I have created a very basic %%stan magic extension to maintain the stan worklow within jupyter notebook . Once a PR for codemirror stan mode gets through (syntax highlighting/autocomplete) could be enabled.
Install: pip install git+https://github.com/Arvinds-ds/stanmagic.git
Extension page: https://github.com/Arvinds-ds/stanmagic
Sample notebook: https://github.com/Arvinds-ds/stanmagic/blob/master/StanMagic-Help.ipynb
Its very preliminary and more of a hacked POC but some may find it useful as I have during the past week.