Synthesis of the parent and substituted tetracyclic ABCD ring cores of camptothecins via 1-(3-aryl-2-propynyl)- 1,6-dihydro-6-oxo-2-pyridinecarbonitriles.
Dai, Weixiang; Petersen, Jeffrey L.; Wang, Kung K.; Organic letters 8 (2006) 4665–4667; doi:10.1021/ol0620242

data_1506248
_publ_section_title
;
 Synthesis of the parent and substituted tetracyclic ABCD ring cores of
 camptothecins via 1-(3-aryl-2-propynyl)-
 1,6-dihydro-6-oxo-2-pyridinecarbonitriles.
;
_journal_issue                   20
_journal_name_full               'Organic letters'
_journal_page_first              4665
_journal_page_last               4667
_journal_paper_doi               10.1021/ol0620242
_journal_volume                  8
_journal_year                    2006
_chemical_formula_sum            'C16 H12 N2 O2'
_chemical_formula_weight         264.28
_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
_cell_angle_alpha                90.00
_cell_angle_beta                 93.528(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   4.4469(4)
_cell_length_b                   11.4613(10)
_cell_length_c                   26.073(2)
_cell_measurement_reflns_used    3567
_cell_measurement_temperature    295(2)
_cell_measurement_theta_max      27.03
_cell_measurement_theta_min      2.86
_cell_volume                     1326.35(19)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      295(2)
_diffrn_measured_fraction_theta_full 0.980
_diffrn_measured_fraction_theta_max 0.980
_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  0.0484
_diffrn_reflns_av_sigmaI/netI    0.0845
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -4
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       33
_diffrn_reflns_limit_l_min       -33
_diffrn_reflns_number            8727
_diffrn_reflns_theta_full        27.51
_diffrn_reflns_theta_max         27.51
_diffrn_reflns_theta_min         1.57
_diffrn_standards_decay_%        none
_exptl_absorpt_coefficient_mu    0.089
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   SADABS
_exptl_crystal_density_diffrn    1.323
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             552
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.26
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.169
_refine_diff_density_min         -0.176
_refine_diff_density_rms         0.042
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.011
_refine_ls_hydrogen_treatment    riding
_refine_ls_matrix_type           full
_refine_ls_number_parameters     182
_refine_ls_number_reflns         2975
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.011
_refine_ls_R_factor_all          0.0861
_refine_ls_R_factor_gt           0.0530
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0670P)^2^+0.1106P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1385
_refine_ls_wR_factor_ref         0.1640
_reflns_number_gt                1898
_reflns_number_total             2975
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol0620242si20060817_125016.cif
_cod_data_source_block           wd34ccd
_cod_original_cell_volume        1326.3(2)
_cod_original_sg_symbol_H-M      P21/c
_cod_database_code               1506248