\documentclass[12pt,border=5pt,crop,multi=false,tikz,class=scrartcl]{standalone}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}
\usepackage{chemfig,chemmacros}
\usepackage{color}
\usepackage{xcolor}

\renewcommand*{\familydefault}{\sfdefault}
\renewcommand*\printatom[1]{\ensuremath{\mathsf{#1} } }
\setatomsep{2em}
\setdoublesep{.6ex}
\setarrowdefault{,1.2, thick}
\setbondstyle{thick,cap=round}

\pagestyle{empty}
\thispagestyle{empty}
\begin{document}
% \renewcommand{\baselinestretch}{.5}
\schemestart[][west]
	\chemfig{=^[:-30]-[::60](=[::60]O)-[::-60]O-[::60]}
	\arrow{->[1. \ch{Hg(OAc)2}, \ch{CH3OH}][2. \ch{KBr}]}[,2.5]
	\chemfig{-[:-30]O-[::60]-[::-60](-[::-60]Br)-[::60](=[::60]O)-[::-60]O-[::60]}
	\arrow{->[\ch{NaOH}]}[,1.5]
	\chemfig{-[:-30]O-[::60]-[::-60](-[::-60]Br)-[::60](=[::60]O)-[::-60]OH}
	\arrow{->[*{0}\ch{NH3}]}[-90,1]
	\chemfig{-[:-30]O-[::60]-[::-60](-[::-60]NH_2)-[::60](=[::60]O)-[::-60]OH}
	\arrow{->[1. \ch{HBr}][2. \ch{NH3}]}[-180,2]
	\chemfig{HO-[:30]-[::-60](-[::-60]NH_2)-[::60](=[::60]O)-[::-60]OH}
\schemestop
\end{document}