Hybrid Peptides: Direct Transformation of α/α, β-Unsaturated γ-Hybrid Peptides to α/γ-Hybrid Peptide 12-Helices.
Bandyopadhyay, Anupam; Gopi, Hosahudya N.; Organic letters 14 (2012) 2770–2773; doi:10.1021/ol300987d

data_1507723
_publ_section_title
;
 Hybrid Peptides: Direct Transformation of \a/\a, \b-Unsaturated \g-Hybrid
 Peptides to \a/\g-Hybrid Peptide 12-Helices.
;
_journal_issue                   11
_journal_name_full               'Organic letters'
_journal_page_first              2770
_journal_page_last               2773
_journal_paper_doi               10.1021/ol300987d
_journal_volume                  14
_journal_year                    2012
_chemical_absolute_configuration syn
_chemical_compound_source        Synthesis
_chemical_formula_moiety         '2(C37 H54 N4 O7), C2 H6 O'
_chemical_formula_sum            'C76 H114 N8 O15'
_chemical_formula_weight         1379.75
_chemical_name_common            'Alpha-gamma mixed peptide'
_chemical_name_systematic        Boc-Aib-gPhe-Aib-gPhe-OEt
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      4
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 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                 98.135(11)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   19.123(10)
_cell_length_b                   20.644(11)
_cell_length_c                   20.129(11)
_cell_measurement_temperature    100(2)
_cell_volume                     7866(7)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_pressure         101.325
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0450
_diffrn_reflns_av_sigmaI/netI    0.0810
_diffrn_reflns_limit_h_max       25
_diffrn_reflns_limit_h_min       -25
_diffrn_reflns_limit_k_max       27
_diffrn_reflns_limit_k_min       -27
_diffrn_reflns_limit_l_max       26
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            79851
_diffrn_reflns_theta_full        28.28
_diffrn_reflns_theta_max         28.28
_diffrn_reflns_theta_min         1.59
_diffrn_source                   'fine-focus sealed tube'
_diffrn_source_type              'Graphite monochromator'
_exptl_absorpt_coefficient_mu    0.081
_exptl_absorpt_correction_T_max  0.971
_exptl_absorpt_correction_T_min  0.959
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.165
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       'Rectangular block'
_exptl_crystal_F_000             2984
_exptl_crystal_recrystallization_method EtOH
_exptl_crystal_size_max          0.58
_exptl_crystal_size_mid          0.43
_exptl_crystal_size_min          0.38
_refine_diff_density_max         0.967
_refine_diff_density_min         -0.619
_refine_diff_density_rms         0.054
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.1(6)
_refine_ls_extinction_coef       0.00073(17)
_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_ref   0.999
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     1820
_refine_ls_number_reflns         36899
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.999
_refine_ls_R_factor_all          0.1074
_refine_ls_R_factor_gt           0.0630
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1527
_refine_ls_wR_factor_ref         0.1793
_reflns_number_gt                24459
_reflns_number_total             36899
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol300987d_si_002.cif
_cod_data_source_block           G1
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               1507723