Dear Rafael :Previously proposed (by Weinreb) formula CH3AlClNH2 with only one Me-group is not correct. "Contrast" is too pallid :-)

(Me2Al-NH3+ Cl- ) or another canonical formula Me2AlCl--NH3+ was confirmed in "Aluminum-Amine Complexes for the Conversion of Carboxylic Esters to Amides. Application to the Synthesis of LTD4 Antagonist MK-0679"

Daniel R. Sidler, Thomas C. Lovelace, James M. McNamara, Paul J. Reider

J. Org. Chem., 1994, 59 (6), pp 1231–1233

DOI: 10.1021/jo00085a001

"...alcohols and phenols are too acidic to be used..." - check Scheme 6 from yours second hyperlink. Aminoalcohol was used successfuly as substrate

Encyclopedia of Reagents for Organic Synthesis (EROS)   - look for archive (part1.rar, part2.rar, part3.rar) by link http://chemistry-chemists.com/forum/viewtopic.php?f=15&t=3692

Omprakash, Here is a link to an old process:

https://www.google.com/patents/US3468930

Hope this helps.

1) R-COOMe(Et) + Me2AlNH2 ->( xylene, reflux ~1 hr) -> R-CN , Yield = 50-91%

"A direct conversion of esters to nitriles" 

Tetrahedron Letters, Volume 20, Issue 51, 1979, Pages 4907-4910

Jeffrey L. Wood, Nazir A. Khatri, Steven M. Weinreb

doi:10.1016/S0040-4039(01)86746-0

2) One-pot treatment with sodium diisobutyl-tert-butoxyaluminium hydride (SDBBA-H), followed by treatment with molecular iodine in aq ammonia.

http://www.sciencedirect.com/science/article/pii/S0040402011012105

"Facile transformation of esters to nitriles" 

Tetrahedron, Volume 67, Issue 41, 14 October 2011, Pages 7956-7962

Yusuke Suzuki, Katsuhiko Moriyama, Hideo Togo

doi:10.1016/j.tet.2011.08.028

Dear

Omprakash Tanwar

Piramal enterprises limited, Ahmedabad, India

You can try using the method in attachment.

Good luck

Prof. Dr. Talaat El-Emary

Dear, Andrei and Talaat,

Thank you very much for your comprehensive guide. I am trying these methods.

Can you please let me know how to prepare dimethylaluminium amide in situ as I cannot use highly basic conditions.

I have seen the methods in which they used 1:1 ration of TMA and ammonia but I am not getting the exact method for preparation of dimethylaluminium amide.

Best regards

(CH3)3Al + HNR2 -> (benzene, hexane, -10oC -> 25oC ) -> (CH3)2Al-NR2

Org. Synth. 1979, 59, 49

DOI: 10.15227/orgsyn.059.0049

For your case xylene will be solvent in place of benzene

Reagent should be poor nucleophile because it is product of reaction of Lewis acid (Me3Al) with Lewis base (NH3). Of course, substrate acidic positions should be in salt form or silylated.

http://www.orgsyn.org/demo.aspx?prep=CV6P0492

Those carbons next to aluminum are strongly basic (though, indeed, not very nucleophilic). If your molecule is indeed very base sensitive, this method is unlikely to work well.

Consider performing a decarboxylative halogenation on your ester; followed by substitution with nitrile. You may be able to do this in one step if the decarboxylation conditions allow for the presence of cyanide. There are decarboxylative cyanations, but they seem to be substrate-specific. 

@Rafael Dera: Statement "Those carbons next to aluminum are strongly basic ..." is false . Product of HCl (proton in common case) addition  to dimethylaluminium amide is stable reagent Me2Al-NH3+ Cl- .

http://onlinelibrary.wiley.com/chemistry/search?csid=407931

Dear Omprakash Tanwar 

The method of  preparing dimethylaluminium amide is exactly as Prof. Andrei Rogoza mentioned. 

Dear Andrei. I had only checked the wiki page, however having read the papers you provided I can only note how their "wide functional group tolerance" does not involve a single species with mobile protons (primary/secondary amines, alcohols or phenols). I would offer this paper http://www.sciencedirect.com/science/article/pii/S0040402013013616 for contrast, where they indeed admit primary alcohols and phenols are too acidic to be used in conjunction with their (stabilised) AlMe3 reagent. I cannot find any paper which uses the dimethylaluminum-ammonium species, and I am unable to access the full text of your link. Is it possible that it referred only to the preparation with ammonium salts, where in fact the alkylchloroaluminum amides were obtained? These effect the same transformation, but seem to require larger excess of the reagent. http://www.tandfonline.com/doi/abs/10.1080/00397918208061938?journalCode=lsyc20 

I was unaware of the richness of organoaluminum chemistry! This has been very interesting.

Dear Rafael :Previously proposed (by Weinreb) formula CH3AlClNH2 with only one Me-group is not correct. "Contrast" is too pallid :-)

(Me2Al-NH3+ Cl- ) or another canonical formula Me2AlCl--NH3+ was confirmed in "Aluminum-Amine Complexes for the Conversion of Carboxylic Esters to Amides. Application to the Synthesis of LTD4 Antagonist MK-0679"

Daniel R. Sidler, Thomas C. Lovelace, James M. McNamara, Paul J. Reider

J. Org. Chem., 1994, 59 (6), pp 1231–1233

DOI: 10.1021/jo00085a001

"...alcohols and phenols are too acidic to be used..." - check Scheme 6 from yours second hyperlink. Aminoalcohol was used successfuly as substrate

Encyclopedia of Reagents for Organic Synthesis (EROS)   - look for archive (part1.rar, part2.rar, part3.rar) by link http://chemistry-chemists.com/forum/viewtopic.php?f=15&t=3692

You can convert in two step (amid-nitrile).

Hello, you can use dimethylaluminium amide in DCM. I tried this in one reaction but the yield was very less. Tried the reaction in toluene, yield got improved. So you can optimize the conditions. I referred below mentioned old paper.

Tetrahedron Letters, Volume 20, Issue 51, 1979, Pages 4907–4910.

Dear Andrei, 

I tried both the methods but could not get the desired nitrile product. With dimethylaluminium amide some amide impurity was fromed and most of the compound degraded. Can I heat dimethylaluminium amide in order to completely remove ammonia from it (I prepared it by purging NH3 gad at -78 degree Celsius and allowed to stand till all gas evolution ceased).

My system contains amide and urea functional groups and it gotdegraded in presence of ammonia. 

Please suggest

Omprakash

Dear Andrei, 

I tried both the methods but could not get the desired nitrile product. With dimethylaluminium amide some amide impurity was fromed and most of the compound degraded. Can I heat dimethylaluminium amide in order to completely remove ammonia from it (I prepared it by purging NH3 gad at -78 degree Celsius and allowed to stand till all gas evolution ceased).

My system contains amide and urea functional groups and it gotdegraded in presence of ammonia. 

Please suggest

Omprakash

You MUST heat reaction mixture  up to room temperature to obtain pure reagent (termally stable >100oC) - as it proposed in cited literature. Transamidation as side reaction (with NH3) is not real danger,IMHO  - it need special catalyst and much more time-consuming in comparison with -OMe or -OEt-displacement. But Al-reagent will coordinate with other carbonyls (heteroatoms in common case) - N,N'-disubstituted urea can transformed probably into carbondiimides. Molecula need different synthetic strategy.

HI!

Omprakash, perhaps your molecule is degraded in the presence of nucleophilic reagents. Try two step method (ester-amide-nitrile), but do not use ammonia or amines. An interesting method for the synthesis of amides from esters without basic medium with La(OTf)3 - catalitic amounts : doi: 10.1021/ol500593v

hi,

 i feel you can have a look on following publication which may help you in getting your desired product;

Facile transformation of esters to nitriles,Tetrahedron,Volume 67, Issue 41, 14 October 2011, Pages 7956–7962.Yusuke Suzuki, Katsuhiko Moriyama, Hideo Togo

doi:10.1016/j.tet.2011.08.028

With Warm Regards,

Pankaj Dawar

thanks for your valuable suggestions Sir.............