\documentclass{standalone} \usepackage{chemfig} \begin{document} \begin{math} \chemfig{ % 1 >[:54]% 2 -[:300]% 3 -% 4 >[:60]% 5 -[:120]% 6 ( -[:180]% 7 ( <[:132]% 8 -[:204]% 9 -[:276]% 10 ( <[:222,,,2]HO% 11 ) -[:348]% -> 2 ) -[:240]% -> 2 ) <:[:60]% 12 -% 13 -[:300]% 14 =_% 15 -[:300]% 16 ( =O% 17 ) -[:240]% 18 -[:180]% 19 -[:120]% 20 ( -[:180]% -> 5 ) ( -[:60]% -> 14 ) <[:240]% 21 }\end{math} \end{document}