Alternative Syntheses of the New D~2d~ Symmetric Tetramethyl Tricyclo- [3.3.0.0^3,7^]octane-1,3,5,7-tetracarboxylate
Carles Ayats; Pelayo Camps; María D. Duque; Mercé Font-Bardia; M. Rosa Muñoz; Xavier Solans; Santiago Vázquez; Journal of Organic Chemistry 68 (2003) 8715–8718; doi:10.1021/jo035062x

data_4022552
_publ_section_title
;
 Alternative Syntheses of the New D~2d~ Symmetric
 Tetramethyl Tricyclo- [3.3.0.0^3,7^]octane-1,3,5,7-tetracarboxylate
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              8715
_journal_page_last               8718
_journal_paper_doi               10.1021/jo035062x
_journal_volume                  68
_journal_year                    2003
_chemical_formula_sum            'C24 H24 O4'
_chemical_formula_weight         376.43
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 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                 109.8580(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.3560(10)
_cell_length_b                   13.7910(10)
_cell_length_c                   15.6330(10)
_cell_measurement_temperature    293(2)
_cell_volume                     1897.2(3)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.774
_diffrn_measured_fraction_theta_max 0.774
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0229
_diffrn_reflns_av_sigmaI/netI    0.0277
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            13970
_diffrn_reflns_theta_full        31.61
_diffrn_reflns_theta_max         31.61
_diffrn_reflns_theta_min         2.95
_exptl_absorpt_coefficient_mu    0.089
_exptl_crystal_density_diffrn    1.318
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             800
_refine_diff_density_max         0.251
_refine_diff_density_min         -0.176
_refine_diff_density_rms         0.036
_refine_ls_extinction_expression Fc
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.075
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     349
_refine_ls_number_reflns         5125
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.075
_refine_ls_R_factor_all          0.0723
_refine_ls_R_factor_gt           0.0558
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0677P)^2^+0.4756P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1425
_refine_ls_wR_factor_ref         0.1538
_reflns_number_gt                4084
_reflns_number_total             5125
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo035062xsi20030723_080058.cif
_cod_data_source_block           pchm26
_cod_depositor_comments
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The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc
w=1/[\s^2^(Fo^2^)+(0.0677P)^2^+0.4756P] 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^)+(0.0677P)^2^+0.4756P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               4022552