Mild deprotection of the N-tert-butyloxycarbonyl (N-Boc) group using oxalyl chloride
George, Nathaniel; Ofori, Samuel; Parkin, Sean; Awuah, Samuel G.; RSC Advances 10 (2020) 24017–24026; doi:10.1039/D0RA04110F

data_7240774
_publ_section_title
;
 Mild deprotection of the N-tert-butyloxycarbonyl (N-Boc) group using
 oxalyl chloride
;
_journal_issue                   40
_journal_name_full               'RSC Advances'
_journal_page_first              24017
_journal_page_last               24026
_journal_paper_doi               10.1039/D0RA04110F
_journal_volume                  10
_journal_year                    2020
_chemical_absolute_configuration ad
_chemical_formula_moiety         '2(C28 H28 N2 O6) C H2 Cl2'
_chemical_formula_sum            'C57 H58 Cl2 N4 O12'
_chemical_formula_weight         1061.97
_space_group_crystal_system      monoclinic
_space_group_IT_number           5
_space_group_name_Hall           'C 2y'
_space_group_name_H-M_alt        'C 1 2 1'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           'SHELXL-2017 and CIFFIX/1'
_audit_update_record
;
2020-04-22 deposited with the CCDC.	2020-06-16 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 103.374(4)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   23.791(2)
_cell_length_b                   6.7169(6)
_cell_length_c                   17.0032(16)
_cell_measurement_reflns_used    9842
_cell_measurement_temperature    90.0(2)
_cell_measurement_theta_max      74.59
_cell_measurement_theta_min      3.82
_cell_volume                     2643.5(4)
_computing_cell_refinement       '<i>APEX3</i> (Bruker-AXS, 2016)'
_computing_data_collection       '<i>APEX3</i> (Bruker-AXS, 2016)'
_computing_data_reduction        '<i>APEX3</i> (Bruker-AXS, 2016)'
_computing_molecular_graphics    '<i>XP in SHELXTL</i> (Sheldrick, 2008)'
_computing_publication_material
'<i>SHELX</i> (Sheldrick, 2008) and <i>CIFFIX</i> (Parkin, 2013)'
_computing_structure_refinement  '<i>SHELXL-2017/1</i> (Sheldrick, 2015b)'
_computing_structure_solution    '<i>SHELXT</i> (Sheldrick, 2015a)'
_diffrn_ambient_temperature      90.0(2)
_diffrn_detector_area_resol_mean 5.6
_diffrn_measured_fraction_theta_full 0.976
_diffrn_measured_fraction_theta_max 0.976
_diffrn_measurement_device_type  'Bruker D8 Venture dual source'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0610
_diffrn_reflns_av_unetI/netI     0.0541
_diffrn_reflns_Laue_measured_fraction_full 0.976
_diffrn_reflns_Laue_measured_fraction_max 0.976
_diffrn_reflns_limit_h_max       29
_diffrn_reflns_limit_h_min       -29
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            25456
_diffrn_reflns_point_group_measured_fraction_full 0.973
_diffrn_reflns_point_group_measured_fraction_max 0.968
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         74.520
_diffrn_reflns_theta_min         2.671
_diffrn_source                   microsource
_exptl_absorpt_coefficient_mu    1.663
_exptl_absorpt_correction_T_max  0.929
_exptl_absorpt_correction_T_min  0.760
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '<i>SADABS</i> (Krause et al., 2015)'
_exptl_crystal_colour            red
_exptl_crystal_density_diffrn    1.334
_exptl_crystal_description       needle
_exptl_crystal_F_000             1116
_exptl_crystal_size_max          0.300
_exptl_crystal_size_mid          0.030
_exptl_crystal_size_min          0.020
_refine_diff_density_max         0.488
_refine_diff_density_min         -0.298
_refine_diff_density_rms         0.040
_refine_ls_abs_structure_details
; 
Flack 'x' determined using 2011 quotients [(I+)-(I-)]/[(I+)+(I-)] 
[Parsons, Flack and Wagner (2013)]. 
;
_refine_ls_abs_structure_Flack   0.068(14)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.033
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     367
_refine_ls_number_reflns         5266
_refine_ls_number_restraints     86
_refine_ls_restrained_S_all      1.041
_refine_ls_R_factor_all          0.0427
_refine_ls_R_factor_gt           0.0380
_refine_ls_shift/su_max          0.005
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0417P)^2^+1.4710P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0975
_refine_ls_wR_factor_ref         0.1008
_reflns_Friedel_coverage         0.823
_reflns_Friedel_fraction_full    0.969
_reflns_Friedel_fraction_max     0.959
_reflns_number_gt                4832
_reflns_number_total             5266
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d0ra04110f2.cif
_cod_data_source_block           c17058
_cod_depositor_comments          'Adding full bibliography for 7240774.cif.'
_cod_original_sg_symbol_H-M      'C 2'
_cod_database_code               7240774
_shelx_shelxl_version_number     2017/1
_shelx_estimated_absorpt_t_min   0.635
_shelx_estimated_absorpt_t_max   0.967
_exptl_absorpt_special_details
; 
In addition to absorption, multi-scan techniques also correct other slowly 
varying changes in scale factor over reciprocal space, such as those caused 
by x-ray beam inhomogeneity, goniometer imperfection, crystal decomposition, 
crystal longer than the x-ray beam cross section, absorption by the crystal 
mount etc.  These account, by and large, for much of the difference between 
estimated values of Tmin and Tmax and the _exptl_absorpt_correction_ values. 
;
_shelx_res_checksum              55334