Organic synthesis (A Level) · 有机合成(A Level)
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| acyl chloride/əˈkɪl ˈklɔːraɪd/ | 酰氯 | xiān lǜ |
| functional group/ˈfʌŋkʃənl ɡruːp/ | 官能团 | guān néng tuán |
| diazonium salt/ˌdaɪəˈzəʊnɪəm sɒlt/ | 重氮盐 | zhòng dàn yán |
| reagent/rɪˈeɪdʒənt/ | 试剂 | shì jì |
| by-product/baɪ ˈprɒdʌkt/ | 副产物 | fù chǎn wù |
Designing a synthesis
- Like AS synthesis, you join up known reactions to build a target.
- Now you also have the reactions of arenes, phenol, amines, amides and acyl chlorides 酰氯.
- Identify the groups, use the map, plan backwards.
设计一个合成
- 像 AS 合成一样,你把已知的反应连接起来构建一个目标。
- 现在你还有芳烃、苯酚、胺、酰胺和酰氯的反应。
- 识别基团,用图谱,反向规划。
A-Level synthesis planner · A-Level 合成规划器
Build a route by matching functional-group changes to reagents.
Planning an organic synthesis means choosing a sequence of reactions to convert a starting material into a target molecule.
Few steps and good yields are preferred.
Identifying functional groups 官能团
- decolourises bromine water with no catalyst (white precipitate) → a phenol or phenylamine (activated ring).
- reacts violently with cold water (HCl fumes) → an acyl chloride.
- purple colour with neutral $\text{FeCl}_3$ → a phenol.
A map of the A Level reactions
识别官能团
- 无催化剂使溴水褪色(白色沉淀)→ 一个苯酚或苯胺(被活化的环)。
- 与冷水剧烈反应(HCl 烟雾)→ 一个酰氯。
- 与中性 $\text{FeCl}_3$ 显紫色 → 一个苯酚。
A Level 反应的一个图谱
A purple colour with neutral iron(III) chloride identifies a:
Neutral FeCl₃ gives a purple colour with phenols.
A compound that reacts violently with cold water, giving fumes of HCl, is a:
Acyl chlorides hydrolyse vigorously with water, releasing HCl.
Match each term to its meaning.
Each item links the term to its correct meaning.
The A Level reaction map
- aromatic chain: benzene → nitrobenzene → phenylamine → diazonium salt 重氮盐 → phenol / azo dye.
- acyl chain: carboxylic acid → acyl chloride → ester / amide.
- plus: amide/nitrile → amine ($\text{LiAlH}_4$); halogenoalkane → nitrile (KCN, +1 carbon).
Identification tests added at A Level
A Level 反应图谱
- 芳香链:苯 → 硝基苯 → 苯胺 → 重氮盐 → 苯酚 / 偶氮染料。
- 酰基链:羧酸 → 酰氯 → 酯 / 酰胺。
- 加上:酰胺/腈 → 胺($\text{LiAlH}_4$);卤代烷 → 腈(KCN,+1 碳)。
A Level 增加的鉴别测试
Phenylamine reacting with HNO₂ below 10 °C gives:
Cold HNO₂ forms a diazonium salt, which can then make phenol or couple to an azo dye.
Ethanoyl chloride reacts with excess ammonia to form the amide ____.
The acyl group stays as CH₃CO– and –NH₂ replaces –Cl, giving CH₃CONH₂.
Replacing a halogen with –CN adds one carbon to the organic molecule.
The carbon in the cyanide group joins the carbon skeleton; count it when planning the product.
Which reagent reduces an amide to an amine?
LiAlH₄ is the reducing agent on the reaction map. FeCl₃ and bromine water are identification tests.
Planning and analysing
- plan by working backwards from the target; write each step's reagent 试剂 and conditions.
- analyse by stating each step's reaction type (electrophilic substitution, addition–elimination, oxidation, reduction…) and watching for by-products 副产物.
Plan backwards from the target, one disconnection at a time, until you reach the starting materials
规划和分析
- 通过从目标反向工作来规划;写出每一步的试剂和条件。
- 通过陈述每一步的反应类型(亲电取代、加成—消去、氧化、还原……)并注意副产物来分析。
从目标向后规划,一次一个断裂,直到到达起始材料
The best way to plan a multi-step synthesis is to:
Working backwards finds which reaction makes the target, and from what, step by step.
You've got it
- tests: neutral FeCl₃ → purple (phenol); violent with cold water (acyl chloride); bromine water, no catalyst (phenol/phenylamine)
- map: benzene → nitrobenzene → phenylamine → diazonium → phenol/azo; acid → acyl chloride → ester/amide
- plan backwards from the target; analyse each step's reaction type and by-products
你掌握了
- 测试:中性 FeCl₃ → 紫色(苯酚);与冷水剧烈(酰氯);溴水,无催化剂(苯酚/苯胺)
- 图谱:苯 → 硝基苯 → 苯胺 → 重氮 → 苯酚/偶氮;酸 → 酰氯 → 酯/酰胺
- 从目标反向规划;分析每一步的反应类型和副产物