Reactive Intermediates in Peptide Synthesis: First Crystal Structures and ab Initio Calculations of 2-Alkoxy-5(4H)-oxazolones from Urethane-Protected Amino Acids
Marco Crisma; Giovanni Valle; Fernando Formaggio; Claudio Toniolo; Alessandro Bagno; Journal of the American Chemical Society 119 (1997) 4136–4142; doi:10.1021/ja9637863

data_4116963
_publ_section_title
;
 Reactive Intermediates in Peptide Synthesis: First Crystal Structures and
 ab Initio Calculations of 2-Alkoxy-5(4H)-oxazolones from
 Urethane-Protected Amino Acids
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              4136
_journal_page_last               4142
_journal_paper_doi               10.1021/ja9637863
_journal_volume                  119
_journal_year                    1997
_chemical_compound_source
;                                                                               
 Crystallization from chloroform - petroleum ether
;
_chemical_formula_sum            'C25 H27 N2 O4'
_chemical_formula_weight         419.50
_chemical_name_common            '5(4H)-oxazolone from Fmoc-TOAC-OH'
_chemical_name_systematic        ?
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      14
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_audit_creation_method           PARSTINT
_cell_angle_alpha                90.
_cell_angle_beta                 98.6(1)
_cell_angle_gamma                90.
_cell_formula_units_Z            4.00
_cell_length_a                   8.266(1)
_cell_length_b                   18.629(2)
_cell_length_c                   14.216(2)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      12
_cell_measurement_theta_min      7
_cell_volume                     2164.5(7)
_computing_publication_material  'PARST 83'
_computing_structure_refinement  'SHELX 76'
_computing_structure_solution    'SHELXS 86'
_diffrn_ambient_temperature      293(2)
_diffrn_measurement_device       'Philips PW1100 diffractometer'
_diffrn_measurement_method       '\q-2\q scan'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71070
_diffrn_reflns_av_R_equivalents  0.016
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       24
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            5413
_diffrn_reflns_theta_max         28
_diffrn_reflns_theta_min         2
_diffrn_standards_interval_count 100
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.0817
_exptl_crystal_colour            red-orange
_exptl_crystal_density_diffrn    1.2873
_exptl_crystal_description
;                                                                               
 plate
;
_exptl_crystal_F_000             892.00
_exptl_crystal_size_max          0.4
_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.3
_refine_diff_density_max         0.23
_refine_diff_density_min         -0.21
_refine_ls_goodness_of_fit_obs   1.018
_refine_ls_hydrogen_treatment    riding
_refine_ls_matrix_type           fullcycle
_refine_ls_number_parameters     280
_refine_ls_number_reflns         1187
_refine_ls_number_restraints     0
_refine_ls_R_factor_obs          0.054
_refine_ls_shift/esd_max         0.16
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     'w = 1/[\s^2(F)+0.0037(F^2)]'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_obs         0.056
_reflns_number_observed          1187
_reflns_number_total             5211
_reflns_observed_criterion       >4sigma(F)
_cod_data_source_file            ja9637863_2.cif
_cod_data_source_block           Ib
_cod_depositor_comments
;
The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value '1/[\s^2(F)+0.0037(F^2)]' was
changed to 'calc'. New tag '_refine_ls_weighting_details' was
created. The value of the new tag was set to 'w =
1/[\s^2(F)+0.0037(F^2)]'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_database_code               4116963