Metal catalyst free cyclization of 3-alkynyl substituted 2-(indol-3-yl)quinoxalines in TFA alone: a new synthesis of indolophenazines.
Kumar, K. Shiva; Bhaskar, Boyapally; Ramulu, Meesa Siddi; Kumar, N. Praveen; Ashfaq, Mohd Ashraf; Pal, Manojit; Organic & biomolecular chemistry 15 (2016) 82–87; doi:10.1039/c6ob02340a

data_7155374
_publ_section_title
;
 Metal catalyst free cyclization of 3-alkynyl substituted
 2-(indol-3-yl)quinoxalines in TFA alone: a new synthesis of
 indolophenazines.
;
_journal_issue                   1
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              82
_journal_page_last               87
_journal_paper_doi               10.1039/c6ob02340a
_journal_volume                  15
_journal_year                    2016
_chemical_formula_moiety         'C25 H25 N3'
_chemical_formula_sum            'C25 H25 N3'
_chemical_formula_weight         367.48
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014
_audit_update_record
;
2016-09-08 deposited with the CCDC.
2016-11-22 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 91.1000(10)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   8.4926(2)
_cell_length_b                   7.9538(2)
_cell_length_c                   28.9887(7)
_cell_measurement_reflns_used    4787
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      27.52
_cell_measurement_theta_min      2.66
_cell_volume                     1957.78(8)
_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-2014 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXL-2014 (Sheldrick, 2014)'
_diffrn_ambient_temperature      296(2)
_diffrn_detector_area_resol_mean 0
_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_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0283
_diffrn_reflns_av_unetI/netI     0.0273
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       35
_diffrn_reflns_limit_l_min       -35
_diffrn_reflns_number            15774
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.999
_diffrn_reflns_theta_min         2.655
_diffrn_source                   'sealed tube'
_exptl_absorpt_coefficient_mu    0.074
_exptl_absorpt_correction_T_max  0.9924
_exptl_absorpt_correction_T_min  0.9849
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.247
_exptl_crystal_density_meas      1.247
_exptl_crystal_density_method    NONE
_exptl_crystal_description       block
_exptl_crystal_F_000             784
_exptl_crystal_size_max          0.200
_exptl_crystal_size_mid          0.150
_exptl_crystal_size_min          0.100
_refine_diff_density_max         0.215
_refine_diff_density_min         -0.167
_refine_diff_density_rms         0.035
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.019
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     255
_refine_ls_number_reflns         3844
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.019
_refine_ls_R_factor_all          0.0658
_refine_ls_R_factor_gt           0.0426
_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^)+(0.0545P)^2^+0.5059P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1054
_refine_ls_wR_factor_ref         0.1207
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2753
_reflns_number_total             3844
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c6ob02340a2.cif
_cod_data_source_block           shelx
_cod_depositor_comments
'Adding full bibliography for 7155374--7155375.cif.'
_cod_database_code               7155374
_shelx_estimated_absorpt_t_min   0.985
_shelx_estimated_absorpt_t_max   0.993
_shelxl_version_number           2014-3
_shelx_res_checksum              18548
_shelx_hkl_checksum              12992