Now amide reduction can be accomplished with LiAlH4, as well as catalytic hydrogenation, but what other practical methods exist out there?
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-the good reverend drone
Ipsa scientia potestas est
Dare I say Red-Al... (https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000127035-file_a82s.gif)
According to the litterature it reduces amides quite nicely.
Strontium
Strontium
To a stirred suspension of NaBH4 (1.89g, 50mmol) and benzamide (1.21g, 10mmol) in dioxane (20ml) is added acetic acid (3.0g, 50mmol) in dioxane (10ml) over a period of 10 minutes at 10°C; the reaction is stirred at reflux for 2hrs. The mixture is concentrated to dryness in vacuo, excess reagent is decomposed with H2O and the solution extracted with CHCl3. The extract is washed with H2O, dried over Na2SO4, gassed with HCl and evaporated to dryness and the residue recrystallised from MeOH/Et2O to give benzylamine hydrochloride (1.09g, 76%).
To a 2-neck 100ml flask are added 16mmol of amide, 1.61g (40mmol9 of NaBH4 and 20ml of DMSO. Methanesulphonic acid (3.4ml, 55mmol) and 20ml DMSO are mixed and added dropwise over a 30 minute period. Gas is evolved and a gelatinous substance is formed, which dissolves when the acid comes to exceed the NaBH4 on a molar basis. If the reduction is to produce a prim. or sec. amine, the reduction is quenched by the addition of 20ml of 10% NaOH. In the case of a tert amine the reaction is kept at 70°C for 2 hrs to liberate the product from the borane complex. Isolation then proceeds in the same way as for prim. and sec. amines. After the quench the product is extracted with 3*10ml DCM, washed with 3*10ml 0.1M NaOH to remove the DMSO, and the product is extracted into 3*10ml 10% HCl. Neutralisation with 10% NaOH is followed by extraction of the product with 3*10ml DCM, drying over CaSO4 and fractional distillation.
hexanamide ---> hexylamine 74%
acetanilide ---> N-ethylanilide 77%
N,N-dimethylbenzamide ---> N,N-dimethylbenzylamine 59%
Both procedures from Vogel, 5th ed., p774
--psyloxy--