A constrained Tricyclic Nucleic Acid Analogue of α-l-LNA: Investigating the Effects of Dual Conformational Restriction on Duplex Thermal Stability
Stephen Hanessian; Jernej Wagger; Bradley L. Merner; Robert D. Giacometti; Michael E. Østergaard; Eric E. Swayze; Punit P. Seth; Journal of Organic Chemistry 78 (2013) 9064–9075; doi:10.1021/jo401170y

data_4028591
_publ_section_title
;
 A constrained Tricyclic Nucleic Acid Analogue of \a-l-LNA: Investigating
 the Effects of Dual Conformational Restriction on Duplex Thermal
 Stability
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              9064
_journal_page_last               9075
_journal_paper_doi               10.1021/jo401170y
_journal_volume                  78
_journal_year                    2013
_chemical_absolute_configuration rmad
_chemical_compound_source        'Synthesized by the authors. See text'
_chemical_formula_moiety         'C14 H18 N2 O6'
_chemical_formula_sum            'C14 H18 N2 O6'
_chemical_formula_weight         310.30
_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'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   6.4711(4)
_cell_length_b                   9.5163(6)
_cell_length_c                   27.7291(17)
_cell_measurement_reflns_used    24767
_cell_measurement_temperature    150
_cell_measurement_theta_max      68.97
_cell_measurement_theta_min      3.19
_cell_volume                     1707.58(18)
_computing_cell_refinement       'SAINT V7.60A(Bruker AXS, 2008)'
_computing_data_collection       'APEX2  (Bruker AXS, 2009)'
_computing_data_reduction        'SAINT V7.60A(Bruker AXS, 2008)'
_computing_molecular_graphics    'SHELXTL v6.12 (Bruker AXS, 2001)'
_computing_publication_material  'UdMX (Maris, 2004)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      150
_diffrn_detector_area_resol_mean 8.3
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker Microstar'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  'Helios optics'
_diffrn_radiation_source         'Rotating Anode'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.045
_diffrn_reflns_av_sigmaI/netI    0.0249
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       24
_diffrn_reflns_limit_l_min       -33
_diffrn_reflns_number            34006
_diffrn_reflns_theta_full        69.25
_diffrn_reflns_theta_max         69.25
_diffrn_reflns_theta_min         4.91
_exptl_absorpt_coefficient_mu    0.806
_exptl_absorpt_correction_T_max  0.9920
_exptl_absorpt_correction_T_min  0.5753
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Sadabs (Sheldrick, 2004)'
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.207
_exptl_crystal_description       needle
_exptl_crystal_F_000             656
_exptl_crystal_size_max          0.29
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.01
_platon_squeeze_details
;
The crystal structure has been squeezed out with PLATON to remove high 
disordered methanol contribution from its solvate structure. 
PLATON found a total of 355.8 A^3 solvent accessible void volume with 
contribution from 86 electrons per cell. More precisely, there are four 
voids of 87 A^3 with 22 electrons contribution estimated to contain 
ethyl acetate used as crystallization solvent.
Considering the solvent the physical data should be:
Formula moiety: 'C14 H18 N2 O6, C H4 O'
Density: 1.332 g cm-3
Absorption coefficient: 0.899 mm-1
F000: 728.0
;
_refine_diff_density_max         0.228
_refine_diff_density_min         -0.150
_refine_diff_density_rms         0.042
_refine_ls_abs_structure_details 'Flack H D (1983), 1309 Friedel Pairs'
_refine_ls_abs_structure_Flack   0.01(17)
_refine_ls_extinction_coef       0.0019(4)
_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   1.075
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     204
_refine_ls_number_reflns         3183
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.075
_refine_ls_R_factor_all          0.0354
_refine_ls_R_factor_gt           0.0338
_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^)+(0.0645P)^2^+0.1574P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0963
_refine_ls_wR_factor_ref         0.0977
_reflns_number_gt                3014
_reflns_number_total             3183
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            jo401170y_si_003.cif
_cod_data_source_block           bent83
_cod_database_code               4028591