A convenient synthesis of difficult medium-sized cyclic peptides by Staudinger mediated ring-closure.
Ha, Khanh; Monbaliu, Jean-Christophe M; Williams, Byron C.; Pillai, Girinath G.; Ocampo, Charles E.; Zeller, Matthias; Stevens, Christian V.; Katritzky, Alan R.; Organic & biomolecular chemistry 10 (2012) 8055–8058; doi:10.1039/c2ob25996f

data_7152639
_publ_section_title
;
 A convenient synthesis of difficult medium-sized cyclic peptides by
 Staudinger mediated ring-closure.
;
_journal_issue                   40
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              8055
_journal_page_last               8058
_journal_paper_doi               10.1039/c2ob25996f
_journal_volume                  10
_journal_year                    2012
_chemical_formula_sum            'C5 H8 N2 O2'
_chemical_formula_weight         128.13
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 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                 91.489(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.243(3)
_cell_length_b                   7.153(2)
_cell_length_c                   8.902(3)
_cell_measurement_reflns_used    2725
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      31.42
_cell_measurement_theta_min      2.20
_cell_volume                     588.4(3)
_computing_cell_refinement       'Apex2 v2011.2-0'
_computing_data_collection       'Apex2 v2011.2-0 (Bruker, 2011)'
_computing_data_reduction        'Apex2 v2011.2-0'
_computing_molecular_graphics    'SHELXTL 6.14'
_computing_publication_material  'SHELXTL 6.14'
_computing_structure_refinement
;
SHELXTL 6.14, Shelxle (H\"ubschle et al., 2011)
;
_computing_structure_solution    'SHELXTL 6.14 (Bruker, 2003; Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.983
_diffrn_measured_fraction_theta_max 0.948
_diffrn_measurement_device_type  'Bruker AXS SMART APEX CCD diffractometer'
_diffrn_measurement_method       '\w scans'
_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  0.0245
_diffrn_reflns_av_sigmaI/netI    0.0231
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            6608
_diffrn_reflns_theta_full        28.00
_diffrn_reflns_theta_max         31.57
_diffrn_reflns_theta_min         4.58
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.113
_exptl_absorpt_correction_T_max  0.7462
_exptl_absorpt_correction_T_min  0.6701
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Apex2 v2011.2-0 (Bruker, 2011)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.447
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             272
_exptl_crystal_size_max          0.55
_exptl_crystal_size_mid          0.45
_exptl_crystal_size_min          0.41
_refine_diff_density_max         0.473
_refine_diff_density_min         -0.200
_refine_diff_density_rms         0.046
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.053
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     106
_refine_ls_number_reflns         1871
_refine_ls_number_restraints     8
_refine_ls_restrained_S_all      1.052
_refine_ls_R_factor_all          0.0370
_refine_ls_R_factor_gt           0.0346
_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^)+(0.0551P)^2^+0.1376P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0943
_refine_ls_wR_factor_ref         0.0965
_reflns_number_gt                1728
_reflns_number_total             1871
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            c2ob25996f.txt
_cod_data_source_block           11mz400_0m
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 1891 2012-01-12 08:04:46Z andrius 
;
_cod_original_cell_volume        588.3(3)
_cod_original_sg_symbol_H-M      P2(1)/c
_cod_database_code               7152639