次黄嘌呤（hypoxanthine）

3D结构

C1=NC2=C(N1)C(=O)NC=N2

-

\usepackage{chemfig}
\begin{document}

\chemfig{
N(-[4,0.3,,,transparent]H)
	-[6,0.5]
	=[7.3,0.5]N
	-[0.8,0.5]
	=[2,0.5]
		(
			-[0.5,0.5]N
			=[6.55,0.5]
			-[5.25,0.5]N(-[6,0.3,,,transparent]H)
			-[3.5,0.4]
		)
	-[3.3,0.5](=[2,0.5]O)
	-[4.8,0.3]
}

\end{document}

-

\usepackage{chemfig}
\begin{document}
\chemfig{N*6(=*5(-N(-[,.3,,,transparent]H)-=N-)-=(-[,,]OH)-N=-)}
\end{document}

-

\usepackage{chemfig}
\begin{document}
\chemfig{N*6(-*5(-N=-N(-[,.3,,,transparent]H)-)=-(-[,,]OH)=N-=)}
\end{document}

• 自己觉得合理的

\usepackage{chemfig}
\begin{document}
\chemfig{N*6(-*5(-N(-[,.3,,,transparent]H)-=N-)=-(-[,,]OH)=N-=)}
\end{document}

-

\usepackage{chemfig}
\begin{document}
\chemfig{N*6(-*5(-N=-N(-[,.3,,,transparent]H)-)=-(=[,,]O)-N(-[,.3,,,transparent]H)-=)}
\end{document}

-

\usepackage{chemfig}
\begin{document}
\chemfig{N*6(-*5(-N(-[,.3,,,transparent]H)-=N-)=-(=[,,]O)-N(-[,.3,,,transparent]H)-=)}
\end{document}

• 这个行吗？

\usepackage{chemfig}
\begin{document}
\chemfig{N*6(=*5(-N(-[,.3,,,transparent]H)--N=)--(=[,,]O)-N=-)}
\end{document}