J. V. SILVERTON, C. KABUTO AND T. AKIYAMA 593 References ALTONA, C., GEISE, H. J. & ROMERS, C. (1968). Tetrahedron, 24, 13-22. BUCHI, G., KITAURA, Y., YUAN, S. S., WRIGHT, H. E., CLARDY, J., DEMAIN, A. L., GLINSUKIN, T., HUNT, N. & WOGAN, G. N. (1973). J. Am. Chem. Soc. 95, 5423-5425. CROMER, D. Z. t~ MANN, J. I. (1968). Acta Cryst. A24, 321-324. DE TITTA, G. T., EDMONDS, J. E., LANGS, D. A. & HAUPTMAN, H. A. (1975). Acta Cryst. A31, 472-479. ENGEL, D. W. (1972). Acta Cryst. B28, 1496-1509. HAUPTMAN, H. A. (1972). Crystal Structure Determination. New York: Plenum. HAUPTMAN, H. A. (1975). Acta Cryst. A31,680-687. KABUTO, C., SILVERTON,J. V., AKIYAMA,T., SANKAWA, V., HUTCHISON, R. D., STEYN, P. S. & VLEGGAR, R. (1976). J. Chem. Soc. Chem. Commun. pp. 728-279. MAIN, P., WOOLFSON, M. M. & GERMAIN, G. (1971). MULTAN, A Computer Program for the Automatic Solution of Crystal Structures. Univs. of York, England, and Louvain, Belgium. PETERSON, S. W. & LEVY, H. A. (1957).Acta Cryst. 10, 70- 76. SILVERTON, J. V. & AKIYAMA, T. (1977). Unpublished results. SILVERTON, J. V., AKIYAMA, T., KABUTO, C., SEKITA, S., YOSHIHIRA, K. & NATORI, S. (1976). Tetrahedron Lett. pp. 1349-1350. SILVERTON, J. V. & KABUTO, C. (1975). Unpublished programs. SPRINGER, J. P., CLARDY, J., WELL, J. M., COLE, R. J., KIRKSEY, J. W., MACFARLANE, R. D. & TORGERSON, D. F. (1976). Tetrahedron Lett. pp. 1355-1358. STEWART, J. M., KRUGER, G. J., AMMON, H. L., DICKINSON, C. & HALL, S. R. (1972). The XRAY system-version of June 1972. Tech. Rep. TR- 192. 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. TSUKUDA, Y. & KOYAMA, H. (1972). J. Chem. Soc. Perkin Trans. 2, pp. 739-744. Acta Cryst. (1978). B34, 593-597 The Crystal and Molecular Structures of Two Derivatives of a Spiro-oxazolone: a cis vs trans X-ray Study BY M. L. MARTiNEZ,F. H. CANO AND S. GARCiA-BLANCO Departamento de Rayos X, Instituto de Qu:mica-Ffsica 'Rocasolano', Serrano 119, Madrid 6, Spain (Received 27 June 1977; accepted 23 September 1977) The typical c&-trans ambiguity for two spiro-oxazolone derivatives has been solved. The compounds (C17H~302N) crystallize in space groups P2~/c and P1, respectively, with Z = 4 and 2, in unit cells of dimensions: a = 5.988 (2), b = 10.703 (4), c = 21.338 (8) A, fl = 94.12 (2) ° and a = 11.099 (2), b = 11.182 (2), c = 5.482 (1) A, a = 82.39 (2), fl = 95.43 (2), y = 94.26 (2) °. Direct methods followed by Fourier and then least-squares analysis, gave final R factors of 0.045 and 0.042, respectively, for the 970 and 2036 observed reflections. Half-normal probability analysis has been used to compare the two compounds. Introduction Table 1. Crystallographic data for cis- and trans- DOAS At the Centro Nacional de Quimica Orgfinica (CSIC Madrid) a search is being carried out for a suitable synthetic route of 1-aminocyclopropane carboxylic Formula acids, compounds that are believed to be of interest for Space group interfering with the biochemistry of naturally occurring z amino acids. In particular 1-amino-2-arylcyclo- u Size propane carboxylic acids could be useful as substrates a as well as inhibitors of dopadecarboxylase, a key b enzyme in the synthesis of biogenic amines. One of the ¢ (t pathways studied was the known oxazolone synthesis /~ of amino acids. It was found that the cis and trans y isomers of 2-phenyl-4-benzylidineoxazolin-5-one, on v cis-DOAS trans-DOAS C 17H 1302N C 17H 1302N P2~/c Pi 4 2 0.89 cm -~ 0.89 cm -~ 0-1 x 0.2 x 0.3mm 0.6 × 0.2 × 0.3mm 5.988 (2) A I1.099 (2) A 10.703 (4) 11.182 (2) 21.338 (8) 5.4816 (5) - 82.39 (2) ° 94.12 (1) ° 95.43 (2) - 94.26 (2) 1364.0 (8)/k 3 670.0 (5)A 3