<MultiModal>![[O-]/[N+](C1=CC=CC=C1)=C(C)/C=C>O=C(C#CC(OCC)=O)OCC,toluene,reflux>[$\mathbf{A}$],$\mathbf{A}$ is the reaction product](/media/uploads/6722b653-0a2e-48b8-8fe1-09e5a402f4d7.png)</MultiModal>

It is believed that the substrate reacts with diethyl butynedioate to generate a seven-membered ring intermediate $\mathbf{X}$; $\mathbf{X}$ is converted to the final product under the action of trace water in the system. It is known that the reaction product $\mathbf{A}$ contains 2 rings, and the molecular formula of $\mathbf{A}$ is $\mathrm{C_{18}H_{21}NO_5}$, try to give the structural formula of $\mathbf{A}$.
<MultiModal>![[O-]/[N+](C1=CC=CC=C1)=C(C)/C=C>O=C(C#CC(OCC)=O)OCC,toluene,reflux>[$\mathbf{A}$],$\mathbf{A}$是反应产物](/media/uploads/6722b653-0a2e-48b8-8fe1-09e5a402f4d7.png)</MultiModal>

人们认为，底物与丁炔二酸二乙酯反应生成含七元环的中间体$\mathbf{X}$；$\mathbf{X}$在体系的痕量水作用下转化为最终产物。已知反应产物$\mathbf{A}$中含有2个环，且$\mathbf{A}$的分子式$\mathrm{C_{18}H_{21}NO_5}$，试给出$\mathbf{A}$的结构式
All other options are incorrect
<MultiModal>![O=C(C)CCC1(C(OCC)=O)C2=C(N=C1C(OCC)=O)C=CC=C2](/media/uploads/8cadd968-b936-4f8b-9260-2ed56f515345.png)</MultiModal>
<MultiModal>![CC1(C=C)N(OC(C(OCC)=O)=C1C(OCC)=O)C2=CC=CC=C2](/media/uploads/b34d4696-ca41-45a8-b384-28477b0120de.png)</MultiModal>
<MultiModal>![O=C(C(OCC)=O)[C@@]1(C(OCC)=O)[C@](C=C)(C)NC2=C1C=CC=C2](/media/uploads/163273b8-c0cd-4fc9-952b-47e00c98cfc8.png)</MultiModal>
<MultiModal>![O=C(C(OCC)=O)[C@@]1(C(OCC)=O)[C@@](C=C)(C)NC2=C1C=CC=C2](/media/uploads/90f7c8fe-b916-4e4c-88ee-43a88ae36208.png)</MultiModal>
<MultiModal>![CC1=CCC(C(OCC)=O)=C(C(OCC)=O)ON1C2=CC=CC=C2](/media/uploads/2cdb9b84-ede3-4c79-8f3d-f5e92d3768a2.png)</MultiModal>
<MultiModal>![O=C([C@@]1(C2=C(NC(C)=CC1)C=CC=C2)C(OCC)=O)C(OCC)=O](/media/uploads/eb65a402-c4ca-4bf5-a889-72bfadabe2a2.png)</MultiModal>
<MultiModal>![O=C(C(OCC)=O)C1(CCC(C)=O)C2=C(NC1=O)C=CC=C2](/media/uploads/026cbd75-ef1e-41e0-b562-897519162456.png)</MultiModal>
其他选项均不正确
<MultiModal>![O=C(C)CCC1(C(OCC)=O)C2=C(N=C1C(OCC)=O)C=CC=C2](/media/uploads/8cadd968-b936-4f8b-9260-2ed56f515345.png)</MultiModal>
<MultiModal>![CC1(C=C)N(OC(C(OCC)=O)=C1C(OCC)=O)C2=CC=CC=C2](/media/uploads/b34d4696-ca41-45a8-b384-28477b0120de.png)</MultiModal>
<MultiModal>![O=C(C(OCC)=O)[C@@]1(C(OCC)=O)[C@](C=C)(C)NC2=C1C=CC=C2](/media/uploads/163273b8-c0cd-4fc9-952b-47e00c98cfc8.png)</MultiModal>
<MultiModal>![O=C(C(OCC)=O)[C@@]1(C(OCC)=O)[C@@](C=C)(C)NC2=C1C=CC=C2](/media/uploads/90f7c8fe-b916-4e4c-88ee-43a88ae36208.png)</MultiModal>
<MultiModal>![CC1=CCC(C(OCC)=O)=C(C(OCC)=O)ON1C2=CC=CC=C2](/media/uploads/2cdb9b84-ede3-4c79-8f3d-f5e92d3768a2.png)</MultiModal>
<MultiModal>![O=C([C@@]1(C2=C(NC(C)=CC1)C=CC=C2)C(OCC)=O)C(OCC)=O](/media/uploads/eb65a402-c4ca-4bf5-a889-72bfadabe2a2.png)</MultiModal>
<MultiModal>![O=C(C(OCC)=O)C1(CCC(C)=O)C2=C(NC1=O)C=CC=C2](/media/uploads/026cbd75-ef1e-41e0-b562-897519162456.png)</MultiModal>
First, according to the problem prompt, the reaction substrate reacts with diethyl butynedioate to generate the seven-membered ring intermediate $\mathbf{X}$

<MultiModal>![Intermediate $\mathbf{X}$: CC1=CCC(C(OCC)=O)=C(C(OCC)=O)ON1C2=CC=CC=C2](/media/uploads/18cac753-81b6-4b21-822e-49bdabc1cbc1.png)</MultiModal>

<Checkpoint>[Intermediate $\mathbf{X}$: CC1=CCC(C(OCC)=O)=C(C(OCC)=O)ON1C2=CC=CC=C2](1)</Checkpoint>

Then, intermediate $\mathbf{X}$ first forms intermediate $\mathbf{1}$ under the action of trace water.

<MultiModal>![Intermediate $\mathbf{1}$: CC1(O)N(OC(C(OCC)=O)=C(CC1)C(OCC)=O)C2=CC=CC=C2](/media/uploads/87add4b1-5b99-4cf9-bb54-1a96f39f8fed.png)</MultiModal>

<Checkpoint>[Intermediate $\mathbf{1}$: CC1(O)N(OC(C(OCC)=O)=C(CC1)C(OCC)=O)C2=CC=CC=C2](1)</Checkpoint>

Then, intermediate $\mathbf{1}$ further undergoes ring-opening to obtain intermediate $\mathbf{2}$

<MultiModal>![Intermediate $\mathbf{2}$: CC(CC/C(C(OCC)=O)=C(C(OCC)=O)\ONC1=CC=CC=C1)=O](/media/uploads/27c155f4-da05-4e79-ba51-23c8bc10ad67.png)</MultiModal>

<Checkpoint>[Intermediate $\mathbf{2}$: CC(CC/C(C(OCC)=O)=C(C(OCC)=O)\ONC1=CC=CC=C1)=O](1)</Checkpoint>

At this time, the conformation of intermediate $\mathbf{2}$ allows it to undergo a 3,3-$\sigma$ rearrangement reaction to obtain intermediate $\mathbf{3}$

<MultiModal>![Intermediate $\mathbf{3}$: N=C1C=CC=CC1C(CCC(C)=O)(C(OCC)=O)C(C(OCC)=O)=O](/media/uploads/0f9c63ef-91e8-4147-a53b-890638db0286.png)</MultiModal>

<Checkpoint>[Intermediate $\mathbf{3}$: N=C1C=CC=CC1C(CCC(C)=O)(C(OCC)=O)C(C(OCC)=O)=O](1)</Checkpoint>

Intermediate $\mathbf{3}$ undergoes aromatization to obtain intermediate $\mathbf{4}$

<MultiModal>![Intermediate $\mathbf{4}$：NC1=C(C(CCC(C)=O)(C(OCC)=O)C(C(OCC)=O)=O)C=CC=C1](/media/uploads/5ebe280a-9645-4e44-8869-c0d943ea3162.png)</MultiModal>

<Checkpoint>[Intermediate $\mathbf{4}$：NC1=C(C(CCC(C)=O)(C(OCC)=O)C(C(OCC)=O)=O)C=CC=C1](1)</Checkpoint>

The carbonyl group in intermediate $\mathbf{4}$ has strong reactivity, so the amino group attacks the carbonyl group to form a five-membered ring, yielding intermediate $\mathbf{5}$

<MultiModal>![Intermediate $\mathbf{5}$: OC1(C(OCC)=O)C(CCC(C)=O)(C(OCC)=O)C2=C(N1)C=CC=C2](/media/uploads/ace29732-a7d1-4063-ad4c-b0417687c1ee.png)</MultiModal>

<Checkpoint>[Intermediate $\mathbf{5}$: OC1(C(OCC)=O)C(CCC(C)=O)(C(OCC)=O)C2=C(N1)C=CC=C2](1)</Checkpoint>

Intermediate $\mathbf{5}$ continues to lose a molecule of water to obtain the final product $\mathbf{A}$

<MultiModal>![Product $\mathbf{A}$: O=C(C)CCC1(C(OCC)=O)C2=C(N=C1C(OCC)=O)C=CC=C2](/media/uploads/e38c0508-610d-497e-8924-a8994374bf74.png)</MultiModal>
首先根据题目提示，反应底物与丁炔二酸二乙酯反应生成含七元环的中间体$\mathbf{X}$

<MultiModal>![中间体$\mathbf{X}$：CC1=CCC(C(OCC)=O)=C(C(OCC)=O)ON1C2=CC=CC=C2](/media/uploads/18cac753-81b6-4b21-822e-49bdabc1cbc1.png)</MultiModal>

<Checkpoint>[中间体$\mathbf{X}$：CC1=CCC(C(OCC)=O)=C(C(OCC)=O)ON1C2=CC=CC=C2](1)</Checkpoint>

接着中间体$\mathbf{X}$在痕量水的作用下，首先形成中间体$\mathbf{1}$

<MultiModal>![中间体$\mathbf{1}$：CC1(O)N(OC(C(OCC)=O)=C(CC1)C(OCC)=O)C2=CC=CC=C2](/media/uploads/87add4b1-5b99-4cf9-bb54-1a96f39f8fed.png)</MultiModal>

<Checkpoint>[中间体$\mathbf{1}$：CC1(O)N(OC(C(OCC)=O)=C(CC1)C(OCC)=O)C2=CC=CC=C2](1)</Checkpoint>

接着中间体$\mathbf{1}$进一步发生开环得到中间体$\mathbf{2}$

<MultiModal>![中间体$\mathbf{2}$：CC(CC/C(C(OCC)=O)=C(C(OCC)=O)\ONC1=CC=CC=C1)=O](/media/uploads/27c155f4-da05-4e79-ba51-23c8bc10ad67.png)</MultiModal>

<Checkpoint>[中间体$\mathbf{2}$：CC(CC/C(C(OCC)=O)=C(C(OCC)=O)\ONC1=CC=CC=C1)=O](1)</Checkpoint>

此时中间体$\mathbf{2}$的构象允许其发生3,3-$\sigma$重排反应得到中间体$\mathbf{3}$

<MultiModal>![中间体$\mathbf{3}$：N=C1C=CC=CC1C(CCC(C)=O)(C(OCC)=O)C(C(OCC)=O)=O](/media/uploads/0f9c63ef-91e8-4147-a53b-890638db0286.png)</MultiModal>

<Checkpoint>[中间体$\mathbf{3}$：N=C1C=CC=CC1C(CCC(C)=O)(C(OCC)=O)C(C(OCC)=O)=O](1)</Checkpoint>

中间体$\mathbf{3}$发生芳构化得到中间体$\mathbf{4}$

<MultiModal>![中间体$\mathbf{4}$：NC1=C(C(CCC(C)=O)(C(OCC)=O)C(C(OCC)=O)=O)C=CC=C1](/media/uploads/5ebe280a-9645-4e44-8869-c0d943ea3162.png)</MultiModal>

<Checkpoint>[中间体$\mathbf{4}$：NC1=C(C(CCC(C)=O)(C(OCC)=O)C(C(OCC)=O)=O)C=CC=C1](1)</Checkpoint>

中间体$\mathbf{4}$中羰基的反应活性较强，因此氨基进攻羰基形成五元环，得到中间体$\mathbf{5}$

<MultiModal>![中间体$\mathbf{5}$：OC1(C(OCC)=O)C(CCC(C)=O)(C(OCC)=O)C2=C(N1)C=CC=C2](/media/uploads/ace29732-a7d1-4063-ad4c-b0417687c1ee.png)</MultiModal>

<Checkpoint>[中间体$\mathbf{5}$：OC1(C(OCC)=O)C(CCC(C)=O)(C(OCC)=O)C2=C(N1)C=CC=C2](1)</Checkpoint>

中间体$\mathbf{5}$继续脱去一分子水得到最终产物$\mathbf{A}$

<MultiModal>![产物$\mathbf{A}$：O=C(C)CCC1(C(OCC)=O)C2=C(N=C1C(OCC)=O)C=CC=C2](/media/uploads/e38c0508-610d-497e-8924-a8994374bf74.png)</MultiModal>