2,2,5,5,8,8-Hexamethyl-2,3,5,6,7,8-hexahydroimidazo[1,2-<i>a</i>]pyrazine-3,6-dione, a bicyclic product of α-aminoisobutyric acid condensation
Basiuk, Vladimir A.; Van Meervelt, Luc; Soloshonok, Vadim A.; Basiuk, Elena V.; Acta Crystallographica Section C 56 (2000) 598–599; doi:10.1107/S0108270100002766

data_2010899
_publ_section_title
;2,2,5,5,8,8-Hexamethyl-2,3,5,6,7,8-hexahydroimidazo[1,2-<i>a</i>]pyrazine-3,6-dione,
 a bicyclic product of \a-aminoisobutyric acid condensation
;
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              598
_journal_page_last               599
_journal_paper_doi               10.1107/S0108270100002766
_journal_volume                  56
_journal_year                    2000
_chemical_formula_moiety         'C12 H19 N3 O2'
_chemical_formula_sum            'C12 H19 N3 O2'
_chemical_formula_weight         237.30
_chemical_name_systematic
; 2,2,5,5,8,8-hexamethyl-4,5,7,8-tetrahydroimidazo[1,2-a]pyrazine-
  -3,6-dione
;
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_cell_angle_alpha                95.020(10)
_cell_angle_beta                 93.340(10)
_cell_angle_gamma                102.450(10)
_cell_formula_units_Z            2
_cell_length_a                   5.9020(10)
_cell_length_b                   8.628(2)
_cell_length_c                   12.949(2)
_cell_measurement_reflns_used    20
_cell_measurement_temperature    289(2)
_cell_measurement_theta_max      21.417
_cell_measurement_theta_min      20.033
_cell_volume                     639.4(2)
_computing_cell_refinement       XSCANS
_computing_data_collection       'XSCANS (Siemens, 1994)'
_computing_data_reduction        XSCANS
_computing_molecular_graphics    'PLATON99 (Spek, 1999)'
_computing_publication_material  PLATON99
_computing_structure_refinement  SHELXTL
_computing_structure_solution    'SHELXTL (Sheldrick, 1997)'
_diffrn_ambient_temperature      289(2)
_diffrn_measured_fraction_theta_full .996
_diffrn_measured_fraction_theta_max .996
_diffrn_measurement_device_type  'Siemens P4'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     .71073
_diffrn_reflns_av_R_equivalents  .0281
_diffrn_reflns_av_sigmaI/netI    .0452
_diffrn_reflns_limit_h_max       1
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            2941
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         1.58
_diffrn_standards_decay_%        .019
_diffrn_standards_interval_count 97
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    .086
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.233
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Needle
_exptl_crystal_F_000             256
_exptl_crystal_size_max          .40
_exptl_crystal_size_mid          .30
_exptl_crystal_size_min          .20
_refine_diff_density_max         .171
_refine_diff_density_min         -.216
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.013
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     167
_refine_ls_number_reflns         2234
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.013
_refine_ls_R_factor_all          .0679
_refine_ls_R_factor_gt           .0424
_refine_ls_shift/su_max          <0.001
_refine_ls_shift/su_mean         .000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w = 1/[\s^2^(Fo^2^)+(0.0495P)^2^+0.1584P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         .1164
_reflns_number_gt                1621
_reflns_number_total             2234
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            da1114.cif
_cod_data_source_block           I
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Triclinic' changed to 'triclinic'
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_enum 1527 2010-12-29 10:47:43Z saulius 

The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Triclinic' changed to 'triclinic'
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 
;
_cod_original_sg_symbol_H-M      P-1
_cod_database_code               2010899
_cod_database_fobs_code          2010899