Synthesis of Pyridopyrazine-1,6-diones from 6-Hydroxypicolinic Acids via a One-Pot Coupling/Cyclization Reaction.
Tran, Tuan P.; Mullins, Patrick B.; Am Ende, Christopher W.; Pettersson, Martin; Organic letters 15 (2013) 642–645; doi:10.1021/ol303463e

data_1508902
_publ_section_title
;
 Synthesis of Pyridopyrazine-1,6-diones from 6-Hydroxypicolinic Acids via
 a One-Pot Coupling/Cyclization Reaction.
;
_journal_issue                   3
_journal_name_full               'Organic letters'
_journal_page_first              642
_journal_page_last               645
_journal_paper_doi               10.1021/ol303463e
_journal_volume                  15
_journal_year                    2013
_chemical_formula_sum            'C12 H10 N4 O'
_chemical_formula_weight         226.24
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   7.5741(3)
_cell_length_b                   13.7438(5)
_cell_length_c                   21.7946(7)
_cell_measurement_reflns_used    2340
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      53.01
_cell_measurement_theta_min      3.80
_cell_volume                     2268.75(14)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0611
_diffrn_reflns_av_sigmaI/netI    0.0361
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            8959
_diffrn_reflns_theta_full        53.07
_diffrn_reflns_theta_max         53.07
_diffrn_reflns_theta_min         4.06
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.734
_exptl_absorpt_correction_T_max  0.8979
_exptl_absorpt_correction_T_min  0.8044
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   SADABS
_exptl_crystal_density_diffrn    1.325
_exptl_crystal_density_meas      0
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             944
_exptl_crystal_size_max          0.31
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.275
_refine_diff_density_min         -0.219
_refine_diff_density_rms         0.035
_refine_ls_extinction_coef       0.0031(4)
_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_ref   1.053
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     155
_refine_ls_number_reflns         1322
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.053
_refine_ls_R_factor_all          0.0567
_refine_ls_R_factor_gt           0.0446
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0668P)^2^+0.7491P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1187
_refine_ls_wR_factor_ref         0.1285
_reflns_number_gt                1071
_reflns_number_total             1322
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol303463e_si_003.cif
_cod_data_source_block           z193
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 1891 2012-01-12 08:04:46Z andrius 
;
_cod_original_sg_symbol_H-M      Pbca
_cod_database_code               1508902