I think there is something wrong in how some Jupyter-related package has been created:

$ ipython
Python 3.5.1 (default, Mar  3 2016, 09:29:07) 
Type "copyright", "credits" or "license" for more information.

IPython 4.1.2 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.
i
In [1]: import nbconvert
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
<ipython-input-1-3d8cf4dbc65f> in <module>()
----> 1 import nbconvert

/usr/lib/python3.5/site-packages/nbconvert/__init__.py in <module>()
      2 
      3 from ._version import version_info, __version__
----> 4 from .exporters import *
      5 from . import filters
      6 from . import preprocessors

/usr/lib/python3.5/site-packages/nbconvert/exporters/__init__.py in <module>()
----> 1 from .export import *
      2 from .html import HTMLExporter
      3 from .slides import SlidesExporter
      4 from .templateexporter import TemplateExporter
      5 from .latex import LatexExporter

/usr/lib/python3.5/site-packages/nbconvert/exporters/export.py in <module>()
      7 from itertools import chain
      8 
----> 9 import entrypoints
     10 
     11 from traitlets.log import get_logger

ImportError: No module named 'entrypoints'

The package 'entrypoints' is a dependency: https://github.com/jupyter/nbconvert/issues/289
So it should installed too or put inside the package.

Anyway, the current state of the Jupyter notebook seems to be broken for this reason.