Synthesis of N,N-Dioxopyridazines.
Rozen, Shlomo; Shaffer, Avshalom; Organic letters 19 (2017) 4707–4709; doi:10.1021/acs.orglett.7b02310

data_1547566
_publ_section_title
;
 Synthesis of N,N-Dioxopyridazines.
;
_journal_issue                   18
_journal_name_full               'Organic letters'
_journal_page_first              4707
_journal_page_last               4709
_journal_paper_doi               10.1021/acs.orglett.7b02310
_journal_volume                  19
_journal_year                    2017
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C4 H4 N2 O2'
_chemical_formula_sum            'C4 H4 N2 O2'
_chemical_formula_weight         112.09
_space_group_crystal_system      monoclinic
_space_group_IT_number           7
_space_group_name_Hall           'P -2yac'
_space_group_name_H-M_alt        'P 1 n 1'
_symmetry_space_group_name_Hall  'P -2yac'
_symmetry_space_group_name_H-M   'P 1 n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 97.068(5)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   3.8868(3)
_cell_length_b                   5.4329(5)
_cell_length_c                   10.8693(10)
_cell_measurement_reflns_used    981
_cell_measurement_temperature    110(2)
_cell_measurement_theta_max      28.312
_cell_measurement_theta_min      3.750
_cell_volume                     227.78(3)
_computing_cell_refinement       'Saint, Bruker-AXS'
_computing_data_collection       'Apex2, Bruker-AXS'
_computing_data_reduction        'Saint, Bruker-AXS'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXT-2014 (Sheldrick, 2015)'
_diffrn_ambient_temperature      110(2)
_diffrn_detector_area_resol_mean 1.75
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'ApexDuo, Bruker-AXS'
_diffrn_measurement_method       '0.5 deg. \f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0195
_diffrn_reflns_av_unetI/netI     0.0270
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.995
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -5
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            2169
_diffrn_reflns_point_group_measured_fraction_full 0.942
_diffrn_reflns_point_group_measured_fraction_max 0.921
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.312
_diffrn_reflns_theta_min         3.750
_diffrn_source                   'ImuS micro-focus'
_exptl_absorpt_coefficient_mu    0.134
_exptl_absorpt_correction_T_max  0.995
_exptl_absorpt_correction_T_min  0.971
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Sadabs, Bruker-AXS'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.634
_exptl_crystal_description       block
_exptl_crystal_F_000             116
_exptl_crystal_size_max          0.328
_exptl_crystal_size_mid          0.184
_exptl_crystal_size_min          0.040
_refine_diff_density_max         0.158
_refine_diff_density_min         -0.188
_refine_diff_density_rms         0.040
_refine_ls_abs_structure_details
;
 Flack x determined using 427 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.3(6)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.092
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     73
_refine_ls_number_reflns         1044
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.091
_refine_ls_R_factor_all          0.0316
_refine_ls_R_factor_gt           0.0292
_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^)+(0.0357P)^2^+0.0394P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0710
_refine_ls_wR_factor_ref         0.0731
_reflns_Friedel_coverage         0.841
_reflns_Friedel_fraction_full    0.886
_reflns_Friedel_fraction_max     0.847
_reflns_number_gt                981
_reflns_number_total             1044
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ol7b02310_si_001.cif
_cod_data_source_block           N,N-dioxopyridazine
_cod_database_code               1547566
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.957
_shelx_estimated_absorpt_t_max   0.995
_shelx_res_checksum              60305
_shelx_hkl_checksum              33162