H6	120.1	C18B—C17B—O17B	91.6 (14)
C6—C7—C8	119.8 (3)	C18B—C17B—H17C	113.4
C6—C7—H7	120.1	O17B—C17B—H17C	113.4
C8—C7—H7	120.1	C18B—C17B—H17D	113.4
C3—C8—C7	121.3 (2)	O17B—C17B—H17D	113.4
C3—C8—H8	119.3	H17C—C17B—H17D	110.7
C7—C8—H8	119.3	C17B—C18B—H18D	109.5
C10—C9—C1	115.78 (17)	C17B—C18B—H18E	109.5
C10—C9—H9A	108.3	H18D—C18B—H18E	109.5
C1—C9—H9A	108.3	C17B—C18B—H18F	109.5
C10—C9—H9B	108.3	H18D—C18B—H18F	109.5
C1—C9—H9B	108.3	H18E—C18B—H18F	109.5
H9A—C9—H9B	107.4	O16A—C16—O16B	18 (2)
C11—C10—C15	116.9 (3)	O16A—C16—O17A	124.4 (8)
C11—C10—C9	122.0 (2)	O16B—C16—O17A	126.8 (12)
C15—C10—C9	121.0 (2)	O16A—C16—O17B	117.3 (10)
C10—C11—C12	120.3 (3)	O16B—C16—O17B	126.3 (14)
C10—C11—H11	119.8	O17A—C16—O17B	18.7 (12)
C12—C11—H11	119.8	O16A—C16—C1	126.3 (7)
C13—C12—C11	120.8 (3)	O16B—C16—C1	120.6 (12)
C13—C12—H12	119.6	O17A—C16—C1	109.3 (4)
C11—C12—H12	119.6	O17B—C16—C1	113.2 (7)
C19—N1—C1—C16	−179.1 (2)	C13—C14—C15—C10	1.0 (5)
C19—N1—C1—C2	62.2 (3)	C11—C10—C15—C14	−0.7 (4)
C19—N1—C1—C9	−59.5 (3)	C9—C10—C15—C14	179.0 (2)
N1—C1—C2—C3	63.3 (2)	C1—N1—C19—O19	−4.3 (4)
C16—C1—C2—C3	−52.8 (2)	C16—O17A—C17A—C18A	−171.9 (10)
C9—C1—C2—C3	−173.30 (17)	C16—O17B—C17B—C18B	82 (2)
C1—C2—C3—C8	−83.0 (2)	C17A—O17A—C16—O16A	−4.4 (16)
C1—C2—C3—C4	97.7 (2)	C17A—O17A—C16—O16B	−26.9 (19)
C8—C3—C4—C5	0.3 (3)	C17A—O17A—C16—O17B	69 (3)
C2—C3—C4—C5	179.7 (2)	C17A—O17A—C16—C1	174.1 (7)
C3—C4—C5—C6	0.2 (4)	C17B—O17B—C16—O16A	2 (2)
C4—C5—C6—C7	−0.4 (4)	C17B—O17B—C16—O16B	−17 (3)
C5—C6—C7—C8	0.2 (4)	C17B—O17B—C16—O17A	−115 (5)
C4—C3—C8—C7	−0.6 (3)	C17B—O17B—C16—C1	163.3 (14)
C2—C3—C8—C7	−179.9 (2)	N1—C1—C16—O16A	−10.9 (11)
C6—C7—C8—C3	0.3 (4)	C2—C1—C16—O16A	109.7 (10)
N1—C1—C9—C10	−52.5 (2)	C9—C1—C16—O16A	−131.1 (10)
C16—C1—C9—C10	63.7 (2)	N1—C1—C16—O16B	10.0 (14)
C2—C1—C9—C10	−176.43 (18)	C2—C1—C16—O16B	130.6 (14)
C1—C9—C10—C11	−81.5 (3)	C9—C1—C16—O16B	−110.2 (14)
C1—C9—C10—C15	98.7 (3)	N1—C1—C16—O17A	170.5 (7)
C15—C10—C11—C12	−0.2 (5)	C2—C1—C16—O17A	−68.9 (7)
C9—C10—C11—C12	−179.9 (3)	C9—C1—C16—O17A	50.3 (7)
C10—C11—C12—C13	1.0 (6)	N1—C1—C16—O17B	−169.9 (9)
C11—C12—C13—C14	−0.8 (7)	C2—C1—C16—O17B	−49.3 (9)
C12—C13—C14—C15	−0.2 (6)	C9—C1—C16—O17B	69.9 (9)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O16A	0.86	2.22	2.657 (15)	111
N1—H1···O16B	0.86	2.11	2.55 (2)	111
C5—H5···O19^i	0.93	2.46	3.314 (3)	152
C2—H2B···O19	0.97	2.57	3.168 (3)	119
C9—H9A···O19	0.97	2.64	3.170 (3)	114

Symmetry code: (i) x, −y+1/2, z−1/2.

(II) ethyl 3-(1,1'-biphenyl-4-yl)-2-(formylamino)-2-(4-phenylbenzyl)propionate

Crystal data

C31H29NO3	F(000) = 984
Mr = 463.55	Dx = 1.230 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 26.761 (5) Å	Cell parameters from 5898 reflections
b = 10.9424 (19) Å	θ = 2.0–28.0°
c = 8.5818 (15) Å	µ = 0.08 mm^−1
β = 95.068 (3)°	T = 293 K
V = 2503.2 (8) Å^3	Rectangular, colorless
Z = 4	0.54 × 0.45 × 0.45 mm

Data collection

Bruker SMART CCD area-detector diffractometer	2853 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.052
Graphite monochromator	θmax = 28.0°, θmin = 2.0°
ω scans	h = −34→34
21471 measured reflections	k = −14→14
5898 independent reflections	l = −11→10

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.080	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.161	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0465P)^2 + 0.6112P] where P = (Fo^2 + 2Fc^2)/3
5898 reflections	(Δ/σ)max = 0.001
316 parameters	Δρmax = 0.19 e Å^−3
317 restraints	Δρmin = −0.12 e Å^−3

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.23415 (10)	1.0037 (2)	0.4135 (3)	0.0582 (7)
C2	0.19373 (11)	1.0697 (2)	0.5011 (3)	0.0723 (8)
H2A	0.1904	1.0268	0.5986	0.087*
H2B	0.2056	1.1515	0.5272	0.087*
C3	0.14267 (11)	1.0793 (2)	0.4142 (3)	0.0642 (7)
C4	0.10641 (12)	0.9919 (3)	0.4309 (3)	0.0716 (8)
H4	0.1139	0.9255	0.4964	0.086*
C5	0.05962 (12)	1.0007 (2)	0.3531 (3)	0.0719 (8)
H5	0.0363	0.9396	0.3675	0.086*
C6	0.04554 (11)	1.0973 (2)	0.2533 (3)	0.0611 (7)
C7	0.08195 (12)	1.1851 (2)	0.2389 (4)	0.0799 (9)
H7	0.0743	1.2522	0.1747	0.096*
C8	0.12903 (13)	1.1767 (2)	0.3159 (4)	0.0818 (9)
H8	0.1524	1.2378	0.3017	0.098*
C9	−0.00455 (11)	1.1045 (2)	0.1681 (3)	0.0625 (7)
C10	−0.04448 (12)	1.0358 (3)	0.2124 (4)	0.0794 (8)
H10	−0.0396	0.9858	0.3000	0.095*
C11	−0.09104 (14)	1.0392 (3)	0.1309 (4)	0.0915 (10)
H11	−0.1169	0.9917	0.1637	0.110*
C12	−0.09944 (13)	1.1121 (3)	0.0017 (4)	0.0861 (9)
H12	−0.1308	1.1138	−0.0542	0.103*
C13	−0.06131 (14)	1.1823 (3)	−0.0441 (4)	0.0860 (9)
H13	−0.0669	1.2334	−0.1305	0.103*
C14	−0.01455 (12)	1.1781 (2)	0.0369 (3)	0.0742 (8)
H14	0.0111	1.2259	0.0029	0.089*
C15	0.28470 (11)	1.0080 (3)	0.5171 (3)	0.0755 (8)
H15A	0.2883	1.0888	0.5633	0.091*
H15B	0.2829	0.9501	0.6020	0.091*
C16	0.33098 (11)	0.9807 (3)	0.4369 (3)	0.0693 (8)
C17	0.34419 (12)	0.8634 (3)	0.3946 (4)	0.0835 (9)
H17	0.3233	0.7983	0.4141	0.100*
C18	0.38742 (12)	0.8414 (3)	0.3245 (4)	0.0842 (9)
H18	0.3949	0.7617	0.2969	0.101*
C19	0.42038 (11)	0.9346 (2)	0.2936 (3)	0.0691 (7)
C20	0.40646 (12)	1.0518 (3)	0.3335 (3)	0.0765 (8)
H20	0.4272	1.1171	0.3131	0.092*
C21	0.36305 (12)	1.0742 (3)	0.4021 (3)	0.0771 (8)
H21	0.3549	1.1543	0.4259	0.092*
C22	0.46846 (12)	0.9127 (2)	0.2257 (3)	0.0713 (8)
C23	0.51116 (13)	0.9770 (3)	0.2778 (4)	0.0803 (8)
H23	0.5095	1.0343	0.3572	0.096*
C24	0.55622 (13)	0.9583 (3)	0.2149 (4)	0.0901 (9)
H24	0.5846	1.0013	0.2535	0.108*
C25	0.55908 (15)	0.8762 (3)	0.0956 (4)	0.0972 (10)
H25	0.5892	0.8645	0.0511	0.117*
C26	0.51730 (16)	0.8117 (3)	0.0426 (4)	0.0997 (11)
H26	0.5191	0.7556	−0.0382	0.120*
C27	0.47252 (13)	0.8289 (3)	0.1076 (4)	0.0876 (9)
H27	0.4446	0.7832	0.0712	0.105*
O28	0.25125 (8)	1.18264 (17)	0.2660 (2)	0.0832 (6)
C28	0.24207 (10)	1.0753 (2)	0.2650 (3)	0.0605 (7)
C29	0.25045 (14)	1.0616 (3)	−0.0089 (3)	0.0948 (10)
H29A	0.2290	1.0272	−0.0949	0.114*
H29B	0.2442	1.1488	−0.0057	0.114*
O29	0.23854 (7)	1.00596 (15)	0.1374 (2)	0.0718 (5)
C30	0.30214 (15)	1.0404 (5)	−0.0344 (4)	0.1436 (18)
H30A	0.3094	1.0781	−0.1308	0.215*
H30B	0.3081	0.9541	−0.0399	0.215*
H30C	0.3233	1.0748	0.0505	0.215*
N31	0.21988 (7)	0.87799 (17)	0.3746 (2)	0.0540 (5)
H31	0.2168	0.8587	0.2771	0.065*
C32	0.21131 (10)	0.7910 (2)	0.4761 (3)	0.0646 (7)
H32	0.2028	0.7144	0.4348	0.077*
O33	0.21336 (8)	0.80074 (17)	0.6185 (2)	0.0859 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0798 (18)	0.0478 (14)	0.0464 (14)	−0.0105 (13)	0.0032 (13)	−0.0042 (12)
C2	0.102 (2)	0.0563 (16)	0.0612 (17)	−0.0057 (15)	0.0191 (16)	−0.0125 (13)
C3	0.085 (2)	0.0522 (16)	0.0588 (16)	0.0010 (15)	0.0278 (15)	−0.0095 (13)
C4	0.091 (2)	0.0633 (18)	0.0649 (18)	0.0027 (16)	0.0287 (16)	0.0131 (14)
C5	0.086 (2)	0.0589 (17)	0.0750 (19)	−0.0045 (15)	0.0285 (16)	0.0111 (15)
C6	0.0819 (19)	0.0432 (14)	0.0634 (16)	0.0058 (13)	0.0360 (15)	−0.0026 (12)
C7	0.090 (2)	0.0489 (16)	0.103 (2)	0.0070 (16)	0.0234 (19)	0.0156 (16)
C8	0.093 (2)	0.0459 (16)	0.110 (3)	−0.0053 (16)	0.0252 (19)	0.0061 (16)
C9	0.0820 (19)	0.0479 (15)	0.0625 (17)	0.0107 (14)	0.0334 (15)	−0.0036 (13)
C10	0.085 (2)	0.075 (2)	0.082 (2)	0.0054 (17)	0.0308 (18)	0.0121 (16)
C11	0.088 (2)	0.094 (2)	0.097 (2)	0.0025 (19)	0.031 (2)	0.005 (2)
C12	0.090 (2)	0.082 (2)	0.089 (2)	0.0199 (18)	0.0207 (19)	−0.0092 (19)
C13	0.113 (3)	0.066 (2)	0.081 (2)	0.022 (2)	0.017 (2)	0.0031 (17)
C14	0.099 (2)	0.0521 (17)	0.075 (2)	0.0074 (16)	0.0325 (17)	0.0045 (15)
C15	0.099 (2)	0.0712 (19)	0.0541 (16)	−0.0174 (16)	−0.0059 (15)	0.0020 (14)
C16	0.079 (2)	0.0624 (18)	0.0619 (17)	−0.0085 (16)	−0.0178 (15)	0.0042 (14)
C17	0.078 (2)	0.0572 (18)	0.111 (3)	−0.0072 (16)	−0.0130 (19)	0.0127 (17)
C18	0.084 (2)	0.0498 (17)	0.113 (3)	−0.0008 (16)	−0.0223 (19)	0.0041 (16)
C19	0.0741 (19)	0.0557 (17)	0.0729 (18)	−0.0005 (15)	−0.0201 (15)	0.0046 (14)
C20	0.081 (2)	0.0550 (17)	0.091 (2)	−0.0106 (15)	−0.0050 (17)	−0.0009 (15)
C21	0.086 (2)	0.0546 (17)	0.088 (2)	−0.0107 (16)	−0.0058 (18)	−0.0051 (15)
C22	0.081 (2)	0.0558 (17)	0.0718 (19)	0.0047 (15)	−0.0217 (16)	0.0085 (15)
C23	0.087 (2)	0.073 (2)	0.079 (2)	−0.0021 (17)	−0.0065 (18)	0.0031 (16)
C24	0.089 (2)	0.078 (2)	0.102 (3)	−0.0029 (19)	−0.002 (2)	0.0146 (19)
C25	0.107 (3)	0.079 (2)	0.105 (3)	0.023 (2)	0.008 (2)	0.018 (2)
C26	0.125 (3)	0.079 (2)	0.091 (3)	0.026 (2)	−0.011 (2)	−0.0064 (19)
C27	0.094 (2)	0.069 (2)	0.095 (2)	0.0113 (18)	−0.0211 (19)	−0.0072 (18)
O28	0.1105 (16)	0.0494 (11)	0.0900 (15)	−0.0113 (11)	0.0117 (12)	0.0073 (10)
C28	0.0720 (19)	0.0524 (16)	0.0568 (16)	0.0004 (14)	0.0042 (13)	0.0040 (14)
C29	0.145 (3)	0.078 (2)	0.0634 (19)	−0.004 (2)	0.016 (2)	0.0231 (16)
O29	0.1116 (15)	0.0563 (11)	0.0489 (10)	−0.0010 (10)	0.0139 (10)	0.0105 (9)
C30	0.115 (3)	0.232 (5)	0.087 (3)	−0.017 (3)	0.025 (2)	0.046 (3)
N31	0.0788 (15)	0.0477 (12)	0.0359 (10)	−0.0066 (10)	0.0063 (10)	0.0011 (9)
C32	0.086 (2)	0.0525 (16)	0.0562 (17)	−0.0061 (14)	0.0118 (15)	0.0054 (14)
O33	0.1376 (19)	0.0734 (13)	0.0480 (12)	−0.0106 (12)	0.0149 (11)	0.0115 (10)

Geometric parameters (Å, º)

C1—N31	1.459 (3)	C17—C18	1.371 (4)
C1—C28	1.527 (3)	C17—H17	0.9300
C1—C2	1.549 (3)	C18—C19	1.390 (4)
C1—C15	1.552 (4)	C18—H18	0.9300
C2—C3	1.501 (4)	C19—C20	1.387 (4)
C2—H2A	0.9700	C19—C22	1.478 (4)
C2—H2B	0.9700	C20—C21	1.370 (4)
C3—C4	1.379 (4)	C20—H20	0.9300
C3—C8	1.388 (4)	C21—H21	0.9300
C4—C5	1.370 (4)	C22—C27	1.378 (4)
C4—H4	0.9300	C22—C23	1.382 (4)
C5—C6	1.391 (3)	C23—C24	1.380 (4)
C5—H5	0.9300	C23—H23	0.9300
C6—C7	1.381 (4)	C24—C25	1.369 (4)
C6—C9	1.471 (4)	C24—H24	0.9300
C7—C8	1.373 (4)	C25—C26	1.366 (5)
C7—H7	0.9300	C25—H25	0.9300
C8—H8	0.9300	C26—C27	1.379 (5)
C9—C10	1.387 (4)	C26—H26	0.9300
C9—C14	1.391 (4)	C27—H27	0.9300
C10—C11	1.374 (4)	O28—C28	1.199 (3)
C10—H10	0.9300	C28—O29	1.329 (3)
C11—C12	1.369 (4)	C29—C30	1.438 (5)
C11—H11	0.9300	C29—O29	1.456 (3)
C12—C13	1.363 (4)	C29—H29A	0.9700
C12—H12	0.9300	C29—H29B	0.9700
C13—C14	1.378 (4)	C30—H30A	0.9600
C13—H13	0.9300	C30—H30B	0.9600
C14—H14	0.9300	C30—H30C	0.9600
C15—C16	1.499 (4)	N31—C32	1.324 (3)
C15—H15A	0.9700	N31—H31	0.8600
C15—H15B	0.9700	C32—O33	1.223 (3)
C16—C21	1.385 (4)	C32—H32	0.9300
C16—C17	1.389 (4)
N31—C1—C28	110.24 (19)	C17—C16—C15	123.0 (3)
N31—C1—C2	111.7 (2)	C18—C17—C16	121.4 (3)
C28—C1—C2	108.7 (2)	C18—C17—H17	119.3
N31—C1—C15	110.9 (2)	C16—C17—H17	119.3
C28—C1—C15	106.5 (2)	C17—C18—C19	122.0 (3)
C2—C1—C15	108.6 (2)	C17—C18—H18	119.0
C3—C2—C1	115.9 (2)	C19—C18—H18	119.0
C3—C2—H2A	108.3	C20—C19—C18	116.3 (3)
C1—C2—H2A	108.3	C20—C19—C22	120.6 (3)
C3—C2—H2B	108.3	C18—C19—C22	123.0 (3)
C1—C2—H2B	108.3	C21—C20—C19	121.8 (3)
H2A—C2—H2B	107.4	C21—C20—H20	119.1
C4—C3—C8	116.5 (3)	C19—C20—H20	119.1
C4—C3—C2	121.1 (3)	C20—C21—C16	121.8 (3)
C8—C3—C2	122.3 (3)	C20—C21—H21	119.1
C5—C4—C3	121.5 (3)	C16—C21—H21	119.1
C5—C4—H4	119.3	C27—C22—C23	117.4 (3)
C3—C4—H4	119.3	C27—C22—C19	121.7 (3)
C4—C5—C6	122.7 (3)	C23—C22—C19	120.9 (3)
C4—C5—H5	118.7	C24—C23—C22	121.6 (3)
C6—C5—H5	118.7	C24—C23—H23	119.2
C7—C6—C5	115.4 (3)	C22—C23—H23	119.2
C7—C6—C9	122.5 (3)	C25—C24—C23	119.9 (3)
C5—C6—C9	122.1 (3)	C25—C24—H24	120.0
C8—C7—C6	122.4 (3)	C23—C24—H24	120.0
C8—C7—H7	118.8	C26—C25—C24	119.3 (4)
C6—C7—H7	118.8	C26—C25—H25	120.3
C7—C8—C3	121.6 (3)	C24—C25—H25	120.3
C7—C8—H8	119.2	C25—C26—C27	120.6 (4)
C3—C8—H8	119.2	C25—C26—H26	119.7
C10—C9—C14	116.0 (3)	C27—C26—H26	119.7
C10—C9—C6	121.7 (3)	C22—C27—C26	121.1 (3)
C14—C9—C6	122.3 (3)	C22—C27—H27	119.5
C11—C10—C9	122.1 (3)	C26—C27—H27	119.5
C11—C10—H10	118.9	O28—C28—O29	124.4 (2)
C9—C10—H10	118.9	O28—C28—C1	122.7 (2)
C12—C11—C10	120.3 (3)	O29—C28—C1	112.9 (2)
C12—C11—H11	119.9	C30—C29—O29	110.5 (3)
C10—C11—H11	119.9	C30—C29—H29A	109.5
C13—C12—C11	119.3 (3)	O29—C29—H29A	109.5
C13—C12—H12	120.4	C30—C29—H29B	109.5
C11—C12—H12	120.4	O29—C29—H29B	109.5
C12—C13—C14	120.4 (3)	H29A—C29—H29B	108.1
C12—C13—H13	119.8	C28—O29—C29	117.8 (2)
C14—C13—H13	119.8	C29—C30—H30A	109.5
C13—C14—C9	121.9 (3)	C29—C30—H30B	109.5
C13—C14—H14	119.0	H30A—C30—H30B	109.5
C9—C14—H14	119.0	C29—C30—H30C	109.5
C16—C15—C1	116.4 (2)	H30A—C30—H30C	109.5
C16—C15—H15A	108.2	H30B—C30—H30C	109.5
C1—C15—H15A	108.2	C32—N31—C1	125.8 (2)
C16—C15—H15B	108.2	C32—N31—H31	117.1
C1—C15—H15B	108.2	C1—N31—H31	117.1
H15A—C15—H15B	107.3	O33—C32—N31	126.8 (2)
C21—C16—C17	116.7 (3)	O33—C32—H32	116.6
C21—C16—C15	120.3 (3)	N31—C32—H32	116.6
N31—C1—C2—C3	−60.1 (3)	C16—C17—C18—C19	0.6 (5)
C28—C1—C2—C3	61.8 (3)	C17—C18—C19—C20	−1.7 (4)
C15—C1—C2—C3	177.3 (2)	C17—C18—C19—C22	176.7 (3)
C1—C2—C3—C4	92.2 (3)	C18—C19—C20—C21	1.1 (4)
C1—C2—C3—C8	−89.0 (3)	C22—C19—C20—C21	−177.4 (3)
C8—C3—C4—C5	0.5 (4)	C19—C20—C21—C16	0.7 (5)
C2—C3—C4—C5	179.4 (2)	C17—C16—C21—C20	−1.9 (4)
C3—C4—C5—C6	−0.1 (4)	C15—C16—C21—C20	177.9 (3)
C4—C5—C6—C7	−0.6 (4)	C20—C19—C22—C27	−141.1 (3)
C4—C5—C6—C9	178.8 (2)	C18—C19—C22—C27	40.5 (4)
C5—C6—C7—C8	0.9 (4)	C20—C19—C22—C23	38.2 (4)
C9—C6—C7—C8	−178.5 (3)	C18—C19—C22—C23	−140.2 (3)
C6—C7—C8—C3	−0.5 (5)	C27—C22—C23—C24	−0.2 (4)
C4—C3—C8—C7	−0.2 (4)	C19—C22—C23—C24	−179.5 (3)
C2—C3—C8—C7	−179.1 (3)	C22—C23—C24—C25	1.4 (5)
C7—C6—C9—C10	−162.9 (3)	C23—C24—C25—C26	−1.4 (5)
C5—C6—C9—C10	17.8 (4)	C24—C25—C26—C27	0.2 (5)
C7—C6—C9—C14	18.5 (4)	C23—C22—C27—C26	−1.0 (4)
C5—C6—C9—C14	−160.9 (2)	C19—C22—C27—C26	178.3 (3)
C14—C9—C10—C11	0.6 (4)	C25—C26—C27—C22	1.0 (5)
C6—C9—C10—C11	−178.1 (3)	N31—C1—C28—O28	175.7 (2)
C9—C10—C11—C12	−0.2 (5)	C2—C1—C28—O28	52.9 (3)
C10—C11—C12—C13	−0.7 (5)	C15—C1—C28—O28	−63.9 (3)
C11—C12—C13—C14	1.3 (4)	N31—C1—C28—O29	−5.4 (3)
C12—C13—C14—C9	−0.9 (4)	C2—C1—C28—O29	−128.2 (2)
C10—C9—C14—C13	−0.1 (4)	C15—C1—C28—O29	115.0 (2)
C6—C9—C14—C13	178.6 (2)	O28—C28—O29—C29	5.0 (4)
N31—C1—C15—C16	73.2 (3)	C1—C28—O29—C29	−173.9 (2)
C28—C1—C15—C16	−46.7 (3)	C30—C29—O29—C28	93.8 (3)
C2—C1—C15—C16	−163.6 (2)	C28—C1—N31—C32	178.4 (2)
C1—C15—C16—C21	105.0 (3)	C2—C1—N31—C32	−60.6 (3)
C1—C15—C16—C17	−75.3 (3)	C15—C1—N31—C32	60.7 (3)
C21—C16—C17—C18	1.2 (4)	C1—N31—C32—O33	0.7 (4)
C15—C16—C17—C18	−178.5 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N31—H31···O29	0.86	2.12	2.556 (2)	111
N31—H31···O33^i	0.86	2.21	2.936 (3)	142
C15—H15B···O33	0.97	2.49	3.137 (3)	124
C2—H2A···O33	0.97	2.55	3.139 (3)	119

Symmetry code: (i) x, −y+3/2, z−1/2.