Conformational Effects through Hydrogen Bonding in a Constrained γ-Peptide Template: From Intraresidue Seven-Membered Rings to a Gel-Forming Sheet Structure.
Awada, Hawraà; Grison, Claire M.; Charnay-Pouget, Florence; Baltaze, Jean-Pierre; Brisset, François; Guillot, Régis; Robin, Sylvie; Hachem, Ali; Jaber, Nada; Naoufal, Daoud; Yazbeck, Ogaritte; Aitken, David J.; The Journal of organic chemistry 82 (2017) 4819–4828; doi:10.1021/acs.joc.7b00494

data_4032539
_publ_section_title
;
 Conformational Effects through Hydrogen Bonding in a Constrained
 \g-Peptide Template: From Intraresidue Seven-Membered Rings to a
 Gel-Forming Sheet Structure.
;
_journal_issue                   9
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              4819
_journal_page_last               4828
_journal_paper_doi               10.1021/acs.joc.7b00494
_journal_volume                  82
_journal_year                    2017
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C18 H25 N O4'
_chemical_formula_sum            'C18 H25 N O4'
_chemical_formula_weight         319.39
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_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
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 93.5120(10)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   5.3002(2)
_cell_length_b                   15.1222(7)
_cell_length_c                   10.5712(5)
_cell_measurement_reflns_used    5210
_cell_measurement_temperature    100(1)
_cell_measurement_theta_max      26.35
_cell_measurement_theta_min      2.35
_cell_volume                     845.70(6)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_diffrn_ambient_temperature      100(1)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0250
_diffrn_reflns_av_unetI/netI     0.0254
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -18
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            10859
_diffrn_reflns_point_group_measured_fraction_full 0.987
_diffrn_reflns_point_group_measured_fraction_max 0.984
_diffrn_reflns_theta_full        25.000
_diffrn_reflns_theta_max         26.400
_diffrn_reflns_theta_min         1.930
_exptl_absorpt_coefficient_mu    0.088
_exptl_absorpt_correction_T_max  0.9977
_exptl_absorpt_correction_T_min  0.9714
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.254
_exptl_crystal_description       plate
_exptl_crystal_F_000             344
_exptl_crystal_size_max          0.310
_exptl_crystal_size_mid          0.170
_exptl_crystal_size_min          0.020
_refine_diff_density_max         0.150
_refine_diff_density_min         -0.169
_refine_diff_density_rms         0.033
_refine_ls_abs_structure_details
;
 Flack x determined using 1400 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.1(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.037
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     211
_refine_ls_number_reflns         3414
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.037
_refine_ls_R_factor_all          0.0330
_refine_ls_R_factor_gt           0.0298
_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^)+(0.0314P)^2^+0.1644P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0676
_refine_ls_wR_factor_ref         0.0695
_reflns_Friedel_coverage         0.891
_reflns_Friedel_fraction_full    0.972
_reflns_Friedel_fraction_max     0.966
_reflns_number_gt                3209
_reflns_number_total             3414
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo7b00494_si_003.cif
_cod_data_source_block           1b
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               4032539
_shelx_estimated_absorpt_t_min   0.973
_shelx_estimated_absorpt_t_max   0.998
_shelx_res_checksum              78262
_shelx_hkl_checksum              60720