<i>N</i>-(<i>tert</i>-Butoxycarbonyl)-α-aminoisobutyryl-α-aminoisobutyric acid methyl ester: two polymorphic forms in the space group <i>P</i>2~1~/<i>n</i>
Gebreslasie, Hadgu Girmay; Jacobsen, Øyvind; Görbitz, Carl Henrik; Acta Crystallographica Section C 67 (2011) o283–o287; doi:10.1107/S0108270111024322

data_2018192
_publ_section_title
;
 <i>N</i>-(<i>tert</i>-Butoxycarbonyl)-\a-aminoisobutyryl-\a-aminoisobutyric
 acid methyl ester: two polymorphic forms in the space group
 <i>P</i>2~1~/<i>n</i>
;
_journal_coeditor_code           JZ3206
_journal_issue                   8
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              o283
_journal_page_last               o287
_journal_paper_doi               10.1107/S0108270111024322
_journal_volume                  67
_journal_year                    2011
_chemical_formula_iupac          'C14 H26 N2 O5'
_chemical_formula_moiety         'C14 H26 N2 O5'
_chemical_formula_sum            'C14 H26 N2 O5'
_chemical_formula_weight         302.37
_chemical_name_common            Boc-Aib-Aib-OMe
_chemical_name_systematic
;
Methyl 2-(2-{[(<i>tert</i>-butoxy)carbonyl]amino}-2-methylpropanamido)-
2-methylpropanoate
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL97
_cell_angle_alpha                90.00
_cell_angle_beta                 92.266(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.0679(15)
_cell_length_b                   33.743(9)
_cell_length_c                   8.583(2)
_cell_measurement_reflns_used    2025
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      22.20
_cell_measurement_theta_min      2.38
_cell_volume                     1756.0(8)
_computing_cell_refinement       'SAINT-Plus (Bruker, 2007)'
_computing_data_collection       'APEX2 (Bruker, 2007)'
_computing_data_reduction        'SAINT-Plus (Bruker, 2007)'
_computing_molecular_graphics    'SHELXTL (Sheldrick, 2008)'
_computing_publication_material  'SHELXTL (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXTL (Sheldrick, 2008)'
_computing_structure_solution    'SHELXTL (Sheldrick, 2008)'
_diffrn_ambient_temperature      293(2)
_diffrn_detector_area_resol_mean 8.3
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'Bruker APEXII CCD area-detector'
_diffrn_measurement_method
'Sets of exposures each taken over 0.5\% \w rotation'
_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  0.0522
_diffrn_reflns_av_sigmaI/netI    0.0615
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       40
_diffrn_reflns_limit_k_min       -40
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -8
_diffrn_reflns_number            10165
_diffrn_reflns_theta_full        25.06
_diffrn_reflns_theta_max         25.06
_diffrn_reflns_theta_min         2.38
_diffrn_standards_decay_%        0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.086
_exptl_absorpt_correction_T_max  0.9914
_exptl_absorpt_correction_T_min  0.8139
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Bruker, 2007)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.144
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             656
_exptl_crystal_size_max          0.80
_exptl_crystal_size_mid          0.11
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.151
_refine_diff_density_min         -0.183
_refine_ls_extinction_coef       0.0055(11)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXTL (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   0.998
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     197
_refine_ls_number_reflns         3105
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.998
_refine_ls_R_factor_all          0.1220
_refine_ls_R_factor_gt           0.0424
_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^)+(0.0488P)^2^+0.2160P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0930
_refine_ls_wR_factor_ref         0.1253
_reflns_number_gt                1584
_reflns_number_total             3105
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            jz3206.cif
_cod_data_source_block           IB
_cod_original_sg_symbol_H-M      'P 21/n'
_cod_database_code               2018192
_cod_database_fobs_code          2018192