Compound Overview and Physical Properties

2-Bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-imidazole (Aladdin SKU B732538) is an N1-protected 2-bromoimidazole in which the tetrahydropyran-2-yl (THP) group serves as a standard acid-labile protecting group on the imidazole nitrogen. The molecule combines the electrophilic character of a C2-bromine substituent with the stability conferred by THP protection, making it a reliable intermediate for multi-step heterocyclic synthesis.

The THP group is introduced via reaction of imidazole with 3,4-dihydro-2H-pyran (DHP) under acidic catalysis, and the resulting N-THP imidazole is then brominated at C2. The C2–Br bond is activated toward both directed metalation (e.g., n-BuLi at low temperature) and palladium-catalyzed cross-coupling. Typical physical characteristics of N-THP-protected bromoimidazoles include a pale-yellow to off-white solid or oil appearance; refer to the product certificate of analysis (CoA) for the confirmed melting point, purity, and spectral data specific to lot B732538.

Materials and Safety Considerations

Required materials: 2-Bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-imidazole (B732538), anhydrous solvents (THF, diethyl ether, or DMF depending on application), inert gas supply (N₂ or Ar), standard glassware for Schlenk or glovebox technique, and appropriate nucleophiles or coupling partners as required by the downstream reaction.

Safety: Organobromine heterocycles should be handled with standard laboratory precautions. Wear appropriate personal protective equipment (PPE) including nitrile gloves, laboratory coat, and safety glasses. Work in a well-ventilated fume hood. Consult the Safety Data Sheet (SDS) for B732538 before use; specific GHS hazard classifications, first-aid measures, and disposal instructions are detailed therein. Because the compound is moisture-sensitive, minimize exposure to ambient air during weighing and transfers.

Waste disposal: Dispose of halogenated organic waste in accordance with local institutional and regulatory requirements for halogenated solvents and reagents.

Step-by-Step Protocol for Halogen–Metal Exchange and Functionalization

The following general procedure outlines the use of B732538 as a precursor for directed lithiation followed by electrophile quench. Adapt stoichiometry and conditions to the specific target molecule.

1. Inert atmosphere setup: Flame-dry all glassware and purge with N₂ or Ar. Transfer all moisture-sensitive reagents via syringe or cannula.
2. Dissolution: Dissolve 2-Bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-imidazole (1.0 equiv, B732538) in anhydrous THF (typically 0.1–0.5 M) under inert gas at −78 °C.
3. Metalation: Add n-butyllithium (1.05–1.1 equiv, 2.5 M in hexanes) dropwise via syringe at −78 °C. Stir for 30–60 minutes to ensure complete halogen–lithium exchange at C2.
4. Electrophile addition: Add the desired electrophile (e.g., aldehyde, ketone, DMF, or iodine) dropwise at −78 °C. Allow the reaction to warm gradually to the temperature required for complete conversion (typically −78 °C to 0 °C or room temperature, depending on electrophile reactivity).
5. Workup: Quench with saturated aqueous NH₄Cl. Extract with ethyl acetate (3×), dry the combined organic layers over Na₂SO₄ or MgSO₄, filter, and concentrate under reduced pressure.
6. THP deprotection (if required): Treat the crude product with dilute aqueous HCl (e.g., 1 N, 5 equiv) in THF/water (1:1) at room temperature for 1–4 hours. Monitor by TLC or LC-MS. Neutralize, extract, and purify.
7. Purification: Purify by silica gel column chromatography using an appropriate solvent gradient. Confirm identity and purity by ¹H NMR, ¹³C NMR, and HRMS.

Note: Reaction times and temperatures are general guidelines. Optimize for each specific substrate and electrophile. All specific yields and conditions should be validated in-house.

Storage, Stability, and Quality Control

Storage: Store B732538 under an inert atmosphere (N₂ or Ar) at 2–8 °C. Keep the container tightly sealed and protected from moisture and light. Improper storage may lead to hydrolysis of the THP protecting group or decomposition of the C–Br bond.

Stability: The THP group is stable under neutral and basic conditions but is cleaved under mild acidic aqueous conditions, which is exploited for deprotection. The C2–Br bond is stable to storage conditions but reactive toward strong nucleophiles, organolithium reagents, and transition-metal catalysts under appropriate reaction conditions.

Quality control: Aladdin Scientific provides a Certificate of Analysis (CoA) for each lot of B732538 confirming identity (NMR, MS), purity (HPLC or GC), and appearance. Request the CoA at time of ordering or download it from the product page. If analytical data are required prior to use (e.g., for GMP-adjacent workflows), contact Aladdin technical support.