Synthesis of Amines from Carboxylic Amides

Treatment of aldehyde A with the modified sodium cyanoborohydride reagent shown gave the natural product buflavine, a bioactive constituent of the bulbs of the Boophane flava plant from southern Africa. Its mass spectral molecular ion occurs at m/z = 283. Suggest a structure. 

In Summary Reductive aminalion furnishes alkanamines by reductive condensation of amines with aldehydes and ketones. 

Carboxylic amides can be versatile precursors of amines by reduction of the carbonyl unit (Section 20-6). Since amides are in turn readily available by reaction of acyl halides with amines (Section 20-2), the sequence acylation-reduction constitutes a controlled monoalkylation of amines. 

Primary amides can also be turned into amines by oxidation with bromine or chlorine in the presence of sodium hydroxide—in other words, by the Hofmann rearrangement (Section 20-7). Recall that in this transformation the carbonyl group is extruded as carbon dioxide, so the resulting amine bears one carbon less than the starting material. 

Show three reactions from any starting materials that would make the C-N bond in A-methyl-hexanamine (margin) according to the indicated retrosynthetic disconnection (— ). 

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Synthesis of Amines from Carboxylic Amides CHAPTER 21... 

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