Hantzsch pyridine synthesis

The Hantzschsche dihydropyridine (also Hantzsch'sche dihydropyridine ) is a name reaction in organic chemistry, which was named after its discoverer, Arthur Hantzsch. This reaction 1,4-dihydropyridine or a derivative thereof is synthesized.

Name Variants

In simplified form, the reaction is referred to as Hantzschsche pyridine, since the resulting 1,4- dihydropyridine is mostly converted to the aromatized pyridine. In Streitwieser the variant Hantzsch reaction will be used. The variant Hantzsch pyridine synthesis is a direct derivation of the English term.

Overview reaction

In this reaction, a β - ketocarbonyl compound 1, 4, 3, an aldehyde and ammonia are 2 (or a primary aliphatic amine ) in the ratio 2:1:1 are reacted together.

Mechanism

In the reaction to go to both the β - ketocarbonyl compound 1 and ammonia 2 and the β - ketocarbonyl compound of the aldehyde 4 and 3 a kind Knoevenagel reaction. An enamine from ammonia is produced 6 The aldehyde reacts to form an unsaturated carbonyl compound 7 The first two reaction products 6, 7 to react in a Michael addition type on to a dihydropyridine or its derivatives 5

A radical R 1 is alkyl or O- alkyl and when R2 and R3 are alkyl or aryl groups may be used.

The synthesis of pharmacologically relevant dihydropyridines is elegantly possible in this way. To get example to nifedipine, using 2 -nitrobenzaldehyde as the aldehyde, methyl acetoacetate as β - ketocarbonyl and ammonia.