--- title: "Vilsmeier–Haack reaction Template – Chemistry Diagram | MolDraw" url: https://www.moldraw.com/templates/vilsmeier-haack/ description: "Vilsmeier–Haack reaction template: DMF and POCl₃ form the chloroiminium ion (Vilsmeier reagent). N,N-dimethylaniline attacks it at the para position, and…" lang: en publisher: Scidart Academy generated: 2026-10-28 --- [MolDraw](https://www.moldraw.com/) › [Templates](https://www.moldraw.com/templates/) › [Name reactions](https://www.moldraw.com/templates/name-reactions/) › Vilsmeier–Haack reaction [Name reactions](https://www.moldraw.com/templates/name-reactions/)Premium # Vilsmeier–Haack reaction template ![Vilsmeier–Haack reaction template: DMF and POCl₃ form the chloroiminium ion (Vilsmeier reagent). N,N-dimethylaniline attacks it at the para position, and water hydrolyses the iminium to 4-(dimethylamino)benzaldehyde.](https://www.moldraw.com/templates/vilsmeier-haack.webp) [Edit in MolDraw](https://www.moldraw.com/)Download with Pro Premium template. Preview and edit it free in MolDraw; downloading and exporting it is part of [MolDraw Pro](https://www.moldraw.com/pricing). DMF and POCl₃ form the chloroiminium ion (Vilsmeier reagent). N,N-dimethylaniline attacks it at the para position, and water hydrolyses the iminium to 4-(dimethylamino)benzaldehyde. ## Mechanism step by step DMF and POCl₃ formylate an electron-rich arene 1. **O attacks P** – The DMF oxygen attacks POCl₃; chloride leaves 2. **Chloride adds** – Cl⁻ adds to the carbon 3. **Vilsmeier reagent** – The N lone pair pushes out dichlorophosphate: the chloroiminium ion 4. **Electrophilic attack** – The ring attacks at the para position (activated by NMe₂) 5. **Rearomatisation** – Loss of H⁺ restores the aromatic ring 6. **Hydrolysis** – Water turns the α-chloroamine (iminium) into the aldehyde ## Key points - The Vilsmeier reagent is a weak electrophile: only electron-rich rings react (anilines, phenol ethers, pyrrole, indole, furan). - Pyrrole and furan react at C-2; indole at C-3. - Other amides give ketones (N,N-dimethylacetamide gives an acetyl group). - Gattermann–Koch and Gattermann are other formylations; they suit benzene and phenols respectively. Drawn with 169 atoms, 17 arrows, 10 shapes – every one editable in MolDraw. ## Sources - [Kürti & Czakó, Strategic Applications of Named Reactions in Organic Synthesis, Elsevier 2005](https://openlibrary.org/isbn/9780124297852) Textbook - [Smith, March's Advanced Organic Chemistry, 8th ed., Wiley 2020](https://openlibrary.org/isbn/9781119371809) Textbook ## How to use this template 1. Press **Edit in MolDraw**. The template opens on the canvas of the free MolDraw editor. 2. Change anything: move structures, edit atoms and labels, recolour highlights or delete what you do not need. 3. Add your own structures, arrows and text next to it, or combine several templates on one page. 4. Export the drawing as PNG, SVG or PDF for slides, worksheets, theses and papers. ## Frequently asked questions ### Is the Vilsmeier–Haack reaction template free? You can preview the Vilsmeier–Haack reaction template here and open and edit it in MolDraw for free. Downloading or exporting it is part of MolDraw Pro, together with the other premium templates. ### Can I edit the Vilsmeier–Haack reaction template? Yes. It opens as an ordinary MolDraw drawing, so every structure, arrow, label and colour can be changed, and you can add your own content around it. ### Is the chemistry checked? Every structure is checked with RDKit and every curly arrow passes MolDraw’s electron-flow audit. The sources used are listed on this page. ### Which name reactions are included? 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