A practical, convergent route to the key precursor to the tetracycline antibiotics.
Kummer, David A.; Li, Derun; Dion, Amelie; Myers, Andrew G.; Chemical science (Royal Society of Chemistry : 2010) 2 (2011) 1710–1718; doi:10.1039/C1SC00303H

data_1515646
_publ_section_title
;
 A practical, convergent route to the key precursor to the tetracycline
 antibiotics.
;
_journal_issue                   9
_journal_name_full
'Chemical science (Royal Society of Chemistry : 2010)'
_journal_page_first              1710
_journal_page_last               1718
_journal_paper_doi               10.1039/C1SC00303H
_journal_volume                  2
_journal_year                    2011
_chemical_absolute_configuration ad
_chemical_formula_sum            'C33.25 H37.25 Cl1.5 N2 O4 Si'
_chemical_formula_weight         610.17
_chemical_name_systematic
;
?
;
_space_group_IT_number           18
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2 2ab'
_symmetry_space_group_name_H-M   'P 21 21 2'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   8.3338(7)
_cell_length_b                   25.680(2)
_cell_length_c                   15.2004(12)
_cell_measurement_reflns_used    2276
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      20.9
_cell_measurement_theta_min      2.56
_cell_volume                     3253.1(5)
_computing_cell_refinement       'SAINT 7.46A (Bruker-AXS, 2009)'
_computing_data_collection       'APEX2 v2009.3.0 (Bruker-AXS, 2009)'
_computing_data_reduction        'SAINT 7.46A (Bruker-AXS, 2009)'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.988
_diffrn_measured_fraction_theta_max 0.988
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega 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  0.0710
_diffrn_reflns_av_sigmaI/netI    0.0814
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       27
_diffrn_reflns_limit_k_min       -31
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            18394
_diffrn_reflns_theta_full        26.13
_diffrn_reflns_theta_max         26.13
_diffrn_reflns_theta_min         1.56
_exptl_absorpt_coefficient_mu    0.234
_exptl_absorpt_correction_T_max  0.9770
_exptl_absorpt_correction_T_min  0.9289
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 2009)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.246
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1289
_exptl_crystal_size_max          0.32
_exptl_crystal_size_mid          0.26
_exptl_crystal_size_min          0.10
_refine_diff_density_max         1.215
_refine_diff_density_min         -0.346
_refine_diff_density_rms         0.077
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.08(10)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.063
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     388
_refine_ls_number_reflns         6403
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.063
_refine_ls_R_factor_all          0.0927
_refine_ls_R_factor_gt           0.0605
_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^)+(0.0871P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1480
_refine_ls_wR_factor_ref         0.1668
_reflns_number_gt                4579
_reflns_number_total             6403
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c1sc00303h.txt
_cod_data_source_block           AD-2-5
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/usr/data/users/saulius/automatic-downloads/retrospective/RSC/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 2281 2013-09-26 08:29:07Z andrius 
;
_cod_original_cell_volume        3253.0(5)
_cod_original_sg_symbol_H-M      P21212
_cod_original_formula_sum        'C33.25 H37.25 Cl1.50 N2 O4 Si'
_cod_database_code               1515646