The molecule of activated carbamate, (S)-2,5-dioxopyrrolidin-1-yl N-[2-(tert-butoxycarbonylamino)propyl]carbamate, tBuOCONHCH(Me)CH2NHCOONC4H4O2 or C13H21N3O6, prepared from N-Boc-β3HAla-OH, assumes a folded conformation with the N—C—C—N torsion angle equal to 55.9 (3)°. Both N—H groups are involved in intermolecular hydrogen bonds, forming infinite chains in the crystal.
Supporting information
CCDC reference: 159850
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.004 Å
- R factor = 0.037
- wR factor = 0.097
- Data-to-parameter ratio = 8.7
checkCIF results
No syntax errors found
ADDSYM reports no extra symmetry
Alert Level C:
ABSMU_01 Alert C The ratio of given/expected absorption coefficient lies
outside the range 0.99 <> 1.01
Calculated value of mu = 0.101
Value of mu given = 0.100
PLAT_353 Alert C Long N-H Bond (0.87A) N(1) - H(1) = 1.01 Ang.
PLAT_353 Alert C Long N-H Bond (0.87A) N(2) - H(2) = 1.02 Ang.
General Notes
REFLT_03
From the CIF: _diffrn_reflns_theta_max 26.30
From the CIF: _reflns_number_total 1792
Count of symmetry unique reflns 1799
Completeness (_total/calc) 99.61%
TEST3: Check Friedels for noncentro structure
Estimate of Friedel pairs measured 0
Fraction of Friedel pairs measured 0.000
Are heavy atom types Z>Si present no
Please check that the estimate of the number of Friedel pairs is
correct. If it is not, please give the correct count in the
_publ_section_exptl_refinement section of the submitted CIF.
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
3 Alert Level C = Please check
O-succinimidyl carbamate was prepared by homologation of Boc-L-Ala-OH,
with subsequent conversion of Boc-(S)-β3HAla-OH [we used the nomenclature
proposed by Seebach & Matthews (1997) for β-amino acids] to the corresponding
acyl azide and trapping of the intermediate isocyanate, resulting from Curtius
rearrangement of the acyl azide, with N-hydroxysuccinimide. Details of
the synthetic procedures are available in the CIF file.
The absolute stereochemistry of the title compound is based on the known
configuration of Boc-L-Ala-OH (purchased from Neosystem, Strasbourg,
France) since the homologation using the Arndt-Eistert reaction is known to
proceed without epimerization at the α carbon. The positions of H atoms
attached to N atoms were located from a difference map and the N—H bond
distance was restrained to 1.03 (1) Å (Taylor & Kennard, 1983). The H atoms
connected to carbon were placed in the calculated positions and included in
the refinement in the riding model approximation (C—H distances are in the
range 0.96–0.98 Å). The isotropic H-atom displacement parameters were
restricted to be 30% higher than the equivalent isotropic displacement
parameters of the parent atom.
Data collection: COLLECT (Nonius, 1998); cell refinement: COLLECT; data reduction: HKL (Otwinoski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: maXus (Mackay et al., 1999).
(S)—O-Succinimidyl
N-[2-(
tert-butoxycarbonylamino)propyl]carbamate
top
Crystal data top
C13H21N3O6 | F(000) = 336 |
Mr = 315.33 | Dx = 1.273 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71070 Å |
a = 5.1260 (2) Å | Cell parameters from 5236 reflections |
b = 8.5650 (4) Å | θ = 4.0–26.3° |
c = 18.7540 (9) Å | µ = 0.10 mm−1 |
β = 91.996 (3)° | T = 293 K |
V = 822.88 (6) Å3 | Prismatic, colorless |
Z = 2 | 0.3 × 0.25 × 0.22 mm |
Data collection top
KappaCCD diffractometer | 1436 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.030 |
Graphite monochromator | θmax = 26.3°, θmin = 4.0° |
oscillation scans | h = 0→6 |
5236 measured reflections | k = 0→10 |
1792 independent reflections | l = −23→23 |
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)] = 0.037 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.097 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0553P)2 + 0.0391P] where P = (Fo2 + 2Fc2)/3 |
1792 reflections | (Δ/σ)max < 0.001 |
205 parameters | Δρmax = 0.11 e Å−3 |
3 restraints | Δρmin = −0.17 e Å−3 |
Crystal data top
C13H21N3O6 | V = 822.88 (6) Å3 |
Mr = 315.33 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 5.1260 (2) Å | µ = 0.10 mm−1 |
b = 8.5650 (4) Å | T = 293 K |
c = 18.7540 (9) Å | 0.3 × 0.25 × 0.22 mm |
β = 91.996 (3)° | |
Data collection top
KappaCCD diffractometer | 1436 reflections with I > 2σ(I) |
5236 measured reflections | Rint = 0.030 |
1792 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.037 | 3 restraints |
wR(F2) = 0.097 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.11 e Å−3 |
1792 reflections | Δρmin = −0.17 e Å−3 |
205 parameters | |
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 | |
C1 | −0.2288 (4) | 0.3268 (3) | 0.57925 (13) | 0.0505 (6) | |
C2 | −0.0629 (5) | 0.4397 (4) | 0.53911 (19) | 0.0799 (10) | |
H2A | 0.0275 | 0.3847 | 0.5028 | 0.104* | |
H2B | 0.0617 | 0.4879 | 0.5716 | 0.104* | |
H2C | −0.1723 | 0.5186 | 0.5173 | 0.104* | |
C3 | −0.4126 (5) | 0.2386 (4) | 0.52903 (14) | 0.0640 (7) | |
H3A | −0.3143 | 0.1870 | 0.4933 | 0.083* | |
H3B | −0.5334 | 0.3103 | 0.5065 | 0.083* | |
H3C | −0.5071 | 0.1624 | 0.5554 | 0.083* | |
C4 | −0.3705 (6) | 0.4101 (4) | 0.63710 (17) | 0.0717 (8) | |
H4A | −0.2470 | 0.4659 | 0.6671 | 0.093* | |
H4B | −0.4612 | 0.3352 | 0.6652 | 0.093* | |
H4C | −0.4937 | 0.4823 | 0.6159 | 0.093* | |
O1 | −0.0307 (3) | 0.2195 (2) | 0.61109 (9) | 0.0533 (5) | |
C5 | −0.0988 (4) | 0.1042 (3) | 0.65552 (13) | 0.0464 (6) | |
O2 | −0.3204 (3) | 0.0650 (3) | 0.66664 (11) | 0.0680 (6) | |
N1 | 0.1146 (3) | 0.0388 (3) | 0.68556 (11) | 0.0497 (5) | |
H1 | 0.283 (3) | 0.081 (4) | 0.6670 (12) | 0.065* | |
C6 | 0.1006 (4) | −0.0925 (3) | 0.73422 (12) | 0.0487 (6) | |
H6 | −0.0739 | −0.0946 | 0.7539 | 0.063* | |
C7 | 0.1472 (7) | −0.2466 (4) | 0.69701 (19) | 0.0802 (10) | |
H7A | 0.0171 | −0.2611 | 0.6596 | 0.104* | |
H7B | 0.1369 | −0.3303 | 0.7308 | 0.104* | |
H7C | 0.3173 | −0.2459 | 0.6771 | 0.104* | |
C8 | 0.3002 (4) | −0.0704 (3) | 0.79532 (12) | 0.0484 (6) | |
H8A | 0.2844 | −0.1552 | 0.8292 | 0.063* | |
H8B | 0.4745 | −0.0741 | 0.7768 | 0.063* | |
N2 | 0.2643 (3) | 0.0775 (3) | 0.83175 (11) | 0.0507 (5) | |
H2 | 0.081 (3) | 0.121 (4) | 0.8364 (13) | 0.066* | |
C9 | 0.4632 (5) | 0.1632 (3) | 0.85544 (13) | 0.0507 (6) | |
O3 | 0.6921 (3) | 0.1383 (3) | 0.85408 (11) | 0.0694 (6) | |
O4 | 0.3633 (3) | 0.2988 (2) | 0.88774 (10) | 0.0644 (5) | |
N3 | 0.5616 (4) | 0.3975 (3) | 0.91066 (11) | 0.0584 (6) | |
C10 | 0.6574 (6) | 0.5138 (4) | 0.86724 (16) | 0.0653 (8) | |
O5 | 0.5707 (6) | 0.5414 (4) | 0.80823 (12) | 0.1015 (8) | |
C11 | 0.8740 (5) | 0.5889 (4) | 0.90923 (16) | 0.0725 (8) | |
H11A | 0.8381 | 0.6990 | 0.9161 | 0.094* | |
H11B | 1.0368 | 0.5789 | 0.8848 | 0.094* | |
C12 | 0.8908 (5) | 0.5049 (4) | 0.98018 (15) | 0.0709 (9) | |
H12A | 1.0620 | 0.4583 | 0.9879 | 0.092* | |
H12B | 0.8601 | 0.5769 | 1.0189 | 0.092* | |
C13 | 0.6842 (5) | 0.3813 (4) | 0.97655 (15) | 0.0606 (7) | |
O6 | 0.6276 (4) | 0.2834 (3) | 1.01994 (12) | 0.0886 (7) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.0311 (10) | 0.0514 (14) | 0.0686 (15) | 0.0023 (10) | −0.0046 (10) | 0.0046 (13) |
C2 | 0.0481 (14) | 0.079 (2) | 0.112 (2) | 0.0056 (15) | −0.0033 (14) | 0.042 (2) |
C3 | 0.0483 (13) | 0.0763 (19) | 0.0667 (17) | 0.0101 (14) | −0.0066 (11) | −0.0067 (16) |
C4 | 0.0622 (16) | 0.0658 (18) | 0.087 (2) | 0.0080 (15) | −0.0030 (14) | −0.0172 (18) |
O1 | 0.0290 (7) | 0.0590 (11) | 0.0718 (11) | 0.0008 (7) | 0.0004 (7) | 0.0189 (10) |
C5 | 0.0313 (12) | 0.0510 (15) | 0.0566 (13) | −0.0035 (10) | −0.0002 (9) | 0.0027 (12) |
O2 | 0.0287 (8) | 0.0807 (14) | 0.0947 (13) | −0.0057 (9) | 0.0038 (8) | 0.0272 (12) |
N1 | 0.0289 (8) | 0.0587 (13) | 0.0614 (12) | −0.0017 (9) | 0.0021 (8) | 0.0118 (11) |
C6 | 0.0411 (11) | 0.0487 (14) | 0.0564 (13) | −0.0054 (11) | 0.0004 (10) | 0.0034 (13) |
C7 | 0.103 (2) | 0.0571 (19) | 0.079 (2) | −0.0039 (17) | −0.0194 (17) | −0.0078 (17) |
C8 | 0.0413 (11) | 0.0508 (15) | 0.0531 (13) | 0.0011 (11) | 0.0014 (9) | 0.0025 (12) |
N2 | 0.0334 (10) | 0.0598 (14) | 0.0589 (12) | 0.0016 (9) | 0.0003 (8) | −0.0079 (11) |
C9 | 0.0413 (13) | 0.0609 (17) | 0.0498 (13) | 0.0011 (12) | 0.0015 (10) | −0.0048 (12) |
O3 | 0.0344 (9) | 0.0810 (14) | 0.0929 (14) | 0.0008 (9) | 0.0027 (8) | −0.0244 (12) |
O4 | 0.0463 (9) | 0.0648 (13) | 0.0819 (12) | 0.0027 (9) | −0.0021 (8) | −0.0224 (11) |
N3 | 0.0545 (12) | 0.0590 (14) | 0.0613 (13) | −0.0045 (11) | −0.0046 (10) | −0.0099 (12) |
C10 | 0.0690 (17) | 0.0602 (19) | 0.0667 (18) | 0.0091 (15) | 0.0035 (13) | −0.0066 (16) |
O5 | 0.130 (2) | 0.099 (2) | 0.0745 (14) | 0.0048 (16) | −0.0167 (14) | 0.0116 (15) |
C11 | 0.0668 (17) | 0.065 (2) | 0.086 (2) | −0.0044 (15) | 0.0131 (14) | −0.0089 (18) |
C12 | 0.0575 (15) | 0.091 (2) | 0.0638 (17) | −0.0073 (16) | 0.0008 (12) | −0.0215 (18) |
C13 | 0.0527 (14) | 0.072 (2) | 0.0568 (15) | 0.0036 (14) | 0.0036 (12) | −0.0066 (16) |
O6 | 0.0862 (14) | 0.108 (2) | 0.0720 (14) | −0.0075 (14) | 0.0033 (11) | 0.0133 (15) |
Geometric parameters (Å, º) top
C1—O1 | 1.479 (3) | C7—H7B | 0.9600 |
C1—C4 | 1.507 (4) | C7—H7C | 0.9600 |
C1—C2 | 1.507 (4) | C8—N2 | 1.454 (3) |
C1—C3 | 1.511 (3) | C8—H8A | 0.9700 |
C2—H2A | 0.9600 | C8—H8B | 0.9700 |
C2—H2B | 0.9600 | N2—C9 | 1.321 (3) |
C2—H2C | 0.9600 | N2—H2 | 1.016 (10) |
C3—H3A | 0.9600 | C9—O3 | 1.194 (3) |
C3—H3B | 0.9600 | C9—O4 | 1.415 (3) |
C3—H3C | 0.9600 | O4—N3 | 1.379 (3) |
C4—H4A | 0.9600 | N3—C13 | 1.374 (3) |
C4—H4B | 0.9600 | N3—C10 | 1.387 (4) |
C4—H4C | 0.9600 | C10—O5 | 1.202 (4) |
O1—C5 | 1.346 (3) | C10—C11 | 1.486 (4) |
C5—O2 | 1.210 (3) | C11—C12 | 1.513 (4) |
C5—N1 | 1.336 (3) | C11—H11A | 0.9700 |
N1—C6 | 1.451 (3) | C11—H11B | 0.9700 |
N1—H1 | 1.010 (10) | C12—C13 | 1.498 (4) |
C6—C7 | 1.516 (4) | C12—H12A | 0.9700 |
C6—C8 | 1.521 (3) | C12—H12B | 0.9700 |
C6—H6 | 0.9800 | C13—O6 | 1.210 (4) |
C7—H7A | 0.9600 | | |
| | | |
O1—C1—C4 | 110.2 (2) | H7A—C7—H7B | 109.5 |
O1—C1—C2 | 102.08 (17) | C6—C7—H7C | 109.5 |
C4—C1—C2 | 110.5 (3) | H7A—C7—H7C | 109.5 |
O1—C1—C3 | 110.2 (2) | H7B—C7—H7C | 109.5 |
C4—C1—C3 | 112.3 (2) | N2—C8—C6 | 111.7 (2) |
C2—C1—C3 | 111.1 (2) | N2—C8—H8A | 109.3 |
C1—C2—H2A | 109.5 | C6—C8—H8A | 109.3 |
C1—C2—H2B | 109.5 | N2—C8—H8B | 109.3 |
H2A—C2—H2B | 109.5 | C6—C8—H8B | 109.3 |
C1—C2—H2C | 109.5 | H8A—C8—H8B | 107.9 |
H2A—C2—H2C | 109.5 | C9—N2—C8 | 122.2 (2) |
H2B—C2—H2C | 109.5 | C9—N2—H2 | 118.2 (17) |
C1—C3—H3A | 109.5 | C8—N2—H2 | 119.5 (17) |
C1—C3—H3B | 109.5 | O3—C9—N2 | 129.9 (2) |
H3A—C3—H3B | 109.5 | O3—C9—O4 | 121.8 (2) |
C1—C3—H3C | 109.5 | N2—C9—O4 | 108.29 (19) |
H3A—C3—H3C | 109.5 | N3—O4—C9 | 111.27 (17) |
H3B—C3—H3C | 109.5 | C13—N3—O4 | 121.8 (2) |
C1—C4—H4A | 109.5 | C13—N3—C10 | 116.2 (2) |
C1—C4—H4B | 109.5 | O4—N3—C10 | 121.9 (2) |
H4A—C4—H4B | 109.5 | O5—C10—N3 | 123.7 (3) |
C1—C4—H4C | 109.5 | O5—C10—C11 | 130.4 (3) |
H4A—C4—H4C | 109.5 | N3—C10—C11 | 105.9 (2) |
H4B—C4—H4C | 109.5 | C10—C11—C12 | 106.2 (3) |
C5—O1—C1 | 121.10 (16) | C10—C11—H11A | 110.5 |
O2—C5—N1 | 124.8 (2) | C12—C11—H11A | 110.5 |
O2—C5—O1 | 125.1 (2) | C10—C11—H11B | 110.5 |
N1—C5—O1 | 110.03 (17) | C12—C11—H11B | 110.5 |
C5—N1—C6 | 122.14 (18) | H11A—C11—H11B | 108.7 |
C5—N1—H1 | 113.6 (17) | C13—C12—C11 | 106.1 (2) |
C6—N1—H1 | 123.9 (17) | C13—C12—H12A | 110.5 |
N1—C6—C7 | 111.9 (2) | C11—C12—H12A | 110.5 |
N1—C6—C8 | 109.31 (19) | C13—C12—H12B | 110.5 |
C7—C6—C8 | 110.0 (2) | C11—C12—H12B | 110.5 |
N1—C6—H6 | 108.5 | H12A—C12—H12B | 108.7 |
C7—C6—H6 | 108.5 | O6—C13—N3 | 124.2 (3) |
C8—C6—H6 | 108.5 | O6—C13—C12 | 130.1 (3) |
C6—C7—H7A | 109.5 | N3—C13—C12 | 105.7 (3) |
C6—C7—H7B | 109.5 | | |
| | | |
O1—C5—N1—C6 | −177.9 (2) | O3—C9—O4—N3 | 4.7 (3) |
C5—N1—C6—C8 | −139.7 (2) | C9—O4—N3—C13 | −86.4 (3) |
N1—C6—C8—N2 | 55.9 (3) | C13—N3—C10—O5 | 179.8 (3) |
C6—C8—N2—C9 | −141.7 (2) | O4—N3—C10—O5 | 2.8 (4) |
C8—N2—C9—O4 | 179.76 (19) | C13—N3—C10—C11 | −0.6 (3) |
N2—C9—O4—N3 | −177.1 (2) | O4—N3—C10—C11 | −177.5 (2) |
C9—O4—N3—C10 | 90.4 (3) | O5—C10—C11—C12 | 179.4 (3) |
C4—C1—O1—C5 | 58.6 (3) | N3—C10—C11—C12 | −0.2 (3) |
C2—C1—O1—C5 | 176.0 (2) | C10—C11—C12—C13 | 0.8 (3) |
C3—C1—O1—C5 | −65.8 (3) | O4—N3—C13—O6 | −1.5 (4) |
C1—O1—C5—O2 | 9.5 (4) | C10—N3—C13—O6 | −178.4 (3) |
C1—O1—C5—N1 | −170.7 (2) | O4—N3—C13—C12 | 178.0 (2) |
O2—C5—N1—C6 | 1.9 (4) | C10—N3—C13—C12 | 1.1 (3) |
C5—N1—C6—C7 | 98.2 (3) | C11—C12—C13—O6 | 178.3 (3) |
C7—C6—C8—N2 | 179.2 (2) | C11—C12—C13—N3 | −1.1 (3) |
C8—N2—C9—O3 | −2.2 (4) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O2i | 1.01 (1) | 2.04 (2) | 2.938 (2) | 147 (2) |
N2—H2···O3ii | 1.02 (1) | 2.04 (1) | 3.022 (3) | 162 (3) |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z. |
Experimental details
Crystal data |
Chemical formula | C13H21N3O6 |
Mr | 315.33 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 293 |
a, b, c (Å) | 5.1260 (2), 8.5650 (4), 18.7540 (9) |
β (°) | 91.996 (3) |
V (Å3) | 822.88 (6) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.3 × 0.25 × 0.22 |
|
Data collection |
Diffractometer | KappaCCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5236, 1792, 1436 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.623 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.097, 1.03 |
No. of reflections | 1792 |
No. of parameters | 205 |
No. of restraints | 3 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.11, −0.17 |
Selected torsion angles (º) topO1—C5—N1—C6 | −177.9 (2) | C8—N2—C9—O4 | 179.76 (19) |
C5—N1—C6—C8 | −139.7 (2) | N2—C9—O4—N3 | −177.1 (2) |
N1—C6—C8—N2 | 55.9 (3) | C9—O4—N3—C10 | 90.4 (3) |
C6—C8—N2—C9 | −141.7 (2) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O2i | 1.010 (10) | 2.037 (18) | 2.938 (2) | 147 (2) |
N2—H2···O3ii | 1.016 (10) | 2.038 (14) | 3.022 (3) | 162 (3) |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z. |
Unnatural biopolymers with a urea backbone, such as N,N-linked oligoureas [N(CONHR)-(CH2)m–]n (Nowick, 1999), N,N'-linked oligoureas [NH-CHR-CH2—NH—CO–]n (Burgess et al., 1995, 1997; Kim et al., 1996; Boeijen & Liskamp, 1999; Guichard et al. 1999, 2000; Tamilarasu et al., 1999), ureidopeptoids [NR—CH2—CH2—NH—CO–]n (Kruijtzer et al., 1997; Wilson & Nowick, 1998) and oligomeric cyclic ureas (Kim et al., 1996) have been described recently as peptide backbone mimetics or as template for the creation of artificial β-sheets. The urea fragment appears particularly promising for drug discovery because of its expected metabolic stability and interesting hydrogen-bonding properties. We have recently reported a simple and effective synthesis of O-succinimidyl 2-(tert-butoxycarbonylamino)-2-subsituted-ethylcarbamate derivatives starting from the corresponding N-protected β-amino acids and their use as activated monomers in the synthesis of di- and trisubstituted ureas and N,N'-linked oligoureas (Guichard et al., 1999). These derivatives are stable compounds that react readily with amines to form substituted ureas. Furthermore, the mild conditions required for their preparation are compatible with most functionalized side chains of amino acids as well as with standard protecting groups used in solid-phase peptide synthesis (Guichard et al., 2000). Herein, we report the crystal structure of (S)—O-succinimidyl N-[2-(tert-butoxycarbonylamino)propyl]carbamate, (I), which was prepared in three steps from Boc-(S)-β3HAla-OH.
Bond distances and angles of the succinimide ring are in good agreement with those recently published by Tenon et al. (2000) and Guichard et al. (1999) for N-methylsuccinimide and O-succinimidyl (2-nitrophenyl)carbamate, respectively. The succinimide ring in (I) is nearly planar, like in the unsubstituted succinimide (Mason, 1961) and O-succinimidyl (2-nitrophenyl)carbamate (Guichard et al., 1999) molecules. Indeed, the puckering parameters of the succinimide ring in the title compound are q = 0.010 Å and ϕ2 = 314.0° for the sequence N3—C10—C11—C12—C13 (Cremer & Pople, 1975).
The molecule (Fig. 1 and Table 1) assumes a folded shape with the gauche conformation about the central C6—C8 bond in the main chain, the N1—C6—C8—N2 torsion angle being equal to 55.9 (3)°. The molecules of the title compound in the crystal are linked into the infinite chains via C═O···H—N hydrogen bonds (Table 2). The chains are stretched along the [100] direction and form parallel β sheet-like arrangement. All interactions between the chains are purely van der Waals in nature.