Química Orgânica 2 · Acetais, iminas e equilíbrios relacionados
Acetone azine from acetone and hydrazine
Condições: N2H4 (0.5 equiv), trace AcOH (assumed)
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Arraste dos elétrons que se movem até onde eles vão, ou toque em um e depois no outro. Cada seta é verificada; Dica ajuda quando você travar. Não precisa de conta.
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Próximo mostra as setas curvas de cada passo e as explica. Os passos escritos estão abaixo.
Ler todos os 14 passos escritos
Hydrazine adds to the first acetone
A hydrazine nitrogen lone pair attacks the carbonyl carbon of acetone. Hydrazine is used here with a trace of acetic acid (assumed catalyst), as in most hydrazone preparations.
As setas curvas
- The nitrogen lone pair forms the C–N bond.
- The π pair moves onto oxygen.
Protonate the alkoxide
Acetic acid protonates the negative oxygen.
As setas curvas
- The alkoxide takes the proton.
- The pair stays on acetate.
Remove the N–H proton
Acetate removes the proton from the positive nitrogen, giving the carbinolamine.
As setas curvas
- Acetate takes the proton.
- The pair returns to nitrogen.
Protonate the OH
Acetic acid protonates the hydroxyl so it can leave as water.
As setas curvas
- The hydroxyl takes the proton.
- The pair stays on acetate.
Water leaves
The nitrogen lone pair forms C=N⁺ as water departs.
As setas curvas
- The nitrogen lone pair forms the C=N π bond.
- The C–O pair leaves with water.
Deprotonate to the hydrazone
Acetate removes the N–H proton, giving acetone hydrazone, which still has a free NH2.
As setas curvas
- Acetate takes the proton.
- The pair becomes the imine-type lone pair.
Check
Answer before you continue.
The NH2 adds to the second acetone
The terminal nitrogen of the hydrazone attacks the second acetone carbonyl.
As setas curvas
- The NH2 lone pair forms the second C–N bond.
- The π pair moves onto oxygen.
Protonate the alkoxide
Acetic acid protonates the second alkoxide.
As setas curvas
- The alkoxide takes the proton.
- The pair stays on acetate.
Remove the N–H proton
Acetate removes the proton from the positive nitrogen.
As setas curvas
- Acetate takes the proton.
- The pair returns to nitrogen.
Protonate the OH
Acetic acid protonates the second carbinolamine OH.
As setas curvas
- The hydroxyl takes the proton.
- The pair stays on acetate.
Second water leaves
The nitrogen lone pair forms the second C=N⁺ as water departs.
As setas curvas
- The nitrogen lone pair forms the C=N π bond.
- The C–O pair leaves with water.
Deprotonate to the azine
Acetate removes the last N–H proton, giving the azine and regenerating acetic acid.
As setas curvas
- Acetate takes the proton.
- The pair becomes the nitrogen lone pair.
Acetone azine
Both nitrogens of hydrazine are now doubly bonded to former carbonyl carbons; two waters are released.
O que você vai praticar
Draw two successive condensations of hydrazine with two acetone molecules, each by addition, proton transfers and loss of water, to acetone azine.
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