Named Reactions

💡 Phenol converted to sodium phenoxide, then carboxylated. Product is sodium salicylate (aspirin precursor). High pressure required.

💡 Introduces −CHO group ortho to −OH. Mechanism: CHCl₃ + NaOH → dichlorocarbene (:CCl₂) which attacks ring. Mainly ortho product.

💡 Best method to make unsymmetrical ethers. SN2 mechanism → use primary alkyl halide with bulky alkoxide (tertiary alkyl halide gives elimination).

💡 Turbidity = RCl (insoluble in reagent). 3° fastest via SN1. Distinguishes primary/secondary/tertiary alcohols.

💡 Converts alcohol → iodoalkane → nitroalkane → reaction with HNO₂. 1°: nitroso compound + NaOH → red. 2°: blue complex. 3°: no α-H → no colour.

💡 Requires α-H. Step 1: nucleophilic addition → β-hydroxy carbonyl (aldol product). Step 2: dehydration → α,β-unsaturated carbonyl. Cross aldol possible (two different carbonyl compounds).

💡 ONLY for aldehydes with NO α-H (HCHO, PhCHO, (CH₃)₃CCHO). Disproportionation: one molecule oxidised (→ acid), one reduced (→ alcohol). Mechanism: hydride transfer.

💡 Silver mirror formed on glass. Positive for: all aldehydes (RCHO), formic acid (HCOOH), glucose. Negative for: ketones, benzaldehyde does give positive.

💡 Brick-red ppt of Cu₂O. Positive for: aliphatic aldehydes, glucose, fructose. Negative for: aromatic aldehydes (benzaldehyde), ketones. More selective than Tollens.

💡 Reduces carbonyl (C=O) to methylene (CH₂). Acid-sensitive compounds: use Wolff-Kishner instead. Used for: PhCOCH₃ → PhCH₂CH₃.

💡 Complementary to Clemmensen. Used for base-stable, acid-sensitive substrates. Hydrazone intermediate decomposes to give N₂ gas (driving force).

💡 α-halogenation of carboxylic acids. Not possible directly with Br₂ alone; PCl₃ activates acid to acyl chloride first. Product: α-bromocarboxylic acid.

💡 Selective reduction of acyl chloride → aldehyde (stops before alcohol). BaSO₄ poisons Pd to prevent over-reduction. Quinoline-S further deactivates catalyst.

💡 Nitrile (RCN) → aldehyde (RCHO). Mechanism via imine intermediate which hydrolyses to aldehyde. Useful for aromatic aldehydes from aromatic nitriles.

💡 Selective oxidation of methyl group on benzene ring to aldehyde. Chromyl chloride is a specific reagent for this transformation.

💡 Gives ONLY primary aliphatic amines (no 2° or 3°). Cannot be used for aromatic amines (ArX won't undergo SN2 with nitrogen nucleophile).

💡 Product has ONE LESS carbon than starting amide (R loses CO). Gives pure primary amine. Mechanism: N-bromoamide → isocyanate → amine.

💡 Temperature CRITICAL (0–5°C): diazonium salts decompose above 5°C. Only primary aromatic amines. Diazonium salt is highly useful for synthesis.

💡 Electrophilic substitution at para position of phenol/aniline. Always occurs in para position preferentially. Azo group (–N=N–) is chromophore (gives colour).

💡 Confirmatory test for PRIMARY amines (both aliphatic and aromatic). 2° and 3° amines do NOT give this test. Mechanism: dichlorocarbene attacks amine.

💡 1° product has N–H → acidic, dissolves in NaOH. 2° product has no N–H → insoluble ppt. 3° can't react (no N–H). Best test to distinguish 1°/2°/3° amines.

💡 Protects amine group. Used in synthesis to reduce reactivity of amine (e.g., aniline → acetanilide before nitration to avoid over-reaction). Reversed by hydrolysis.

💡 Replaces N₂ group with halide or CN. Uses cuprous salt. Important for introducing Cl/Br/CN into benzene ring without using Friedel-Crafts (which has limitations).

💡 Similar to Sandmeyer but uses Cu metal instead of CuX. Less efficient but cheaper. Cu acts as reducing agent and catalyst.

💡 Only way to introduce F into benzene ring via diazonium salt. Diazonium fluoroborate is stable solid; decomposes on heating to give aryl fluoride.

💡 Converts aniline → phenol via diazonium salt. Better route than direct hydroxylation of benzene. Diazonium salt solution warmed with dilute acid.

💡 Removes N₂ group and replaces with H. Useful for making compounds that cannot be obtained by direct substitution (e.g., 1,3,5-tribromobenzene from 2,4,6-tribromoaniline).