Acta Cryst. (2003). E59, o1514-o1516  [ doi:10.1107/S1600536803019640 ]

tert-Butyl 6-O-benzyl-2,2-dichloro-2,5-dideoxy-4-O-methyl--D-ribo-oct-3-pyranulosonate

G. J. Gainsford and P. C. Tyler

Online 24 September 2003

Key indicators

• Single-crystal X-ray study
• T = 153 K
• Mean (C-C) = 0.014 Å
• R factor = 0.069
• wR factor = 0.169
• Data-to-parameter ratio = 7.9

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT027_ALERT_3_A _diffrn_reflns_theta_full too Low ..............      24.74 Deg.  

Alert level B
PLAT213_ALERT_2_B Atom C13'    has ADP max/min Ratio .............       4.50 prolat
PLAT220_ALERT_2_B Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       3.52 Ratio 
PLAT222_ALERT_3_B Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       4.11 Ratio 
PLAT340_ALERT_3_B Low Bond Precision on C-C bonds (x 1000) Ang ...         14       
PLAT415_ALERT_2_B Short Inter D-H..H-X       H3O    ..  H20'     =       1.93 Ang.  
PLAT417_ALERT_2_B Short Inter D-H..H-D       H7'O   ..  H7O      =       1.78 Ang.  

Alert level C
REFNR01_ALERT_3_C  Ratio of reflections to parameters is < 8 for a
            non-centrosymmetric structure, where ZMAX < 18
            sine(theta)/lambda               -0.5901
            Proportion of unique data used    1.0000
            Ratio reflections to parameters   7.8628
THETM01_ALERT_3_C  The value of sine(theta_max)/wavelength is less than 0.590
            Calculated sin(theta_max)/wavelength =    0.5880

PLAT023_ALERT_3_C Resolution (too) Low [sin(th)/Lambda < 0.6].....      24.70 Deg.  
PLAT089_ALERT_3_C Poor Data / Parameter Ratio (Zmax .LT. 18) .....       7.86       
PLAT165_ALERT_3_C Nr. of Status R Flagged Non-Hydrogen Atoms .....         12       
PLAT213_ALERT_2_C Atom C10'    has ADP max/min Ratio .............       3.50 prolat
PLAT220_ALERT_2_C Large Non-Solvent    O     Ueq(max)/Ueq(min) ...       2.64 Ratio 
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.23 Ratio 
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....        C9'     
PLAT431_ALERT_2_C Short Inter HL..A Contact  Cl1    ..  O5'      =       3.01 Ang.  
PLAT601_ALERT_2_C Structure Contains Solvent Accessible VOIDS of .      36.00 A   3  
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          6       
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2       
              C20 H28 Cl2 O7                                                    

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           24.70
           From the CIF: _reflns_number_total               3955
           Count of symmetry unique reflns         3946
           Completeness (_total/calc)            100.23%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         9
           Fraction of Friedel pairs measured     0.002
           Are heavy atom types Z>Si present          yes

   1 ALERT level A = In general: serious problem
   6 ALERT level B = Potentially serious problem
  13 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   9 ALERT type 2 Indicator that the structure model may be wrong or deficient
   9 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion

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