\chemfig{
                              HO% 16
                     -[:60,,2]% 13
                -[:120,,,,drh]% 12
                        -[:60]% 11
                    -[,,,,drh]% 8
                        -[:60]% 7
                             -% 10
                       -[:300]% 1
                             -% 6
                -[:300,,,,drh]% 5
                       -[:240]% 4
                                 (
                       -[:300,,,1]OH% 17
                                 )
                       -[:180]% 3
                       -[:120]% 2
                                 (
                            -[:60]% -> 1
                                 )
                                 (
                           -[:180]% 9
                                     (
                               -[:120]% -> 8
                                     )
                    -[:240,,,,drh]% 14
                                     (
                       -[:327.1,1.233]O% 15
                        -[:34.8,1.174]% -> 3
                                     )
                           -[:180]% -> 13
                                 )
               -[:123.3,0.928]% 19
    -[:89.9,1.239,,,draw=none]% 20
                -[:30.1,1.163]N% 18
                                 (
                           -[:240]% -> 10
                                 )
                      -[:37.5]% 21
                                 (
       -[:233.4,3.026,,,draw=none]% -> 19
    -[:89.9,1.239,,,mcfx={10}{10}]% -> 20
                                 )
}

.
