synthesis method of a pramipexole inpurity

a verified route for BI-10460BS:

the overall yield is acceptable for mg scale preparation.

Transformation wanted!

This reaction will be very useful if can be done！

25-hydroxy Vitamin D2 is an important intermediate for many VD2 analogs such as paricalcitol.
Nature did this transformation using an enzyme to oxidize the 25 postion directly.
there is no chemical ways with acceptable yield for this transformation yet.