Tizanidine and tizanidine hydrochloride: on the correct tautomeric form of tizanidine
Bekö, Sándor L.; Thoms, Silke D.; Schmidt, Martin U.; Bolte, Michael; Acta Crystallographica Section C 68 (2012) o28–o32; doi:10.1107/S0108270111052012

data_2018356
_publ_section_title
;
 Tizanidine and tizanidine hydrochloride: on the correct tautomeric form
 of tizanidine
;
_journal_coeditor_code           SK3425
_journal_issue                   1
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              o28
_journal_page_last               o32
_journal_paper_doi               10.1107/S0108270111052012
_journal_volume                  68
_journal_year                    2012
_chemical_formula_iupac          'C9 H8 Cl N5 S'
_chemical_formula_moiety         'C9 H8 Cl N5 S'
_chemical_formula_sum            'C9 H8 Cl N5 S'
_chemical_formula_weight         253.71
_chemical_name_common            Tizanidine
_chemical_name_systematic
;
5-chloro-<i>N</i>-(imidazolidin-2-ylidene)-2,1,3-benzothiadiazol-4-amine
;
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                95.794(7)
_cell_angle_beta                 100.349(7)
_cell_angle_gamma                92.125(7)
_cell_formula_units_Z            4
_cell_length_a                   7.5935(6)
_cell_length_b                   10.8712(9)
_cell_length_c                   12.8862(12)
_cell_measurement_reflns_used    8083
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      26.0
_cell_measurement_theta_min      3.4
_cell_volume                     1039.45(16)
_computing_cell_refinement       'X-AREA (Stoe & Cie, 2001)'
_computing_data_collection       'X-AREA (Stoe & Cie, 2001)'
_computing_data_reduction        'X-AREA (Stoe & Cie, 2001)'
_computing_molecular_graphics    'XP (Sheldrick, 2008)'
_computing_publication_material
;
SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and
<i>publCIF</i> (Westrip,
2010)
;
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'Stoe IPDS II two-circle'
_diffrn_measurement_method       \w
_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  0.0330
_diffrn_reflns_av_sigmaI/netI    0.0275
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            9426
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.55
_diffrn_reflns_theta_min         3.42
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.545
_exptl_absorpt_correction_T_max  0.7915
_exptl_absorpt_correction_T_min  0.7837
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(MULABS; Spek, 2009; Blessing, 1995)'
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    1.621
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             520
_exptl_crystal_size_max          0.47
_exptl_crystal_size_mid          0.47
_exptl_crystal_size_min          0.45
_refine_diff_density_max         0.285
_refine_diff_density_min         -0.272
_refine_ls_extinction_coef       0.0305(18)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL97 (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   1.059
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     306
_refine_ls_number_reflns         3872
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.059
_refine_ls_R_factor_all          0.0321
_refine_ls_R_factor_gt           0.0285
_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^)+(0.0395P)^2^+0.3667P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0745
_refine_ls_wR_factor_ref         0.0762
_reflns_number_gt                3537
_reflns_number_total             3872
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            sk3425.cif
_cod_data_source_block           I
_cod_original_cell_volume        1039.45(15)
_cod_database_code               2018356
_cod_database_fobs_code          2018356