Conformational studies on peptides containing α,α-disubstituted α-amino acids: chiral cyclic α,α-disubstituted α-amino acid as an α-helical inducer.
Demizu, Yosuke; Doi, Mitsunobu; Kurihara, Masaaki; Okuda, Haruhiro; Nagano, Masanobu; Suemune, Hiroshi; Tanaka, Masakazu; Organic & biomolecular chemistry 9 (2011) 3303–3312; doi:10.1039/c0ob01146k

data_7151825
_publ_section_title
;
 Conformational studies on peptides containing \a,\a-disubstituted
 \a-amino acids: chiral cyclic \a,\a-disubstituted \a-amino acid as an
 \a-helical inducer.
;
_journal_issue                   9
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              3303
_journal_page_last               3312
_journal_paper_doi               10.1039/c0ob01146k
_journal_volume                  9
_journal_year                    2011
_chemical_absolute_configuration rm
_chemical_compound_source        synthesis
_chemical_formula_moiety         '2(C49 H80 N6 O13), C H4 O, H2 O'
_chemical_formula_sum            'C49.5 H83 N6 O14'
_chemical_formula_weight         986.22
_chemical_melting_point          116.0(10)
_chemical_name_systematic
;
Cbz-[Leu-Leu-(S,S)-Ac5cdOM]2-OMe
;
_space_group_IT_number           1
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  'P 1'
_symmetry_space_group_name_H-M   'P 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                104.8790(10)
_cell_angle_beta                 93.483(2)
_cell_angle_gamma                112.9180(10)
_cell_formula_units_Z            2
_cell_length_a                   12.9034(12)
_cell_length_b                   14.8243(13)
_cell_length_c                   16.6694(15)
_cell_measurement_reflns_used    6962
_cell_measurement_temperature    200(2)
_cell_measurement_theta_max      26.03
_cell_measurement_theta_min      2.30
_cell_volume                     2791.8(4)
_computing_cell_refinement       'SMART (Bruker, 1998)'
_computing_data_collection       'SMART (Bruker, 1998)'
_computing_data_reduction        'SAINTPLUS (Bruker, 1998)'
_computing_molecular_graphics    'PLATON (Spek, 2001)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      200(2)
_diffrn_detector_area_resol_mean 8.366
_diffrn_measured_fraction_theta_full 0.990
_diffrn_measured_fraction_theta_max 0.990
_diffrn_measurement_device_type  'Bruker AXS, SMART APEX CCD area detector'
_diffrn_measurement_method       \w-scan
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'MacScience, M18XCE rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0248
_diffrn_reflns_av_sigmaI/netI    0.0297
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -18
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            32311
_diffrn_reflns_theta_full        27.10
_diffrn_reflns_theta_max         27.10
_diffrn_reflns_theta_min         1.70
_diffrn_standards_decay_%        0.0
_diffrn_standards_interval_count 32311
_diffrn_standards_interval_time  200
_diffrn_standards_number         299
_exptl_absorpt_coefficient_mu    0.086
_exptl_absorpt_correction_T_max  0.9848
_exptl_absorpt_correction_T_min  0.7597
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   'SADABS (Sheldrick, 1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.173
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             1068
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.40
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.786
_refine_diff_density_min         -0.311
_refine_diff_density_rms         0.048
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.2(7)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.010
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     1253
_refine_ls_number_reflns         12192
_refine_ls_number_restraints     8
_refine_ls_restrained_S_all      1.013
_refine_ls_R_factor_all          0.0574
_refine_ls_R_factor_gt           0.0522
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1052P)^2^+0.3407P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1427
_refine_ls_wR_factor_ref         0.1493
_reflns_number_gt                10971
_reflns_number_total             12192
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            c0ob01146k.txt
_cod_data_source_block           5061
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Triclinic' changed to 'triclinic'
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 1555 2011-01-17 13:19:09Z saulius 

The following automatic conversions were performed:

'_chemical_melting_point' value '115-117' was changed to '116.0(10)'
- the average value was taken and precision was estimated.

Automatic conversion script
Id: cif_fix_values 1569 2011-02-09 13:29:24Z adriana 

The following automatic conversions were performed:

'_refine_ls_hydrogen_treatment' value 'contr' was replaced with the
value 'constr' as specified in the replacement file
'src/cod-tools/trunk/data/replacement-values/replacement_values.lst'.

Automatic conversion script
Id: cif_fix_values 5376 2017-05-30 11:51:03Z andrius 
;
_cod_original_sg_symbol_H-M      P1
_cod_original_formula_sum        'C49.50 H83 N6 O14'
_cod_database_code               7151825