--- title: "Hantzsch pyridine synthesis Template | MolDraw" url: https://www.moldraw.com/templates/hantzsch-pyridine-synthesis/ description: "Hantzsch pyridine synthesis template: Benzaldehyde condenses with one ethyl acetoacetate (Knoevenagel) and ammonia with the other (enamine). Michael addition…" lang: en publisher: Scidart Academy generated: 2026-11-13 --- [MolDraw](https://www.moldraw.com/) › [Templates](https://www.moldraw.com/templates/) › [Name reactions](https://www.moldraw.com/templates/name-reactions/) › Hantzsch pyridine synthesis [Name reactions](https://www.moldraw.com/templates/name-reactions/)Premium # Hantzsch pyridine synthesis template ![Hantzsch pyridine synthesis template: Benzaldehyde condenses with one ethyl acetoacetate (Knoevenagel) and ammonia with the other (enamine). Michael addition of the enamine to the benzylidene keto ester, ring closure of NH₂ onto the ketone and loss of water give the Hantzsch 1,4-dihydropyridine, which is oxidised to the aromatic pyridine.](https://www.moldraw.com/templates/hantzsch-pyridine-synthesis.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). Benzaldehyde condenses with one ethyl acetoacetate (Knoevenagel) and ammonia with the other (enamine). Michael addition of the enamine to the benzylidene keto ester, ring closure of NH₂ onto the ketone and loss of water give the Hantzsch 1,4-dihydropyridine, which is oxidised to the aromatic pyridine. ## Mechanism step by step Two β-keto esters, an aldehyde and ammonia give a 1,4-dihydropyridine; oxidation gives the pyridine 1. **Knoevenagel condensation** – Aldehyde + one keto ester: the benzylidene keto ester 2. **Enamine** – NH₃ + the other keto ester: ethyl 3-aminocrotonate 3. **Michael addition** – The enamine carbon adds to the β-carbon of the enone 4. **Proton transfers** – Back to an enamine and a ketone 5. **Ring closure, dehydration** – NH₂ adds to the ketone C=O (six-membered ring) and water is lost: the Hantzsch 1,4-dihydropyridine 6. **Aromatisation** – Oxidation (HNO₃, DDQ, MnO₂) removes two H ## Key points - A four-component reaction: 2 × β-keto ester + aldehyde + NH₃; the aldehyde carbon becomes C-4. - Gain of aromaticity drives the final oxidation of the 1,4-dihydropyridine. - 1,4-Dihydropyridines are calcium-channel blockers (nifedipine, amlodipine) and are oxidised in the liver. - Hantzsch esters are NADH mimics: they deliver hydride from C-4 in transfer hydrogenations. Drawn with 325 atoms, 12 arrows, 11 shapes – every one editable in MolDraw. ## Sources - [Kürti & Czakó, Strategic Applications of Named Reactions in Organic Synthesis, Elsevier 2005, Hantzsch dihydropyridine synthesis](https://openlibrary.org/isbn/9780124297852) Textbook - [Clayden, Greeves & Warren, Organic Chemistry, 2nd ed., OUP 2012, ch. 30](https://openlibrary.org/isbn/9780199270293) 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 Hantzsch pyridine synthesis template free? You can preview the Hantzsch pyridine synthesis 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 Hantzsch pyridine synthesis 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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