<i>cyclo</i>-<i>N</i>-Acetyl-<small>L</small>-alanyl-<i>N</i>-methyl-<small>L</small>-alanyl (<i>cyclo</i>-<i>N</i>-Ac-<small>L</small>-Ala-<i>N</i>-Me-<small>L</small>-Ala)
Chai, C. L. L.; King, A. R.; Hockless, D. C. R.; Acta Crystallographica Section C 51 (1995) 1836–1838; doi:10.1107/S0108270195002745

data_2003921
_publ_contact_author
;
Dr. David C. R. Hockless
Research School of Chemistry
Australian National University
Canberra
ACT 0200
Australia
;
_publ_section_title
;<i>cyclo</i>-<i>N</i>-Acetyl-<small>L</small>-alanyl-<i>N</i>-methyl-<small>L</small>-alanyl
 (<i>cyclo</i>-<i>N</i>-Ac-<small>L</small>-Ala-<i>N</i>-Me-<small>L</small>-Ala)
;
_journal_issue                   9
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              1836
_journal_page_last               1838
_journal_paper_doi               10.1107/S0108270195002745
_journal_volume                  51
_journal_year                    1995
_chemical_compound_source
;
cyclo-NMe-L-Ala-L-Ala (3) was synthesised from the corresponding
dipeptide ester following the procedures of Slater (1969).
The diketopiperazine was then treated with acetic anhydride (10 x mass)
at 293 K for 4 h. The desired compound (1) was purified by flash
chromatography and recrystallised from a solvent mixture of ethyl acetate and
petroleum spirit.
;
_chemical_formula_sum            'C9 H14 N2 O3'
_chemical_formula_weight         198.22
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_audit_creation_method           'from TEXRAY.INF file'
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.799(1)
_cell_length_b                   11.2750(8)
_cell_length_c                   11.622(1)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    213
_cell_measurement_theta_max      49.9
_cell_measurement_theta_min      43.1
_cell_volume                     1021.97(17)
_computing_cell_refinement       'MSC/AFC Diffractometer Control Software'
_computing_data_collection
;MSC/AFC Diffractometer Control Software (Molecular Structure Corporation,
 1988)
;
_computing_data_reduction
;
TEXSAN (Molecular Structure Corporation, 1992)
;
_computing_publication_material  TEXSAN
_computing_structure_refinement  TEXSAN
_computing_structure_solution    'SAPI91 (Fan, 1991)'
_diffrn_ambient_temperature      213
_diffrn_measurement_device       'Rigaku AFC6R'
_diffrn_measurement_method       '\w/2\q scans'
_diffrn_radiation_monochromator  'equatorial graphite'
_diffrn_radiation_source         'Rigaku RU200B rotating Cu anode'
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.5418
_diffrn_reflns_av_R_equivalents  0.00
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            923
_diffrn_reflns_theta_max         60.04
_diffrn_reflns_theta_min         1.5
_diffrn_standards_decay_%        -3.16
_diffrn_standards_interval_count 150
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.815
_exptl_absorpt_correction_T_max  0.998
_exptl_absorpt_correction_T_min  0.907
_exptl_absorpt_correction_type   'empirical, \y scan'
_exptl_absorpt_process_details   psi-scan
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.288
_exptl_crystal_density_meas      0.000
_exptl_crystal_description       Sphere
_exptl_crystal_F_000             424.00
_exptl_crystal_size_max          0.240
_exptl_crystal_size_mid          0.220
_exptl_crystal_size_min          0.180
_refine_diff_density_max         0.11
_refine_diff_density_min         -0.10
_refine_ls_extinction_coef       223E-5(8)
_refine_ls_extinction_method
'Zachariasen (1963) type 2 Gaussian isotropic'
_refine_ls_goodness_of_fit_obs   3.56
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     184
_refine_ls_number_reflns         830
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0329
_refine_ls_R_factor_obs          0.029
_refine_ls_shift/esd_max         0.042
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     w=4F~o~^2^/[\s^2^(F~o~^2^)+(0.003F~o~^2^)^2^]
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0229
_refine_ls_wR_factor_obs         0.023
_reflns_number_observed          830
_reflns_number_total             923
_reflns_observed_criterion       I>=3\s(I)
_cod_data_source_file            kh1020.cif
_cod_data_source_block           Christina
_cod_depositor_comments
;
The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value '
w=4F~o~^2^/[\s^2^(F~o~^2^)+(0.003F~o~^2^)^2^]' was changed to 'calc'.
New tag '_refine_ls_weighting_details' was created. The value of the
new tag was set to 'w=4F~o~^2^/[\s^2^(F~o~^2^)+(0.003F~o~^2^)^2^]'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        1022.0(2)
_cod_original_sg_symbol_H-M      'P 21 21 21 '
_cod_database_code               2003921