An eco-friendly Pictet-Spengler approach to pyrrolo- and indolo[1,2-a]quinoxalines using p-dodecylbenzenesulfonic acid as an efficient Brønsted acid catalyst
Nath, Mahendra; Preetam, Amreeta; RSC Adv.  (2015) –; doi:10.1039/C4RA16651E

data_7219560
_publ_section_title
;
 An eco-friendly Pictet-Spengler approach to pyrrolo- and
 indolo[1,2-a]quinoxalines using p-dodecylbenzenesulfonic acid as an
 efficient Br\/onsted acid catalyst
;
_journal_name_full               'RSC Adv.'
_journal_paper_doi               10.1039/C4RA16651E
_journal_year                    2015
_chemical_formula_moiety         'C19 H15 N3 O'
_chemical_formula_sum            'C19 H15 N3 O'
_chemical_formula_weight         301.35
_chemical_melting_point          535
_chemical_name_systematic
1-Methyl-5'H-spiro[indoline-3,4'-pyrrolo[1,2-a]quinoxalin]-2-one
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_audit_update_record
;
2014-07-18 deposited with the CCDC.
2015-02-13 downloaded from the CCDC.
;
_cell_angle_alpha                90.00
_cell_angle_beta                 97.994(5)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   8.1561(4)
_cell_length_b                   10.4240(4)
_cell_length_c                   17.6525(10)
_cell_measurement_reflns_used    5069
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      29.2153
_cell_measurement_theta_min      2.9157
_cell_volume                     1486.22(13)
_computing_cell_refinement       'CrysAlisPro, Oxford Diffraction Ltd.'
_computing_data_collection       'CrysAlisPro, Oxford Diffraction Ltd.'
_computing_data_reduction        'CrysAlisPro, Oxford Diffraction Ltd.'
_computing_molecular_graphics    'OLEX 2-2.1'
_computing_publication_material  'WINGX V1.80.01'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      298(2)
_diffrn_detector_area_resol_mean 15.9853
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Xcalibur, Sapphire3'
_diffrn_measurement_method       'w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0236
_diffrn_reflns_av_sigmaI/netI    0.0157
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            20207
_diffrn_reflns_theta_full        26.37
_diffrn_reflns_theta_max         26.37
_diffrn_reflns_theta_min         3.04
_exptl_absorpt_coefficient_mu    0.086
_exptl_absorpt_correction_T_max  0.9915
_exptl_absorpt_correction_T_min  0.9764
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'CrysAlisPro 1.171.34.40 (2006)'
_exptl_crystal_colour            white
_exptl_crystal_density_diffrn    1.347
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Rectangular
_exptl_crystal_F_000             632
_exptl_crystal_recrystallization_method
'Re-crystallisation from solvent: Chloroform/Hexane'
_exptl_crystal_size_max          0.28
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.453
_refine_diff_density_min         -0.412
_refine_diff_density_rms         0.041
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.082
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     208
_refine_ls_number_reflns         3031
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.082
_refine_ls_R_factor_all          0.0575
_refine_ls_R_factor_gt           0.0515
_refine_ls_shift/su_max          0.006
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0663P)^2^+0.6250P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1354
_refine_ls_wR_factor_ref         0.1394
_reflns_number_gt                2712
_reflns_number_total             3031
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c4ra16651e2.cif
_cod_data_source_block           shelxl
_cod_database_code               7219560