Modular Synthesis of Constrained Ethyl (cEt) Purine and Pyrimidine Nucleosides.
Blade, Helen; Bradley, Derek; Diorazio, Louis; Evans, Timothy; Hayter, Barry R.; Howell, Gareth P.; The Journal of organic chemistry 80 (2015) 5337–5343; doi:10.1021/acs.joc.5b00607

data_4036212
_publ_section_title
;
 Modular Synthesis of Constrained Ethyl (cEt) Purine and Pyrimidine
 Nucleosides.
;
_journal_issue                   10
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              5337
_journal_page_last               5343
_journal_paper_doi               10.1021/acs.joc.5b00607
_journal_volume                  80
_journal_year                    2015
_chemical_formula_moiety         C24H28O6
_chemical_formula_sum            'C24 H28 O6'
_chemical_formula_weight         412.46
_chemical_melting_point          345.15
_chemical_name_common            'epoxide; Structure 10'
_chemical_name_systematic
;
(3aR,5S,6S,6aR)-6-benzyloxy-5-

(benzyloxymethyl)-2,2-dimethyl-5-[(2R)-oxiran-2-yl]-6,6a-dihydro-3aH-furo[2,3

-d][1,3]dioxole
;
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90
_cell_angle_beta                 109.451(5)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   10.6029(15)
_cell_length_b                   8.4121(11)
_cell_length_c                   13.0245(17)
_cell_measurement_reflns_used    3851
_cell_measurement_temperature    200.(2)
_cell_measurement_theta_max      23.1996
_cell_measurement_theta_min      2.9309
_cell_volume                     1095.4(3)
_computing_cell_refinement       'SAINT V8.34A (Bruker AXS Inc., 2013)'
_computing_data_reduction        'SAINT V8.34A (Bruker AXS Inc., 2013)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      200.(2)
_diffrn_detector_area_resol_mean 8.3330
_diffrn_measured_fraction_theta_full 0.996
_diffrn_measured_fraction_theta_max 0.996
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0524
_diffrn_reflns_av_unetI/netI     0.0484
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            12079
_diffrn_reflns_theta_full        25.07
_diffrn_reflns_theta_max         25.07
_diffrn_reflns_theta_min         1.66
_exptl_absorpt_coefficient_mu    0.089
_exptl_absorpt_correction_T_max  0.98
_exptl_absorpt_correction_T_min  0.63
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS V2014/5 (Bruker AXS Inc.)'
_exptl_crystal_colour            white
_exptl_crystal_density_diffrn    1.251
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       rod
_exptl_crystal_F_000             440
_exptl_crystal_size_max          1.000
_exptl_crystal_size_mid          0.600
_exptl_crystal_size_min          0.200
_refine_diff_density_max         0.281
_refine_diff_density_min         -0.257
_refine_ls_abs_structure_details
;
Flack x determined using 1178 quotients [(I+)-(I-)]/[(I+)+(I-)]
(Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.8(7)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.125
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     273
_refine_ls_number_reflns         3671
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.125
_refine_ls_R_factor_all          0.0516
_refine_ls_R_factor_gt           0.0379
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0607P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1003
_refine_ls_wR_factor_ref         0.1165
_reflns_number_gt                3129
_reflns_number_total             3671
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo5b00607_si_002.cif
_cod_data_source_block           I
_cod_database_code               4036212
_shelx_res_checksum              3544
_shelx_hkl_checksum              78346