Synthesis of 5<i>H</i>-chromeno[3,4-<i>b</i>]pyridines <i>via</i> DABCO-catalyzed [3 + 3] annulation of 3-nitro-2<i>H</i>-chromenes and allenoates.
Soares, Maria I. L.; Gomes, Clara S. B.; Oliveira, M Conceição; Marçalo, Joaquim; Pinho E Melo, Teresa M V D; Organic & biomolecular chemistry 19 (2021) 9711–9722; doi:10.1039/d1ob01130h

data_7158349
_publ_section_title
;
 Synthesis of 5<i>H</i>-chromeno[3,4-<i>b</i>]pyridines <i>via</i>
 DABCO-catalyzed [3 + 3] annulation of 3-nitro-2<i>H</i>-chromenes and
 allenoates.
;
_journal_issue                   44
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              9711
_journal_page_last               9722
_journal_paper_doi               10.1039/d1ob01130h
_journal_volume                  19
_journal_year                    2021
_chemical_formula_moiety         'C22 H19 N O6'
_chemical_formula_sum            'C22 H19 N O6'
_chemical_formula_weight         393.38
_chemical_name_systematic
'Benzyl 2-hydroxy-8,10-dimethoxy-5H-chromeno[3,4-b]pyridine-3-carboxylate'
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2018/3
_audit_update_record
;
2021-06-11 deposited with the CCDC.	2021-10-22 downloaded from the CCDC.
;
_cell_angle_alpha                66.753(6)
_cell_angle_beta                 79.781(7)
_cell_angle_gamma                88.762(7)
_cell_formula_units_Z            4
_cell_length_a                   8.708(2)
_cell_length_b                   13.624(4)
_cell_length_c                   17.004(5)
_cell_measurement_reflns_used    9945
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      24.78
_cell_measurement_theta_min      2.38
_cell_volume                     1821.5(9)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX3'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    ORTEP
_computing_publication_material  WinGX
_computing_structure_refinement  'SHELXL-2018/3 (Sheldrick, 2018)'
_computing_structure_solution    'SHELXT 2014/5 (Sheldrick, 2014)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker D8 VENTURE PHOTON 100 CMOS'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.2185
_diffrn_reflns_av_unetI/netI     0.1178
_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       -10
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            64553
_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         25.350
_diffrn_reflns_theta_min         2.653
_exptl_absorpt_coefficient_mu    0.105
_exptl_absorpt_correction_T_max  0.7453
_exptl_absorpt_correction_T_min  0.5276
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
 SADABS 2016/2: Krause, L., Herbst-Irmer, R., Sheldrick G.M. & Stalke D.,
 J. Appl. Cryst. 48 (2015) 3-10
;
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.434
_exptl_crystal_description       prism
_exptl_crystal_F_000             824
_exptl_crystal_size_max          0.600
_exptl_crystal_size_mid          0.200
_exptl_crystal_size_min          0.200
_refine_diff_density_max         0.259
_refine_diff_density_min         -0.284
_refine_diff_density_rms         0.060
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.025
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     529
_refine_ls_number_reflns         6676
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.025
_refine_ls_R_factor_all          0.1917
_refine_ls_R_factor_gt           0.0946
_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^)+(0.0436P)^2^+3.8242P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1675
_refine_ls_wR_factor_ref         0.1941
_reflns_Friedel_coverage         0.000
_reflns_number_gt                3564
_reflns_number_total             6676
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d1ob01130h2.cif
_cod_data_source_block           4
_cod_depositor_comments
'Adding full bibliography for 7158348--7158349.cif.'
_cod_database_code               7158349
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_min   0.940
_shelx_estimated_absorpt_t_max   0.979
_shelx_res_checksum              36194
_shelx_hkl_checksum              26429