organic compounds Dimethyl (1-methyl-1,3-benzimidazol- 5-yl)aminomethylenepropanedioate monohydrate Comment

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1 organic compounds Acta Crystallographica Section C Crystal Structure Communications ISSN Dimethyl (1-methyl-1,3-benzimidazol- 5-yl)aminomethylenepropanedioate monohydrate Viktor Kettmann, a * Jan Lokaj, b Christoph Kratky, c Viktor Milata b and Pavol Hodul b a Faculty of Pharmacy, Comenius University, Odbojarov 10, Bratislava 83232, Slovak Republic, b Faculty of Chemical Technology, Slovak Technical University, Radlinskeho 9, Bratislava 81237, Slovak Republic, and c Institut fuèr Physikalische Chemie, Karl-Franzens-UniversitaÈt Graz, Heinrichstrasse 28, Graz 8010, Austria Correspondence kettmann@fpharm.uniba.sk Received 10 February 2000 Accepted 8 May 2000 In the title compound, C 14 H 15 N 3 O 4 H 2 O, there is a strong conjugation push±pull effect across the central double bond, as re ected in the molecular dimensions and the planarity of the enaminone portion of the molecule. The molecule has an intramolecular hydrogen bond between the NH and CO groups in the Z con guration, adopting the chelated form. The two systems of the molecule (1-methylbenzimidazole and enaminone) are deconjugated and tilted with respect to each other by 15.6 (2). The solvent water molecule is hydrogen bonded to the N 1 atom of the 1-methylbenzimidazolyl group. Comment Benzimidazole derivatives having carboxylate group(s) bonded to various positions of the heterocyclic ring are known as orally active non-peptide angiotensin II receptor antagonists with clinical use in the treatment of hypertension and congestive heart failure (Duncia et al., 1992). Some of these compounds have also been found to antagonize the vascular constrictor and platelet-aggregating effects of thromboxanes, which make them useful in the treatment of a variety of cardiovascular, renal and respiratory diseases (Nicolai et al., 1993). One point of interest in the present structure, (I), was therefore the disposition of the functional (pharmacophoric) groups which, in turn, is determined by the () electronic structure of the molecule. Another point of interest stems from the fact that compound (I) chemically belongs to the push±pull ethylenes, a class of compounds with an unusually low rotational barrier around the C C double bond with an absorption in the near-uv and visible regions due to delocalization of electrons. Consequently, it is of interest to examine the extent of conjugation in the title molecule by a combined use of theoretical and experimental methods. In this communication, we report on the crystal structure of (I). An ORTEPII (Johnson, 1976) view of the molecule is shown in Fig. 1. All bond distances and angles within the 1- methylbenzimidazolyl part of the molecule are normal and close to those found for unsubstituted 1-methylbenzimidazole (Dik-Edixhoven et al., 1973; Hamilton et al., 1979; Rapta et al., 1995). The ring is planar within the limits of experimental error [r.m.s. deviation (3) A Ê ]. As mentioned above, the () electronic structure of the `enaminone' portion of the molecule is of prime interest here. As judged from the pattern of bond lengths (Table 1), there is extensive -electron delocalization involving the donor aminic nitrogen and the acceptor methoxycarbonyl groups. The C11 C12 bond length of (4) A Ê is considerably longer than the reported value of (6) A Ê in unpolarized ethylene (van Nes & Vos, 1977). There is a corresponding reduction in the length of the donorethylenic and acceptor-ethylenic bonds: the N10ÐC11 distance is (4) A Ê, which is much shorter than a value of (3) A Ê found for a pure Csp 2 ÐNsp 2 single bond (Adler et al., 1976). On the acceptor side, the C12ÐC13 and C12ÐC17 bond distances of (4) and (4) A Ê, respectively, are signi cantly shorter than the value of (5) A Ê reported for acsp 2 ÐCsp 2 single bond (Shmueli et al., 1973). These facts indicate that the structure of this molecular fragment cannot be expressed by a single canonical formula; consequently, there is structural evidence that forms (Ia)±(Ic) contribute to the electronic structure of the enaminone portion of the molecule. The high degree of conjugation across the ethylenic bond is also seen in near coplanarity of the ester groups with the plane of the C C bond (atoms N10, C11, H11, C12, C13 and C17); the dihedral angles of the ester groups with the double-bond plane are 1.8 (3) and 14.9 (3) for C13/O14/O15/C16, and C17/O18/O19/C20, respectively. Although both ester groups are nearly coplanar with the C C plane, their conformation is different; while the carbonyl bond of the former ester group (Z to the amine nitrogen) is oriented syn to the C C bond, the conformation of the latter (E to N10) is anti (Fig. 1). The reason for the syn conformation of the Z methoxycarbonyl group is most likely formation of an intramolecular hydrogen bond between N10 and O14 [N10ÐHO14: NÐH 0.86, HO 1.99, NO (4) A Ê and NÐHO 132 ]. The twist about the ethylenic bond, as measured by the angle between the N10/C11/H11 and C12/C13/C17 planes is also small [2.9 (6) ]. Thus, the molecule as a whole consists of two planar systems, which are mutually deconjugated, as shown by the C5ÐN10 bond length [1.418 (4) A Ê ] approximating the Csp 2 Ð N single bond [1.425 (3) A Ê ; Adler et al., 1976]. The angle Acta Cryst. (2000). C56, 1007±1008 # 2000 International Union of Crystallography Printed in Great Britain ± all rights reserved 1007

2 organic compounds between the mean planes through the two planar segments is, however, small [15.8 (2) ]. The molecules related by the twofold axes associate in pairs in an antiparallel fashion due to face-to-face stacking interactions acting between the terminal 1-methylimidazole moieties. The overlapping geometry of the molecules in the dimers is in line with the model of ± interactions presented by Hunter & Saunders (1990). As the only hydrogen-bond donor of the molecule (N10ÐH) is involved in the intramolecular hydrogen-bond interaction, the dimers are packed by van der Waals forces. The solvent water molecule is held in the crystal by a hydrogen bond which it forms with the N3 atom of the 1-methylbenzimidazole moiety [OWÐHN3: OÐH 0.84, HN 2.10, ON (4) A Ê and OÐHN 170 ]. Re nement Re nement on F 2 R(F ) = wr(f 2 ) = S = re ections 199 parameters Table 1 Selected geometric parameters (A Ê, ). N1ÐC (4) N1ÐC (4) C2ÐN (4) N3ÐC (4) C5ÐN (4) C2ÐN1ÐC (3) N3ÐC2ÐN (3) C2ÐN3ÐC (3) N1ÐC8ÐC (3) C8ÐC9ÐN (3) C11ÐN10ÐC (3) N10ÐC11ÐC (3) H atoms: see below w = 1/[ 2 (F o 2 ) + (0.1223P) 2 ] where P =(F o 2 +2F c 2 )/3 (/) max = max = 0.35 e A Ê 3 min = 0.28 e A Ê 3 C8ÐC (4) N10ÐC (4) C13ÐO (4) C17ÐO (3) O14ÐC13ÐO (3) O14ÐC13ÐC (3) O15ÐC13ÐC (3) O18ÐC17ÐO (3) O18ÐC17ÐC (3) O19ÐC17ÐC (3) C4ÐC5ÐN10ÐC (5) C5ÐN10ÐC11ÐC (3) N10ÐC11ÐC12ÐC (5) C11ÐC12ÐC13ÐO (5) C12ÐC13ÐO15ÐC (3) C11ÐC12ÐC17ÐO (3) C12ÐC17ÐO19ÐC (3) Figure 1 A view of the title molecule showing the labelling of the non-h atoms. Displacement ellipsoids are shown at the 35% probability level and H atoms are drawn as small circles of arbitrary radii. Experimental 5-Nitro-1-methylbenzimidazole (10 mmol) in ethanol was hydrogenated at 120 kpa on Raney nickel until 660 ml of hydrogen was consumed. After the catalyst was ltered off, dimethyl methoxymethylenepropanedioate (10 mmol) was added and the mixture was re uxed for 30 min. The mixture was boiled brie y with charcoal, ltered, the majority of solvent evaporated, the separated product ltered off and nally washed with cold ethanol. Crystallization from ethanol/water (4:1 v/v) afforded an analytically pure product (m.p. 451±452 K). Crystal data C 14 H 15 N 3 O 4 H 2 O M r = Monoclinic, C2=c a = (8) A Ê b = (3) A Ê c = (5) A Ê = (4) V = 2939 (2) A Ê 3 Z =8 D x = Mg m 3 D m = 1.39 (1) Mg m 3 Data collection Siemens P4 diffractometer!/2 scans 2734 measured re ections 2592 independent re ections 1334 re ections with I > 2(I) R int = max = D m measured by otation in bromoform/cyclohexane Mo K radiation Cell parameters from 25 re ections = 8±22 = mm 1 T = 293 (2) K Plate, brown mm h =0! 23 k =0! 10 l = 19! 19 3 standard re ections every 97 re ections intensity decay: 2% All H atoms were re ned riding with xed geometry (U iso = 1.2U eq or 1.5U eq for the methyl H atoms), except for the water H atoms, the coordinates of which were calculated using HYDROGEN (Nardelli, 1999) and kept xed during the re nement [U iso = 1.2U eq (OW)]. Data collection, cell re nement and data reduction: XSCANS (Siemens, 1991); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to re ne structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97. This work was supported by the Grant Agency of the Slovak Republic (project No. 1/5014/98). Supplementary data for this paper are available from the IUCr electronic archives (Reference: NA1459). Services for accessing these data are described at the back of the journal. References Adler, R. W., Goode, N. C., King, T. S., Mellor, J. M. & Miller, B. W. (1976). J. Chem. Soc. Chem. Commun. pp. 173±174. Dik-Edixhoven, C. J., Schenk, H. & van der Meer, H. (1973). Cryst. Struct. Commun. 2, 23±24. Duncia, J. V., Carini, D. J., Chiu, A. T., Johnson, A. L., Price, W. A., Wong, P. C., Wexler,R.R.&Timmermans,P.B.M.W.M.(1992).Med. Res. Rev. 12, 149±191. Hamilton, G. J., Ferraro, J. R. & Sinn, E. (1979). J. Chem. Soc. Dalton Trans. pp. 515±519. Hunter, C. A. & Saunders, J. K. M. (1990). J. Am. Chem. Soc. 112, 5525±5534. Johnson, C. K. (1976). ORTEPII. Report ORNL Oak Ridge National Laboratory, Tennessee, USA. Nardelli, M. (1999). J. Appl. Cryst. 32, 563±571. Nes, G. J. K. van & Vos, A. (1977). Acta Cryst. B33, 1653±1654. Nicolai, E., Goyard, J., Benchetrit, T., Teulon, J.-M., Caussade, F., Virone, A., Delehambre, C. & Cloarec, A. (1993). J. Med. Chem. 36, 1175±1187. Rapta, M., Kamaras, P., Brewer, G. A. & Jameson, G. B. (1995). J. Am. Chem. Soc. 117, 12865± Sheldrick, G. M. (1990). SHELXS97. University of GoÈttingen, Germany. Sheldrick, G. M. (1997). SHELXL97. University of GoÈttingen, Germany. Shmueli, U., Shanan-Atidi, H., Horwitz, H. & Shvo, Y. (1973). J. Chem. Soc. Perkin Trans. 2, pp. 657±662. Siemens (1991). XSCANS. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA Viktor Kettmann et al. C 14 H 15 N 3 O 4 H 2 O Acta Cryst. (2000). C56, 1007±1008

3 supporting information [doi: /s ] Dimethyl (1-methyl-1,3-benzimidazol-5-yl)aminomethylenepropanedioate monohydrate Viktor Kettmann, Jan Lokaj, Christoph Kratky, Viktor Milata and Pavol Hodul Computing details Data collection: XSCANS (Siemens, 1991); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97. Dimethyl (1-Methyl-5-benzimidazolyl)aminomethylenepropanedioate Monohydrate Crystal data C 14 H 15 N 3 O 4.H 2 O M r = Monoclinic, C2/c a = (8) Å b = (3) Å c = (5) Å β = (4) V = 2939 (2) Å 3 Z = 8 F(000) = 1296 Data collection Siemens P4 diffractometer Radiation source: fine-focus sealed tube Graphite monochromator ω/2θ scans 2734 measured reflections 2592 independent reflections 1334 reflections with I > 2σ(I) Refinement Refinement on F 2 Least-squares matrix: full R[F 2 > 2σ(F 2 )] = wr(f 2 ) = S = reflections 199 parameters 0 restraints D x = Mg m 3 D m = 1.39 (1) Mg m 3 D m measured by flotation in bromoform/chexane Melting point: 452 K Mo Kα radiation, λ = Å Cell parameters from 25 reflections θ = 8 22 µ = 0.11 mm 1 T = 293 K Plate, brown mm R int = θ max = 25.0, θ min = 2.0 h = 0 23 k = 0 10 l = standard reflections every 97 reflections intensity decay: 2% H atoms treated by a mixture of independent and constrained refinement Calculated w = 1/[σ 2 (F o2 ) + (0.1223P) 2 ] where P = (F o 2 + 2F c2 )/3 (Δ/σ) max = Δρ max = 0.35 e Å 3 Δρ min = 0.28 e Å 3 sup-1

4 Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 ) x y z U iso */U eq N (12) (3) (14) (7) C (17) (4) (2) (10) H1A * H1B * H1C * C (16) (4) (2) (9) H * N (14) (3) (17) (9) C (16) (4) (19) (9) H * C (14) (4) (17) (8) C (15) (4) (2) (9) H * C (16) (4) (19) (9) H * C (14) (4) (17) (7) C (15) (4) (18) (8) N (12) (3) (15) (7) H * C (15) (4) (18) (8) H * C (14) (3) (17) (8) C (16) (4) (2) (9) O (13) (3) (18) (9) O (11) (2) (14) (7) C (18) (4) (3) (12) H16A * H16B * H16C * C (15) (4) (19) (8) O (11) (3) (14) (7) O (11) (3) (14) (7) C (2) (4) (3) (13) H20A * H20B * H20C * OW (2) (4) (3) (17) H1OW * H2OW * Atomic displacement parameters (Å 2 ) U 11 U 22 U 33 U 12 U 13 U 23 N (15) (18) (14) (13) (12) (13) C (2) (2) (2) (18) (19) (19) sup-2

5 C (19) (2) (2) (18) (16) (17) N (18) (18) (19) (15) (16) (15) C (2) (2) (2) (17) (18) (16) C (17) (2) (18) (16) (14) (16) C (18) (2) (2) (17) (16) (17) C (19) (2) (2) (16) (17) (17) C (16) (2) (16) (15) (14) (15) C (18) (2) (18) (16) (15) (16) N (15) (18) (17) (14) (13) (15) C (18) (2) (17) (16) (15) (16) C (17) (19) (18) (14) (14) (15) C (19) (2) (2) (17) (17) (18) O (19) (17) (2) (14) (17) (16) O (13) (15) (15) (11) (12) (12) C (2) (3) (3) (2) (2) (2) C (17) (2) (19) (16) (16) (16) O (14) (15) (14) (12) (12) (12) O (15) (15) (15) (12) (12) (13) C (3) (3) (3) (2) (2) (2) OW (4) (2) (4) (3) (4) (3) Geometric parameters (Å, º) N1 C (4) C8 C (4) N1 C (4) N10 C (4) N1 C (4) C11 C (4) C2 N (4) C12 C (4) N3 C (4) C12 C (4) C4 C (4) C13 O (4) C4 C (4) C13 O (4) C5 C (4) O15 C (4) C5 N (4) C17 O (3) C6 C (4) C17 O (4) C7 C (4) O19 C (4) C2 N1 C (3) C8 C9 C (3) C2 N1 C (3) N3 C9 C (3) C8 N1 C (3) C11 N10 C (3) N3 C2 N (3) N10 C11 C (3) C2 N3 C (3) C11 C12 C (3) C5 C4 C (3) C11 C12 C (3) C4 C5 C (3) C13 C12 C (3) C4 C5 N (3) O14 C13 O (3) C6 C5 N (3) O14 C13 C (3) C7 C6 C (3) O15 C13 C (3) C6 C7 C (3) C13 O15 C (3) C7 C8 N (3) O18 C17 O (3) C7 C8 C (3) O18 C17 C (3) sup-3

6 N1 C8 C (3) O19 C17 C (3) C8 C9 N (3) C17 O19 C (3) C8 N1 C2 N3 0.2 (4) C5 C4 C9 C8 1.8 (5) C1 N1 C2 N (3) C5 C4 C9 N (3) N1 C2 N3 C9 0.0 (4) C4 C5 N10 C (5) C9 C4 C5 C6 1.8 (5) C6 C5 N10 C (3) C9 C4 C5 N (3) C5 N10 C11 C (3) C4 C5 C6 C7 0.3 (5) N10 C11 C12 C (5) N10 C5 C6 C (3) N10 C11 C12 C (3) C5 C6 C7 C8 1.2 (5) C11 C12 C13 O (5) C6 C7 C8 N (3) C17 C12 C13 O (3) C6 C7 C8 C9 1.3 (5) C11 C12 C13 O (3) C2 N1 C8 C (3) C17 C12 C13 O (5) C1 N1 C8 C7 1.6 (5) O14 C13 O15 C (5) C2 N1 C8 C9 0.3 (3) C12 C13 O15 C (3) C1 N1 C8 C (3) C11 C12 C17 O (3) C7 C8 C9 N (3) C13 C12 C17 O (5) N1 C8 C9 N3 0.3 (4) C11 C12 C17 O (4) C7 C8 C9 C4 0.2 (5) C13 C12 C17 O (3) N1 C8 C9 C (3) O18 C17 O19 C (5) C2 N3 C9 C8 0.2 (4) C12 C17 O19 C (3) C2 N3 C9 C (4) sup-4