Chemical Identity and Structure

6-Methyl-2-(methylthio)-1H-pyrimidin-4-one (CAS registry; molecular formula C₆H₈N₂OS; MW ≈ 156.20 g/mol) belongs to the pyrimidin-4(1H)-one family of heterocycles. The compound features a six-membered aromatic ring containing two nitrogen atoms at positions 1 and 3, a lactam carbonyl at position 4, a methylthio (–SCH₃) group at position 2, and a methyl group at position 6. This substitution pattern endows the molecule with both hydrogen-bond donor (N–H) and acceptor (C=O, ring nitrogens, sulfur) capabilities, making it a highly functionalized scaffold.

The compound exists predominantly in the 4-oxo tautomeric form rather than the 4-hydroxy tautomer in solid state and polar solvents, consistent with the behavior of other 2-substituted pyrimidin-4(1H)-ones. The methylthio group at C-2 is particularly amenable to nucleophilic displacement or oxidative activation, providing a reactive handle for further derivatization.

Handling, Storage, and Safety Guidelines

Personal Protective Equipment (PPE): Always wear nitrile gloves, a laboratory coat, and safety glasses when handling this compound. Work in a well-ventilated fume hood, particularly when weighing powders, to minimize inhalation of fine particulates.

Storage: Store at room temperature (15–25 °C) in a tightly sealed container, away from moisture, strong oxidizing agents, and direct light. The methylthio group may be susceptible to oxidation upon prolonged exposure to air; storage under an inert atmosphere (nitrogen or argon) is recommended for long-term preservation of purity.

Disposal: Dispose of waste material in accordance with local institutional and governmental regulations for organic chemical waste. Do not pour down the drain without verified compatibility with local wastewater treatment standards.

Note: Consult the current Safety Data Sheet (SDS) for complete hazard classification, first-aid measures, and regulatory information before use.

Solubility and Solution Preparation

6-Methyl-2-(methylthio)-1H-pyrimidin-4-one is a solid at room temperature. Based on the general physicochemical properties of methylthiopyrimidinones, the compound is expected to show moderate solubility in polar aprotic solvents such as dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF), limited solubility in water, and good solubility in lower alcohols such as ethanol and methanol.

Recommended dissolution protocol:

1. Accurately weigh the required amount of compound using an analytical balance.
2. Add a small volume of DMSO or ethanol and vortex or sonicate (30–60 s) until fully dissolved.
3. If required, dilute the resulting stock solution into the aqueous buffer of choice. Maintain the co-solvent content below 1% (v/v) for biological assays to minimize solvent interference.
4. Prepare fresh solutions where possible; store stock solutions at –20 °C if intermediate storage is necessary, protected from light.

Exact solubility values have not been independently verified in the source material; experimentally determine solubility for critical applications.

Research Applications and Synthetic Utility

The 2-(methylthio)pyrimidin-4(1H)-one scaffold is a well-recognized pharmacophore and synthetic intermediate in heterocyclic chemistry. Key application areas include:

• Medicinal Chemistry: The methylthio group at C-2 can be displaced by nitrogen, oxygen, or carbon nucleophiles, or oxidized to the sulfoxide/sulfone to increase electrophilicity, enabling rapid diversification of the pyrimidine core toward libraries of drug-like molecules. Pyrimidinone derivatives have been explored in the context of kinase inhibitors, antiviral agents, and antimicrobial compounds.
• Agrochemical Research: Methylthiopyrimidines and their oxidized counterparts serve as key intermediates in the synthesis of herbicides and fungicides.
• Material Science: Pyrimidinone motifs have been incorporated into supramolecular assemblies and hydrogen-bonded polymers due to their strong and directional H-bonding capacity.
• Fluorescent Probe Intermediates: The reactive C-2 position allows coupling to chromophores for the development of fluorescent probes.

Researchers should consult the primary literature for specific reaction conditions, yields, and biological activity data relevant to their target applications.

Quality, Purity, and Ordering Information

Aladdin Scientific supplies 6-Methyl-2-(methylthio)-1H-pyrimidin-4-one under catalog number M589742. The compound is referenced under BD159811 in cross-referenced databases.

Recommended quality checks before use:

• Verify identity by ¹H NMR or LC-MS against published spectral data.
• Confirm purity by HPLC (UV detection at 254 nm or compound-appropriate wavelength); target ≥ 95% for synthetic applications.
• Check melting point as a rapid purity indicator.

For bulk quantities, custom purity grades, or certificate of analysis (CoA) requests, contact Aladdin Scientific technical support or your regional sales representative. Always cite the SKU (M589742) when ordering to ensure the correct material is supplied.