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Topic: Synthesis of 1H-pyrrolo[2,3-b]pyridine  (Read 7154 times)

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jonisoft

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Synthesis of 1H-pyrrolo[2,3-b]pyridine
« on: November 21, 2005, 05:39:28 PM »
Hello, working on a school project! Need some help to write the mechanism of this molecule. The problem is how to make the ring closing..
« Last Edit: November 21, 2005, 05:39:44 PM by jonisoft »

Offline Jiro

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Re:Synthesis of 1H-pyrrolo[2,3-b]pyridine
« Reply #1 on: November 21, 2005, 10:57:34 PM »
first you would need to these conditions H2/lindler to hydrogenate that alkyl group to a a Cis-double bond.

Offline AWK

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Re:Synthesis of 1H-pyrrolo[2,3-b]pyridine
« Reply #2 on: November 22, 2005, 02:34:59 AM »
Read something on Chichibabin reaction
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jonisoft

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Re:Synthesis of 1H-pyrrolo[2,3-b]pyridine
« Reply #3 on: November 22, 2005, 06:44:03 AM »
I think i solved it:

Offline AWK

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Re:Synthesis of 1H-pyrrolo[2,3-b]pyridine
« Reply #4 on: November 22, 2005, 10:20:57 AM »
NaNH2 introduces aminogroup into pyridines in alpha-position, next cyclization
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jonisoft

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Re:Synthesis of 1H-pyrrolo[2,3-b]pyridine
« Reply #5 on: November 22, 2005, 11:20:49 AM »
"NaNH2 introduces aminogroup into pyridines in alpha-position, next cyclization "

If so you will have 2st nucleophiles, no cyclization..
The alkyn hydrogen are very acidic and the NaNH2 will surtently reakt with that in the first steep.
« Last Edit: November 22, 2005, 11:22:37 AM by jonisoft »

Offline AWK

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Re:Synthesis of 1H-pyrrolo[2,3-b]pyridine
« Reply #6 on: November 23, 2005, 01:37:34 AM »
THis is a multistep reaction. Jonisoft is right. To proceed we need much more NaNH2
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Arsenic

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Re:Synthesis of 1H-pyrrolo[2,3-b]pyridine
« Reply #7 on: November 23, 2005, 02:34:52 AM »
:protection of the acidic hydrogen of acetylene
:Chichibabin (NaNH2)
: LiCl,Na2CO3,DMF,100'c or CuI,DMF,80'C (1,2)
:deprotection

if you have chosen the starting material yourself I reccomend changing it else you need to protect/deprotect  the acidic hydrogen of acetylene

ref:
two methods for the synthesis azaindoles
1)Tetrahedron Lett., 1998,39,5355
2)Tetrahedron Lett., 1998,39,5159

« Last Edit: November 23, 2005, 02:39:57 AM by Arsenic »

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