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_1506250
_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 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 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                 110.805(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   7.1640(9)
_cell_length_b                   20.240(3)
_cell_length_c                   9.0634(13)
_cell_measurement_reflns_used    2817
_cell_measurement_temperature    295(2)
_cell_measurement_theta_max      27.34
_cell_measurement_theta_min      2.60
_cell_volume                     1228.5(3)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      295(2)
_diffrn_measured_fraction_theta_full 0.982
_diffrn_measured_fraction_theta_max 0.982
_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  0.0420
_diffrn_reflns_av_sigmaI/netI    0.0655
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       25
_diffrn_reflns_limit_k_min       -26
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -10
_diffrn_reflns_number            8503
_diffrn_reflns_theta_full        27.54
_diffrn_reflns_theta_max         27.54
_diffrn_reflns_theta_min         2.01
_diffrn_standards_decay_%        none
_exptl_absorpt_coefficient_mu    0.096
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   SADABS
_exptl_crystal_density_diffrn    1.429
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             552
_exptl_crystal_size_max          0.50
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.224
_refine_diff_density_min         -0.141
_refine_diff_density_rms         0.039
_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         2779
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.011
_refine_ls_R_factor_all          0.1068
_refine_ls_R_factor_gt           0.0496
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0546P)^2^+0.0854P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1168
_refine_ls_wR_factor_ref         0.1397
_reflns_number_gt                1479
_reflns_number_total             2779
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol0620242si20060817_125102.cif
_cod_data_source_block           wd33ccd
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               1506250