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_7155428
_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_moiety         'C18 H24 N2 O2'
_chemical_formula_sum            'C18 H24 N2 O2'
_chemical_formula_weight         300.39
_chemical_melting_point          136.5(5)
_chemical_name_systematic
'4-Acetyl-1-(2,6-dimethylphenyl)-6-methyl-3-propyl-3,4-dihydropyrazin-2(1H)-one '
_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
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2014
_audit_update_record
;
2016-07-26 deposited with the CCDC.
2016-11-24 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 97.6360(10)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.2997(3)
_cell_length_b                   8.7192(3)
_cell_length_c                   27.1071(11)
_cell_measurement_reflns_used    5857
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      27.25
_cell_measurement_theta_min      2.46
_cell_volume                     1710.00(12)
_computing_cell_refinement       'APEX2 v2012.10.0(Bruker, 2012)'
_computing_data_collection       'APEX2 v2012.10.0(Bruker, 2012)'
_computing_data_reduction        'SAINT V8.27B (Bruker, 2012)'
_computing_molecular_graphics    'XP V 5.1 (Bruker, 1998)'
_computing_publication_material  'CIFTAB V 2013/2 (Sheldrick, 2013)'
_computing_structure_refinement  'SHELXL-2014/1 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-2012 (Bruker, 2013)'
_diffrn_ambient_temperature      298(2)
_diffrn_detector_area_resol_mean 8.333
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type
'Bruker Smart Apex CCD diffractometer 01-670-01'
_diffrn_measurement_method       \w-scans
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0343
_diffrn_reflns_av_unetI/netI     0.0303
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.996
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       35
_diffrn_reflns_limit_l_min       -34
_diffrn_reflns_number            16910
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.996
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.518
_diffrn_reflns_theta_min         2.456
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.076
_exptl_absorpt_correction_T_max  0.9790
_exptl_absorpt_correction_T_min  0.9635
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(Sheldrick, 2012)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.167
_exptl_crystal_description       prism
_exptl_crystal_F_000             648
_exptl_crystal_recrystallization_method
'Re-crystallisation from solvent: Acetone-Hexanes'
_exptl_crystal_size_max          0.491
_exptl_crystal_size_mid          0.305
_exptl_crystal_size_min          0.279
_refine_diff_density_max         0.201
_refine_diff_density_min         -0.180
_refine_diff_density_rms         0.035
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.035
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     204
_refine_ls_number_reflns         3930
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.035
_refine_ls_R_factor_all          0.0708
_refine_ls_R_factor_gt           0.0472
_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^)+(0.0586P)^2^+0.3143P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1161
_refine_ls_wR_factor_ref         0.1310
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2836
_reflns_number_total             3930
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c6ob02266a2.cif
_cod_data_source_block           361MGL14
_cod_depositor_comments
;
The following automatic conversions were performed:

'_chemical_melting_point' value '136-137' was changed to '136.5(5)' -
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_database_code               7155428
_shelx_estimated_absorpt_t_min   0.963
_shelx_estimated_absorpt_t_max   0.979
_shelxl_version_number           2014-3
_shelx_res_checksum              63911