J Chem Crystallogr (2009) 39:372–376 DOI 10.1007/s10870-008-9489-5
ORIGINAL PAPER
Crystal Structures of a Series of Bis{(2-Aminobenzoyl-)amino} alkanes Valerio Bertolasi Æ Naomi Hunter Æ Keith Vaughan
Received: 26 August 2008 / Accepted: 9 October 2008 / Published online: 23 October 2008 Ó Springer Science+Business Media, LLC 2008
Abstract The crystal structures of 1,2-bis-{(2-aminobenzoyl-)amino}ethane(1), 1,4-bis-{(2-aminobenzoyl-)amino} butane(2) and 2,2-dimethyl-1,3-bis-{(2-aminobenzoyl-)amino} -propane(3) have been determined by single crystal X-ray diffraction analysis. 1 and 2 are centrosymmetric molecules which lie on crystallographic centers of symmetry and adopt extended conformations. On the other hand, owing to the odd number of carbon atoms in the spacer unit, 3 does not show centrosymmetry, but crystallizes in a non-centrosymmetric space group and assumes a folded conformation. The crystal structures of 1, 2 and 3 are compared with the known structures of anthranilamide (7) and the N-alkyl anthranilamide derivative 8. Crystal data: 1 C16H18N4O2, monoclinic, ˚ , b = 5.4200(5) A ˚,c = space group P21/a, a = 9.5262(8) A ˚ ˚ 3, 15.3821(14) A, b = 105.980(5)° and V = 763.52(12) A for Z = 2. 2 C18H22N4O2, monoclinic, space group C2/c, ˚ , b = 5.4732(4) A ˚ , c = 9.7326(5) A ˚, a = 32.0710(17) A 3 ˚ b = 102.570(4)° and V = 1667.42(17) A , for Z = 4. 3 C19H24N4O2, orthorhombic, space group Pca21, a = ˚ , b = 10.1847(2) A ˚ , c = 10.5338(5) A ˚ , and 16.7676(4) A ˚ 3, for Z = 4. V = 1798.89(7) A
V. Bertolasi Dipartimento di Chimica, Centro di Strutturistica Diffrattometrica, Universita’ di Ferrara, Via L. Borsari, 46, 44100 Ferrara, Italy N. Hunter K. Vaughan (&) Department of Chemistry, Saint Mary’s University, Halifax, NS, Canada e-mail:
[email protected]
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Keywords Benzamide 2-Aminobenzamide Anthranilamide Bis-benzamide X-ray
Introduction This paper describes the X-ray crystallographic study of the compounds 1, 2 and 3. Compounds 1, 2 and 3 are essentially bis-{(2-aminobenzoyl-)amino}alkanes, which differ in the length and the degree of branching of the carbon spacer between the amide end-groups. These bisamides were originally synthesized as precursors of the bis-(4-oxo-1,2,3-benzotriazin-3-yl-)alkanes series 4; bisdiazotization of either 1, 2 or 3 affords the bis-benzotriazinone (4) [1]. It was of interest to undertake a crystallographic study of the bis-amides, 1, 2 and 3, in order to see what effect the spacer group would have on the tendency of these molecules to adopt linear or folded conformations. Previous crystallographic studies of simple N-alkyl-2aminobenzamides (5) are quite rare. Murakami et al. [2] investigated the structure of (2R,3S)-2-(3S)-3-((2-amino5-chlorophenyl)carboxamido-1,1-dimethyl-2-oxobutyl)-3methyl-4-oxo-oxetane (ÒBelactin A), a beta-lactonecontaining serine carboxypeptidase inhibitor, and Gulbis et al. [3] reported the X-ray structure of 2-aminoN-(2,3,4,5-tetrahydro-2,5-dioxo-1H-1-benzazepin-3-yl) benzamide (8). There are several reported crystal structures of N-aryl-2-aminobenzamides (6) [4] and one report of the crystal structure of o-aminobenzamide itself (7) [5]. The benzazepine derivative (8) was chosen for comparison with compounds 1, 2 and 3, which are also compared with the unsubstituted molecule (7).
J Chem Crystallogr (2009) 39:372–376
373
NH2
Crystallography
NH2 H N
H N
(CH2)n
C
C 1 n=2
O
O
2 n=4 NH2
NH2 CH3 H N
C
CH3 H N
C C H2
C H2
C
3
O
O
O NH2
O
H N
X N
N
N
C
N
N
R
O
N
Results and Discussion
5 R=alkyl 6 R=aryl 7 R=H
4
ORTEP [10] views of compounds 1, 2 and 3 are shown in Figs. 1a, 2a and 3a. 1 and 2 are centrosymmetric molecules which lie on crystallographic centres of symmetry and adopt extended conformations. Conversely, owing to the odd number of the carbon atom chain C8–C9–C10 linking the amide groups, 3 does not show centrosymmetry, crystallizes in a non-centrosymmetric space group
O
O C
NH
N H O NH2
Table 1 Crystal data
X-ray diffraction data were collected on a Nonius Kappa CCD diffractometer with graphite monochromated Mo ˚ ). Data sets were integrated Ka radiation (k = 0.7107 A with Denzo-SMN package [6]. The structures were solved by direct methods (SIR97) [7] and refined (SHELXL-97) [8] by full matrix least squares with anisotropic non-H and isotropic hydrogen atoms. All other calculations were accomplished using the system of programs PARST [9]. Crystal data are given in Table 1. Selected bond distances and angles and hydrogen bond parameters are shown in Tables 2 and 3, respectively.
8
Compound
1
Formula
C16H18N4O2
C18H22N4O2
C19H24N4O2
Mr
298.34
326.40
340.42
2
3
Crystal system
Monoclinic
Monoclinic
Orthorhombic
Space group ˚) a (A
P21/a (N.14)
C2/c (N.15)
Pca21 (N.29)
˚) b (A ˚ c (A)
9.5262(8)
32.0710(17)
16.7676(4)
5.4200(5)
5.4732(4)
10.1847(2)
15.3821(14)
9.7326(5)
10.5338(5)
b (°) ˚ 3) V (A
105.980(5)
102.570(4)
90
763.52(12)
1667.42(17)
1798.89(7)
Z
2
4
4
Dc (g-3 cm)
1.298
1.300
1.257
F(000)
316
696
728
l (cm-1)
0.89
0.87
0.84
Temperature (K)
295
295
295
Crystal form, colour
Prism, colorless
Prism, colorless
Prism, colorless
Crystal size (mm)
0.41 9 0.34 9 0.12
0.34 9 0.12 9 0.10
0.50 9 0.31 9 0.19
hmin–hmax (°)
4.0–27.0
3.8–27.0
4.9–30.0
h,k,l range
-11,12; -6,5; -19,19
-39,40; -6,6; -12,12
-23,23; -14,14; -14,14
Unique reflections
1,642
1,809
2,740
Rint
0.050
0.041
0.033
Obs. reflections [I C 2r(I)]
1163
1273
2309
R(F2) (Obs. reflections)
0.057
0.044
0.034
wR(F2) (All reflections)
0.169
0.129
0.089
No. parameters
137
154
322
GOF
1.05
1.04
1.02
Dqmin, Dqmax
-0.190, 0.194
-0.162, 0.163
-0.127, 0.114
CCDC deposition number
697643
697737
697738
123
374
J Chem Crystallogr (2009) 39:372–376
˚ and °) Table 2 Selected geometrical parameters (A 1
2
3
Bond lengths N1–C2
1.370(3)
1.368(2)
1.363(3)
C1–C2
1.413(3)
1.415(2)
1.408(2)
C1–C7
1.483(3)
1.489(2)
1.498(2)
O1–C7
1.243(2)
1.240(2)
1.233(2)
N2–C7
1.334(2)
1.338(2)
1.339(2)
N2–C8
1.455(3)
1.456(2)
1.457(2)
N4–C13
1.364(3)
C12–C13
1.419(2)
C11–C12
1.481(3)
O2–C11 N3–C11
1.246(2) 1.350(2)
N3–C10
1.453(2)
Bond angles N1–C2–C1
122.4(2)
122.3(1)
122.9(2)
C2–C1–C7
119.9(2)
120.5(1)
120.5(1)
O1–C7–C1
121.8(2)
122.3(1)
121.5(2)
O1–C7–N2
121.0(2)
120.2(1)
121.5(2)
C7–N2–C8
123.8(2)
121.7(1)
124.2(2)
N4–C13–C12
122.3(2)
C11–C12–C13
120.0(2)
O2–C11–C12
122.0(2)
O2–C11–N3
120.4(2)
C10–N3–C11
123.2(2)
Torsion angles C2–C1–C7–N2
149.3(2)
-155.6(1)
-168.6(2)
C1–C7–N2–C8 C7–N2–C8–C80
178.0(2)
-171.2(1)
176.2(2)
C7–N2–C8–C9
165.6(1)
112.3(2)
N2–C8–C9–C90
-179.1(1)
-110.8(2)
C8–C9–C10–N3
55.3(2)
C9–C10–N3–C11
-100.3(2)
Fig. 1 a ORTEP view of compound 1 showing the thermal ellipsoids at 30% probability level. b The hydrogen bond scheme for compound 1
and assumes a folded conformation. All compounds display intramolecular hydrogen bonds between the o-amino and the amide groups with N1O1 and N4O2 dis˚ , very similar to tances, in the range 2.662(3)–2.747(2) A those found in several other o-amino-benzamide derivatives [3–5]. In 1 and 2 the amide groups, related by a centre of symmetry, form in the crystals antidromic H-bond chains (Figs. 1b, 2b) where each molecule is linked to four other molecules. Conversely, in 3, an amido NH moiety is involved in an intramolecular hydrogen bond with the oxygen atom O2 of the other amide, while
C10–N3–C11–C12
179.3(2)
Table 3 Hydrogen bond parameters
Symm. Op.
˚) D–H (A
0.89(3)
2.02(3)
2.729(3)
136(2)
1/2 ? x, 1/2 - y, z
0.93(3)
1.92(3)
2.787(2)
154(2)
0.94(2)
2.04(2)
2.747(2)
131(2)
0.85(2)
2.03(2)
2.858(2)
162(2)
N1–H1AO1
0.88(4)
1.99(3)
2.662(3)
133(3)
N2–H2O2
0.90(3)
2.08(2)
2.880(2)
147(2)
N4–H4BO2
0.94(3)
1.98(3)
2.701(3)
132(2)
0.88(4)
2.14(4)
2.940(2)
150(3)
˚) HA (A
˚) DA (A
D–HA (°)
1 N1–H1BO1 N2–H2O1 2 N1–H1BO1 N2–H2O1
x, 1 - y, 1/2 ? z
3
N4–H4AO1
123
2 - x, 1 - y, z - 1/2
J Chem Crystallogr (2009) 39:372–376
375 Table 4 Comparison of bond lengths, bond angles and H-bond parameters in 1, 7 and 8 1
7a
8b
C1–C2
1.413(3)
1.414(3)
1.406(6)
C1–C7
1.483(3)
1.480(3)
1.489(7)
N1–C2
1.370(3)
1.391(3)
1.390(8)
O1–C7
1.243(2)
1.240(3)
1.226(7)
N2–C7
1.334(2)
1.327(3)
1.335(6)
Parameter ˚) Bond length (A
N2–C8
1.455(3)
–
1.453(7)
Angle (°) N1–C2–C1
122.4(2)
121.8(2)
120.9(4)
C2–C1–C7
119.9(2)
120.9(2)
121.4(4)
O1–C7–C1
121.8(2)
120.6(2)
122.5(3)
O1–C7–N2
121.0(2)
121.3(2)
121.1(3)
C7–N2–C8
123.8(2)
–
121.3(3)
˚) N1O1 H-bond (A
2.729(3)
2.749(3)
2.829(3)
N1–HO1 angle (°)
136(2)
115(2)
H-bonding parameter
Fig. 2 a ORTEP view of compound 2 showing the thermal ellipsoids at 30% probability level. b The hydrogen bond scheme for compound 2
Fig. 3 a ORTEP view of compound 3 showing the thermal ellipsoids at 30% probability level. b The hydrogen bond scheme for compound 3
a
Ref. [5]
b
Ref. [3]
128
the packing is assured by helical arrangement of the molecules linked by intermolecular N4–HO1 H-bonds (Fig. 3b). The amide moieties exhibit the well known electron delocalisation, where the carbonyl C=O distances, in the ˚ , show a significant elongation range 1.233(2)–1.246(2) A with respect to C=O bonds in aldehydes and ketones of ˚ , [11] while the adjacent C–N distances, in the about 1.20 A ˚ , display a shortening with range 1.334(2)–1.350(2) A ˚ respect to the standard C(sp2)–N(sp2) bond of 1.355 A [11]. The shorter intermolecular N2O1 H-bond distances ˚ , in 1 and 2, with respect to of 2.787(2) and 2.858(2) A ˚ N4O1 in 3 of 2.940(2) A, can be imputed to the cooperative effect in amide hydrogen bonding chains [12, 13]. Interactions of this type have been referred to as resonance assisted hydrogen bonds (RAHB) [14, 15]. Table 4 gives a list of selected bond lengths, bond angles and hydrogen bond parameters of compound 1, compared with the same data observed for anthranilamide (7) [5] and the N-alkyl-anthranilamide (8) [3]. With a little variation, there is excellent agreement in the bond lengths in the three compounds. The exception is the carbonyl group {O1–C7}, which is significantly shorter in compound 8. The crucial bond angles in the zone between N1 and N2 show a significant variation leading to the general observation that the bond angles C2–C1– C7 and O1–C7–C1 are larger in compound 8. In other words, the six-membered ring bounded by O1–C7–C1– C2–N1–H1B is opened up in 8, compared with 1 and 7.
123
376
J Chem Crystallogr (2009) 39:372–376
O
N C
H N H C
NH2
O
NH2
Centre and allocated the deposition numbers CCDC 697643 (1), 697737 (2) and 697738 (3). These data can be obtained free of charge via www.ccdc.cam.ac.uk/conts/ retrieving.html or on application to CCDC, Union Road, Cambridge CB2 1EZ, UK (fax: ?44-1223-336033, e-mail:
[email protected]). Acknowledgements The authors are grateful to the Natural Sciences and Engineering Research Council of Canada (NSERC) for a Discovery Grant to the principal author (KV) and an undergraduate Summer Research Award to Naomi Hunter. The authors thank the Faculty of Graduate Studies and Research at Saint Mary’s University for on-going financial support.
Fig. 4 Hypothetical folded conformation of a molecule of compound 2
References
This hypothesis is confirmed by the comparison of the H-bond parameters. The N1O1 H-bond distance is significantly larger in 8 than in 1 or 7. The angle of the N1–HO1 H-bond is much less in the unsubstituted anthranilamide (7) than it is in the N-alkyl derivatives, 1 and 8.
1. Hunter N, Vaughan K (2006) J Heterocycl Chem 43:1 2. Murakami S, Takahashi Y, Takeuchi T, Kodama Y, Aoyagi T (1999) J Enzyme Inhib 14:437 3. Gulbis JM, Mackay MF, Rivett DE (1990) Acta Crystallogr C 46:829. doi:10.1107/S0108270189009601 4. Wiesbrock F, Schmidbaur H (2004) J Inorg Biochem 98:473. doi: 10.1016/j.jinorgbio.2003.12.017 5. Kashino S, Tateno S, Tanabe H, Haisa M, Katsube Y (1991) Acta Crystallogr C 47:2236. doi:10.1107/S0108270191004067 6. Otwinowski Z, Minor W (1997) In: Carter CW, Sweet RM (eds) Methods in enzymology, vol 276 part A. Academic Press, London, pp 307–326 7. Altomare A, Burla MC, Camalli M, Cascarano GL, Giacovazzo C, Guagliardi C, Moliterni AG, Polidori G, Spagna R (1999) J Appl Crystallogr 32:115. doi:10.1107/S0021889898007717 8. Sheldrick GM (1997) SHELXL-97, program for refinement of crystal structures. University of Go¨ttingen, Germany 9. Nardelli M (1995) J Appl Crystallogr 28:659. doi:10.1107/S002 1889895007138 10. Burnett MN, Johnson CK (1996) ORTEP-III, report ORNL-6895. Oak Ridge National Laboratory, Oak Ridge, TN 11. Allen FH, Kennard O, Watson DG, Brammer L, Orpen AG, Taylor R (1987) J Chem Soc Perkin Trans 2:S1–S19. doi:10.1039/ p298700000s1 12. Kobko N, Paraskevas L, del Rio E, Dannenberg JJ (2001) J Am Chem Soc 123:4348. doi:10.1021/ja004271l 13. Kobko N, Dannenberg JJ (2003) J Phys Chem A 107:10389. doi: 10.1021/jp0365209 14. Gilli G, Bellucci F, Ferretti V, Bertolasi V (1989) J Am Chem Soc 111:1023. doi:10.1021/ja00185a035 15. Bertolasi V, Gilli P, Ferretti V, Gilli G (1995) Acta Crystallogr B 51:1004. doi:10.1107/S0108768195004009
Conclusion Compounds 1 and 2 exhibit extended conformations in the solid state, whereas compound 3 has a definite folded conformation, which is attributed to the odd-number of carbon atoms in the spacer in 3. It was a little surprising to find that the molecule of compound 2 showed no tendency towards a folded conformation, such as the one shown crudely in Fig. 4. Such a conformation might be favoured by two factors: (a) the p–p stacking between the phenyl groups, and (b) the intramolecular N–HN Hbond. Evidently, the antidromic H-bond chains shown in Fig. 2b are sufficiently energetic to overcome any benefit from p–p stacking in the form of Fig. 4.
Supplementary Material Crystallographic data (excluding structure factors) have been deposited with the Cambridge Crystallographic Data
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