A Convenient Synthesis of C-22 and C-25 Stereoisomers of Cephalostatin North 1 Side Chain from Spirostan Sapogenins
Betancor, Carmen; Freire, Raimundo; Pérez-Martín, Inés; Prangé, Thierry; Suárez, Ernesto; Organic Letters 4 (2002) 1295–; doi:10.1021/ol025580e

data_1507444
_publ_section_title
;
 A Convenient Synthesis of C-22 and C-25 Stereoisomers of Cephalostatin
 North 1 Side Chain from Spirostan Sapogenins
;
_journal_issue                   8
_journal_name_full               'Organic Letters'
_journal_page_first              1295
_journal_paper_doi               10.1021/ol025580e
_journal_volume                  4
_journal_year                    2002
_chemical_formula_sum            'C28 H44 N0 O5'
_chemical_formula_weight         460.63
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           4
_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     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 102.40(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   17.185(4)
_cell_length_b                   7.4080(12)
_cell_length_c                   10.450(9)
_cell_measurement_temperature    293(2)
_cell_volume                     1299.3(12)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.930
_diffrn_measured_fraction_theta_max 0.930
_diffrn_measurement_device_type  'Philpis PW1100'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54180
_diffrn_reflns_av_R_equivalents  0.0000
_diffrn_reflns_av_sigmaI/netI    0.0531
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -18
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            1962
_diffrn_reflns_theta_full        60.00
_diffrn_reflns_theta_max         60.00
_diffrn_reflns_theta_min         2.63
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.626
_exptl_crystal_density_diffrn    1.177
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             504
_refine_diff_density_max         0.234
_refine_diff_density_min         -0.287
_refine_diff_density_rms         0.063
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.5(7)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.049
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     300
_refine_ls_number_reflns         1962
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.049
_refine_ls_R_factor_all          0.0920
_refine_ls_R_factor_gt           0.0790
_refine_ls_shift/su_max          1.343
_refine_ls_shift/su_mean         0.139
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0971P)^2^+2.5654P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1975
_refine_ls_wR_factor_ref         0.1997
_reflns_number_gt                1772
_reflns_number_total             1962
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol025580e_s2.cif
_cod_data_source_block           compound_15
_cod_depositor_comments
;
The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc
w=1/[\s^2^(Fo^2^)+(0.0971P)^2^+2.5654P] where P=(Fo^2^+2Fc^2^)/3' 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^)+(0.0971P)^2^+2.5654P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        1299.3(11)
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               1507444