Polymorphism of the antiviral agent clevudine
Noonan, T. J.; Mzondo, B.; Bourne, S. A.; Caira, M. R.; CrystEngComm 18 (2016) 8172–; doi:10.1039/C6CE01975G

data_7226664
_publ_section_title
;
 Polymorphism of the antiviral agent clevudine
;
_journal_issue                   42
_journal_name_full               CrystEngComm
_journal_page_first              8172
_journal_paper_doi               10.1039/C6CE01975G
_journal_volume                  18
_journal_year                    2016
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C10 H13 F N2 O5'
_chemical_formula_sum            'C10 H13 F N2 O5'
_chemical_formula_weight         260.22
_chemical_melting_point          469.0(10)
_chemical_name_common            'Clevudine (Form 3)'
_chemical_name_systematic
1-(2-Deoxy-2-fluoro-\&s-L-arabinofuranosyl)-5-methyl-2,4-(1H,3H)-pyrimidinedione
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2016-08-31 deposited with the CCDC.
2016-09-27 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 101.604(2)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   10.4391(13)
_cell_length_b                   16.017(2)
_cell_length_c                   13.8687(18)
_cell_measurement_reflns_used    9932
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      27.98
_cell_measurement_theta_min      2.24
_cell_volume                     2271.5(5)
_computing_cell_refinement       'SAINT, V.7.60a, Bruker AXS Inc, 2006'
_computing_data_collection       'SAINT, V.7.60a, Bruker AXS Inc, 2006'
_computing_data_reduction        'SAINT, V.7.60a, Bruker AXS Inc, 2006'
_computing_molecular_graphics    'POV-Ray for Windows, 2003'
_computing_publication_material  'PLATON (A.L. Spek, 2009)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS (Sheldrick, 1997)'
_diffrn_ambient_temperature      173(2)
_diffrn_detector_area_resol_mean n/a
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker Apex Duo diffractometer'
_diffrn_measurement_method       'phi- and omega-scans of 0.50 deg.'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0259
_diffrn_reflns_av_unetI/netI     0.0297
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            42390
_diffrn_reflns_point_group_measured_fraction_full 0.997
_diffrn_reflns_point_group_measured_fraction_max 0.992
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.447
_diffrn_reflns_theta_min         1.499
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.133
_exptl_absorpt_correction_T_max  0.963
_exptl_absorpt_correction_T_min  0.929
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 2006)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.522
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1088
_exptl_crystal_recrystallization_method
'Clevudine Form 3 was obtained by heating Form 1 to 195 deg.C until the sample melted. On cooling the melt, Form 3 crystallized. '
_exptl_crystal_size_max          0.380
_exptl_crystal_size_mid          0.350
_exptl_crystal_size_min          0.290
_refine_diff_density_max         0.283
_refine_diff_density_min         -0.216
_refine_diff_density_rms         0.038
_refine_ls_abs_structure_details
;
 Flack x determined using 4224 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.2(2)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.031
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     661
_refine_ls_number_reflns         11355
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.031
_refine_ls_R_factor_all          0.0419
_refine_ls_R_factor_gt           0.0355
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0484P)^2^+0.1585P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0831
_refine_ls_wR_factor_ref         0.0862
_reflns_Friedel_coverage         0.923
_reflns_Friedel_fraction_full    0.994
_reflns_Friedel_fraction_max     0.986
_reflns_number_gt                10137
_reflns_number_total             11355
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c6ce01975g2.cif
_cod_data_source_block           clevudine3
_cod_depositor_comments
;
The following automatic conversions were performed:

'_chemical_melting_point' value '468-470 K' was changed to
'469.0(10)' - the average value was taken and precision was
estimated.

Automatic conversion script
Id: cif_fix_values 4268 2015-11-12 08:31:59Z antanas 

 Adding full bibliography for 7226662--7226664.cif.
;
_cod_original_cell_volume        2271.4(5)
_cod_database_code               7226664
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.951
_shelx_estimated_absorpt_t_max   0.963
_shelx_res_checksum              80396