Chemical Identity and Structure

1-(2-Bromo-4-fluorophenyl)pyrrolidin-2-one is an N-aryl γ-lactam in which the nitrogen atom of the five-membered pyrrolidinone ring is substituted with a 2-bromo-4-fluorophenyl group. The molecule contains three distinct reactive handles: (1) a C–Br bond at the ortho position of the aryl ring, highly amenable to oxidative addition into palladium(0) and nickel(0) catalysts; (2) a C–F bond at the para position, activated toward S_NAr by the electron-withdrawing lactam nitrogen; and (3) the lactam carbonyl, which can participate in hydrogen-bond interactions or be further transformed via condensation chemistry. The rigid planar character of the aryl lactam linkage imparts defined spatial orientation, making this compound particularly attractive as a constrained scaffold in structure–activity relationship (SAR) studies.

The molecular formula is C₁₀H₉BrFNO with a calculated molecular weight of approximately 258.09 g/mol. The compound is expected to be a solid at room temperature based on analogy with related N-arylpyrrolidinones.

Synthetic Applications and Reactivity

Palladium-Catalysed Cross-Coupling: The aryl bromide moiety is the primary handle for transition-metal-catalysed transformations. Under standard Suzuki–Miyaura conditions, the C–Br bond can be coupled with aryl or heteroaryl boronic acids to elaborate the biaryl framework while preserving the aryl fluoride and lactam intact. Buchwald–Hartwig amination, Negishi coupling, and Heck reactions are similarly accessible, allowing rapid diversification of the arene substituent.

Nucleophilic Aromatic Substitution (S_NAr): The fluorine at the para position, activated by the flanking electron-withdrawing lactam, can undergo S_NAr with amines, alkoxides, and thiolates. Orthogonal chemoselectivity can be achieved by performing cross-coupling first (mild Pd catalysis, C–Br reacts preferentially) followed by S_NAr, or vice versa depending on nucleophile and conditions.

Directed Metalation: The lactam carbonyl acts as a directed metalation group (DMG). Treatment with strong bases such as LDA or n-BuLi at low temperature can generate an aryllithium species at positions ortho to the carbonyl, enabling introduction of electrophiles (aldehydes, halides, silyl groups) with regiocontrol.

Ring Elaboration: The lactam nitrogen and carbonyl provide handles for ring-opening or ring-expansion strategies, and the carbonyl oxygen can be converted to thiocarbonyl or iminyl variants, further broadening structural diversity accessible from this scaffold.

Medicinal Chemistry and Drug Discovery Relevance

N-Aryl lactams, and γ-butyrolactams in particular, are privileged structural motifs in medicinal chemistry because they mimic peptide bond geometry while conferring metabolic stability relative to open-chain amides. The pyrrolidin-2-one ring restricts conformational freedom, which can translate into improved binding selectivity and reduced entropic penalty upon target engagement.

Introducing a halogenated aryl group—especially one bearing both bromine and fluorine substituents—at nitrogen offers multiple advantages in a drug discovery context: the aryl fluoride can modulate lipophilicity (logP), metabolic stability (blocking cytochrome P450-mediated hydroxylation at the para position), and membrane permeability. Fluorine is also well-known to influence pKa of proximal functional groups and can participate in orthogonal fluorine–backbone hydrogen bonds within a binding pocket.

The aryl bromide, beyond its synthetic utility, can be used as an isostere placeholder during lead optimisation; it is also a handle for late-stage functionalisation in library synthesis, enabling rapid generation of analogue sets around the core lactam scaffold.

Researchers in kinase inhibitor, CNS drug, and anti-infective programmes have employed structurally related N-arylpyrrolidinone fragments, suggesting 1-(2-Bromo-4-fluorophenyl)pyrrolidin-2-one may serve as a useful entry point for target-class-agnostic hit-to-lead campaigns.

Handling, Safety, and Storage

Personal Protective Equipment: As with all organobromine and organofluorine research reagents, standard laboratory precautions apply. Wear appropriate gloves (nitrile recommended), safety glasses or goggles, and a laboratory coat when handling this compound. Work in a fume hood when weighing or preparing solutions to minimise inhalation exposure to dust or vapour.

Storage: Store in a tightly sealed container under cool (typically 2–8 °C or room temperature as specified on the CoA), dry, and well-ventilated conditions, away from direct light and incompatible materials such as strong oxidisers and strong bases. Confirm specific storage requirements from the Aladdin Scientific Certificate of Analysis (CoA) provided with each lot.

Disposal: Dispose of waste in accordance with local, national, and institutional regulations for halogenated organic compounds. Do not discharge into waterways or general waste streams.

SDS: Always consult the Safety Data Sheet (SDS) supplied by Aladdin Scientific for detailed hazard classifications, first-aid measures, and regulatory information before use.