Squaric Acid N-Hydroxylamides: Synthesis, Structure, and Properties of Vinylogous Hydroxamic Acid Analogues
Nathaniel C. Lim; Martha D. Morton; Hilary A. Jenkins; Christian Brückner; Journal of Organic Chemistry 68 (2003) 9233–9241; doi:10.1021/jo035175g

data_4022565
_publ_contact_author_address
;   Department of Chemistry
     University of Connecticut
     Storrs, CT 06269-3060
;
_publ_contact_author_email       c.bruckner@uconn.edu
_publ_contact_author_fax         '860 486 2981'
_publ_contact_author_name        'Dr. Christian Bruckner'
_publ_contact_author_phone       '860 486 2743'
_publ_section_title
;
 Squaric Acid N-Hydroxylamides: Synthesis, Structure,
 and Properties of Vinylogous Hydroxamic Acid Analogues
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              9233
_journal_page_last               9241
_journal_paper_doi               10.1021/jo035175g
_journal_volume                  68
_journal_year                    2003
_chemical_formula_sum            'C8 H11 N O4'
_chemical_formula_weight         185.18
_chemical_melting_point          422.1(10)
_chemical_name_systematic
;
3-Methoxy-4-N-isopropylhydroxylaminocyclobut-3-ene-1,2-dione
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_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                 113.915(8)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   29.730(16)
_cell_length_b                   4.577(2)
_cell_length_c                   13.538(7)
_cell_measurement_temperature    291(2)
_cell_volume                     1684.2(15)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      291(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_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  0.0281
_diffrn_reflns_av_sigmaI/netI    0.0303
_diffrn_reflns_limit_h_max       25
_diffrn_reflns_limit_h_min       -36
_diffrn_reflns_limit_k_max       5
_diffrn_reflns_limit_k_min       -5
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            4375
_diffrn_reflns_theta_full        26.50
_diffrn_reflns_theta_max         26.50
_diffrn_reflns_theta_min         3.00
_exptl_absorpt_coefficient_mu    0.118
_exptl_crystal_density_diffrn    1.461
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             784
_refine_diff_density_max         0.220
_refine_diff_density_min         -0.180
_refine_diff_density_rms         0.043
_refine_ls_extinction_coef       0.0044(13)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.030
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     119
_refine_ls_number_reflns         1743
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.030
_refine_ls_R_factor_all          0.0724
_refine_ls_R_factor_gt           0.0449
_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^)+(0.0781P)^2^+0.1960P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1210
_refine_ls_wR_factor_ref         0.1336
_reflns_number_gt                1164
_reflns_number_total             1743
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo035175gsi20030814_084736.cif
_cod_data_source_block           Lim_et_al._compound_5b
_cod_depositor_comments
;
The following automatic conversions were performed:

'_chemical_melting_point' value '148-150 degC' was changed to
'422.1(10)' - it was converted from degrees Celsius(C) to Kelvins(K),
the average value was taken and precision was estimated.

Automatic conversion script
Id: cif_fix_values 1646 2011-03-28 12:23:43Z adriana 
;
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               4022565