O-Vanillin CAS 148-53-8 2-Hydroxy-3-methoxybenzaldehyde Pharmaceutical Intermediate & Schiff Base Precursor
Product Introduction
o-Vanillin, also known as ortho-vanillin, 2-hydroxy-3-methoxybenzaldehyde, or 3-methoxysalicylaldehyde, is the ortho positional isomer of vanillin. Unlike its widely recognized para-isomer (vanillin, CAS 121-33-5) that dominates the global food flavoring market, o-Vanillin occupies a distinct and valuable niche as a versatile pharmaceutical intermediate, Schiff base ligand precursor, and fine chemical building block. The key structural difference—the hydroxyl group at position 2 and methoxy group at position 3 on the benzene ring (versus positions 4 and 3 in vanillin)—fundamentally alters its chemical reactivity, coordination behavior, and biological activity profile.
Product Identification
| Parameter | Specification |
| Product Name | o-Vanillin |
| IUPAC Name | 2-Hydroxy-3-methoxybenzaldehyde |
| Alternative Names | 3-Methoxysalicylaldehyde, Ortho-Vanillin, 2-Vanillin, o-Vanillic aldehyde |
| CAS Registry Number | 148-53-8 |
| EINECS Number | 205-715-3 |
| Molecular Formula | C₈H₈O₃ |
| Molecular Weight | 152.15 g/mol |
| InChIKey | JJVNINGBHGBWJH-UHFFFAOYSA-N |
| SMILES Notation | COc1cccc(C=O)c1O |
| Beilstein Reference | 471913 |
| UNII | Not assigned (research chemical) |
| HS Code | 2912.49.00 (Aldehyde-ethers) |
| RTECS Number | CU6530000 |
Application
| Application | Description | Recommended Grade |
| Schiff Base Drug Precursors | Synthesis of imine-linked bioactive molecules; broad-spectrum pharmacological screening libraries | 99.0–99.9% (GC/HPLC) |
| Anticancer Metal Complexes | Cu(II), Zn(II), Ni(II), Co(II) complexes for targeted cancer therapy research; DNA binding and cleavage | 99.5%+ (HPLC) |
| Antimicrobial Drug Development | Lead compound for novel antifungal/antibacterial agents; MRSA-active Cu(II) complexes | 99.0%+ (GC) |
| Anti-inflammatory Research | NF-κB pathway inhibitor for inflammatory disease models; adjuvant in chemotherapy | 99.0–99.5% (GC/HPLC) |
| Drug Excipient | Taste-masking agent for bitter APIs in oral liquid formulations; vanilla-like flavor at 0.01–0.1% w/v | 99.0%+ (GC) |
| API Intermediate | Starting material for synthesizing heterocyclic APIs including benzofurans, coumarins, and spiro compounds | 99.5%+ (HPLC) |
FAQ
Q1: What is o-Vanillin and how is it different from regular vanillin?
o-Vanillin (2-hydroxy-3-methoxybenzaldehyde, CAS 148-53-8) is the ortho positional isomer of vanillin. The key difference is the position of the hydroxyl group: o-Vanillin has -OH at position 2 (adjacent to the aldehyde), while vanillin has -OH at position 4. This structural difference creates intramolecular hydrogen bonding in o-Vanillin, which fundamentally alters its chemical reactivity, making it far superior for Schiff base ligand formation and metal complex synthesis. While vanillin is primarily a food flavoring, o-Vanillin is primarily a pharmaceutical intermediate and research chemical.
Q2: Is o-Vanillin a natural product?
Yes. o-Vanillin occurs naturally in Vanilla planifolia (vanilla orchid), Pinus koraiensis (Korean pine) fruits, various tobacco species (Nicotiana tabacum), benzoin resin (Styrax benzoin), Peru balsam (Myroxylon balsamum), and Tolu balsam. However, commercial quantities are predominantly produced through chemical synthesis from guaiacol due to the prohibitively low natural abundance. Natural-isolated o-Vanillin is available in research quantities for premium natural-product applications.
Q3: What purity grades do you offer for o-Vanillin?
We offer multiple purity grades to meet diverse application requirements: Industrial Grade (≥98.0%, GC), Synthesis Grade (≥99.0%, GC), Pharmaceutical Grade (≥99.5%, GC/HPLC), Research Grade (≥99.9%, HPLC), and Custom Grade (tailored to your specifications). Each grade comes with a comprehensive Certificate of Analysis (CoA) and full traceability documentation.
Q4: How is o-Vanillin used in Schiff base synthesis?
o-Vanillin is an ideal precursor for Schiff base ligands due to its ortho-hydroxyl-aldehyde geometry, which creates a perfect N₂O₂ tetradentate donor set upon condensation with diamines. The typical procedure involves dissolving equimolar amounts of o-Vanillin and a diamine (e.g., ethylenediamine, 1,3-diaminopropane, o-phenylenediamine) in ethanol, adding catalytic acetic acid (1–3 drops), and refluxing for 2–4 hours. The resulting Schiff base typically precipitates upon cooling and can be recrystallized from ethanol. Yields exceed 85% under optimized conditions. The Schiff base can then be complexed with transition metal salts to generate bioactive metal complexes.
Q5: What metal complexes can be formed with o-Vanillin?
o-Vanillin forms stable complexes with most first-row transition metals including Cu(II), Zn(II), Ni(II), Co(II), Mn(II), Fe(III), VO(IV), and Cd(II). The complexes are typically synthesized by reacting the pre-formed o-Vanillin Schiff base ligand with the metal acetate or chloride salt in a 1:1 or 1:2 (M:L) molar ratio in ethanol or methanol at 60–80 °C for 2–6 hours. Cu(II) and Zn(II) complexes generally show the highest biological activity enhancement over the free ligand. These metal complexes have applications in anticancer research, antimicrobial studies, catalysis, magnetic materials, and fluorescent sensing.
Q6: Does o-Vanillin have antifungal activity?
Yes, o-Vanillin demonstrates significant antifungal activity. It works through a dual mechanism: (1) disruption of fungal cell wall integrity by interfering with chitin and β-glucan biosynthesis, and (2) permeabilization of the fungal cell membrane causing leakage of intracellular contents. It is effective against Candida albicans, Aspergillus niger, and various dermatophyte species. The nickel(II) Schiff base complexes of o-Vanillin show 5–10× enhanced antifungal potency compared to the free ligand, making them promising candidates for antifungal drug development.
