Regioselective synthesis of pyrimido[1,2-a][1,3,5]triazin-6-ones via reaction of 1-(6-oxo-1,6-dihydropyrimidin-2-yl)guanidines with triethylorthoacetate: observation of an unexpected rearrangement.
Sachdeva, Nikhil; Dolzhenko, Anton V.; Keung Chui, Wai; Organic & biomolecular chemistry 10 (2012) 4586–4596; doi:10.1039/c2ob25195g

data_7152367
_publ_section_title
;
 Regioselective synthesis of pyrimido[1,2-a][1,3,5]triazin-6-ones via
 reaction of 1-(6-oxo-1,6-dihydropyrimidin-2-yl)guanidines with
 triethylorthoacetate: observation of an unexpected rearrangement.
;
_journal_issue                   23
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              4586
_journal_page_last               4596
_journal_paper_doi               10.1039/c2ob25195g
_journal_volume                  10
_journal_year                    2012
_chemical_formula_sum            'C14 H20 N6 O'
_chemical_formula_weight         288.36
_space_group_IT_number           33
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2n'
_symmetry_space_group_name_H-M   'P n 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                   7.4179(9)
_cell_length_b                   11.2238(15)
_cell_length_c                   17.288(2)
_cell_measurement_reflns_used    707
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      23.52
_cell_measurement_theta_min      2.16
_cell_volume                     1439.3(3)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_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  0.0389
_diffrn_reflns_av_sigmaI/netI    0.0393
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            9771
_diffrn_reflns_theta_full        27.48
_diffrn_reflns_theta_max         27.48
_diffrn_reflns_theta_min         2.16
_exptl_absorpt_coefficient_mu    0.090
_exptl_absorpt_correction_T_max  0.9893
_exptl_absorpt_correction_T_min  0.9701
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Sadabs, (Sheldrick 2001)'
_exptl_crystal_colour            Yellow
_exptl_crystal_density_diffrn    1.331
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Block
_exptl_crystal_F_000             616
_exptl_crystal_size_max          0.34
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.12
_refine_diff_density_max         0.361
_refine_diff_density_min         -0.223
_refine_diff_density_rms         0.059
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.5(16)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.061
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     196
_refine_ls_number_reflns         2799
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.061
_refine_ls_R_factor_all          0.0519
_refine_ls_R_factor_gt           0.0478
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0735P)^2^+0.1541P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1168
_refine_ls_wR_factor_ref         0.1193
_reflns_number_gt                2597
_reflns_number_total             2799
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2ob25195g.txt
_cod_data_source_block           b367
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.1 from
2010-06-29.

'_exptl_absorpt_correction_type' value 'Multi-scan'
changed to 'multi-scan' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 

The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'Not measured' was changed to '?'
- the value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 
;
_cod_original_cell_volume        1439.4(3)
_cod_original_sg_symbol_H-M      Pna2(1)
_cod_database_code               7152367