Structure and Absolute Configuration of 4-(a-D-Erythrofuranosyl)-1,3-dihydro-3-methyll-( p-tolyl)-2H-imidazole-2-thione, C 15 H18N2038

1212 TWO MODIFICATIONS OF C36Ha0NP2+.BaHI3(NCS)-.0.5CH2C12 We thank the SERC for support and Dr J. H. Morris for supplying us with the samples used in this study. References ANDREWS, S. J. & WELCH, A. J. (1984). Inorg. Chim. Acta, 88, 153-160. ARUNCHAIYA, M., MORI~IS, J. H., ANDREWS, S. J., WELCH, D. A. & WELCH, A. J. (1984). J. Chem. Soc. Dalton Trans. pp. 2525-2533. BARTON, L. (1982). Top. Curr. Chem. 100, 169-206. BROWN, L. D. & LIPSCOMB, W. N. (1977). Inorg. Chem. 16, 1-7. CASEY, J. B., EVANS, W. J. & POWELL, W. H. (1983). Inorg. Chem. 22, 2228-2235, 2236-2245. CROMER, D. T. & LIBERMAN, D. (1970). J. Chem. Phys. 53, 1891-1898. FRrrci-nE, C. J. (1967). Inorg. Chem. 6, 1199-1203. GAINES, D. F., LOTT, J. W. 86. CALABRESE, J. C. (1974). Inorg. Chem. 13, 2419-2423. GLIDEWELL, C. & LILES, D. C. (1981). J. Organomet. Chem. 212, 291-300. GLORE, J. D., RATHKE, J. W. & SCHAEFFER, R. (1973). Inorg. Chem. 12, 2175-2178. GREENWOOD, N. N., MCGINNETY, J. A. & OWEN, J. D. (1972). J. Chem. Soc. Dalton Trans. pp. 986-989. HOWELL, J., RossI, A., WALLACE, D., HARAKI, K. & HOFFMANN, R. (1977). Quantum Chem. Program Exch. 10, 344. HUFFMAN, J. C. & SCHAEFFER, R. (1984). Personal communication to N. N. GREENWOOD, Liversedge Lecture of the Royal Society of Chemistry. JACOBSEN, G. B., MORRIS, J. H. & REED, D. (1984). J. Chem. Soc. Dalton Trans. pp. 415-421. JOHNSON, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee. LOT'r, J. W. & GAINES, D. F. (1974). Inorg. Chem. 13, 2261-2267. MITCHELL, G. F. 8/. WELCH, A. J. (1985). To be published. PETERS, C. R. & NORDMAN, C. E. (1960). J. Am. Chem. Soc. 82, 5758. PIPAL, J. R. & GRIMES, R. N., (1977). Inorg. Chem. 16, 3251-3255. ROBERTS, P. & SHELDRICK, G. M. (1976). XANADU. Program for crystallographic calculations. Univ. of Cambridge, England. SHELDRICK, G. M. (1976). SHELX76. Program for crystal structure determination. Univ. of Cambridge, England. SHELDRICK, G. M. (1984). SHELX84. Program for crystal structure determination. Univ. of G6ttingen, FRG. STEWART, J. M., MACHIN, P. A., DICKINSON, C. W., AMMON, H. L., HECK, H. & FLACK, H. (1976). The XRA Y76 system. Tech. Rep. TR-446. Computer Science Center, Univ. of Maryland, College Park, Maryland. STEWART, R. F., DAVIDSON, E. R. & SIMPSON, W. T. (1965). J. Chem. Phys. 42, 3175-3187. TIPPE, A. & HAMILTON, W. C. (1969). Inorg. Chem. 8, 464-470. WANG, F. E., SIMPSON, P. G. & LIPSCOMB, W. N. (1961). J. Chem. Phys. 35, 1335-1339. Acta Cryst. (1985). C41, 1212-1214 Structure and Absolute Configuration of 4-(a-D-Erythrofuranosyl)-1,3-dihydro-3-methyll-(p-tolyl)-2H-imidazole-2-thione, C 15 H18N2038 BY A. CRIADO, A. CONDE AND R. MA, RQUEZ Departamento de Optica y Centro Coordinado del CSIC, Facultad de Ffsica, Universidad de Sevilla, Spain (Received 2 January 1985; accepted 1 April 1985) Abstract. M r = 306.4, monoclinic, P21, a = 14.686 (6), b=5.359(4), c=9.439(3) A, fl=98.68(3) ° , V= 734.4 (7)/I,3, Z = 2, D x = 1.38 Mg m -3, 2(Mo Kct) = 0.7107 A, /t = 0-22 mm -1, F(000) = 324, T= 300 K, final R=0.042 (wR=0.037) for 1987 observed independent reflections. The sugar ring has a conformation intermediate between 3T 2 and 3E. The configuration of the imidazole ring with respect to the furanose ring is anti, the glycosidic angle being -9.3 (4) ° . The crystal packing is governed by hydrogen bonds involving OH groups and S atoms, forming infinite chains along [001]. Introduction. The title compound (I) was obtained (Fernfindez-Bolafios, Fuentes-Mota & FernfindezBolafios Guzm~n, 1983) by the catalysed formation of the anhydride of 1,3-dihydro-3-methyl-4-(D-arabino1,2,3,4 -tetr ahydroxybutyl) - 1 - (p-tolyl)- 2H-imid az ole2 - 0108-2701/85/081212-03501.50 thione. By the same process the fl anomer was also obtained, and its structure reported by Criado, Conde & Mfirquez (1983). The structural study of both anomers forms part of a systematic research project dealing with D-erythrofuranosyldihydroimidazole-2thione compounds (Conde, L6pez-Castro & Mfirquez, 1978) prepared in the Organic Chemistry Department of this University. CH a OH OH CH:] (I) © 1985 International Union of Crystallography A. CRIADO, A. CONDE AND R. MARQUEZ 1213 A conformational study of sugar rings for both compounds has been performed by means of the 1H NMR technique in solution, and the results (FernfindezBolafios Guzmfin, 1984) agree with X-ray data in the solid state. Experimental. Needle-shaped colourless crystals, supplied by Professor Fernfindez-Bolafios of the Organic Chemistry Department of this University. Weissenberg diagram s showed monoclinic symmetry; space group P21 from systematic absences. CAD-4 computer-controlled diffractometer, graphite-monochromated radiation. Crystal 0.1 x 0.2 × 1.1 mm. Unit-cell parameters from least-squares fit of 0 values of 25 reflections, 6 < 0< 15 °. 2352 reflections measured with 0<30" (-20<h_<20, 0<k<7, 0<l<13). 09-20 scan mode. 1987 reflections with I>2tr(I) considered observed. Two reference reflections controlled periodicaUy, intensity changes less than 3%. Lorentz and polarization corrections. No absorption or extinction effects considered. Weighted tangent-formula refinement (MULTAN80; Main, Fiske, Hull, Lessinger, Germain, Declercq & Woolfson, 1980) of 234 reflections with E > 1.5. Full-matrix least-squares refinement of 189 parameters based on F o with all observed reflections (CR YLSQ of XRA Y70; Stewart, Kundell & Baldwin, 1970). Fourier difference synthesis up to sinS/2= 0.7 A -1 gave all H-atom positions; a leastsquares refinement in a mixed mode with H atoms, each with an isotropic temperature factor equal to that of the attached skeleton atom, gave wR = 0.037 (R = 0.042). Final-cycle parameter shifts less than 0. l a, average 0.053. Final difference Fourier map --0-21 <Ap< 0.29 e A -a. S = 2.35 for 244 parameters. Atomic scattering factors and anomalous-dispersion corrections for S from International Tables for X-ray Crystallography (1974). Weighting scheme 1/a2(I) based on counting statistics. The enantiomorphic form was considered and the final wR = 0-038 (R = 0.043). The application of the ~ test (Hamilton, 1965) indicated that the first form is correct {[wR(2)/wR(1)] = 1.027; ~1,~744,0.005= 1.002} and can be retained as the absolute configuration. This form is consistent with the configuration of the sugar used in the synthesis. Diseusslon. Final atomic coordinates and equivalent isotropic thermal parameters (Hamilton, 1956) for non-H atoms are given in Table 1.* Bond lengths and angles are shown in Table 2. The C--H distances are 0.84 (4) to 1.10 (4) A with a mean of 0.97 (3) A. The average O-H bond length is 0.90 (3) A. * Lists of structure factors, anisotropic thermal parameters and H-atom parameters have been deposited with the British Library Lending Division as Supplementary Publication No. SUP 42175 (13 pp.). Copies may be obtained through The Executive Secretary, International Union of Crystallography, 5 Abbey Square, Chester CH 1 2HU, England. Imidazole ring. Bond lengths and angles in the imidazole ring are quite similar to those found in the fl anomer (Criado, Conde & Mfirquez, 1983) and other aiaalogous imidazole-2-thione compounds studied previously (Conde, L6pez-Castro & M~quez, 1978). Partial double-bond character is found for the S-C bond, also present in the above-mentioned compounds, in agreement with canonical resonance forms in the thiourea system. Table 1. Positional parameters (x 104) and equivalent isotropic thermal parameters (×104) for the non-H atoms, with e.s.d.'s in parentheses __1 ~ Ueq -- ~ZtZjUIja I a3 at.aj. X y z Ueq(A 2) S 8330 (1) 5000 -3021 (1) 449 (3) N(1) 7238 (1) 5112 (5) -901 (2) 334 (6) N(2) 8400 (1) 7656 (5) -545 (2) 316 (7) O(1) 7426 (1) 9943 (5) 2583 (2) 484 (7) O(2) 9330 (1) 9447 (4) 5460 (2) 439 (7) O(3) 9098 (I) 6517 (4) 2964 (2) 567 (8) C(1) 7984 (2) 5924 (5) -1486 (3) 308 (8) C(2) 7199 (2) 6381 (6) 375 (3) 380 (9) C(3) 7912 (2) 7958 (6) 598 (2) 332 (8) C(4) 8173 (1) 9794 (6) 1770 (2) 363 (8) C(5) 7768 (2) 9841 (9) 4068 (3) 560 (11) C(6) 8794 (2) 10335 (6) 4201 (3) 375 (8) C(7) 9030 (2) 9128 (6) 2844 (3) 368 (9) C(8) 6502 (2) 3565 (5) -1596 (3) 327 (8) C(9) 6670 (2) 1420 (6) -2324 (3) 373 (9) C(10) 5935 (2) 42 (7) -3006 (3) 432 (9) C(11) 5030 (2) 774 (6) -2981 (3) 433 (10) C(12) 4879 (2) 2915 (7) -2217 (3) 447 (I0) C(13) 5601 (2) 4303 (6) -1525 (3) 413 (9) C(14) 4225 (2) -681 (7) -3753 (4) 647 (13) C(15) 9215 (2) 9062 (6) -756 (3) 433 (9) Table 2. Bond distances (A) and angles (o) with e.s.d.'s in parentheses S-C(1) 1.681 (3) N(1)-C(I) 1.370 (3) N(1)--C(2) 1.391 (3) N(I)-C(8) 1.439 (3) N(2)--C(1) 1.364 (3) N(2)--C(3) 1.391 (3) N(2)--C(15) 1.453 (4) O(1)-C(4) 1.433 (3) O(1)-C(5) 1.418 (3) O(2)-C(6) 1.406 (3) O(3)-C(7) 1.406 (4) C(2)-C(3) 1.337 (4) C(2)-N(1)-C(8) 123.4 (2) C(I)--N(1)--C(8) 126.2 (2) C(1)-N(1)--C(2) 109.5 (2) C(3)-N(2)-C(15) 125.2 (2) C(1)-N(2)--C(15) 124.1 (2) C(1)-N(2)-C(3) 110.6 (2) C(4)-O(1)--C(5) 109.9 (2) N(1)-C(I)-N(2) 105.1 (2) S-C(I)-N(2) 126.7 (2) S-C(1)-N(1) 128.2 (2) N(1)-C(2)-C(3) 108.2 (2) N(2)--C(3)--C(2) 106.7 (2) C(2)-C(3)-C(4) 130.0 (3) N(2)-C(3)-C(4) 123.3 (2) O(1)-C(4)-C(3) 107.6 (2) C(3)-C(4)-C(7) 115.5 (3) O(1)-C(4)-C(7) 106.1 (2) C(3)-C(4) 1.487 (4) C(4)-C(7) 1.534 (3) C(5)-C(6) 1.515 (4) C(6)-C(7) 1.522 (4) C(8)-C(9) 1.380 (4) C(8)--C(13) 1.392 (4) C(9)-C(10) 1.384 (4) C(10)--C(11) 1.390 (4) C(11)-C(12) 1.391 (5) C(11)-C(14) 1.508 (4) C(12)-C(13) 1.377 (4) O(1)-C(5)-C(6) 106.0 (2) O(2)-C(6)-C(5) 115.7 (2) C(5)-C(6)-C(7) 101.9 (2) O(2)-C(6)-C(7) 113.4 (2) C(4)-C(7)-C(6) 100.9 (2) O(3)-C(7)-C(6) 112.2 (3) O(3)-C(7)-C(4) 109.0 (3) N(1)-C(8)-C(13) 117.9 (3) N(1)-C(8)-C(9) 121.9 (3) C(9)-C(8)-C(13) 120.2 (3) C(8)-C(9)-C(10) 119.4 (3) C(9)-C(10)-C(11) 121.4 (3) C(10)-C(l 1)-C(14) 121.8 (3) C(10)-C(11)-C(12) 118.0 (3) C(12)-C(11)-C(14) 120.2 (3) C(11)-C(12)-C(13) 121.3 (3) C(8)-C(13)-C(12) 119.5 (3) 1214 C15HlaN203S The ring deviates very slightly from expected planarity [~(zJ/tT) 2= 11.74; X 2 for two degrees of freedom at 95% is 5.99]. The maximum atomic deviation from the least-squares plane is 0.006 (3)/~. Phenyl ring. The mean value of the C-C bond length in the phenyl group is 1-385 (4)A and the average C-C-C bond angle is 120.0(3) °. The observed deviation from planarity [~,(A/a) 2 = 36.0] could not be real. The dihedral angle between the phenyl and imidazole rings is 42.2 (1) °, very close to the 40.7 (2) ° found in the fl anomer and the same conclusions are derived here: crystal forces contribute significantly to phenyl-imidazole subrotation. Furanosyl ring. Bond lengths and angles are in agreement with the values corresponding to the fl anomer and other similar reported compounds. The typical asymmetry of the endocyclic bonds O(1)-C(4) 1.433 (3) and O(1)-C(5)-- 1.418 (3)/k due to anomeric effects is observed. Average values for C-C-C 101.4 (3), C-C-O 106.0 (2) and C-O-C 109.9(2) ° agree with the mean values reported previously (Conde, L6pez-Castro & Mhrquez, 1978). The furanosyl ring is not planar, and in terms of the ring-puckering coordinates (Cremer & Pople, 1975) the amplitude phase magnitudes are Q = 0.382 (4)/k and ~0=-86.2 (6) ° for the sequence O(1)-C(4)-C(7)- C(6)-C(5). The conformation is different from that of the fl anomer, but the values of the pseudorotational parameters r m and P place the conformation in one of the most statistically crowded regions of the conformational wheel (Pullman, 1976), whereas the fl anomer lies in another crowded region. The asymmetry parameters AC2[O(1 )] =0.0155 (24) and ACs[C(6)] = 0.0738 (33) (Nardelli, 1983) show a conformation intermediate between aT E and 32. | o 0c Z! j P ,go ~ oc2~ Fig. 1. The unit cell viewed along b. Broken lines are hydrogen bonds. Molecular conformation. The orientation of imidazole with respect to furanose is anti. The glycosidic torsion angle O(1)-C(4)-C(3)-C(2) (Sundaralingam, 1969) is -9.3 (4) °. The fl anomer has a value of 24.6 (7) ° , and is also anti; no correlation has been found between sugar conformation and glycosidic angles. Both anti and syn conformations have been found in previous structural analysis of imidazole C-nucleosides. Crystal packing. Fig. 1 shows the contents of the unit cell viewed along b. Packing is due to hydrogen bonds. Each molecule is linked by a hydrogen bond to another molecule related to the former by a lattice translation along e, resulting in a pattern of infinite chains parallel to e: O(2)--H(O2)...S(x, y, 1 + z) with H(O2)...S 2.35 (3), O(2)--H(O2) 0.90 (3), O(2)...S 3.244 (3)/k, O(2)-H(O2)...S 172(3) °. On the other hand, molecules related by a twofold screw axis are linked by O(3)--H(O3)...O(2)(2 - x, y - ½, 1 - z) to form helical chains parallel to [010]: O(3)-H(O3) 0.91(3), H(O3)...O(2) 1.91 (3), 0(3)...0(2) 2.781 (2)/k, O(3)--H(O3)...O(2) 160 (3) ° . No other intermolecular contacts shorter than the sum of the van der Waals radii have been detected. The authors thank Professor Fernhndez-Bolafios for supplying the crystals and Professor L6pez-Castro for her valuable help in the data collection. The present work forms part of a program supported by the Government through the 'Comisi6n Asesora de Investigaci6n Cientifica y T~cnica'. References CONDE, A., LOPEZ-CASTRO, A. & M.~RQUEZ, R. (1978). Rev. Iberoam. Cristalogr. Miner. Metalogen. 1, 23-36. CREMER, D. & POPLE, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358. CRIADO, A., CONDE, A. • MARQUEZ, R. (1983). Acta Cryst. C39, 122-125. FERNANDEZ-BOLAI~IOS, J., FUENTES-MOTA, J. & FERNANDEZBOLA~OS GUZMAN, J. (1983). An. Quim. 79, 345-349. FERNANDEZ-BOLAr~OS GUZMAN, J. (1984). Doctoral thesis, Univ. de SeviUa. HAMILTON, W. C. (1956). Acta Cryst. 12, 609-610. HAMILTON, W. C. (1965). Acta Cryst. 18, 502-510. International Tables for X-ray Crystallography (1974). Vol. IV. Birmingham: Kynoch Press. (Present distributor D. Reidel, Dordrecht.) MAIN, P., FISKE, S. J., HULL, S. E., LESSINGER, L., GERMAIN, G., DECLERCQ, J.-P. & WOOLFSON, M. M. (1980). MULTAN80. A System of Computer Programs for Automatic Solution of Crystal Structures from X-ray Diffraction Data. Univs. of York, England, and Louvain, Belgium. NARDELLI, M. (1983). Acta Cryst. C39, 1141-1142. PULLMAN, B. (1976). Quantum Mechanics of Molecular Conformations, edited by B. PULLMAN, p. 373. London, New York: John Wiley. STEWART, J. M., KUNDELL, F. A. & BALDWIN, J. C. (1970). The XRA Y70 system. Computer Science Center, Univ. of Maryland, College Park, Maryland. SUNDARALINGAM, M. (1969). Biopolymers, 7, 821-860.