6-(3,5-Di-O-acetyl-β-D-2-deoxyribofuranosyl)-3,4-dihydro-8-H-pyrimido[4,5-c][1,2]oxazin-7-one
Van Meervelt, Luc; Kong Thoo Lin, Paul; Brown, Daniel M.; Acta Crystallographica Section C 51 (1995) 1347–1350; doi:10.1107/S0108270195000096

data_2003685
_publ_section_title
6-(3,5-Di-O-acetyl-\b-D-2-deoxyribofuranosyl)-3,4-dihydro-8-H-pyrimido[4,5-c][1,2]oxazin-7-one
_journal_issue                   7
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              1347
_journal_page_last               1350
_journal_paper_doi               10.1107/S0108270195000096
_journal_volume                  51
_journal_year                    1995
_chemical_compound_source        'grown from ethanol'
_chemical_formula_sum            'C15 H19 N3 O7'
_chemical_formula_weight         353.33
_chemical_name_systematic
6-(3,5-Di-O-acetyl-\b-D-2-deoxyribofuranosyl)-3,4-dihydro-8-H-pyrimido[4,5-c][1,2]oxazin-7-one
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     'Patterson search methods'
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL
_cell_angle_alpha                90.00
_cell_angle_beta                 101.66(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   14.662(3)
_cell_length_b                   5.4190(10)
_cell_length_c                   21.475(4)
_cell_measurement_reflns_used    20
_cell_measurement_temperature    289(2)
_cell_measurement_theta_max      21
_cell_measurement_theta_min      11
_cell_volume                     1671.1(6)
_computing_cell_refinement       XSCANS
_computing_data_collection       'XSCANS (Fait, 1991)'
_computing_data_reduction        'Siemens REDUCE'
_computing_molecular_graphics    'SHELXTL-PC (Sheldrick, 1990)'
_computing_publication_material  SHELXL93
_computing_structure_refinement  'SHELXL93 (Sheldrick, 1993)'
_computing_structure_solution    'DIRDIF (Beurskens et al., 1992)'
_diffrn_ambient_temperature      289(2)
_diffrn_measurement_device       'Siemens P4-PC diffractometer'
_diffrn_measurement_method       '\q-2\q scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0000
_diffrn_reflns_av_sigmaI/netI    0.1177
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       5
_diffrn_reflns_limit_k_min       -1
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            2121
_diffrn_reflns_theta_max         47.22
_diffrn_reflns_theta_min         2.10
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 100
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.959
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            white
_exptl_crystal_density_diffrn    1.404
_exptl_crystal_density_method    .
_exptl_crystal_description       needles
_exptl_crystal_F_000             744
_exptl_crystal_size_max          0.3
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.242
_refine_diff_density_min         -0.271
_refine_ls_abs_structure_details
;
The absolute configuration was assigned to agree with the known chirality
at C4' arising from its synthetic precursor.
;
_refine_ls_abs_structure_Flack   -1.28(88)
_refine_ls_extinction_coef       0.00018(8)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_all   1.073
_refine_ls_goodness_of_fit_obs   1.313
_refine_ls_hydrogen_treatment
;
The H atoms were placed at calculated positions (C-H = 0.98\%A for tertiary
C-H, C-H = 0.97\%A for secondary CH~2~, C-H = 0.93\%A for Csp^2^-H,
C-H = 0.96\%A for an idealized methyl group and N-H = 0.90\%A, U = 1.2 x Ueq
of the parent atom) and refined in the riding mode or rotating mode
(methyl groups).
;
_refine_ls_matrix_type           full
_refine_ls_number_parameters     470
_refine_ls_number_reflns         2121
_refine_ls_number_restraints     737
_refine_ls_restrained_S_all      0.942
_refine_ls_restrained_S_obs      1.016
_refine_ls_R_factor_all          0.1235
_refine_ls_R_factor_obs          0.0692
_refine_ls_shift/esd_max         -0.198
_refine_ls_shift/esd_mean        0.022
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
;
 w=1/[\s^2^(Fo^2^)+(0.0332P)^2^+5.4135P] where P=(Fo^2^+2Fc^2^)/3
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.1726
_refine_ls_wR_factor_obs         0.1468
_reflns_number_observed          1256
_reflns_number_total             2121
_reflns_observed_criterion       >2sigma(I)
_cod_depositor_comments
;
The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc
w=1/[\s^2^(Fo^2^)+(0.0332P)^2^+5.4135P]' was changed to 'calc'. New
tag '_refine_ls_weighting_details' was created. The value of the new
tag was set to 'w=1/[\s^2^(Fo^2^)+(0.0332P)^2^+5.4135P]'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               2003685