Biginelli Dihydropyrimidines: A Tunable Class of Alkyl Radical Precursors
Ratnam, Shahilan; Unone, Shreya; Alia, Nabeel; Hafeneger, Enyu Denny; Janssen-Müller, Daniel; Chemical Science  (2026) –; doi:10.1039/D6SC00376A

data_1576876
_publ_section_title
;
 Biginelli dihydropyrimidines: a tunable class of alkyl radical
 precursors.
;
_journal_issue                   18
_journal_name_full               'Chemical science'
_journal_page_first              8998
_journal_page_last               9005
_journal_paper_doi               10.1039/d6sc00376a
_journal_volume                  17
_journal_year                    2026
_chemical_formula_moiety         'C16 H27 N3 O2, H2 O'
_chemical_formula_sum            'C16 H29 N3 O3'
_chemical_formula_weight         311.42
_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   mixed
_atom_sites_solution_primary     dual
_audit_creation_date             2023-08-09
_audit_creation_method
;FinalCif V123 by Daniel Kratzert, Freiburg 2023, 
https://dkratzert.de/finalcif.html
;
_audit_update_record
;
2024-03-08 deposited with the CCDC.	2026-03-13 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 94.913(3)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   11.7086(15)
_cell_length_b                   9.5131(12)
_cell_length_c                   31.662(4)
_cell_measurement_reflns_used    2387
_cell_measurement_temperature    100.00
_cell_measurement_theta_max      77.996
_cell_measurement_theta_min      2.803
_cell_volume                     3513.7(8)
_computing_cell_refinement       'SAINT V8.40B (?, 2016)'
_computing_data_collection
'Bruker BIS V6.2.15/2021-03-16 && APEX4 2022.1-1'
_computing_data_reduction        'SAINT V8.40B (?, 2016)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'XL  (Sheldrick, 2008)'
_computing_structure_solution    'XT  (Sheldrick, 2015)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      100.00
_diffrn_detector                 CPAD
_diffrn_detector_area_resol_mean 7.41
_diffrn_detector_type            'Bruker PHOTON III'
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.982
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'Bruker D8 VENTURE dual wavelength Mo/Cu'
_diffrn_measurement_method       '\w and \f scans'
_diffrn_measurement_specimen_support 'MiTeGen micromount'
_diffrn_radiation_monochromator  'mirror optics'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.1048
_diffrn_reflns_av_unetI/netI     0.0462
_diffrn_reflns_Laue_measured_fraction_full 0.995
_diffrn_reflns_Laue_measured_fraction_max 0.982
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       39
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            8927
_diffrn_reflns_point_group_measured_fraction_full 0.995
_diffrn_reflns_point_group_measured_fraction_max 0.982
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         78.598
_diffrn_reflns_theta_min         2.801
_diffrn_source                   'microfocus sealed X-ray tube'
_diffrn_source_current           1.0
_diffrn_source_power             0.05
_diffrn_source_type              'Incoatec I\ms'
_diffrn_source_voltage           50.0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.658
_exptl_absorpt_correction_T_max  0.445117
_exptl_absorpt_correction_T_min  0.253174
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
 TWINABS-2012/1 (Bruker,2012) was used for absorption correction.
 
For component 1:
 wR2(int) was 0.1205 before and 0.0687 after correction.
 
For component 2:
 wR2(int) was 0.1787 before and 0.0736 after correction.
 
For component 3:
 wR2(int) was 0.1652 before and 0.0819 after correction.
 The Ratio of minimum to maximum transmission is 0.57.

Final HKLF 4 output contains 188191 reflections, Rint = 0.1048
 (128998 with I > 3sig(I), Rint = 0.0999)
;
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.177
_exptl_crystal_description       block
_exptl_crystal_F_000             1360
_exptl_crystal_recrystallization_method
'from a mixture of ethyl acetate and pentane by vapor diffusion.'
_exptl_crystal_size_max          1.045
_exptl_crystal_size_mid          0.604
_exptl_crystal_size_min          0.372
_refine_diff_density_max         0.368
_refine_diff_density_min         -0.307
_refine_diff_density_rms         0.065
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.091
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     431
_refine_ls_number_reflns         8927
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.091
_refine_ls_R_factor_all          0.0744
_refine_ls_R_factor_gt           0.0693
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1501P)^2^+0.9557P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2155
_refine_ls_wR_factor_ref         0.2248
_reflns_Friedel_coverage         0.000
_reflns_number_gt                8293
_reflns_number_total             8927
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d6sc00376a2.cif
_cod_data_source_block           cu_2067_cg_0m_4
_cod_depositor_comments
'Adding full bibliography for 1576876--1576878.cif.'
_cod_database_code               1576876
_olex2_refinement_description
;
1. Twinned data refinement
 Scales: 0.662(4)
 0.198(3) 0.140(3)
2. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
3.a Ternary CH refined with riding coordinates:
 C2(H2), C3(H3), C18(H18), C19(H19)
3.b Secondary CH2 refined with riding coordinates:
 C4(H4A,H4B), C5(H5A,H5B), C6(H6A,H6B), C7(H7A,H7B), C8(H8A,H8B), C15(H15A,
 H15B), C20(H20A,H20B), C21(H21A,H21B), C22(H22A,H22B), C23(H23A,H23B),
 C24(H24A,H24B), C31(H31A,H31B)
3.c Idealised Me refined as rotating group:
 C11(H11A,H11B,H11C), C13(H13A,H13B,H13C), C14(H14A,H14B,H14C), C16(H16A,H16B,
 H16C), C27(H27A,H27B,H27C), C29(H29A,H29B,H29C), C30(H30A,H30B,H30C), C32(H32A,
 H32B,H32C)
;
_olex2_submission_special_instructions 'No special instructions were received'
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_min   0.547
_shelx_estimated_absorpt_t_max   0.792
_diffrn_measurement_ambient_temperature_device_make 'Oxford Cryostream 800'
_shelx_res_checksum              39465