##############################################################################
#                                                                            #
# This CIF contains the data for a data article accepted for                 #
# publication in IUCrData. It conforms to the requirements of                #
# Notes for Authors for IUCrData, and has been                               #
# peer reviewed under the auspices of IUCrData.                              #
#                                                                            #
# Full details of the Crystallographic Information File format               #
# are given in the paper "The Crystallographic Information File (CIF):       #
# a New Standard Archive File for Crystallography" by S. R. Hall, F. H.      #
# Allen and I. D. Brown [Acta Cryst. (1991), A47, 655-685].                  #
#                                                                            #
# The current version of the core CIF dictionary is obtainable from          #
# ftp://ftp.iucr.org/pub/cif_core.dic.                                       #
#                                                                            #
# Software is freely available for graphical display of the structure(s)     #
# in this CIF. For information consult the CIF software page                 #
# http://www.iucr.org/resources/cif/software.                                #
#                                                                            #
# This file may be used for bona fide research purposes within the           #
# scientific community so long as proper attribution is given to the data    # 
# article from which it was obtained.                                        #
#                                                                            #
##############################################################################
data_I
_audit_creation_method     'SHELXL-2018/3'
_chemical_name_systematic
;\
Methyl 3,3,6,6-tetramethyl-1,8-dioxo-4,5,7,9-tetrahydro-\
2H-xanthene-9-carboxylate
;
_chemical_name_common     ?
_chemical_formula_moiety     'C19 H24 O5'
_chemical_formula_sum     'C19 H24 O5'
_chemical_formula_iupac     'C19 H24 O5'
_chemical_formula_weight     332.38
_chemical_melting_point     ?
_space_group_crystal_system     monoclinic
_space_group_name_H-M_alt     'P 21/c'
_space_group_name_Hall     '-P 2ybc'
loop_
    _space_group_symop_operation_xyz
    'x, y, z'
    '-x, y+1/2, -z+1/2'
    '-x, -y, -z'
    'x, -y-1/2, z-1/2'
_cell_length_a     13.1494(10)
_cell_length_b     9.6899(6)
_cell_length_c     14.8185(13)
_cell_angle_alpha     90
_cell_angle_beta     113.295(6)
_cell_angle_gamma     90
_cell_volume     1734.2(2)
_cell_formula_units_Z     4
_cell_measurement_reflns_used     9146
_cell_measurement_theta_min     2.58
_cell_measurement_theta_max     28.22
_cell_measurement_temperature     120(2)
_exptl_crystal_description     plate
_exptl_crystal_colour     colourless
_exptl_crystal_size_max     0.220
_exptl_crystal_size_mid     0.110
_exptl_crystal_size_min     0.060
_exptl_crystal_density_diffrn     1.273
_exptl_crystal_density_meas     ?
_exptl_crystal_density_method     ?
_exptl_crystal_F_000     712
_exptl_absorpt_coefficient_mu     0.091
_exptl_absorpt_correction_type     none
_exptl_absorpt_process_details     ?
_exptl_absorpt_correction_T_min     ?
_exptl_absorpt_correction_T_max     ?
_diffrn_ambient_temperature     120(2)
_diffrn_source     'sealed X-ray tube, 12 x 0.4 mm long-fine focus'
_diffrn_radiation_type     MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_measurement_device_type     'STOE IPDS 2T'
_diffrn_measurement_method     'rotation method, ω scans'
_diffrn_detector_area_resol_mean     6.67
_diffrn_reflns_number     8583
_diffrn_reflns_av_R_equivalents     0.0362
_diffrn_reflns_av_unetI/netI     0.0457
_diffrn_reflns_theta_min     2.580
_diffrn_reflns_theta_max     27.949
_diffrn_reflns_theta_full     25.242
_diffrn_measured_fraction_theta_max     0.991
_diffrn_measured_fraction_theta_full     0.998
_diffrn_reflns_limit_h_min     -16
_diffrn_reflns_limit_h_max     17
_diffrn_reflns_limit_k_min     -12
_diffrn_reflns_limit_k_max     12
_diffrn_reflns_limit_l_min     -19
_diffrn_reflns_limit_l_max     19
_refine_special_details
;
Hydrogen atoms attached to carbons were placed at calculated
positions and were refined in the riding-model approximation with C--H = 0.95
Å, and with Uiso(H) = 1.2 Ueq(C).
;
_reflns_number_total     4123
_reflns_number_gt     2784
_reflns_threshold_expression     'I > 2σ(I)'
_refine_ls_structure_factor_coef     Fsqd
_refine_ls_matrix_type     full
_refine_ls_R_factor_all     0.1134
_refine_ls_R_factor_gt     0.0719
_refine_ls_wR_factor_gt     0.1551
_refine_ls_wR_factor_ref     0.1845
_refine_ls_goodness_of_fit_ref     1.048
_refine_ls_restrained_S_all     1.048
_refine_ls_number_reflns     4123
_refine_ls_number_parameters     222
_refine_ls_number_restraints     0
_refine_ls_hydrogen_treatment     constr
_refine_ls_weighting_scheme     calc
_refine_ls_weighting_details
              'w=1/[σ²(Fo²)+(0.0577P)²+2.4014P] where P=(Fo²+2Fc²)/3'
_atom_sites_solution_hydrogens     geom
_atom_sites_solution_primary     dual
_atom_sites_solution_secondary     ?
_refine_ls_shift/su_max     0.002
_refine_ls_shift/su_mean     0.000
_refine_diff_density_max     0.242
_refine_diff_density_min     -0.300
_refine_ls_extinction_method     none
_refine_ls_extinction_coef     .
loop_
    _atom_type_symbol
    _atom_type_description
    _atom_type_scat_dispersion_real
    _atom_type_scat_dispersion_imag
    _atom_type_scat_source
    'C' 'C' 0.0033 0.0016
                         'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
    'H' 'H' 0.0000 0.0000
                         'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
    'O' 'O' 0.0106 0.0060
                         'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
_computing_data_collection
;
X-AREA WinXpose (Stoe & Cie, 2019)
;
_computing_cell_refinement
;
X-AREA Recipe (Stoe & Cie, 2019)
;
_computing_data_reduction
;
X-AREA Integrate (Stoe & Cie, 2019)
;
_computing_structure_solution
;
SIR-2004 (Burla et al.,  2005)
;
_computing_structure_refinement
;
SHELXL2018/3 (Sheldrick, 2015)
;
_computing_molecular_graphics
;
PLATON (Spek, 2020)
;
_computing_publication_material     ?
loop_
    _atom_site_type_symbol
    _atom_site_label
    _atom_site_fract_x
    _atom_site_fract_y
    _atom_site_fract_z
    _atom_site_U_iso_or_equiv
    _atom_site_adp_type
    _atom_site_calc_flag
    _atom_site_occupancy
    _atom_site_disorder_assembly
    _atom_site_disorder_group
    C C1 0.6910(2) 0.3522(3) 0.3759(2) 0.0290(5) Uani d 1 . .
    H H1 0.715526 0.337644 0.320767 0.035 Uiso calc 1 . .
    C C2 0.7343(2) 0.2359(3) 0.4490(2) 0.0284(5) Uani d 1 . .
    C C3 0.8403(2) 0.1694(3) 0.4650(2) 0.0292(5) Uani d 1 . .
    C C4 0.8801(2) 0.0564(3) 0.5415(2) 0.0327(6) Uani d 1 . .
    H H4A 0.962100 0.056545 0.570806 0.039 Uiso calc 1 . .
    H H4B 0.855649 -0.033835 0.508675 0.039 Uiso calc 1 . .
    C C5 0.8385(2) 0.0705(3) 0.6237(2) 0.0302(6) Uani d 1 . .
    C C6 0.7113(2) 0.0808(3) 0.5759(2) 0.0313(6) Uani d 1 . .
    H H6A 0.679951 -0.010095 0.548221 0.038 Uiso calc 1 . .
    H H6B 0.683107 0.105346 0.626632 0.038 Uiso calc 1 . .
    C C7 0.67398(19) 0.1865(3) 0.49633(19) 0.0270(5) Uani d 1 . .
    O O8 0.56625(14) 0.22547(18) 0.47408(13) 0.0293(4) Uani d 1 . .
    C C9 0.5126(2) 0.2955(3) 0.38683(19) 0.0283(5) Uani d 1 . .
    C C10 0.3910(2) 0.3002(3) 0.3590(2) 0.0301(6) Uani d 1 . .
    H H10A 0.375949 0.313286 0.418829 0.036 Uiso calc 1 . .
    H H10B 0.358002 0.211094 0.328896 0.036 Uiso calc 1 . .
    C C11 0.3362(2) 0.4177(3) 0.2862(2) 0.0312(6) Uani d 1 . .
    C C12 0.3794(2) 0.4120(3) 0.2043(2) 0.0329(6) Uani d 1 . .
    H H12A 0.354823 0.324715 0.167285 0.040 Uiso calc 1 . .
    H H12B 0.347003 0.489267 0.158080 0.040 Uiso calc 1 . .
    C C13 0.5040(2) 0.4207(3) 0.2430(2) 0.0302(5) Uani d 1 . .
    C C14 0.5668(2) 0.3511(3) 0.33598(19) 0.0276(5) Uani d 1 . .
    C C15 0.7354(2) 0.4908(3) 0.4252(2) 0.0307(6) Uani d 1 . .
    O O16 0.68175(18) 0.5800(2) 0.4402(2) 0.0579(7) Uani d 1 . .
    O O17 0.84313(17) 0.5003(2) 0.4521(2) 0.0606(8) Uani d 1 . .
    C C18 0.8958(3) 0.6248(3) 0.5039(3) 0.0611(11) Uani d 1 . .
    H H18A 0.976272 0.616654 0.525273 0.092 Uiso calc 1 . .
    H H18B 0.877556 0.637293 0.561397 0.092 Uiso calc 1 . .
    H H18C 0.869276 0.704400 0.460044 0.092 Uiso calc 1 . .
    O O19 0.89116(15) 0.19842(19) 0.41368(14) 0.0334(4) Uani d 1 . .
    C C20 0.8901(2) 0.1983(3) 0.6859(2) 0.0369(6) Uani d 1 . .
    H H20A 0.971000 0.190656 0.712677 0.055 Uiso calc 1 . .
    H H20B 0.865283 0.204928 0.740014 0.055 Uiso calc 1 . .
    H H20C 0.867042 0.281133 0.644830 0.055 Uiso calc 1 . .
    C C21 0.8723(2) -0.0569(3) 0.6899(2) 0.0407(7) Uani d 1 . .
    H H21A 0.841283 -0.139699 0.650705 0.061 Uiso calc 1 . .
    H H21B 0.844160 -0.048635 0.741779 0.061 Uiso calc 1 . .
    H H21C 0.953273 -0.063927 0.719617 0.061 Uiso calc 1 . .
    C C22 0.3647(2) 0.5576(3) 0.3387(2) 0.0386(7) Uani d 1 . .
    H H22A 0.332418 0.631853 0.290953 0.058 Uiso calc 1 . .
    H H22B 0.445306 0.568687 0.369190 0.058 Uiso calc 1 . .
    H H22C 0.334574 0.561723 0.389470 0.058 Uiso calc 1 . .
    C C23 0.2108(2) 0.3990(3) 0.2434(2) 0.0386(7) Uani d 1 . .
    H H23A 0.175703 0.475736 0.198843 0.058 Uiso calc 1 . .
    H H23B 0.184611 0.397602 0.296837 0.058 Uiso calc 1 . .
    H H23C 0.191455 0.311806 0.207127 0.058 Uiso calc 1 . .
    O O24 0.55164(16) 0.4811(2) 0.19806(15) 0.0394(5) Uani d 1 . .
_geom_special_details
;
 All esds (except the esd in the dihedral angle between two l.s. planes)
 are estimated using the full covariance matrix.  The cell esds are taken
 into account individually in the estimation of esds in distances, angles
 and torsion angles; correlations between esds in cell parameters are only
 used when they are defined by crystal symmetry.  An approximate (isotropic)
 treatment of cell esds is used for estimating esds involving l.s. planes.
;
loop_
    _geom_bond_atom_site_label_1
    _geom_bond_atom_site_label_2
    _geom_bond_site_symmetry_2
    _geom_bond_distance
    _geom_bond_publ_flag
    C1 C14 . 1.501(3) ?
    C1 C2 . 1.510(4) ?
    C1 C15 . 1.530(4) ?
    C1 H1 . 1.0000 ?
    C2 C7 . 1.337(3) ?
    C2 C3 . 1.468(3) ?
    C3 O19 . 1.228(3) ?
    C3 C4 . 1.513(4) ?
    C4 C5 . 1.526(4) ?
    C4 H4A . 0.9900 ?
    C4 H4B . 0.9900 ?
    C5 C21 . 1.529(4) ?
    C5 C20 . 1.533(4) ?
    C5 C6 . 1.541(3) ?
    C6 C7 . 1.490(4) ?
    C6 H6A . 0.9900 ?
    C6 H6B . 0.9900 ?
    C7 O8 . 1.374(3) ?
    O8 C9 . 1.381(3) ?
    C9 C14 . 1.338(3) ?
    C9 C10 . 1.486(3) ?
    C10 C11 . 1.538(4) ?
    C10 H10A . 0.9900 ?
    C10 H10B . 0.9900 ?
    C11 C23 . 1.526(3) ?
    C11 C12 . 1.532(4) ?
    C11 C22 . 1.534(4) ?
    C12 C13 . 1.508(3) ?
    C12 H12A . 0.9900 ?
    C12 H12B . 0.9900 ?
    C13 O24 . 1.229(3) ?
    C13 C14 . 1.461(4) ?
    C15 O16 . 1.191(3) ?
    C15 O17 . 1.314(3) ?
    O17 C18 . 1.450(4) ?
    C18 H18A . 0.9800 ?
    C18 H18B . 0.9800 ?
    C18 H18C . 0.9800 ?
    C20 H20A . 0.9800 ?
    C20 H20B . 0.9800 ?
    C20 H20C . 0.9800 ?
    C21 H21A . 0.9800 ?
    C21 H21B . 0.9800 ?
    C21 H21C . 0.9800 ?
    C22 H22A . 0.9800 ?
    C22 H22B . 0.9800 ?
    C22 H22C . 0.9800 ?
    C23 H23A . 0.9800 ?
    C23 H23B . 0.9800 ?
    C23 H23C . 0.9800 ?
loop_
    _geom_angle_atom_site_label_1
    _geom_angle_atom_site_label_2
    _geom_angle_atom_site_label_3
    _geom_angle_site_symmetry_1
    _geom_angle_site_symmetry_3
    _geom_angle
    _geom_angle_publ_flag
    C14 C1 C2 . . 108.7(2) ?
    C14 C1 C15 . . 110.2(2) ?
    C2 C1 C15 . . 110.4(2) ?
    C14 C1 H1 . . 109.2 ?
    C2 C1 H1 . . 109.2 ?
    C15 C1 H1 . . 109.2 ?
    C7 C2 C3 . . 118.7(2) ?
    C7 C2 C1 . . 120.7(2) ?
    C3 C2 C1 . . 120.5(2) ?
    O19 C3 C2 . . 121.0(2) ?
    O19 C3 C4 . . 121.2(2) ?
    C2 C3 C4 . . 117.7(2) ?
    C3 C4 C5 . . 114.0(2) ?
    C3 C4 H4A . . 108.8 ?
    C5 C4 H4A . . 108.8 ?
    C3 C4 H4B . . 108.8 ?
    C5 C4 H4B . . 108.8 ?
    H4A C4 H4B . . 107.7 ?
    C4 C5 C21 . . 109.6(2) ?
    C4 C5 C20 . . 109.8(2) ?
    C21 C5 C20 . . 108.6(2) ?
    C4 C5 C6 . . 107.8(2) ?
    C21 C5 C6 . . 109.6(2) ?
    C20 C5 C6 . . 111.5(2) ?
    C7 C6 C5 . . 111.5(2) ?
    C7 C6 H6A . . 109.3 ?
    C5 C6 H6A . . 109.3 ?
    C7 C6 H6B . . 109.3 ?
    C5 C6 H6B . . 109.3 ?
    H6A C6 H6B . . 108.0 ?
    C2 C7 O8 . . 123.0(2) ?
    C2 C7 C6 . . 125.6(2) ?
    O8 C7 C6 . . 111.4(2) ?
    C7 O8 C9 . . 117.1(2) ?
    C14 C9 O8 . . 122.5(2) ?
    C14 C9 C10 . . 125.8(2) ?
    O8 C9 C10 . . 111.7(2) ?
    C9 C10 C11 . . 111.8(2) ?
    C9 C10 H10A . . 109.2 ?
    C11 C10 H10A . . 109.2 ?
    C9 C10 H10B . . 109.2 ?
    C11 C10 H10B . . 109.2 ?
    H10A C10 H10B . . 107.9 ?
    C23 C11 C12 . . 110.2(2) ?
    C23 C11 C22 . . 108.8(2) ?
    C12 C11 C22 . . 109.9(2) ?
    C23 C11 C10 . . 109.5(2) ?
    C12 C11 C10 . . 108.1(2) ?
    C22 C11 C10 . . 110.2(2) ?
    C13 C12 C11 . . 112.6(2) ?
    C13 C12 H12A . . 109.1 ?
    C11 C12 H12A . . 109.1 ?
    C13 C12 H12B . . 109.1 ?
    C11 C12 H12B . . 109.1 ?
    H12A C12 H12B . . 107.8 ?
    O24 C13 C14 . . 120.7(2) ?
    O24 C13 C12 . . 122.0(2) ?
    C14 C13 C12 . . 117.2(2) ?
    C9 C14 C13 . . 119.2(2) ?
    C9 C14 C1 . . 121.3(2) ?
    C13 C14 C1 . . 119.4(2) ?
    O16 C15 O17 . . 122.7(3) ?
    O16 C15 C1 . . 125.7(2) ?
    O17 C15 C1 . . 111.6(2) ?
    C15 O17 C18 . . 116.8(2) ?
    O17 C18 H18A . . 109.5 ?
    O17 C18 H18B . . 109.5 ?
    H18A C18 H18B . . 109.5 ?
    O17 C18 H18C . . 109.5 ?
    H18A C18 H18C . . 109.5 ?
    H18B C18 H18C . . 109.5 ?
    C5 C20 H20A . . 109.5 ?
    C5 C20 H20B . . 109.5 ?
    H20A C20 H20B . . 109.5 ?
    C5 C20 H20C . . 109.5 ?
    H20A C20 H20C . . 109.5 ?
    H20B C20 H20C . . 109.5 ?
    C5 C21 H21A . . 109.5 ?
    C5 C21 H21B . . 109.5 ?
    H21A C21 H21B . . 109.5 ?
    C5 C21 H21C . . 109.5 ?
    H21A C21 H21C . . 109.5 ?
    H21B C21 H21C . . 109.5 ?
    C11 C22 H22A . . 109.5 ?
    C11 C22 H22B . . 109.5 ?
    H22A C22 H22B . . 109.5 ?
    C11 C22 H22C . . 109.5 ?
    H22A C22 H22C . . 109.5 ?
    H22B C22 H22C . . 109.5 ?
    C11 C23 H23A . . 109.5 ?
    C11 C23 H23B . . 109.5 ?
    H23A C23 H23B . . 109.5 ?
    C11 C23 H23C . . 109.5 ?
    H23A C23 H23C . . 109.5 ?
    H23B C23 H23C . . 109.5 ?
loop_
    _geom_torsion_atom_site_label_1
    _geom_torsion_atom_site_label_2
    _geom_torsion_atom_site_label_3
    _geom_torsion_atom_site_label_4
    _geom_torsion_site_symmetry_1
    _geom_torsion_site_symmetry_2
    _geom_torsion_site_symmetry_3
    _geom_torsion_site_symmetry_4
    _geom_torsion
    _geom_torsion_publ_flag
    C14 C1 C2 C7 . . . . -25.2(3) ?
    C15 C1 C2 C7 . . . . 95.7(3) ?
    C14 C1 C2 C3 . . . . 151.0(2) ?
    C15 C1 C2 C3 . . . . -88.1(3) ?
    C7 C2 C3 O19 . . . . 170.0(2) ?
    C1 C2 C3 O19 . . . . -6.3(4) ?
    C7 C2 C3 C4 . . . . -5.4(4) ?
    C1 C2 C3 C4 . . . . 178.2(2) ?
    O19 C3 C4 C5 . . . . 156.8(2) ?
    C2 C3 C4 C5 . . . . -27.7(3) ?
    C3 C4 C5 C21 . . . . 173.5(2) ?
    C3 C4 C5 C20 . . . . -67.3(3) ?
    C3 C4 C5 C6 . . . . 54.3(3) ?
    C4 C5 C6 C7 . . . . -49.8(3) ?
    C21 C5 C6 C7 . . . . -168.9(2) ?
    C20 C5 C6 C7 . . . . 70.8(3) ?
    C3 C2 C7 O8 . . . . -168.6(2) ?
    C1 C2 C7 O8 . . . . 7.7(4) ?
    C3 C2 C7 C6 . . . . 9.2(4) ?
    C1 C2 C7 C6 . . . . -174.5(2) ?
    C5 C6 C7 C2 . . . . 20.1(4) ?
    C5 C6 C7 O8 . . . . -161.9(2) ?
    C2 C7 O8 C9 . . . . 13.7(3) ?
    C6 C7 O8 C9 . . . . -164.4(2) ?
    C7 O8 C9 C14 . . . . -14.7(4) ?
    C7 O8 C9 C10 . . . . 165.5(2) ?
    C14 C9 C10 C11 . . . . -20.5(4) ?
    O8 C9 C10 C11 . . . . 159.3(2) ?
    C9 C10 C11 C23 . . . . 167.9(2) ?
    C9 C10 C11 C12 . . . . 47.7(3) ?
    C9 C10 C11 C22 . . . . -72.5(3) ?
    C23 C11 C12 C13 . . . . -176.3(2) ?
    C22 C11 C12 C13 . . . . 63.7(3) ?
    C10 C11 C12 C13 . . . . -56.7(3) ?
    C11 C12 C13 O24 . . . . -144.6(3) ?
    C11 C12 C13 C14 . . . . 36.9(3) ?
    O8 C9 C14 C13 . . . . 178.5(2) ?
    C10 C9 C14 C13 . . . . -1.7(4) ?
    O8 C9 C14 C1 . . . . -5.9(4) ?
    C10 C9 C14 C1 . . . . 173.9(2) ?
    O24 C13 C14 C9 . . . . 174.9(3) ?
    C12 C13 C14 C9 . . . . -6.5(4) ?
    O24 C13 C14 C1 . . . . -0.8(4) ?
    C12 C13 C14 C1 . . . . 177.8(2) ?
    C2 C1 C14 C9 . . . . 24.4(3) ?
    C15 C1 C14 C9 . . . . -96.7(3) ?
    C2 C1 C14 C13 . . . . -160.0(2) ?
    C15 C1 C14 C13 . . . . 78.9(3) ?
    C14 C1 C15 O16 . . . . 7.8(4) ?
    C2 C1 C15 O16 . . . . -112.2(3) ?
    C14 C1 C15 O17 . . . . -173.5(2) ?
    C2 C1 C15 O17 . . . . 66.4(3) ?
    O16 C15 O17 C18 . . . . 1.4(5) ?
    C1 C15 O17 C18 . . . . -177.2(3) ?
loop_
    _geom_hbond_atom_site_label_D
    _geom_hbond_atom_site_label_H
    _geom_hbond_atom_site_label_A
    _geom_hbond_site_symmetry_A
    _geom_hbond_distance_DH
    _geom_hbond_distance_HA
    _geom_hbond_distance_DA
    _geom_hbond_angle_DHA
    C6 H6B O24 4_566 0.99 2.50 3.324(4) 140
    C18 H18A O17 3_766 0.98 2.53 3.451(5) 156
    C18 H18A O19 3_766 0.98 2.41 3.093(4) 126
_shelx_space_group_comment
;
The symmetry employed for this shelxl refinement is uniquely defined
by the following loop, which should always be used as a source of
symmetry information in preference to the above space-group names.
They are only intended as comments.
;
_shelx_estimated_absorpt_T_min     0.980
_shelx_estimated_absorpt_T_max     0.995
data_global
_journal_date_recd_electronic     2020-05-27
_journal_date_accepted     2020-07-23
_journal_name_full     'IUCrData'
_journal_year     2020
_journal_volume     5
_journal_issue      7
_journal_page_first     0
_journal_page_last     0
_journal_paper_category     HO
_journal_paper_doi     10.1107/S2414314620010184
_journal_coeditor_code     GG4005
_publ_contact_author_name     'Heiner Detert'
_publ_contact_author_address
;
Johannes Gutenberg University Mainz
Department of Chemistry
Duesbergweg 10-14
55099 Mainz
Germany
;
_publ_contact_author_email     'detert@uni-mainz.de'
_publ_contact_author_fax     '+496131-3925338'
_publ_contact_author_phone     '+496131-3924189'
_publ_section_title
;\
Methyl
3,3,6,6-tetramethyl-1,8-dioxo-4,5,7,9-tetrahydro-2H-xanthene-9-\
carboxylate
;
loop_
    _publ_author_name
    _publ_author_address
    'Detert, Heiner'
;
Johannes Gutenberg University Mainz
Department of Chemistry
Duesbergweg 10-14
55099 Mainz
Germany
;
    'Kluge, Laura'
;
Johannes Gutenberg University Mainz
Department of Chemistry
Duesbergweg 10-14
55099 Mainz
Germany
;
    'Schollmeyer, Dieter'
;
Johannes Gutenberg University Mainz
Department of Chemistry
Duesbergweg 10-14
55099 Mainz
Germany
;
_publ_section_synopsis
;
The title molecule is built by annulation of a half-chair cyclohexenone and a
twist-cyclohexenone to a flat 4-H-pyrane boat. In the crystal,
molecules are connected via van der Waals interactions and C---H...O
hydrogen bonds.
;
