Synthesis of 6-methyl-3,4-dihydropyrazinones using an Ugi 4-CR/allenamide cycloisomerization protocol.
Icelo-Ávila, Estefanía; Amador-Sánchez, Yoarhy A; Polindara-García, Luis A; Miranda, Luis D.; Organic & biomolecular chemistry 15 (2017) 360–372; doi:10.1039/c6ob02266a

data_7155429
_publ_section_title
;
 Synthesis of 6-methyl-3,4-dihydropyrazinones using an Ugi 4-CR/allenamide
 cycloisomerization protocol.
;
_journal_issue                   2
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              360
_journal_page_last               372
_journal_paper_doi               10.1039/c6ob02266a
_journal_volume                  15
_journal_year                    2017
_chemical_formula_sum            'C21 H20 N2 O2'
_chemical_formula_weight         332.39
_chemical_melting_point          201.5(15)
_chemical_name_systematic
2-(2,6-Dimethylphenyl)-1,4-dimethylpyrazino[2,1-a]isoindole-3,6(2H,4H)-dione
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2016-07-26 deposited with the CCDC.
2016-11-24 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 108.859(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   8.2348(7)
_cell_length_b                   26.914(2)
_cell_length_c                   8.2642(7)
_cell_measurement_reflns_used    9965
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      25.28
_cell_measurement_theta_min      2.60
_cell_volume                     1733.3(2)
_computing_cell_refinement       'APEX2 V2012 (Bruker, 2012)'
_computing_data_collection       'APEX2 V2012 (Bruker, 2012)'
_computing_data_reduction        'SAINT V8.27B  (Bruker, 2012)'
_computing_molecular_graphics    'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_publication_material  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-2014/7 (Sheldrick, 2014)'
_diffrn_ambient_temperature      298(2)
_diffrn_detector_area_resol_mean 0.83
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker APEX2 CCD area detector'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0826
_diffrn_reflns_av_unetI/netI     0.0416
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       31
_diffrn_reflns_limit_k_min       -32
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            19869
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.997
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.319
_diffrn_reflns_theta_min         2.712
_exptl_absorpt_coefficient_mu    0.083
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.274
_exptl_crystal_description       Prism
_exptl_crystal_F_000             704
_exptl_crystal_recrystallization_method
'Liquid-Liquid Difussion: Dichlormethane-Acetone'
_exptl_crystal_size_max          0.360
_exptl_crystal_size_mid          0.280
_exptl_crystal_size_min          0.200
_refine_diff_density_max         0.250
_refine_diff_density_min         -0.209
_refine_diff_density_rms         0.059
_refine_ls_extinction_coef       0.018(3)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2014/7 (Sheldrick 2014'
_refine_ls_goodness_of_fit_ref   1.070
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     231
_refine_ls_number_reflns         3138
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.070
_refine_ls_R_factor_all          0.0664
_refine_ls_R_factor_gt           0.0532
_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^)+(0.0924P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1406
_refine_ls_wR_factor_ref         0.1508
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2384
_reflns_number_total             3138
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c6ob02266a2.cif
_cod_data_source_block           364mgl15
_cod_depositor_comments
;
The following automatic conversions were performed:

'_chemical_melting_point' value '200-203' was changed to '201.5(15)'
- the average value was taken and precision was estimated.

Automatic conversion script
Id: cif_fix_values 4268 2015-11-12 08:31:59Z antanas 
;
_cod_original_cell_volume        1733.3(3)
_cod_database_code               7155429
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.971
_shelx_estimated_absorpt_t_max   0.984
_shelx_res_checksum              21638