Synthesis of indoline-2,3-fused tetrahydroquinolines bearing two free N-H groups using a protecting-group-free approach.
Chouhan, Raju; Kumar Das, Sajal; Chemical communications (Cambridge, England) 62 (2026) 2322–2325; doi:10.1039/d5cc06157a

data_7135522
_publ_section_title
;
 Synthesis of indoline-2,3-fused tetrahydroquinolines bearing two free N-H
 groups using a protecting-group-free approach.
;
_journal_issue                   7
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              2322
_journal_page_last               2325
_journal_paper_doi               10.1039/d5cc06157a
_journal_volume                  62
_journal_year                    2026
_chemical_formula_moiety         'C21 H18 N2'
_chemical_formula_sum            'C21 H18 N2'
_chemical_formula_weight         298.37
_chemical_name_systematic        Rc1205
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_atom_sites_solution_hydrogens   mixed
_audit_creation_date             2025-08-04
_audit_creation_method
;
Olex2 1.5
(compiled 2024.02.16 svn.r378c4104 for OlexSys, GUI svn.r6928)
;
_audit_update_record
;
2025-08-29 deposited with the CCDC.	2025-12-12 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   6.466(11)
_cell_length_b                   12.77(2)
_cell_length_c                   19.58(3)
_cell_measurement_reflns_used    178
_cell_measurement_temperature    296.15
_cell_measurement_theta_max      11.47
_cell_measurement_theta_min      3.32
_cell_volume                     1617(4)
_computing_cell_refinement       'SAINT V8.38A (Bruker, 2018)'
_computing_data_reduction        'SAINT V8.38A (Bruker, 2018)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2019/3 (Sheldrick, 2015)'
_diffrn_ambient_temperature      296.15
_diffrn_measured_fraction_theta_full 0.999
_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  0.2463
_diffrn_reflns_av_unetI/netI     0.3101
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            9991
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.997
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.679
_diffrn_reflns_theta_min         1.904
_diffrn_source_current           0.0
_diffrn_source_power             0.0
_diffrn_source_voltage           0.0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.072
_exptl_absorpt_correction_T_max  0.7457
_exptl_absorpt_correction_T_min  0.3577
_exptl_absorpt_correction_type   none
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1526 before and 0.0945 after correction.
The Ratio of minimum to maximum transmission is 0.4797.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            'clear light brown'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_modifier   light
_exptl_crystal_colour_primary    brown
_exptl_crystal_density_diffrn    1.226
_exptl_crystal_description       block
_exptl_crystal_F_000             632
_exptl_crystal_size_max          0.16
_exptl_crystal_size_mid          0.13
_exptl_crystal_size_min          0.11
_refine_diff_density_max         0.313
_refine_diff_density_min         -0.280
_refine_diff_density_rms         0.074
_refine_ls_abs_structure_details
;
 Flack x determined using 260 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   10.0(10)
_refine_ls_extinction_coef       0.022(6)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2019/2 (Sheldrick 2019)'
_refine_ls_goodness_of_fit_ref   0.935
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     212
_refine_ls_number_reflns         3069
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.935
_refine_ls_R_factor_all          0.2388
_refine_ls_R_factor_gt           0.0831
_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^)+(0.0190P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1625
_refine_ls_wR_factor_ref         0.2361
_reflns_Friedel_coverage         0.713
_reflns_Friedel_fraction_full    0.999
_reflns_Friedel_fraction_max     0.995
_reflns_number_gt                1162
_reflns_number_total             3069
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5cc06157a2.cif
_cod_data_source_block           rc1205_a
_cod_original_cell_volume        1616(5)
_cod_database_code               7135522
_shelx_shelxl_version_number     2019/3
_shelx_estimated_absorpt_t_max   0.992
_shelx_estimated_absorpt_t_min   0.989
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups, All N(H) groups
2.a Ternary CH refined with riding coordinates:
 C1(H1A)
2.b Secondary CH2 refined with riding coordinates:
 C9(H9A,H9B)
2.c Aromatic/amide H refined with riding coordinates:
 N2(H2), C15(H15), C13(H13), C12(H12), C4(H4), C14(H14), C20(H20), C17(H17),
 C19(H19), C7(H7), C6(H6), C21(H21), C18(H18), C5(H5)
;
_shelx_res_checksum              96879
_olex2_submission_special_instructions 'No special instructions were received'