Crystallographic Evidence of [1,5]Prototropic Shifts Occurring upon Transannular Diels–Alder Reaction of a 14-Membered Macrocycle leading to a 5α-Steroid Skeleton
Drouin, Marc; Couturier, Michel; Deslongchamps, Pierre; Acta Crystallographica Section C 54 (1998) 256–261; doi:10.1107/S0108270197013310

data_2007007
_publ_section_title
;
 Crystallographic Evidence of [1,5]Prototropic Shifts Occurring upon
 Transannular Diels--Alder Reaction of a 14-Membered Macrocycle leading
 to a 5\a-Steroid Skeleton
;
_journal_issue                   2
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              256
_journal_page_last               261
_journal_paper_doi               10.1107/S0108270197013310
_journal_volume                  54
_journal_year                    1998
_chemical_formula_structural     'C24 H30 O8'
_chemical_formula_sum            'C24 H30 O8'
_chemical_formula_weight         446.48
_chemical_name_systematic
;
rac-3,3-Bis(methoxycarbonyl)-18-oxo-5\a,9\b-androst-6-en-11,17-dione
;
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
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_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   8.0693(9)
_cell_length_b                   10.9292(5)
_cell_length_c                   24.951(2)
_cell_measurement_reflns_used    32
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      40
_cell_measurement_theta_min      30
_cell_volume                     2200.5(3)
_computing_cell_refinement       'NRCCAD TRUANG'
_computing_data_collection       'NRCCAD DATCOL (Le Page, White & Gabe, 1986)'
_computing_data_reduction
'NRCVAX DATRD2  (Gabe, Le Page, Charland, Lee & White, 1989)'
_computing_molecular_graphics    'ORTEP in Xtal_GX (Johnson, 1995)'
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_computing_structure_solution    'NRCVAX SOLVER'
_diffrn_ambient_temperature      293(2)
_diffrn_measurement_device       'Nonius CAD-4'
_diffrn_measurement_method       \w/2\q
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
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_diffrn_standards_decay_%        0
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_exptl_crystal_colour            colorless
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_exptl_crystal_density_meas      ?
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_exptl_crystal_size_mid          .30
_exptl_crystal_size_min          .20
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_refine_diff_density_min         -.198
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_refine_ls_restrained_S_obs      1.255
_refine_ls_R_factor_all          0.0489
_refine_ls_R_factor_obs          .0487
_refine_ls_shift/esd_max         0.001
_refine_ls_shift/esd_mean        0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w = 1/[\s^2^(Fo^2^)+(0.0376P)^2^+1.1699P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.1162
_refine_ls_wR_factor_obs         .1161
_reflns_number_observed          2881
_reflns_number_total             2894
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            fg1350.cif
_cod_data_source_block           3
_cod_depositor_comments
;
The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'not measured' was changed to '?'
- the value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc w =
1/[\s^2^(Fo^2^)+(0.0376P)^2^+1.1699P] 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^)+(0.0376P)^2^+1.1699P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_database_code               2007007