A nonpeptidic reverse-turn scaffold stabilized by urea-based dual intramolecular hydrogen bonding.
Medda, Amiya K.; Park, Chul Min; Jeon, Aram; Kim, Hyunwoo; Sohn, Jeong-Hun; Lee, Hee-Seung; Organic letters 13 (2011) 3486–3489; doi:10.1021/ol201247x

data_1502272
_publ_section_title
;
 A nonpeptidic reverse-turn scaffold stabilized by urea-based dual
 intramolecular hydrogen bonding.
;
_journal_issue                   13
_journal_name_full               'Organic letters'
_journal_page_first              3486
_journal_page_last               3489
_journal_paper_doi               10.1021/ol201247x
_journal_volume                  13
_journal_year                    2011
_chemical_formula_sum            'C23 H41 N5 O3'
_chemical_formula_weight         435.61
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_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                 96.2770(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   10.1633(2)
_cell_length_b                   9.9300(2)
_cell_length_c                   12.1706(3)
_cell_measurement_temperature    130
_cell_volume                     1220.91(5)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      130
_diffrn_measured_fraction_theta_full 0.988
_diffrn_measured_fraction_theta_max 0.988
_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  0.0166
_diffrn_reflns_av_sigmaI/netI    0.0275
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            12037
_diffrn_reflns_theta_full        28.32
_diffrn_reflns_theta_max         28.32
_diffrn_reflns_theta_min         1.68
_exptl_absorpt_coefficient_mu    0.080
_exptl_crystal_colour            white
_exptl_crystal_density_diffrn    1.185
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             476
_exptl_crystal_size_max          0.34
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.468
_refine_diff_density_min         -0.193
_refine_diff_density_rms         0.037
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.0(8)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.042
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     444
_refine_ls_number_reflns         5837
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.042
_refine_ls_R_factor_all          0.0417
_refine_ls_R_factor_gt           0.0357
_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^)+(0.0492P)^2^+0.1685P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0860
_refine_ls_wR_factor_ref         0.0904
_reflns_number_gt                5310
_reflns_number_total             5837
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol201247x_si_001.cif
_cod_data_source_block           p21
_cod_original_sg_symbol_H-M      P21
_cod_database_code               1502272