Benzyl
N-[8-(4,4-dimethyl-5-oxo-4,5-dihydrooxazol-2-yl)-2,5,5,8-tetramethyl-3,6-dioxo-4,7-diazanon-2-yl]carbamate, C
24H
34N
4O
6, an oxazol-5(4
H)-one from
N-α-benzyloxycarbonyl-(Aib)
4-OH (Aib = α-aminoisobutyryl) represents the longest peptide oxazolone so far characterized by X-ray diffraction. The overall geometry of the oxazolone ring compares well with literature data. The Aib(1) and Aib(2) residues are folded into a type III β-bend, while the conformation adopted by Aib(3), preceding the oxazolone moiety, is semi-extended. The disposition of the oxazolone ring relative to the preceding residue is stabilized by C—H
N and C—H
O intramolecular interactions.
Supporting information
Data collection: FEBO (Belletti, 1993); cell refinement: FEBO; data reduction: FEBO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1998); software used to prepare material for publication: SHELXL97.
benzyl
N-[8-(4,4-dimethyl-5-oxooxazol-2-yl)-2,5,5,8-tetramethyl-3,6-dioxo-4,7-
diazanon-2-yl]carbamate
top
Crystal data top
C24H34N4O6 | Dx = 1.203 Mg m−3 |
Mr = 474.55 | Melting point: 430 K K |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 9.324 (2) Å | Cell parameters from 48 reflections |
b = 25.149 (3) Å | θ = 7–12° |
c = 11.753 (2) Å | µ = 0.09 mm−1 |
β = 108.00 (5)° | T = 293 K |
V = 2621.1 (8) Å3 | Prism, colourless |
Z = 4 | 0.6 × 0.4 × 0.4 mm |
F(000) = 1016 | |
Data collection top
Philips PW1100 diffractometer | Rint = 0.020 |
Radiation source: fine-focus sealed tube | θmax = 24.7°, θmin = 4.4° |
Graphite monochromator | h = −10→10 |
θ–2θ scans | k = 0→29 |
4649 measured reflections | l = 0→13 |
4427 independent reflections | 3 standard reflections every 50 reflections |
3058 reflections with I > 2σ(I) | intensity decay: none |
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)] = 0.043 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.132 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0835P)2] where P = (Fo2 + 2Fc2)/3 |
4427 reflections | (Δ/σ)max = 0.021 |
315 parameters | Δρmax = 0.15 e Å−3 |
3 restraints | Δρmin = −0.22 e Å−3 |
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 >
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 (Å2) top | x | y | z | Uiso*/Ueq | |
C01 | 0.0368 (3) | 0.43196 (7) | −0.03121 (17) | 0.0664 (6) | |
C02 | 0.1106 (4) | 0.44277 (10) | −0.1132 (2) | 0.1002 (9) | |
H02 | 0.0551 | 0.4493 | −0.1925 | 0.120* | |
C03 | 0.2652 (6) | 0.44402 (13) | −0.0797 (4) | 0.1282 (13) | |
H03 | 0.3131 | 0.4523 | −0.1361 | 0.154* | |
C04 | 0.3505 (4) | 0.43322 (11) | 0.0365 (4) | 0.1110 (10) | |
H04 | 0.4553 | 0.4340 | 0.0586 | 0.133* | |
C05 | 0.2793 (3) | 0.42144 (10) | 0.1184 (2) | 0.0908 (7) | |
H05 | 0.3351 | 0.4137 | 0.1969 | 0.109* | |
C06 | 0.1249 (3) | 0.42101 (9) | 0.08467 (18) | 0.0730 (6) | |
H06 | 0.0777 | 0.4131 | 0.1417 | 0.088* | |
C07 | −0.1310 (3) | 0.43294 (8) | −0.0658 (2) | 0.0888 (8) | |
H07A | −0.1618 | 0.4495 | −0.0026 | 0.107* | |
H07B | −0.1707 | 0.4541 | −0.1378 | 0.107* | |
OU | −0.19353 (17) | 0.37942 (5) | −0.08716 (11) | 0.0736 (4) | |
C0 | −0.2332 (2) | 0.35644 (7) | 0.00284 (15) | 0.0554 (5) | |
O0 | −0.22556 (16) | 0.37858 (5) | 0.09709 (11) | 0.0710 (4) | |
N1 | −0.27910 (16) | 0.30639 (5) | −0.02583 (11) | 0.0495 (4) | |
H1 | −0.2736 | 0.2936 | −0.0922 | 0.059* | |
C1A | −0.33805 (18) | 0.27258 (7) | 0.05049 (14) | 0.0489 (4) | |
C1B1 | −0.3704 (2) | 0.21860 (8) | −0.01060 (17) | 0.0655 (5) | |
H1B1 | −0.4474 | 0.2223 | −0.0864 | 0.098* | |
H1B2 | −0.4042 | 0.1944 | 0.0390 | 0.098* | |
H1B3 | −0.2802 | 0.2050 | −0.0229 | 0.098* | |
C1B2 | −0.4812 (2) | 0.29611 (10) | 0.0676 (2) | 0.0793 (6) | |
H1B4 | −0.4574 | 0.3290 | 0.1106 | 0.119* | |
H1B5 | −0.5222 | 0.2716 | 0.1120 | 0.119* | |
H1B6 | −0.5540 | 0.3025 | −0.0092 | 0.119* | |
C1 | −0.21910 (19) | 0.26420 (6) | 0.17437 (14) | 0.0459 (4) | |
O1 | −0.25888 (15) | 0.25267 (6) | 0.26155 (11) | 0.0661 (4) | |
N2 | −0.07483 (15) | 0.26892 (5) | 0.17929 (11) | 0.0451 (3) | |
H2 | −0.0557 | 0.2761 | 0.1139 | 0.054* | |
C2A | 0.05393 (19) | 0.26267 (7) | 0.28876 (14) | 0.0494 (4) | |
C2B1 | 0.1952 (2) | 0.27702 (9) | 0.25552 (18) | 0.0683 (5) | |
H2B1 | 0.2050 | 0.2533 | 0.1944 | 0.102* | |
H2B2 | 0.2823 | 0.2739 | 0.3249 | 0.102* | |
H2B3 | 0.1869 | 0.3129 | 0.2263 | 0.102* | |
C2B2 | 0.0652 (2) | 0.20610 (8) | 0.33699 (18) | 0.0700 (6) | |
H2B4 | −0.0281 | 0.1965 | 0.3502 | 0.105* | |
H2B5 | 0.1458 | 0.2040 | 0.4111 | 0.105* | |
H2B6 | 0.0849 | 0.1821 | 0.2800 | 0.105* | |
C2 | 0.0453 (2) | 0.30334 (7) | 0.38514 (14) | 0.0541 (4) | |
O2 | 0.11412 (18) | 0.29478 (6) | 0.49065 (11) | 0.0781 (5) | |
N3 | −0.02424 (16) | 0.34978 (6) | 0.34785 (12) | 0.0545 (4) | |
H3 | −0.0802 | 0.3525 | 0.2747 | 0.065* | |
C3A | −0.00871 (19) | 0.39639 (7) | 0.42708 (14) | 0.0526 (4) | |
C3B1 | −0.0935 (2) | 0.38971 (9) | 0.51831 (18) | 0.0719 (6) | |
H3B1 | −0.1998 | 0.3875 | 0.4774 | 0.108* | |
H3B2 | −0.0736 | 0.4197 | 0.5715 | 0.108* | |
H3B3 | −0.0605 | 0.3577 | 0.5634 | 0.108* | |
C3B2 | −0.0678 (3) | 0.44463 (8) | 0.34730 (18) | 0.0722 (6) | |
H3B4 | −0.0047 | 0.4511 | 0.2979 | 0.108* | |
H3B5 | −0.0668 | 0.4752 | 0.3964 | 0.108* | |
H3B6 | −0.1691 | 0.4379 | 0.2976 | 0.108* | |
C3 | 0.15714 (19) | 0.40438 (7) | 0.49153 (14) | 0.0493 (4) | |
N4 | 0.22054 (16) | 0.41749 (6) | 0.59869 (12) | 0.0552 (4) | |
C4A | 0.3832 (2) | 0.41893 (8) | 0.61541 (17) | 0.0624 (5) | |
C4B1 | 0.4596 (3) | 0.37348 (11) | 0.7001 (2) | 0.0917 (8) | |
H4B1 | 0.4482 | 0.3794 | 0.7776 | 0.137* | |
H4B2 | 0.5649 | 0.3724 | 0.7071 | 0.137* | |
H4B3 | 0.4134 | 0.3403 | 0.6686 | 0.137* | |
C4B2 | 0.4510 (3) | 0.47288 (11) | 0.6589 (3) | 0.0954 (8) | |
H4B4 | 0.3973 | 0.5000 | 0.6049 | 0.143* | |
H4B5 | 0.5552 | 0.4733 | 0.6622 | 0.143* | |
H4B6 | 0.4435 | 0.4796 | 0.7373 | 0.143* | |
C4 | 0.3931 (2) | 0.40755 (8) | 0.49141 (18) | 0.0628 (5) | |
O3 | 0.24888 (14) | 0.39839 (5) | 0.41824 (10) | 0.0612 (3) | |
O4 | 0.49883 (18) | 0.40632 (7) | 0.45418 (15) | 0.0864 (5) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C01 | 0.1006 (17) | 0.0397 (10) | 0.0556 (11) | −0.0099 (10) | 0.0195 (11) | −0.0006 (8) |
C02 | 0.172 (3) | 0.0730 (16) | 0.0660 (15) | −0.0173 (18) | 0.0520 (18) | −0.0021 (12) |
C03 | 0.186 (4) | 0.098 (2) | 0.149 (3) | −0.007 (2) | 0.122 (3) | −0.005 (2) |
C04 | 0.105 (2) | 0.0824 (19) | 0.166 (3) | 0.0012 (16) | 0.071 (2) | −0.002 (2) |
C05 | 0.0877 (18) | 0.0897 (18) | 0.0955 (17) | −0.0049 (14) | 0.0288 (15) | 0.0088 (13) |
C06 | 0.0862 (16) | 0.0753 (14) | 0.0601 (12) | −0.0088 (11) | 0.0265 (11) | 0.0059 (10) |
C07 | 0.111 (2) | 0.0461 (12) | 0.0870 (16) | −0.0124 (12) | −0.0021 (14) | 0.0169 (11) |
OU | 0.1014 (11) | 0.0525 (8) | 0.0535 (8) | −0.0163 (7) | 0.0043 (7) | 0.0058 (6) |
C0 | 0.0621 (11) | 0.0471 (10) | 0.0433 (9) | 0.0071 (8) | −0.0039 (8) | 0.0013 (8) |
O0 | 0.0910 (10) | 0.0538 (8) | 0.0555 (8) | 0.0089 (7) | 0.0039 (7) | −0.0129 (6) |
N1 | 0.0605 (9) | 0.0459 (8) | 0.0360 (7) | −0.0002 (6) | 0.0057 (6) | −0.0035 (6) |
C1A | 0.0438 (9) | 0.0538 (10) | 0.0457 (9) | 0.0018 (7) | 0.0088 (7) | −0.0028 (7) |
C1B1 | 0.0680 (13) | 0.0635 (12) | 0.0602 (11) | −0.0178 (10) | 0.0129 (9) | −0.0096 (9) |
C1B2 | 0.0538 (12) | 0.1050 (18) | 0.0762 (14) | 0.0183 (11) | 0.0160 (10) | −0.0003 (12) |
C1 | 0.0513 (10) | 0.0412 (9) | 0.0431 (9) | 0.0022 (7) | 0.0113 (7) | −0.0019 (7) |
O1 | 0.0730 (9) | 0.0796 (9) | 0.0504 (7) | 0.0060 (7) | 0.0260 (6) | 0.0120 (6) |
N2 | 0.0463 (8) | 0.0501 (8) | 0.0348 (7) | 0.0014 (6) | 0.0066 (6) | −0.0009 (6) |
C2A | 0.0498 (10) | 0.0472 (10) | 0.0413 (9) | 0.0051 (7) | −0.0004 (7) | −0.0005 (7) |
C2B1 | 0.0501 (11) | 0.0804 (14) | 0.0638 (12) | 0.0045 (10) | 0.0022 (9) | −0.0087 (10) |
C2B2 | 0.0773 (14) | 0.0524 (11) | 0.0640 (12) | 0.0134 (10) | −0.0021 (10) | 0.0031 (9) |
C2 | 0.0601 (11) | 0.0521 (10) | 0.0403 (9) | 0.0027 (8) | 0.0013 (8) | 0.0005 (8) |
O2 | 0.1074 (11) | 0.0687 (9) | 0.0393 (7) | 0.0173 (8) | −0.0047 (7) | 0.0019 (6) |
N3 | 0.0666 (10) | 0.0474 (8) | 0.0378 (7) | 0.0055 (7) | −0.0011 (6) | −0.0046 (6) |
C3A | 0.0572 (11) | 0.0501 (10) | 0.0446 (9) | 0.0010 (8) | 0.0073 (8) | −0.0095 (7) |
C3B1 | 0.0649 (13) | 0.0821 (15) | 0.0704 (13) | −0.0102 (11) | 0.0235 (10) | −0.0190 (11) |
C3B2 | 0.0885 (15) | 0.0526 (11) | 0.0623 (12) | 0.0160 (10) | 0.0041 (11) | −0.0094 (9) |
C3 | 0.0594 (11) | 0.0461 (10) | 0.0428 (9) | −0.0029 (8) | 0.0162 (8) | −0.0042 (7) |
N4 | 0.0575 (9) | 0.0581 (9) | 0.0457 (8) | −0.0037 (7) | 0.0097 (7) | −0.0081 (7) |
C4A | 0.0554 (11) | 0.0664 (12) | 0.0589 (11) | −0.0028 (9) | 0.0080 (9) | −0.0071 (9) |
C4B1 | 0.0844 (16) | 0.112 (2) | 0.0667 (14) | 0.0209 (14) | 0.0066 (12) | 0.0070 (13) |
C4B2 | 0.0806 (16) | 0.0981 (18) | 0.1058 (18) | −0.0279 (14) | 0.0263 (14) | −0.0344 (15) |
C4 | 0.0658 (13) | 0.0560 (11) | 0.0694 (12) | 0.0023 (9) | 0.0251 (10) | 0.0024 (9) |
O3 | 0.0664 (8) | 0.0707 (8) | 0.0489 (7) | −0.0021 (7) | 0.0213 (6) | −0.0057 (6) |
O4 | 0.0754 (10) | 0.0940 (12) | 0.1024 (12) | 0.0049 (8) | 0.0458 (9) | 0.0041 (9) |
Geometric parameters (Å, º) top
C01—C02 | 1.374 (3) | C2A—C2B1 | 1.528 (3) |
C01—C06 | 1.384 (3) | C2A—C2B2 | 1.523 (2) |
C01—C07 | 1.490 (3) | C2A—C2 | 1.547 (2) |
C02—C03 | 1.373 (5) | C2—O2 | 1.226 (2) |
C03—C04 | 1.378 (5) | C2—N3 | 1.342 (2) |
C04—C05 | 1.360 (4) | N3—C3A | 1.476 (2) |
C05—C06 | 1.370 (3) | C3A—C3 | 1.510 (3) |
C07—OU | 1.457 (2) | C3A—C3B1 | 1.525 (3) |
OU—C0 | 1.353 (2) | C3A—C3B2 | 1.528 (3) |
C0—O0 | 1.222 (2) | C3—N4 | 1.259 (2) |
C0—N1 | 1.339 (2) | C3—O3 | 1.397 (2) |
N1—C1A | 1.461 (2) | N4—C4A | 1.468 (2) |
C1A—C1B1 | 1.522 (2) | C4A—C4 | 1.516 (3) |
C1A—C1B2 | 1.529 (3) | C4A—C4B2 | 1.518 (3) |
C1A—C1 | 1.548 (2) | C4A—C4B1 | 1.539 (3) |
C1—O1 | 1.227 (2) | C4—O4 | 1.196 (2) |
C1—N2 | 1.334 (2) | C4—O3 | 1.374 (2) |
N2—C2A | 1.472 (2) | | |
| | | |
C02—C01—C06 | 117.1 (2) | N2—C2A—C2 | 110.89 (13) |
C02—C01—C07 | 121.1 (2) | C2B1—C2A—C2 | 105.97 (15) |
C06—C01—C07 | 121.7 (2) | C2B2—C2A—C2 | 111.00 (14) |
C03—C02—C01 | 120.8 (3) | O2—C2—N3 | 122.15 (16) |
C04—C03—C02 | 120.9 (3) | O2—C2—C2A | 119.66 (15) |
C03—C04—C05 | 119.0 (3) | N3—C2—C2A | 117.75 (14) |
C06—C05—C04 | 119.8 (3) | C2—N3—C3A | 122.80 (13) |
C05—C06—C01 | 122.3 (2) | N3—C3A—C3 | 107.93 (14) |
OU—C07—C01 | 111.22 (18) | N3—C3A—C3B1 | 112.64 (15) |
C0—OU—C07 | 116.83 (16) | C3—C3A—C3B1 | 109.56 (14) |
O0—C0—N1 | 125.52 (18) | N3—C3A—C3B2 | 107.27 (13) |
O0—C0—OU | 124.09 (17) | C3—C3A—C3B2 | 108.74 (16) |
N1—C0—OU | 110.38 (15) | C3B1—C3A—C3B2 | 110.58 (16) |
C0—N1—C1A | 122.99 (14) | N4—C3—O3 | 117.23 (15) |
N1—C1A—C1B1 | 106.68 (14) | N4—C3—C3A | 128.92 (16) |
N1—C1A—C1B2 | 111.39 (16) | O3—C3—C3A | 113.79 (14) |
C1B1—C1A—C1B2 | 110.68 (16) | C3—N4—C4A | 106.66 (15) |
N1—C1A—C1 | 111.14 (13) | N4—C4A—C4 | 103.53 (16) |
C1B1—C1A—C1 | 107.60 (14) | N4—C4A—C4B2 | 111.88 (17) |
C1B2—C1A—C1 | 109.28 (15) | C4—C4A—C4B2 | 110.49 (19) |
O1—C1—N2 | 123.08 (16) | N4—C4A—C4B1 | 108.71 (17) |
O1—C1—C1A | 120.25 (15) | C4—C4A—C4B1 | 109.18 (17) |
N2—C1—C1A | 116.65 (14) | C4B2—C4A—C4B1 | 112.63 (19) |
C1—N2—C2A | 124.59 (14) | O4—C4—O3 | 121.66 (19) |
N2—C2A—C2B1 | 106.61 (14) | O4—C4—C4A | 131.2 (2) |
N2—C2A—C2B2 | 111.63 (14) | O3—C4—C4A | 107.14 (17) |
C2B1—C2A—C2B2 | 110.50 (16) | C4—O3—C3 | 105.28 (14) |
| | | |
C06—C01—C02—C03 | −1.8 (3) | C2B2—C2A—C2—O2 | 34.1 (2) |
C07—C01—C02—C03 | 177.2 (2) | N2—C2A—C2—N3 | −28.7 (2) |
C01—C02—C03—C04 | 1.6 (4) | C2B1—C2A—C2—N3 | 86.64 (19) |
C02—C03—C04—C05 | −0.3 (5) | C2B2—C2A—C2—N3 | −153.36 (17) |
C03—C04—C05—C06 | −0.7 (4) | O2—C2—N3—C3A | 7.6 (3) |
C04—C05—C06—C01 | 0.4 (4) | C2A—C2—N3—C3A | −164.78 (16) |
C02—C01—C06—C05 | 0.9 (3) | C2—N3—C3A—C3 | 48.4 (2) |
C07—C01—C06—C05 | −178.1 (2) | C2—N3—C3A—C3B1 | −72.7 (2) |
C02—C01—C07—OU | 99.8 (2) | C2—N3—C3A—C3B2 | 165.42 (18) |
C06—C01—C07—OU | −81.2 (3) | N3—C3A—C3—N4 | −140.36 (18) |
C01—C07—OU—C0 | 99.2 (2) | C3B1—C3A—C3—N4 | −17.4 (3) |
C07—OU—C0—O0 | 3.2 (3) | C3B2—C3A—C3—N4 | 103.6 (2) |
C07—OU—C0—N1 | −175.88 (16) | N3—C3A—C3—O3 | 42.75 (19) |
O0—C0—N1—C1A | 4.9 (3) | C3B1—C3A—C3—O3 | 165.72 (15) |
OU—C0—N1—C1A | −176.01 (14) | C3B2—C3A—C3—O3 | −73.31 (18) |
C0—N1—C1A—C1B1 | −177.49 (15) | O3—C3—N4—C4A | −3.9 (2) |
C0—N1—C1A—C1B2 | 61.6 (2) | C3A—C3—N4—C4A | 179.27 (17) |
C0—N1—C1A—C1 | −60.5 (2) | C3—N4—C4A—C4 | 3.89 (19) |
N1—C1A—C1—O1 | 156.08 (15) | C3—N4—C4A—C4B2 | 122.88 (19) |
C1B1—C1A—C1—O1 | −87.47 (19) | C3—N4—C4A—C4B1 | −112.11 (18) |
C1B2—C1A—C1—O1 | 32.7 (2) | N4—C4A—C4—O4 | 176.5 (2) |
N1—C1A—C1—N2 | −25.5 (2) | C4B2—C4A—C4—O4 | 56.5 (3) |
C1B1—C1A—C1—N2 | 90.98 (17) | C4B1—C4A—C4—O4 | −67.8 (3) |
C1B2—C1A—C1—N2 | −148.80 (16) | N4—C4A—C4—O3 | −2.73 (19) |
O1—C1—N2—C2A | −2.0 (2) | C4B2—C4A—C4—O3 | −122.67 (19) |
C1A—C1—N2—C2A | 179.64 (14) | C4B1—C4A—C4—O3 | 112.94 (19) |
C1—N2—C2A—C2B1 | −174.26 (15) | O4—C4—O3—C3 | −178.61 (18) |
C1—N2—C2A—C2B2 | 65.0 (2) | C4A—C4—O3—C3 | 0.69 (18) |
C1—N2—C2A—C2 | −59.4 (2) | N4—C3—O3—C4 | 2.1 (2) |
N2—C2A—C2—O2 | 158.77 (17) | C3A—C3—O3—C4 | 179.40 (14) |
C2B1—C2A—C2—O2 | −85.9 (2) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3···O0 | 0.86 | 2.21 | 3.052 (2) | 167 |
N1—H1···O1i | 0.86 | 2.11 | 2.9627 (18) | 169 |
Symmetry code: (i) x, −y+1/2, z−1/2. |