Selective functionalization of the 1H-imidazo[1,2-b]pyrazole scaffold. A new potential non-classical isostere of indole and a precursor of push‒pull dyes
Schwärzer, Kuno; Rout, Saroj K.; Bessinger, Derya; Lima, Fabio; Brocklehurst, Cara E.; Karaghiosoff, Konstantin; Bein, Thomas; Knochel, Paul; Chemical Science  (2021) –; doi:10.1039/D1SC04155J

data_1564611
_publ_section_title
;
 Selective functionalization of the 1H-imidazo[1,2-b]pyrazole scaffold. A
 new potential non-classical isostere of indole and a precursor of
 push--pull dyes
;
_journal_name_full               'Chemical Science'
_journal_paper_doi               10.1039/D1SC04155J
_journal_year                    2021
_chemical_formula_moiety         'C12 H21 N3 O S Si'
_chemical_formula_sum            'C12 H21 N3 O S Si'
_chemical_formula_weight         283.47
_chemical_name_systematic
;
7-(methylthio)-1-((2-(trimethylsilyl)ethoxy)methyl)-1H-imidazo[1,2-b]pyrazole
;
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2018/1
_audit_update_record
;
2021-07-18 deposited with the CCDC.	2021-09-10 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 102.656(8)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   15.4782(12)
_cell_length_b                   8.4222(7)
_cell_length_c                   12.5728(9)
_cell_measurement_reflns_used    1071
_cell_measurement_temperature    123(2)
_cell_measurement_theta_max      22.4350
_cell_measurement_theta_min      2.7550
_cell_volume                     1599.2(2)
_computing_cell_refinement       'CrysAlisPro 1.171.40.81a (Rigaku OD, 2020)'
_computing_data_collection       'CrysAlisPro 1.171.40.81a (Rigaku OD, 2020)'
_computing_data_reduction        'CrysAlisPro 1.171.40.81a (Rigaku OD, 2020)'
_computing_molecular_graphics
;
'ORTEP (M. N. Burnett, C. K. Johnson, ORTEP-III: Oak Ridge Thermal Ellipsoid
;
_computing_publication_material
;
PLATON (A. L. Spek, Acta Crystallogr, Sect. A, 1990, 46, C34, 1995 version).
;
_computing_structure_refinement  'SHELXL-2018/1 (Sheldrick, 2018)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      123(2)
_diffrn_detector_area_resol_mean 15.9809
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'Xcalibur, Sapphire3'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0776
_diffrn_reflns_av_unetI/netI     0.0972
_diffrn_reflns_Laue_measured_fraction_full 0.995
_diffrn_reflns_Laue_measured_fraction_max 0.995
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -19
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            10569
_diffrn_reflns_point_group_measured_fraction_full 0.995
_diffrn_reflns_point_group_measured_fraction_max 0.995
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         26.021
_diffrn_reflns_theta_min         2.769
_diffrn_source                   'fine-focus sealed X-ray tube'
_exptl_absorpt_coefficient_mu    0.271
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.80050
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.40.81a (Rigaku Oxford Diffraction, 2020)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.177
_exptl_crystal_description       platelet
_exptl_crystal_F_000             608
_exptl_crystal_size_max          0.250
_exptl_crystal_size_mid          0.050
_exptl_crystal_size_min          0.020
_refine_diff_density_max         0.276
_refine_diff_density_min         -0.281
_refine_diff_density_rms         0.059
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.988
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     177
_refine_ls_number_reflns         3139
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.988
_refine_ls_R_factor_all          0.1074
_refine_ls_R_factor_gt           0.0568
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0269P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0844
_refine_ls_wR_factor_ref         0.0998
_reflns_Friedel_coverage         0.000
_reflns_number_gt                1968
_reflns_number_total             3139
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d1sc04155j2.cif
_cod_data_source_block           test1
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               1564611
_shelx_shelxl_version_number     2018/1
_shelx_estimated_absorpt_t_min   0.935
_shelx_estimated_absorpt_t_max   0.995
_shelx_res_checksum              63198