The Supertristeroids: Large, Chiral, Molecular Bowls Prepared by Trimerization of Pentacyclic Steroidal Ketones
Qiuling Song; Douglas M. Ho; Robert A. Pascal Jr.; Journal of Organic Chemistry 72 (2007) 4449–4453; doi:10.1021/jo070458k

data_4022955
_publ_contact_author_address
;
Princeton University
Department of Chemistry
Princeton, NJ   08544-1009
USA
;
_publ_contact_author_email       rpascal@princeton.edu
_publ_contact_author_fax         '(609) 258 6746'
_publ_contact_author_name        'Professor Robert A. Pascal, Jr.'
_publ_contact_author_phone       '(609) 258 5417'
_publ_section_title
;
 The Supertristeroids: Large, Chiral, Molecular Bowls Prepared
 by Trimerization of Pentacyclic Steroidal Ketones
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              4449
_journal_page_last               4453
_journal_paper_doi               10.1021/jo070458k
_journal_volume                  72
_journal_year                    2007
_chemical_absolute_configuration rm
_chemical_compound_source        'chemical synthesis'
_chemical_formula_iupac          'C31 H52 O'
_chemical_formula_moiety         'C31 H52 O'
_chemical_formula_structural     'C31 H52 O'
_chemical_formula_sum            'C31 H52 O'
_chemical_formula_weight         440.73
_chemical_melting_point          429.1(10)
_chemical_name_systematic
;
2alpha,3alpha-(3'-oxocyclohexano)-5beta-cholestane
;
_space_group_IT_number           5
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      5
_symmetry_space_group_name_Hall  'C 2y'
_symmetry_space_group_name_H-M   'C 1 2 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_date             'February 26, 2007'
_audit_creation_method
;
SHELXL and manual editing of form.cif
;
_audit_update_record
;
Feb. 26, 2007  rap125f.cif        Initial CIF created by DMH.

Feb. 26, 2007  README sections    See _exptl_special_details for a brief
                                  discussion of the data collection and
                                  data reduction procedures and results.
                                  (Located about a third of the way from
                                  the begin of this file.)

                                  See _refine_special_details for a
                                  brief discussion of the structure
                                  solution and refinement, disorder
                                  treatment, etc.  (Located about a
                                  third-to-halfway from the begin of
                                  this file.)

                                  See _geom_special_details for a brief
                                  discussion of miscellaneous structural
                                  features.  (Located at the bottom of
                                  this file.)

Feb. 26, 2007  Sent to Checkcif.  See rap125f_checkcif.pdf for
                                  the alerts that were generated.
                                  Selected responses follow.

-------------------------------------------------------------------------

THETM01_ALERT_3_A The value of sine(theta_max)/wavelength is      < 0.550
                  Calculated sin(theta_max)/wavelength =           0.5382
PLAT027_ALERT_3_A _diffrn_reflns_theta_full (too) Low ........ 22.49 Deg.

                  The alerts THETM01_ALERT_3_A and PLAT027_ALERT_3_A are
                  not a problem.  They simply reflect the fact that the
                  crystal available for the experiment was not of
                  sufficient quality to provide usable data to higher
                  angles.  Also, there is extensive disorder in the
                  2alpha,3alpha-(3'-oxocyclohexano)-5beta-cholestane
                  molecule.  It is not uncommon to find that extensive
                  disorder will diminish the effective resolution of a
                  data set.  Therefore, only a 0.93 Angstrom resolution
                  data set was targeted.  Nevertheless, such a data set
                  is still considered to be of "atomic resolution", and
                  still meets the community's standards of acceptability
                  in such severe disorder cases.

PLAT024_ALERT_4_B Merging of Friedel Pairs is STRONGLY Indicated ...... !
REFLT03_ALERT_4_G MoKa measured Friedel data cannot be used to determine
                  absolute structure in a light-atom study EXCEPT under
                  VERY special conditions. It is preferred that Friedel
                  data is merged in such cases.

                  PLAT024_ALERT_4_B and REFLT03_ALERT_4_G are the same,
                  and is only a recommendation.  In truth and on theoret-
                  ical grounds, Friedel data are unique and should not be
                  merged.  Therefore, it is not wrong to ignore this
                  CheckCif recommendation, and to exercise our right to
                  retain the data as unmerged.

PLAT220_ALERT_2_A Large Non-Solvent C Ueq(max)/Ueq(min) ...... 6.01 Ratio
PLAT222_ALERT_3_A Large Non-Solvent H Ueq(max)/Ueq(min) ...... 7.39 Ratio
PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for ....... C13
PLAT241_ALERT_4_B Check High Ueq as Compared to Neighbors for ...... C18
PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for ....... C21
PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for ...... C16*
PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for ...... C21*
PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for ...... C24*
PLAT242_ALERT_2_B Check Low Ueq as Compared to Neighbors for ....... C25*
PLAT301_ALERT_3_B Main Residue Disorder ..................... 30.00 Perc.
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ........ 6
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ............ 18

                  PLAT220_ALERT_2_A to PLAT720_ALERT_4_C are the result
                  of extensive disorder in 30.00 percent of the molecule.
                  The disorder was modelled as well as might be expected
                  (see _refine_special_details).  The atoms for the
                  second component of that disorder were given labels
                  ending with *.  The validation routine considers the
                  C13*, C14*, H14*, C15*, C16*, C17*, H17*, C18*, C20*,
                  H20*, C21*, C22*, C23*, C24*, C25*, H25*, C26* and C27*
                  atom labels to be unusual.  That is of course just a
                  subjective preference in the validation software, i.e.,
                  there is no hard rule that says that * may not be used.

STRVA01_ALERT_4_C Flack parameter is too small.
                  From the CIF: _refine_ls_abs_structure_Flack     -1.060
                  From the CIF: _refine_ls_abs_structure_Flack_su   3.950
PLAT032_ALERT_4_C Std. Uncertainty in Flack Parameter too High ..... 4.00
PLAT033_ALERT_2_C Flack Parameter Value Deviates from Zero ........ -1.00

                  STRVA01_ALERT_4_C to PLAT033_ALERT_2_C are obviously
                  all saying the same thing.  Yes, we agree that the
                  absolute structure cannot be determined based on the
                  intensity data.  Fortunately, the compound is derived
                  from a steroid, and hence, contains centers of known
                  chirality to begin with.  Since the chemical procedures
                  used in synthesizing the compound do not involve bond
                  making or breaking at those centers of known chirality,
                  the absolute structure of the compound remains fully
                  discernible and unequivocal based on the pre-existing
                  internal chiral labels within the molecule itself.

PLAT791_ALERT_1_G Confirm the Absolute Configuration of ....... C2  =  S
PLAT791_ALERT_1_G Confirm the Absolute Configuration of ....... C3  =  S
PLAT791_ALERT_1_G Confirm the Absolute Configuration of ....... C5  =  R
PLAT791_ALERT_1_G Confirm the Absolute Configuration of ....... C9  =  R
PLAT791_ALERT_1_G Confirm the Absolute Configuration of ....... C10 =  S

                  The CheckCif recommendation for the assignment of the
                  chiral centers in 2alpha,3alpha-(3'-oxocyclohexano)-
                  5beta-cholestane is (2S,3S,5R,9R,10S).  In truth,
                  steroids are rather notoriously difficult when it comes
                  to R/S assignments.  In this case, the validation
                  routine has missed 5 of the 10 stereocenters in the
                  molecule and has misassigned the configuration at C9.
                  We believe that the correct assignment is (2S,3S,5R,8S,
                  9S,10S,13R,14S,17R,20R).  Regardless, by visual
                  inspection of the molecule with any molecular viewer,
                  it is obvious that the standard correct hand for
                  steroids is depicted, and any discrepancy between the
                  CheckCif assigments and our own is merely book-keeping,
                  i.e., the refined absolute structure is correct as it
                  stands.
;
_cell_angle_alpha                90.00
_cell_angle_beta                 91.284(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   12.5645(5)
_cell_length_b                   6.7283(3)
_cell_length_c                   33.721(2)
_cell_measurement_reflns_used    13664
_cell_measurement_temperature    200(2)
_cell_measurement_theta_max      22.49
_cell_measurement_theta_min      1.21
_cell_volume                     2850.0(2)
_computing_cell_refinement       'DENZO-SMN (Otwinowski & Minor, 1997)'
_computing_data_collection       'COLLECT (Nonius, 1998)'
_computing_data_reduction        'DENZO-SMN (Otwinowski & Minor, 1997)'
_computing_molecular_graphics    'Siemens SHELXTL (Sheldrick, 1996)'
_computing_publication_material  'Siemens SHELXTL (Sheldrick, 1996)'
_computing_structure_refinement  'Siemens SHELXTL (Sheldrick, 1996)'
_computing_structure_solution    'Siemens SHELXTL (Sheldrick, 1996)'
_diffrn_ambient_temperature      200(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device       'Nonius KappaCCD'
_diffrn_measurement_method       '\w scans, 1340 0.5\% rotations'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0430
_diffrn_reflns_av_sigmaI/netI    0.0420
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       35
_diffrn_reflns_limit_l_min       -36
_diffrn_reflns_number            13664
_diffrn_reflns_theta_full        22.49
_diffrn_reflns_theta_max         22.49
_diffrn_reflns_theta_min         1.21
_diffrn_standards_decay_%        0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.059
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.027
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Needle
_exptl_crystal_F_000             984
_exptl_crystal_size_max          0.33
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.169
_refine_diff_density_min         -0.125
_refine_diff_density_rms         0.036
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -1.06(395)
_refine_ls_extinction_coef       0.0230(41)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_all   1.026
_refine_ls_goodness_of_fit_ref   1.110
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     417
_refine_ls_number_reflns         3703
_refine_ls_number_restraints     499
_refine_ls_restrained_S_all      1.063
_refine_ls_restrained_S_obs      1.142
_refine_ls_R_factor_all          0.0927
_refine_ls_R_factor_gt           0.0700
_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^)+(0.1259P)^2^+0.6385P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.2034
_refine_ls_wR_factor_ref         0.1860
_reflns_number_gt                2736
_reflns_number_total             3703
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            jo070458ksi20070305_110750.cif
_cod_data_source_block           rap125f
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 

The following automatic conversions were performed:

'_chemical_melting_point' value '155-157\%C' was changed to
'429.1(10)' - it was converted from degrees Celsius(C) to Kelvins(K),
the average value was taken and precision was estimated.

Automatic conversion script
Id: cif_fix_values 1646 2011-03-28 12:23:43Z adriana 
;
_cod_original_sg_symbol_H-M      'C 2'
_cod_database_code               4022955