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_7152365
_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_iupac          'C8 H9 N5 O'
_chemical_formula_moiety         'C8 H9 N5 O'
_chemical_formula_sum            'C8 H9 N5 O'
_chemical_formula_weight         191.20
_chemical_melting_point          545
_chemical_name_systematic
;
4-Amino-2,8-dimethyl-6<i>H</i>-pyrimido[1,2-<i>a</i>][1,3,5]triazin-6-one
;
_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                   11.1369(19)
_cell_length_b                   18.913(3)
_cell_length_c                   4.0311(7)
_cell_measurement_reflns_used    614
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      26.80
_cell_measurement_theta_min      2.83
_cell_volume                     849.1(2)
_computing_cell_refinement       'SAINT (Bruker, 2001)'
_computing_data_collection       'SMART (Bruker, 2001)'
_computing_data_reduction        'SAINT (Bruker, 2001)'
_computing_molecular_graphics    'SHELXTL (Sheldrick, 2008)'
_computing_publication_material  'SHELXTL (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker SMART APEX CCD'
_diffrn_measurement_method       '\f and \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  0.0503
_diffrn_reflns_av_sigmaI/netI    0.0376
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       -24
_diffrn_reflns_limit_l_max       4
_diffrn_reflns_limit_l_min       -5
_diffrn_reflns_number            5774
_diffrn_reflns_theta_full        27.49
_diffrn_reflns_theta_max         27.49
_diffrn_reflns_theta_min         2.15
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.107
_exptl_absorpt_correction_T_max  0.9936
_exptl_absorpt_correction_T_min  0.9383
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 2001)'
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.496
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Needle
_exptl_crystal_F_000             400
_exptl_crystal_size_max          0.60
_exptl_crystal_size_mid          0.08
_exptl_crystal_size_min          0.06
_refine_diff_density_max         0.334
_refine_diff_density_min         -0.251
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.145
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     137
_refine_ls_number_reflns         1119
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.144
_refine_ls_R_factor_all          0.0588
_refine_ls_R_factor_gt           0.0527
_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^)+(0.0530P)^2^+0.4545P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1137
_refine_ls_wR_factor_ref         0.1169
_reflns_number_gt                1019
_reflns_number_total             1119
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            c2ob25195g.txt
_cod_data_source_block           I
_cod_original_cell_volume        849.1(3)
_cod_database_code               7152365