April 26, 2024, 02:04:07 AM
Forum Rules: Read This Before Posting


Topic: Pyrrole + heat  (Read 3885 times)

0 Members and 1 Guest are viewing this topic.

Offline ricecake

  • Regular Member
  • ***
  • Posts: 21
  • Mole Snacks: +0/-0
Pyrrole + heat
« on: December 30, 2014, 03:08:54 PM »
This is part of a reaction chain:
Pyrrole + CH3MgBr  :rarrow: A + C2H5I   :rarrow: B + t°  :rarrow: C + KOH  :rarrow: D

This is what I got so far:
A is C1=CC=CN([Mg]Br)1
B is C1=CC=C[N+](CC)(CC)1
I got stuck at C. Would the ring just pop open because of the heat?

Offline orgopete

  • Chemist
  • Sr. Member
  • *
  • Posts: 2636
  • Mole Snacks: +213/-71
    • Curved Arrow Press
Re: Pyrrole + heat
« Reply #1 on: January 01, 2015, 07:53:05 AM »
This looks like a case of the missing reactant. I don't think you can quaternize pyrrole like that. Okay for an N-alkylation. Heating B makes more sense if a dienophile were present. Then reacting with KOH with its functionality would seem more plausible. I'm just guessing though.
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

Offline ricecake

  • Regular Member
  • ***
  • Posts: 21
  • Mole Snacks: +0/-0
Re: Pyrrole + heat
« Reply #2 on: January 05, 2015, 07:19:07 PM »
This looks like a case of the missing reactant. I don't think you can quaternize pyrrole like that. Okay for an N-alkylation. Heating B makes more sense if a dienophile were present. Then reacting with KOH with its functionality would seem more plausible. I'm just guessing though.

I was following the Hoffmann elimination reaction for a simple cyclic nitrogen...I tried to google reactions for pyrrole but not much coming up. Should I look at some specific sites?

Offline orgopete

  • Chemist
  • Sr. Member
  • *
  • Posts: 2636
  • Mole Snacks: +213/-71
    • Curved Arrow Press
Re: Pyrrole + heat
« Reply #3 on: January 05, 2015, 11:25:39 PM »
If this is a problem covered in a class or textbook, I missed that class. I was simply guessing. You could give us more information or tell me I'm wrong. Can anyone else solve this?
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

Offline discodermolide

  • Chemist
  • Sr. Member
  • *
  • Posts: 5038
  • Mole Snacks: +405/-70
  • Gender: Male
    • My research history
Re: Pyrrole + heat
« Reply #4 on: January 06, 2015, 02:37:19 AM »
According to literature http://pubs.acs.org/doi/abs/10.1021/jo01013a008?journalCode=joceah  the pyrrole Grignard reagent gives a mixture of products with chlorobutyronitrile:

N#CCCCC1=CC=CN1
and
N#CCCCC1=CNC=C1

with the 2-substituted product the major one.
See where you can go from there?
Development Chemists do it on Scale, Research Chemists just do it!
My Research History

Offline ricecake

  • Regular Member
  • ***
  • Posts: 21
  • Mole Snacks: +0/-0
Re: Pyrrole + heat
« Reply #5 on: January 06, 2015, 09:58:29 PM »
If this is a problem covered in a class or textbook, I missed that class. I was simply guessing. You could give us more information or tell me I'm wrong. Can anyone else solve this?
No sorry  :'( I didn't mean to say that you were incorrect or anything. I just wanted to tell you where I got my information :( https://books.google.com/books?id=7quC1QxHAG0C&pg=PA74&lpg=PA74&dq=Pyrrole+%2B+CH3MgBr&source=bl&ots=Gb497HVFE0&sig=uJM_WM_o9S-kFywiSSbUs--OYbg&hl=en&sa=X&ei=eZ-sVIGNEc6OyAS0yIHwCg&ved=0CCQQ6AEwAQ#v=onepage&q=Pyrrole%20%2B%20CH3MgBr&f=false

Sponsored Links