Amide reduction is a reaction in organic synthesis where an amide is reduced to either an amine or an aldehyde functional group.[1][2]
Catalytic hydrogenation
Catalytic hydrogenation can be used to reduce amides to amines; however, the process often requires high hydrogenation pressures and reaction temperatures to be effective (i.e. often requiring pressures above 197 atm and temperatures exceeding 200 °C).[1] Selective catalysts for the reaction include copper chromite, rhenium trioxide and rhenium(VII) oxide or bimetallic catalyst.[3][4][5]
Amines from other hydride sources
Reducing agents able to effect this reaction include metal hydrides such as lithium aluminium hydride,[6][7][8][9][10] or lithium borohydride in mixed solvents of tetrahydrofuran and methanol.[11]
Iron catalysis by triiron dodecacarbonyl in combination with polymethylhydrosiloxane has been reported.[12]
Lawesson's reagent converts amides to thioamides, which then catalytically desulfurize.[13]
Noncatalytic routes to aldehydes
Some amides can be reduced to aldehydes in the Sonn-Müller method, but most routes to aldehydes involve a well-chosen organometallic reductant.
Lithium aluminum hydride reduces an excess of N,N-disubstituted amides to an aldehyde:[citation needed]
- R(CO)NRR' + LiAlH4 → RCHO + HNRR'
With further reduction the alcohol is obtained.
Schwartz's reagent reduces amides to aldehydes,[14] and so does hydrosilylation with a suitable catalyst.
References
External links
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