Thioacetic Acid/NaSH-Mediated Synthesis of N-Protected Amino Thioacids and Their Utility in Peptide Synthesis.
Mali, Sachitanand M.; Gopi, Hosahudya N.; The Journal of organic chemistry 79 (2014) 2377–2383; doi:10.1021/jo402872p

data_4029184
_publ_section_title
;
 Thioacetic Acid/NaSH-Mediated Synthesis of N-Protected Amino Thioacids
 and Their Utility in Peptide Synthesis.
;
_journal_issue                   6
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              2377
_journal_page_last               2383
_journal_paper_doi               10.1021/jo402872p
_journal_volume                  79
_journal_year                    2014
_chemical_compound_source        synthesis
_chemical_formula_sum            'C18 H32 N2 O6 S2'
_chemical_formula_weight         436.58
_chemical_name_common            (Boc-Aib-S)2
_space_group_IT_number           29
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2ac'
_symmetry_space_group_name_H-M   'P c a 21'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   23.375(11)
_cell_length_b                   9.575(4)
_cell_length_c                   10.580(5)
_cell_measurement_temperature    100(2)
_cell_volume                     2368.0(19)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.987
_diffrn_measured_fraction_theta_max 0.987
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0806
_diffrn_reflns_av_sigmaI/netI    0.0974
_diffrn_reflns_limit_h_max       32
_diffrn_reflns_limit_h_min       -17
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            23816
_diffrn_reflns_theta_full        29.74
_diffrn_reflns_theta_max         29.74
_diffrn_reflns_theta_min         1.74
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.258
_exptl_absorpt_correction_T_max  0.992
_exptl_absorpt_correction_T_min  0.982
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.225
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       'rod shape'
_exptl_crystal_F_000             936
_exptl_crystal_recrystallization_method EtOAc/n-hexane
_exptl_crystal_size_max          0.1
_exptl_crystal_size_mid          0.06
_exptl_crystal_size_min          0.03
_refine_diff_density_max         0.205
_refine_diff_density_min         -0.249
_refine_diff_density_rms         0.044
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.12(5)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.766
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     263
_refine_ls_number_reflns         6601
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.766
_refine_ls_R_factor_all          0.0748
_refine_ls_R_factor_gt           0.0386
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0312P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0680
_refine_ls_wR_factor_ref         0.0767
_reflns_number_gt                4198
_reflns_number_total             6601
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo402872p_si_002.cif
_cod_data_source_block           SM_Aib-S-Dimer
_cod_original_cell_volume        2368.1(19)
_cod_original_sg_symbol_H-M      Pca21
_cod_database_code               4029184