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Crystallography Reports, Vol. 49, No. 3, 2004, pp. 430436. Translated from Kristallografiya, Vol. 49, No. 3, 2004, pp. 495501. Original Russian Text Copyright © 2004 by Albov, Rybakov, Babaev, Aslanov.

STRUCTURE OF ORGANIC COMPOUNDS

X-ray Mapping in Heterocyclic Design: XIII. Structure of Substituted Tetrahydroquinolines
D. V. Albov, V. B. Rybakov, E. V. Babaev, and L. A. Aslanov
Faculty of Chemistry, Moscow State University, Leninskie gory, Moscow, 119899 Russia e-mail: albov@biocryst.phys.msu.su
Received July 3, 2003

Abstract--The structures of 4-methyl-2-chloro-5,6,7,8-tetrahydroquinoline [a = 8.138(2) е, b = 11.127(4) е, c = 11.234(2) е, = 111.30(2)°, Z = 4, space group P21/c, 4-methyl-2-methoxy-5,6,7,8- tetrahydroquinoline [a = 5.7651(16) е, b = 8.530(2) е, c = 10.455(3) е, = 73.76(2)°, = 86.95(2)°, = 83.97(2)°, Z = 2, space group P 1 , 4-methyl-2-(4-chlorophenacyl)-5,6,7,8-tetrahydro-1H-quinolin-2-one [a = 8.873(2) е, b = 17.137(2) е, c = 24.515(4) е, Z = 8, space group Pbn21], and 2-(4-chlorophenyl)-5-methyl-6,7,8,9-tetrahydrooxazolo[3.2-a]quinolin-10-ylium perchlorate [a = 8.110(6) е, b = 17.818(7) е, c = 17.721(5) е, = 100.46(4)°, Z = 4, space group P21/c] are studied by single-crystal X-ray diffraction. The structures are solved by direct methods and refined by the full-matrix least-squares procedures in the anisotropic approximation to R = 0.0581, 0.0667, 0.0830, and 0.0607, respectively. © 2004 MAIK "Nauka / Interperiodica".

INTRODUCTION This study continues our structural investigation of heterocyclic compounds that are able to undergo various rearrangements, in particular, to enter into cyclization reactions [113]. As was done in our previous works, we perform X-ray diffraction analysis of all the intermediates and final products of multistage cyclization reactions and rearrangements. 2-Pyridone derivatives are structural precursors in many of the systems studied earlier. In this work, we studied a series of transformations from 4-methyl-5,6,7,8-tetrahydro-1H-quinolin-2-one (I) into 2-(4-chlorophenyl)-5-methyl-6,7,8,9-tetrahyCH3

drooxazolo[3.2-a]quinolin-10-ylium perchlorate (V) (Scheme 1). The data on the molecular structures of compounds IIV discussed in this paper are not available in the Cambridge Structural Database (version 11.02) [14]. EXPERIMENTAL Compound I was synthesized and characterized in our earlier work [11]. This paper reports the synthesis and structures of compounds IIV. 4-Methyl-2-chloro-5,6,7,8-tetrahydroquinoline (II). Our attempt to convert pyridone I into chloropyridine II
CH3

CH3

I

N H

O

N II CH3

Cl

N III CH3

OCH3

ClO4

N+ V

O IV

N

O Cl

O

Cl
Scheme 1. 1063-7745/04/4903-0430$26.00 © 2004 MAIK "Nauka / Interperiodica"

X-RAY MAPPING IN HETEROCYCLIC DESIGN Table 1. Crystal data, data collection, and refinement parameters for the crystal structures of compounds IIV Empirical formula Molecular weight Crystal system Space group a, е b, е c, е , deg , deg , deg V, е3 Z calcd, g/cm3 µ(K), cm1 range, deg Index ranges C10H12NCl (II) 181.66 Monoclinic P21/c 8.138(2) 11.127(4) 11.234(2) 90 111.30(2) 90 947.8(4) 4 1.273 3.46 2.6725.97 10 h 9 0 k 13 0 l 13 0.26 в 0.29 в 0.30 1892 1799 1799/114 C11H15NO (III) 177.24 Triclinic P1 5.7651(16) 8.530(2) 10.455(3) 73.76(2) 86.95(2) 83.79(2) 490.6(2) 2 1.200 0.77 2.0325.95 7 h 1 10 k 10 0 l 12 0.31 в 0.32 в 0.35 1158 1140 1140/121 C20H21N2O2Cl (IV) 356.84 Orthorhombic Pbn2
1

431

C18H17NO5Cl2 (V) 398.23 Monoclinic P21/c 8.110(6) 17.818(7) 17.721(5) 90 100.46(4) 90 1807.7(17) 4 1.463 34.97 5.5469.77 7 h 7 0 k 18 0 l 17 0.27 в 0.29 в 0.30 3271 3271 3271/237

Crystal size, mm Number of reflections measured Number of unique reflections Number of reflections used in the least-squares refinement/number of parameters refined GooF R1/wR2 [I 2(I)] max/min, eе3

8.873(2) 17.137(2) 24.515(4) 90 90 90 3727.7(13) 8 1.272 19.33 3.6069.78 0 h 10 0 k 20 0 l 29 0.22 в 0.24 в 0.29 3342 3342 3342/456

1.020 0.0581/0.1474 0.284/ 0.232

1.026 0.0667/0.1793 0.172/ 0.151

0.914 0.0830/0.1991 0.592/ 0.208

0.998 0.0607/0.1604 0.303/ 0.325

Table 2. Bond lengths d (е) in structure II Bond N(1)C(2) N(1)C(10) C(2)C(3) C(2)Cl(2) C(3)C(4) C(4)C(5) C(4)C(11) d 1.301(4) 1.344(4) 1.357(4) 1.754(3) 1.377(4) 1.388(4) 1.502(4) Bond C(5)C(10) C(5)C(6) C(6)C(7) C(7)C(8) C(8)C(9) C(9)C(10) d 1.384(4) 1.516(4) 1.468(7) 1.350(8) 1.496(8) 1.510(5)

Table 3. Bond angles (deg) in structure II Angle C(2)N(1)C(10) N(1)C(2)C(3) N(1)C(2)Cl(2) C(3)C(2)Cl(2) C(2)C(3)C(4) C(3)C(4)C(5) C(3)C(4)C(11) C(5)C(4)C(11) C(10)C(5)C(4) 116.1(2) 126.5(3) 115.4(2) 118.1(2) 117.8(3) 118.2(3) 119.9(3) 121.9(3) 118.5(2) Angle C(10)C(5)C(6) C(4)C(5)C(6) C(7)C(6)C(5) C(8)C(7)C(6) C(7)C(8)C(9) C(8)C(9)C(10) N(1)C(10)C(5) N(1)C(10)C(9) C(5)C(10)C(9) 120.9(3) 120.5(3) 114.3(4) 119.9(5) 120.5(5) 111.9(4) 122.8(3) 114.7(3) 122.5(3)

simply through boiling in POCl3 failed. The procedure described in [15] requires heating to 180°C in a sealed ampule, which is impracticable. Therefore, we worked out an original path of synthesis of compound II. Weighed portions of I (10 g) and benzyltrimethylammonium chloride (11 g) were refluxed in POCl3 (33 ml)
CRYSTALLOGRAPHY REPORTS Vol. 49 No. 3 2004

until the formation of HCl ceased (within about 5 h). A hot homogeneous dark solution was poured in a glass with ice. Activated carbon was added, and the solution was stirred and filtered off. The light solution thus prepared was neutralized with solid sodium hydrogen carbonate to pH = 7, and the precipitate was filtered off. A

432 Table 4. Bond lengths d (е) in structure III Bond N(1)C(2) N(1)C(10) C(2)O(1) C(2)C(3) C(3)C(4) C(4)C(5) C(4)C(11) d 1.328(5) 1.368(4) 1.363(4) 1.381(6) 1.369(4) 1.422(5) 1.492(6) Bond C(5)C(10) C(5)C(6) C(6)C(7) C(7)C(8) C(8)C(9) C(9)C(10) O(1)C(1) d

ALBOV et al.

1.337(5) 1.537(4) 1.531(6) 1.444(7) 1.501(5) 1.514(5) 1.402(6)

Table 5. Bond angles (deg) in structure III Angle C(2)N(1)C(10) N(1)C(2)O(1) N(1)C(2)C(3) O(1)C(2)C(3) C(4)C(3)C(2) C(3)C(4)C(5) C(3)C(4)C(11) C(5)C(4)C(11) C(10)C(5)C(4) C(10)C(5)C(6) Angle 118.5(3) 111.2(3) 115.1(3) 113.2(4) 112.4(3) 124.5(3) 122.8(3) 112.6(3) 118.1(3)

115.3(3) C(4)C(5)C(6) 118.7(4) C(7)C(6)C(5) 124.8(3) C(8)C(7)C(6) 116.5(3) C(7)C(8)C(9) 118.7(3) C(8)C(9)C(10) 117.9(4) C(5)C(10)N(1) 120.7(3) C(5)C(10)C(9) 121.4(3) N(1)C(10)C(9) 118.7(3) C(2)O(1)C(1) 122.8(3)

4-Methyl-2-methoxy-5,6,7,8-tetrahydroquinoline (III). No indications of the reaction (precipitation of sodium chloride) were observed in our attempt to prepare methoxy pyridine III from chloropyridine II according to the procedure described in [16]. An analysis of the reaction mixture showed that the product was not formed and the starting substance remained without changes. We proposed an original procedure with the use of a high-boiling inert solvent that dissolves both the initial substance and sodium methylate and is watermixable for the facilitation of the product isolation. Diglym satisfies these conditions. Metallic sodium (2.8 g) was dissolved in absolute methanol (20 ml), the excess methanol was distilled off, and a solution of compound II (7.8 g) in absolute diglyme (40 ml) was added. The mixture was heated at 120°C for 3 h. This process was accompanied by a thickening of the mixture because of the copious precipitate formation. The reaction mixture was poured into water and stirred. The precipitate was filtered off and washed with water. The white powder obtained was recrystallized from chloroform. The yield was 6.1 g (80%). The melting point was equal to 3540°C. 1H NMR (DMSO-d6 , , ppm): 1.80 (m, 4H, 6-CH3 + 7-CH2), 2.15 (s, 3H, 4-CH3), 2.54 (t, 2H, 5-CH2), 2.70 (t, 2H, 8-CH2), 3.78 (s, 3H, OCH3), 6.35 (s, 1H, 3-CH). 4-Methyl-2-(4-chlorophenacyl)-5,6,7,8-tetrahydro1H-quinolin-2-one (IV). Compound IV was synthesized according to a modified procedure described in [16]. Weighed portions of compound III (3 g) and 4-chlorophenacyl bromide (4 g) were refluxed in CH3CN (20 ml) for 5 h. As a result, a poorly soluble compound, namely, 4-chlorophenacyl bromide, dissolved. The degree of conversion was controlled by thin-layer chromatography (hexane : ethyl acetate = 1 : 1). For both initial substances, we obtained Rf = 0.72, and, for the product, Rf = 0.1. Upon cooling of the solution, colorless crystals of the product containing solvate CH3CN molecules precipitated. Only minor amounts of the product remained in the mother liquor. The yield was 2 g (40%). The melting point was equal to 163 165°C. 1H NMR (DMSO-d6 , , ppm): 1.75 (m, 4H, 6CH2 + 7-CH2), 2.13 (s, 3H, 4-CH3), 2.50 (m, 4H, 5-CH2 + 8-CH2), 5.45 (s, 2H, NCH2CO), 6.15 (s, 1H, 3-CH), 7.55, 8.10 (dd, 4H, Ar). 2-(4-Chlorophenyl)-5-methyl-6,7,8,9-tetrahydrooxazolo[3.2-a]quinolin-10-ylium perchlorate (V). The synthesis of compound V was also performed according to the procedure worked out earlier in [16]. Compound IV (1.2 g) was dissolved in concentrated H2SO4 (12 ml) and allowed to stand for a night. The solution was poured into a 3% HClO4 solution (100 ml). The precipitate was left in the solution for a night and then filtered off and washed with water. The white powder obtained was recrystallized from CH3CN. The yield was 1.5 g (98%). The melting point was 300°C (with explosion). 1H NMR (DMSO-d6 , ,
CRYSTALLOGRAPHY REPORTS Vol. 49 No. 3 2004

Table 6. Bond lengths d (е) in structure IV Bond Cl(1)C(17) N(1)C(2) N(1)C(10) N(1)C(12) C(2)O(2) C(2)C(3) C(3)C(4) C(4)C(5) C(4)C(11) C(5)C(10) C(5)C(6) C(6)C(7) d 1.728(9) 1.361(10) 1.422(10) 1.456(10) 1.232(11) 1.417(12) 1.355(11) 1.459(12) 1.591(14) 1.376(12) 1.498(11) 1.552(15) Bond C(7)C(8) C(8)C(9) C(9)C(10) C(12)C(13) C(13)O(13) C(13)C(14) C(14)C(19) C(14)C(15) C(15)C(16) C(16)C(17) C(17)C(18) C(18)C(19) d 1.438(15) 1.471(13) 1.513(11) 1.509(11) 1.215(9) 1.495(10) 1.390(10) 1.402(10) 1.375(10) 1.376(10) 1.377(11) 1.389(11)

white powder obtained was recrystallized from chloroform. The yield was 8.6 g (78%). The melting point was equal to 3540°C. 1H NMR (DMSO-d6 , , ppm): 1.82 (m, 4H, 6-CH2 + 7-CH2), 2.19 (s, 3H, 4-CH3), 2.60 (t, 2H, 5-CH2), 2.78 (t, 2H, 8-CH2), 6.95 (s, 1H, 3-CH).

X-RAY MAPPING IN HETEROCYCLIC DESIGN

433

C(11) C(6) C(7) C(5) C(4) C(7) C(5) C(3) C(2) C(10) C(9) N(1) Cl(2) C(8) C(10) C(9) N(1) C(6)

C(11)

C(4)

C(3) C(2)

C(8)

O(1) C(1)

Fig. 1. Molecular structure and atomic numbering for compound II. Hereafter, the ellipsoids of thermal vibrations are shown at the 50% probability level.

Fig. 2. Molecular structure and atomic numbering for compound III.

ppm): 1.95 (m, 2H, 7-CH2), 2.05 (m, 2H, 8-CH2), 2.58 (s, 3H, 5-CH3), 2.85 (t, 2H, 6-CH2), 3.15 (t, 2H, 9-CH2), 7.637.66, 8.038.06 (dd, 4H, Ar), 8.11 (s, 1H, 4-CH), 9.37 (s, 1H, 1-CH). X-ray Diffraction Experiment For single crystals of compounds II and III, the experimental intensities were measured on a CAD4 diffractometer [17] (MoK, graphite monochromator) at room temperature. The unit cell parameters were determined and refined using 25 reflections in the range 12°15°. For compounds IV and V, the experiment was performed on a CAD4 diffractometer (CuK, graphite monochromator). The unit cell parameters were determined and refined using 25 reflections in the range 25°30°. Since the crystals of the compounds studied were small in size and had small linear absorption coefficients (µR 0.4), the experimental data were not corrected for absorption. The primary processing of the sets of diffraction data was performed with the WinGX program package [18]. All the subsequent calculations were performed with the SHELX97 program package [19]. The crystal structures were determined by direct methods. All the non-hydrogen atoms were refined in the anisotropic approximation of thermal parameters. The main parameters of the X-ray diffraction experiments and crystal data for the compounds studied are summarized in Table 1. The interatomic distances and bond angles are listed in Tables 29. The molecular structures with atomic numberings are shown in Figs. 14. The drawings were obtained with the ORTEP-3 program [20, 21].
CRYSTALLOGRAPHY REPORTS Vol. 49 No. 3 2004

Crystal data for the compounds studied are deposited in the Cambridge Structural Database (deposit nos. 231747231750). RESULTS AND DISCUSSION In molecule II (Fig. 1), the N(1)C(10) six-membered ring is planar within 0.011 е. The Cl(2), C(6), C(9), and C(11) atoms lie in the plane of this ring. The C(7) and C(8) atoms deviate from this plane by 0.124 and 0.290 е, respectively. The thermal ellipsoids of
Table 7. Bond angles (deg) in structure IV Angle C(2)N(1)C(10) C(2)N(1)C(12) C(10)N(1)C(12) O(2)C(2)N(1) O(2)C(2)C(3) N(1)C(2)C(3) C(4)C(3)C(2) C(3)C(4)C(5) C(3)C(4)C(11) C(5)C(4)C(11) C(10)C(5)C(4) C(10)C(5)C(6) C(4)C(5)C(6) C(5)C(6)C(7) C(8)C(7)C(6) C(7)C(8)C(9) C(8)C(9)C(10) 124.7(8) 115.1(7) 120.1(7) 120.7(8) 123.9(9) 115.1(8) 125.5(10) 116.0(9) 125.8(10) 118.0(9) 121.6(8) 118.5(9) 119.8(9) 112.3(9) 119.4(13) 109.4(12) 114.6(10) Angle C(5)C(10)N(1) C(5)C(10)C(9) N(1)C(10)C(9) N(1)C(12)C(13) O(13)C(13)C(14) O(13)C(13)C(12) C(14)C(13)C(12) C(19)C(14)C(15) C(19)C(14)C(13) C(15)C(14)C(13) C(16)C(15)C(14) C(15)C(16)C(17) C(16)C(17)C(18) C(16)C(17)Cl(1) C(18)C(17)Cl(1) C(17)C(18)C(19) C(18)C(19)C(14) 117.0(7) 125.1(8) 117.9(8) 112.3(7) 122.8(7) 120.7(8) 116.4(7) 119.7(8) 123.3(7) 117.0(7) 122.1(9) 118.3(9) 119.6(9) 123.1(8) 117.2(8) 123.4(10) 116.7(9)

434

ALBOV et al.
O(22) C(11) Cl(2) C(4) C(6) C(5) C(3) C(7) C(2) C(9) C(7) O(23) O(24) C(14) O(21)

C(8) C(10) C(9)

N(1)

O(2)

C(10)

C(8) C(6)

C(12) O(13) C(13) C(14)

C(11) C(13) C(12) N(1)

C(5) C(4) C(3) C(2) C(15) C(16)

C(15) C(19) C(16) C(18) C(17) C(20) C(19) C(17) C(18) Cl(1)

Cl(1)

Fig. 3. Molecular structure and atomic numbering for compound IV. Acetonitrile solvate molecules are omitted.

Fig. 4. Molecular structure and atomic numbering for compound V.

the C(7) and C(8) atoms are characterized by strong anisotropy, which results in a significant shortening of the distance between these atoms (1.35 е) with respect to the C(5)C(6), C(6)C(7), C(8)C(9), and C(9) C(10) distances (Table 2). However, with due regard for the anisotropy of thermal parameters [22], this distance is 1.58 е, which corresponds to the C(sp3)C(sp3) bond length. In the heterocyclic bicycle of II, the single bonds shortened and the double bonds slightly elongated compared to the initial compound I [11], which is
CH3 N+ A O Cl CH3 N+ B O

in accord with the expected aromatic structure of the pyridine fragment (Scheme 1). In molecule III (Fig. 2), the N(1)C(10) six-membered ring is planar within 0.01 е. The O(1), C(1), C(6), C(9), and C(11) atoms lie in the plane of this ring. The C(7) and C(8) atoms deviate from this plane by -0.237 and 0.405 е, respectively. As in molecule II, the ellipsoids of thermal vibrations of the C(7) and C(8) atoms exhibit strong anisotropy and, as a consequence, the distance between these atoms (1.44 е) is shorter than the C(5)C(6), C(6)C(7), C(8)C(9), and C(9)
CH3 Cl N C O+ Cl

Scheme 2. CRYSTALLOGRAPHY REPORTS Vol. 49 No. 3 2004

X-RAY MAPPING IN HETEROCYCLIC DESIGN

435

C(10) distances (Table 4). However, with due regard for the anisotropy of thermal parameters [22], the C(7) C(8) distance is 1.57 е, which corresponds to the C(sp3)C(sp3) bond length. As in the previous case, the structure of the pyridine fragment of the bicycle agrees with the expected aromatic structure (Scheme 1). In crystals IV (Fig. 3), the incomplete occupancy of the positions of the CH3CN solvate molecules led to problems in the course of structure refinement. For their solution, the lengths of the corresponding pairs of bonds in two crystallographically independent molecules were averaged. The N(1)C(10) six-membered ring is planar within 0.02 е. The O(1), C(1), C(6), C(9), and C(12) atoms lie in the plane of this ring. The C(7), C(8), and C(11) atoms deviate from this plane by -0.256, 0.340, and 0.204 е, respectively. The alternation of single and double bonds in the heterocycle corresponds to a nonaromatic pyridone structure (Scheme 1). As in structures IIII, the distance between the C(7) and C(8) atoms is short (1.44 е, Table 6). However, after the correction for anisotropy of thermal vibrations was introduced [22], this distance was found to be 1.54 е. The C(14)C(19) phenyl ring is planar within 0.013 е. The Cl(1), C(13), and C(12) atoms lie in the plane of this ring. The O(13) and N(1) atoms deviate from this plane by 0.116 and 0.373 е, respectively. The dihedral angle between the planes of the pyridone fragment and the aryl group is 86.45°. The structure of two CH3CN solvent molecules is standard and needs no comments. In cation V (Fig. 4), the N(1)C(13) nine-membered oxazolopyridinium bicycle is planar within 0.03 е. The C(12), C(14), C(15), C(19), and C(20) atoms lie in the plane of this ring. The C(9), C(10), C(11), C(16), C(17), and C(18) atoms deviate from this plane by 0.119, 0.562, 0.225, 0.275, 0.348, and 0.226 е, respectively. The C(15)C(20) phenyl ring is planar within 0.01 е. The Cl(1) and C(3) atoms lie in the plane of this ring. The structure of the phenyl ring corresponds to the expected aromatic structure. The dihedral angle between the planes of the heterocycle and the phenyl ring is only 7.37°, which indicates the conjugation of the aromatic rings. The structure of the oxazolopyridinium cation can be represented by three resonance forms; in two of them, the positive charge is localized at the nitrogen atom, and, in the third form, the positive charge is localized at the oxygen atom (see Scheme 2). The question arises as to which of these formulas represents the structure of the cation more adequately. The C(6)C(7), C(7)C(8), and C(8)C(13) bond lengths (Fig. 5) are equal to 1.378(5), 1.423(5), and 1.359(5) е, respectively (Table 8). This location of double bonds in the pyridine fragment of the molecule suggests that structure A makes a minor contribution. For the final decision between structures B and C, we searched in the Cambridge Structural Database (Version 11.02) [14] for compounds that contain an amide
CRYSTALLOGRAPHY REPORTS Vol. 49 No. 3 2004

Table 8. Bond lengths d (е) in structure V Bond Cl(1)C(18) Cl(2)O(23) Cl(2)O(21) Cl(2)O(24) Cl(2)O(22) N(1)C(5) N(1)C(13) N(1)C(2) C(2)C(3) C(3)O(4) C(3)C(15) O(4)C(5) C(5)C(6) C(6)C(7) d 1.727(4) 1.334(4) 1.357(4) 1.367(4) 1.392(5) 1.339(4) 1.381(4) 1.398(4) 1.335(5) 1.394(4) 1.450(5) 1.339(4) 1.374(5) 1.378(5) Bond C(7)C(8) C(7)C(14) C(8)C(13) C(8)C(9) C(9)C(10) C(10)C(11) C(11)C(12) C(12)C(13) C(15)C(20) C(15)C(16) C(16)C(17) C(17)C(18) C(18)C(19) C(19)C(20) d 1.423(5) 1.506(5) 1.359(5) 1.515(5) 1.555(6) 1.467(7) 1.520(6) 1.501(5) 1.382(5) 1.388(5) 1.376(5) 1.387(6) 1.380(6) 1.370(5)

Table 9. Bond angles (deg) in structure V Angle O(23)Cl(2)O(21) O(23)Cl(2)O(24) O(21)Cl(2)O(24) O(23)Cl(2)O(22) O(21)Cl(2)O(22) O(24)Cl(2)O(22) C(5)N(1)C(13) C(5)N(1)C(2) C(13)N(1)C(2) C(3)C(2)N(1) C(2)C(3)O(4) C(2)C(3)C(15) O(4)C(3)C(15) C(5)O(4)C(3) N(1)C(5)O(4) N(1)C(5)C(6) O(4)C(5)C(6) C(5)C(6)C(7) C(6)C(7)C(8) C(6)C(7)C(14) C(8)C(7)C(14) 112.7(5) 108.3(3) 120.1(4) 107.1(6) 100.0(4) 107.5(4) 121.2(3) 108.2(3) 130.5(3) 106.5(3) 109.0(3) 133.5(3) 117.5(3) 106.9(2) 109.4(3) 123.1(3) 127.4(3) 116.9(3) 120.1(3) 120.2(3) 119.8(3) Angle C(13)C(8)C(7) C(13)C(8)C(9) C(7)C(8)C(9) C(8)C(9)C(10) C(11)C(10)C(9) C(10)C(11)C(12) C(13)C(12)C(11) C(8)C(13)N(1) C(8)C(13)C(12) N(1)C(13)C(12) C(20)C(15)C(16) C(20)C(15)C(3) C(16)C(15)C(3) C(17)C(16)C(15) C(16)C(17)C(18) C(19)C(18)C(17) C(19)C(18)Cl(1) C(17)C(18)Cl(1) C(20)C(19)C(18) C(19)C(20)C(15) 120.6(3) 119.0(3) 120.3(3) 110.5(3) 112.9(4) 109.8(4) 111.8(4) 118.0(3) 126.6(3) 115.4(3) 118.7(3) 119.8(3) 121.6(3) 121.5(3) 118.3(4) 121.1(3) 119.7(3) 119.1(3) 119.3(4) 121.0(4)

group protonated at the oxygen or nitrogen atom (or alkylated at the oxygen atom). As a result, we found that the C=O bond length in these fragments falls in the range 1.251.30 е. Sixty formulas are drawn with a positive charge at the oxygen atom, and more than 200 formulas have a charge at the nitrogen atom. In

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ALBOV et al. 3. V. B. Rybakov, S. G. Zhukov, E. V. Babaev, et al., Kristallografiya 45 (2), 292 (2000) [Crystallogr. Rep. 45, 261 (2000)]. 4. V. B. Rybakov, S. G. Zhukov, K. Yu. Pasichnichenko, and E. V. Babaev, Koord. Khim. 26 (9), 714 (2000). 5. V. B. Rybakov, S. G. Zhukov, E. V. Babaev, and E. J. Sonneveld, Kristallografiya 46 (3), 435 (2001) [Crystallogr. Rep. 46, 385 (2001)]. 6. V. B. Rybakov, S. I. Troyanov, E. V. Babaev, et al., Kristallografiya 46 (6), 1069 (2001) [Crystallogr. Rep. 46, 986 (2001)]. 7. V. B. Rybakov, E. V. Babaev, K. Yu. Pasichnichenko, and E. J. Sonneveld, Kristallografiya 47 (1), 76 (2002) [Crystallogr. Rep. 47, 69 (2002)]. 8. V. B. Rybakov, E. V. Babaev, and V. V. Chernyshev, Kristallografiya 47 (3), 473 (2002) [Crystallogr. Rep. 47, 428 (2002)]. 9. V. B. Rybakov, E. V. Babaev, and K. Yu. Pasichnichenko, Kristallografiya 47 (4), 678 (2002) [Crystallogr. Rep. 47, 622 (2002)]. 10. V. B. Rybakov, E. V. Babaev, A. A. Tsisevich, et al., Kristallografiya 47 (6), 1042 (2002) [Crystallogr. Rep. 47, 973 (2002)]. 11. D. V. Al'bov, V. B. Rybakov, E. V. Babaev, and L. A. Aslanov, Kristallografiya 48 (2), 277 (2003) [Crystallogr. Rep. 48, 280 (2003)]. 12. V. B. Rybakov, L. G. Boboshko, N. I. Burakov, et al., Kristallografiya 48 (4), 627 (2003) [Crystallogr. Rep. 48, 576 (2003)]. 13. D. V. Al'bov, O. S. Mazina, V. B. Rybakov, et al., Kristallografiya 49 (2), 208 (2004) [Crystallogr. Rep. 49, 158 (2004)]. 14. F. H. Allen, Acta Crystallogr., Sect. B: Struct. Sci. 58, 380 (2002). 15. H. E. Mertel, Pyridine and Derivatives, Ed. by E. Klingsberg (Interscience, New York, 1962), Part 3, p. 525. 16. E. V. Babaev, A. V. Efimov, D. A. Maiboroda, and K. Jug, Eur. J. Org. Chem., 193 (1998). 17. EnrafNonius CAD4 Software, Version 5.0 (EnrafNonius, Delft, Netherlands, 1989). 18. L. J. Farrugia, J. Appl. Crystallogr. 32, 837 (1999). 19. G. M. Sheldrick, SHELX97: Program for the Solution and Refinement of Crystal Structures (Univ. of GЖttingen, Germany, 1997). 20. M. N. Burnett and C. K. Johnson, ORTEP. Report ORNL 6895 (Oak Ridge National Laboratory, Tennessee, USA, 1996). 21. L. J. Farrugia, J. Appl. Crystallogr. 30, 565 (1997). 22. W. R. Busing and H. A. Levy, Acta Crystallogr. 17, 142 (1964).

pyridones, the C=O bond lengths fall in the range between 1.21 and 1.25 е, which indicates that protonation (or alkylation) of the oxygen heteroatom results in an elongation of the double carbonoxygen bond. In structure V, the C(5)O(4) bond length is 1.339(4) е. This value is intermediate between the single and double CO bond lengths in the positively charged amide group. The N(1)C(5) bond length is also 1.339(4) е. This bond is shorter than the two other CN bonds at the same nitrogen atom [1.381(4) and 1.398(4) е]. Based on these arguments, we concluded that the structure of the oxazolopyridinium cation can be described by a superposition of the B and C formulas (with a slightly larger contribution of the B structure). Probably, the structure of the cation is most adequately represented by the following charge delocalization:
CH3 N+ O Cl

Scheme 3.

The thermal ellipsoids of the oxygen atoms in the perchlorate anion exhibit strong anisotropy in the plane perpendicular to the ClO bond (Fig. 4). This suggests some degree of rotational freedom of the perchlorate ion about the chlorine atom. ACKNOWLEDGMENTS This work was supported by the International Association of Assistance for the promotion of cooperation with scientists from the New Independent States of the Former Soviet Union (project INTAS no. 00-0711). We also acknowledge the support of the Russian Foundation for Basic Research in the payment of the license for using the Cambridge Structural Database, project no. 02-07-90322. REFERENCES
1. V. B. Rybakov, stallografiya 44 997 (1999)]. 2. V. B. Rybakov, stallografiya 45 103 (2000)]. S. G. Zhukov, E. V. Babaev, et al., Kri(6), 1067 (1999) [Crystallogr. Rep. 44, S. G. Zhukov, E. V. Babaev, et al., Kri(1), 108 (2000) [Crystallogr. Rep. 45,

Translated by I. Polyakova

CRYSTALLOGRAPHY REPORTS

Vol. 49

No. 3

2004