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The title compound, C15H17NO8, is a pyrrole–ethene derivative with potential biological activity. Although a large part of the mol­ecule is planar, there is no structural evidence for any conjugation push–pull effect across the ethyl­enic bond, which is usually observed for substituted ethyl­enes; π-electron delocalization appears to be restricted to the 2-(methoxy­carbonyl)­pyrrole moiety.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101008204/jz1455sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101008204/jz1455Isup2.hkl
Contains datablock I

CCDC reference: 170201

Comment top

Over the last decade, 2-alkoxycarbonyl pyrrole derivatives have attracted considerable interest as they display a broad spectrum of biological activities, the analgesic, morphine agonist, spasmolytic, antipyretic and antiinflammatory properties being some of the most important (Gribble, 1996). Recently, it has been reported that introduction of additional alkoxycarbonyl group(s) to the 4- and/or 1-position of the pyrrole ring has a favourable effect on the spasmolytic activity. Therefore, our strategy was to incorporate extra 2,2-bis(methoxycarbonyl)vinyl and methoxycarbonylmethyl substituents in the 4- and 1-positions of the parent 2-methoxycarbonylpyrrole in order to design novel compounds possessing spasmolytic and possibly other types of biological activity. Moreover, the title molecule, (I), can also be regarded as a push-pull ethylene, a class of compounds exhibiting a variable degree of conjugation across the CC double bond and also an associated polarization of the molecule, which is responsible for some unique properties of the compounds (e.g. absorption in the near-ultraviolet and visible regions). Thus, the purpose of this X-ray structural analysis was twofold: (1) to determine the spatial distribution of the functional groups as one of the main determinants of the biological activity and (2) to assess the extent of conjugation for the future study of the relationship between the electronic and physicochemical properties of this class of compounds. \sch

The title molecule along with the atom-numbering scheme is illustrated in Fig. 1. As expected, the central pyrrole ring is planar within experimental error [r.m.s. deviation 0.007 (2) Å] and is nearly coplanar with the plane of the ethylenic (C15C16) bond [dihedral angle 8.8 (1)°]. The twist about the CC bond, as measured by the angle between the planes through C4,C15,H15 and C16,C17,C21 is 2.3 (1)°. As shown by torsion angles in Table 1, the ester group O22,C21,O23,C24 is approximately coplanar with the CC double bond while the other, oriented Z to the pyrrolyl ring, is almost perpendicular to the CC plane, obviously attributable to steric collision with the heterocyclic ring. As to other pyrrole substituents, the methoxycarbonyl group at C2 is also essentially coplanar with the pyrrole plane [dihedral angle 3.8 (1)°] and the methoxycarbonyl group O8,C7,O9,C10 is rotated around the N1—C6 and C6—C7 bonds so that it makes an angle of 72.5 (4)° with the plane of the pyrrole ring.

Although the pyrrole ring and one of the ester groups at C16 are coplanar with the ethylenic plane, there is no conjugation push-pull effect across the C C double bond, as shown by the C15C16 bond distance [1.334 (4) Å], which corresponds to the value of 1.336 (2) Å observed in unpolarized ethylene (Bartell et al., 1965). Similarly, the C16—C17 and C16—C21 bond lengths of 1.513 (4) and 1.494 (4) Å, respectively, are in good agreement with the value 1.487 (5) Å found for a pure C(sp2)—C(sp2) single bond (Shmueli et al., 1973). The absence of polarization across the ethylenic bond explains the colourlessness of the compound. Nevertheless, on the other side of the molecule, some effect of the methoxycarbonyl group (at C2) on the π-electron distribution of the pyrrole ring is visible in the shortening of the C2—C11 bond distance (Table 1) with respect to the value given above for the C(sp2)—C(sp2) single bond, and also in the non-equivalency of the two N—C bonds within the heterocyclic ring. Other bond lengths and angles within the pyrrole ring agree well with those found for unsubstituted pyrrole (Nygaard et al., 1969).

Related literature top

For related literature, see: Bartell et al. (1965); Gribble (1996); Lokaj et al. (2001); Nygaard et al. (1969); Shmueli et al. (1973).

Experimental top

To a stirred solution of methyl (4-formyl-2-methoxycarbonylpyrrolyl)acetate (10 mmol) prepared previously (Lokaj et al., 2001) in 20 ml of TMF was added at once sodium dimethylmalonate (prepared freshly from dimethylmalonate and sodium hydride) in 15 ml of TMF. The reaction was quickly quenched with a saturated aqueous solution of ammonium chloride, extracted with diethyl ether, dried with sodium sulfate and evaporated to dryness. Then the remaining dimethylmalonate was evaporated using a high-vacuum pump (0.1 Pa) and the residue crystallized from diethyl ether/n-pentane (m.p. 410–412 K).

Refinement top

Although most of the H atoms were seen in a difference Fourier map, they were refined with fixed geometry, riding on their carrier atoms, with Uiso set to 1.2 (or 1.5 for the methyl H atoms) times Ueq of the parent atom. The methyl groups were allowed to rotate about their local threefold axis.

Computing details top

Data collection: Syntex software (Syntex, 1973); cell refinement: Syntex software; data reduction: XP21 (Pavelčík, 1987); 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.

Figures top
[Figure 1] Fig. 1. A view of the title molecule showing the labelling of the non-H atoms. Displacement ellipsoids are shown at 30% probability level and H atoms are drawn as small circles of arbitrary radius.
Dimethyl 2-[(2-Methoxycarbonyl-1-methoxycarbonylmethyl-4-pyrrolyl)methylene]- propanedioate top
Crystal data top
C15H17NO8Dx = 1.347 Mg m3
Dm = 1.35 (1) Mg m3
Dm measured by flotation in bromoform/c-hexane
Mr = 339.30Melting point: 411 K
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 9.906 (4) ÅCell parameters from 15 reflections
b = 12.528 (5) Åθ = 8–17°
c = 13.991 (5) ŵ = 0.11 mm1
β = 105.44 (4)°T = 293 K
V = 1673.7 (11) Å3Plate, colourless
Z = 40.35 × 0.30 × 0.10 mm
F(000) = 712
Data collection top
Syntex P21
diffractometer
Rint = 0.037
Radiation source: fine-focus sealed tubeθmax = 25.0°, θmin = 2.7°
Graphite monochromatorh = 110
θ/2θ scansk = 140
3064 measured reflectionsl = 1616
2883 independent reflections2 standard reflections every 98 reflections
1837 reflections with I > 2σ(I) intensity decay: 2%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.059Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.197Riding
S = 1.00 w = 1/[σ2(Fo2) + (0.1083P)2]
where P = (Fo2 + 2Fc2)/3
2883 reflections(Δ/σ)max = 0.002
221 parametersΔρmax = 0.23 e Å3
0 restraintsΔρmin = 0.18 e Å3
Crystal data top
C15H17NO8V = 1673.7 (11) Å3
Mr = 339.30Z = 4
Monoclinic, P21/nMo Kα radiation
a = 9.906 (4) ŵ = 0.11 mm1
b = 12.528 (5) ÅT = 293 K
c = 13.991 (5) Å0.35 × 0.30 × 0.10 mm
β = 105.44 (4)°
Data collection top
Syntex P21
diffractometer
Rint = 0.037
3064 measured reflections2 standard reflections every 98 reflections
2883 independent reflections intensity decay: 2%
1837 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0590 restraints
wR(F2) = 0.197Riding
S = 1.00Δρmax = 0.23 e Å3
2883 reflectionsΔρmin = 0.18 e Å3
221 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.1372 (2)0.13077 (19)0.59636 (18)0.0661 (7)
C20.0084 (3)0.1083 (2)0.6196 (2)0.0634 (7)
C30.0218 (3)0.0002 (2)0.62588 (19)0.0602 (7)
H30.10590.03750.63920.072*
C40.1144 (3)0.0473 (2)0.60868 (19)0.0557 (7)
C50.2090 (3)0.0374 (2)0.5890 (2)0.0646 (8)
H50.30600.03110.57340.078*
C60.2020 (3)0.2372 (2)0.5814 (2)0.0645 (8)
H6A0.15740.28290.63680.077*
H6B0.30040.23130.57920.077*
C70.1875 (3)0.2869 (2)0.4857 (2)0.0610 (7)
O80.1687 (2)0.23988 (18)0.41503 (16)0.0775 (6)
O90.2007 (2)0.39301 (16)0.48993 (16)0.0778 (6)
C100.1805 (5)0.4537 (3)0.4061 (3)0.1008 (12)
H10A0.18390.52860.41950.151*
H10B0.25330.43610.34770.151*
H10C0.09110.43630.39570.151*
C110.1130 (3)0.1929 (2)0.6296 (2)0.0634 (7)
O120.0870 (2)0.28645 (18)0.61594 (18)0.0885 (7)
O130.2428 (2)0.15240 (15)0.65611 (16)0.0718 (6)
C140.3556 (3)0.2324 (3)0.6720 (3)0.0883 (10)
H14A0.44430.19810.69890.133*
H14B0.34120.28570.71760.133*
H14C0.35470.26540.61000.133*
C150.1410 (3)0.1606 (2)0.6151 (2)0.0612 (7)
H150.06390.20470.62020.073*
C160.2598 (3)0.2109 (2)0.6149 (2)0.0614 (7)
C170.3979 (3)0.1538 (2)0.6029 (2)0.0634 (7)
O180.4825 (2)0.13889 (18)0.52388 (17)0.0853 (7)
O190.4141 (2)0.12245 (17)0.68969 (15)0.0768 (6)
C200.5433 (4)0.0646 (3)0.6862 (3)0.0934 (11)
H20A0.54330.04270.75190.140*
H20B0.62220.11030.65970.140*
H20C0.54940.00290.64470.140*
C210.2585 (3)0.3296 (2)0.6261 (2)0.0657 (8)
O220.1547 (2)0.38419 (18)0.6431 (2)0.0980 (9)
O230.3874 (2)0.36713 (16)0.62029 (18)0.0809 (7)
C240.3958 (4)0.4819 (2)0.6340 (3)0.0881 (10)
H24A0.49190.50220.62500.132*
H24B0.34260.50080.69980.132*
H24C0.35860.51850.58640.132*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0551 (14)0.0702 (16)0.0712 (15)0.0083 (12)0.0139 (11)0.0047 (11)
C20.0516 (16)0.0723 (18)0.0636 (17)0.0062 (14)0.0109 (13)0.0037 (13)
C30.0574 (17)0.0643 (18)0.0593 (16)0.0036 (13)0.0161 (13)0.0046 (12)
C40.0457 (14)0.0630 (16)0.0562 (14)0.0080 (12)0.0098 (12)0.0058 (12)
C50.0611 (17)0.0661 (18)0.0643 (17)0.0010 (14)0.0127 (14)0.0020 (13)
C60.0651 (18)0.0544 (16)0.0742 (18)0.0025 (13)0.0189 (15)0.0027 (12)
C70.0565 (16)0.0506 (16)0.0738 (19)0.0044 (12)0.0134 (14)0.0075 (13)
O80.0826 (15)0.0781 (15)0.0743 (13)0.0006 (11)0.0249 (12)0.0044 (11)
O90.0930 (16)0.0580 (12)0.0848 (14)0.0073 (11)0.0279 (12)0.0055 (10)
C100.130 (3)0.073 (2)0.110 (3)0.012 (2)0.049 (3)0.0248 (19)
C110.0562 (17)0.0620 (18)0.0729 (18)0.0063 (14)0.0183 (14)0.0026 (14)
O120.0713 (14)0.0657 (14)0.124 (2)0.0052 (11)0.0177 (13)0.0103 (12)
O130.0572 (12)0.0666 (13)0.0855 (14)0.0003 (10)0.0088 (10)0.0014 (10)
C140.063 (2)0.102 (3)0.093 (2)0.0203 (18)0.0091 (18)0.0061 (19)
C150.0535 (16)0.0565 (16)0.0681 (17)0.0061 (13)0.0065 (13)0.0057 (13)
C160.0578 (17)0.0559 (16)0.0659 (17)0.0089 (13)0.0083 (14)0.0016 (12)
C170.0523 (16)0.0673 (18)0.0666 (18)0.0009 (14)0.0087 (14)0.0002 (14)
O180.0612 (13)0.1110 (19)0.0760 (14)0.0201 (12)0.0048 (11)0.0046 (12)
O190.0692 (14)0.0845 (15)0.0759 (14)0.0167 (11)0.0180 (11)0.0029 (10)
C200.084 (2)0.090 (2)0.111 (3)0.0199 (19)0.034 (2)0.018 (2)
C210.0570 (17)0.0631 (18)0.0725 (19)0.0030 (14)0.0095 (14)0.0012 (14)
O220.0581 (14)0.0657 (14)0.162 (2)0.0134 (11)0.0152 (14)0.0152 (13)
O230.0642 (14)0.0687 (14)0.1133 (18)0.0020 (10)0.0297 (12)0.0048 (11)
C240.098 (3)0.067 (2)0.102 (3)0.0158 (19)0.030 (2)0.0102 (17)
Geometric parameters (Å, º) top
N1—C51.358 (4)O13—C141.472 (4)
N1—C21.420 (4)C14—H14A0.9600
N1—C61.470 (3)C14—H14B0.9600
C2—C31.366 (4)C14—H14C0.9600
C2—C111.462 (4)C15—C161.334 (4)
C3—C41.433 (4)C15—H150.9300
C3—H30.9300C16—C211.494 (4)
C4—C51.394 (4)C16—C171.513 (4)
C4—C151.451 (4)C17—O181.211 (3)
C5—H50.9300C17—O191.326 (3)
C6—C71.517 (4)O19—C201.460 (4)
C6—H6A0.9700C20—H20A0.9600
C6—H6B0.9700C20—H20B0.9600
C7—O81.208 (3)C20—H20C0.9600
C7—O91.338 (3)C21—O221.205 (3)
O9—C101.455 (4)C21—O231.342 (3)
C10—H10A0.9600O23—C241.456 (4)
C10—H10B0.9600C24—H24A0.9600
C10—H10C0.9600C24—H24B0.9600
C11—O121.204 (3)C24—H24C0.9600
C11—O131.340 (3)
C5—N1—C2109.0 (2)C11—O13—C14114.7 (2)
C5—N1—C6124.8 (2)O13—C14—H14A109.5
C2—N1—C6126.2 (2)O13—C14—H14B109.5
C3—C2—N1106.7 (3)H14A—C14—H14B109.5
C3—C2—C11131.4 (3)O13—C14—H14C109.5
N1—C2—C11121.9 (3)H14A—C14—H14C109.5
C2—C3—C4109.2 (2)H14B—C14—H14C109.5
C2—C3—H3125.4C16—C15—C4129.6 (3)
C4—C3—H3125.4C16—C15—H15115.2
C5—C4—C3105.8 (2)C4—C15—H15115.2
C5—C4—C15129.3 (2)C15—C16—C21119.1 (2)
C3—C4—C15124.8 (2)C15—C16—C17123.2 (3)
N1—C5—C4109.3 (2)C21—C16—C17117.7 (2)
N1—C5—H5125.4O18—C17—O19124.6 (3)
C4—C5—H5125.4O18—C17—C16124.0 (3)
N1—C6—C7111.0 (2)O19—C17—C16111.4 (2)
N1—C6—H6A109.4C17—O19—C20115.8 (2)
C7—C6—H6A109.4O19—C20—H20A109.5
N1—C6—H6B109.4O19—C20—H20B109.5
C7—C6—H6B109.4H20A—C20—H20B109.5
H6A—C6—H6B108.0O19—C20—H20C109.5
O8—C7—O9123.9 (3)H20A—C20—H20C109.5
O8—C7—C6126.4 (3)H20B—C20—H20C109.5
O9—C7—C6109.6 (2)O22—C21—O23124.1 (3)
C7—O9—C10116.6 (3)O22—C21—C16124.6 (3)
O9—C10—H10A109.5O23—C21—C16111.1 (2)
O9—C10—H10B109.5C21—O23—C24115.2 (2)
H10A—C10—H10B109.5O23—C24—H24A109.5
O9—C10—H10C109.5O23—C24—H24B109.5
H10A—C10—H10C109.5H24A—C24—H24B109.5
H10B—C10—H10C109.5O23—C24—H24C109.5
O12—C11—O13124.1 (3)H24A—C24—H24C109.5
O12—C11—C2125.0 (3)H24B—C24—H24C109.5
O13—C11—C2110.8 (2)
C5—N1—C2—C30.0 (3)C3—C2—C11—O135.1 (4)
C6—N1—C2—C3179.4 (3)N1—C2—C11—O13177.2 (2)
C5—N1—C2—C11178.3 (2)O12—C11—O13—C142.5 (4)
C6—N1—C2—C111.2 (4)C2—C11—O13—C14177.6 (2)
N1—C2—C3—C41.1 (3)C5—C4—C15—C168.3 (5)
C11—C2—C3—C4179.1 (3)C3—C4—C15—C16169.2 (3)
C2—C3—C4—C51.7 (3)C4—C15—C16—C21177.9 (3)
C2—C3—C4—C15176.2 (2)C4—C15—C16—C172.7 (5)
C2—N1—C5—C41.1 (3)C15—C16—C17—O1891.5 (4)
C6—N1—C5—C4179.5 (2)C21—C16—C17—O1887.9 (4)
C3—C4—C5—N11.7 (3)C15—C16—C17—O1988.5 (3)
C15—C4—C5—N1176.2 (3)C21—C16—C17—O1992.0 (3)
C5—N1—C6—C7109.3 (3)O18—C17—O19—C201.1 (4)
C2—N1—C6—C770.1 (3)C16—C17—O19—C20179.0 (2)
N1—C6—C7—O822.4 (4)C15—C16—C21—O226.0 (5)
N1—C6—C7—O9158.4 (2)C17—C16—C21—O22174.5 (3)
O8—C7—O9—C104.6 (4)C15—C16—C21—O23177.5 (2)
C6—C7—O9—C10176.2 (3)C17—C16—C21—O231.9 (4)
C3—C2—C11—O12174.9 (3)O22—C21—O23—C241.4 (4)
N1—C2—C11—O122.9 (5)C16—C21—O23—C24177.8 (2)

Experimental details

Crystal data
Chemical formulaC15H17NO8
Mr339.30
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)9.906 (4), 12.528 (5), 13.991 (5)
β (°) 105.44 (4)
V3)1673.7 (11)
Z4
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.35 × 0.30 × 0.10
Data collection
DiffractometerSyntex P21
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
3064, 2883, 1837
Rint0.037
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.059, 0.197, 1.00
No. of reflections2883
No. of parameters221
H-atom treatmentRiding
Δρmax, Δρmin (e Å3)0.23, 0.18

Computer programs: Syntex software (Syntex, 1973), Syntex software, XP21 (Pavelčík, 1987), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEPII (Johnson, 1976), SHELXL97.

Selected geometric parameters (Å, º) top
N1—C51.358 (4)C4—C51.394 (4)
N1—C21.420 (4)C4—C151.451 (4)
N1—C61.470 (3)C15—C161.334 (4)
C2—C31.366 (4)C16—C211.494 (4)
C2—C111.462 (4)C16—C171.513 (4)
C3—C41.433 (4)
C5—N1—C2109.0 (2)C5—C4—C15129.3 (2)
C5—N1—C6124.8 (2)C3—C4—C15124.8 (2)
C2—N1—C6126.2 (2)N1—C5—C4109.3 (2)
C3—C2—N1106.7 (3)C16—C15—C4129.6 (3)
C3—C2—C11131.4 (3)C15—C16—C21119.1 (2)
N1—C2—C11121.9 (3)C15—C16—C17123.2 (3)
C2—C3—C4109.2 (2)C21—C16—C17117.7 (2)
C5—C4—C3105.8 (2)
C2—N1—C6—C770.1 (3)C4—C15—C16—C172.7 (5)
N1—C6—C7—O822.4 (4)C15—C16—C17—O1891.5 (4)
N1—C2—C11—O122.9 (5)C15—C16—C21—O226.0 (5)
C5—C4—C15—C168.3 (5)
 

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