\documentclass{book}

\usepackage{graphicx}       
\usepackage{hyperref}   
\usepackage{chemnum}
\usepackage{auto-pst-pdf}
\begin{document}

\begin{figure}
    \centering
    \replacecmpd{cmpd:1}
    \replacecmpd{cmpd:2}
    \replacecmpd{cmpd:3}
    \includegraphics[width=1\textwidth]{CyAZIDES.eps}
\end{figure}

\begin{figure}
    \centering
    \replacecmpd{cmpd:1}
    \replacecmpd{cmpd:2}
    \replacecmpd{cmpd:3}
    \replacecmpd{cmpd:4}
    \includegraphics[width=1\textwidth]{CyAZIDES2.eps}
\end{figure}
\end{document}