1-(3-Bromophenyl)-1H-Pyrrole

In commercial-scale manufacturing of vacuum-deposited phosphorescent organic light-emitting diodes (OLEDs), the hole-transport host material based on a triphenylamine–pyrrole hybrid architecture demands a halogenated aryl building block with precise regiochemistry. 1-(3-Bromophenyl)-1H-pyrrole serves as the exclusive electrophilic component in a palladium-catalyzed Suzuki–Miyaura cross-coupling that installs the electron-rich N-phenylpyrrole donor onto a triarylamine core. Batches destined for this application are subject to compliance with IEC 62341-1-1:2009 sub-clause optical stability requirements and must conform to the sublimation-grade purity specifications detailed in the consortium’s material acceptance documents; non-volatile residue after thermogravimetric analysis according to ASTM E1131-20 is limited to ≤0.02%. Addition levels in the synthetic procedure are typically held at 1.08–1.12 molar equivalents relative to the pinacol boronate ester partner, with the slight excess compensating for dehalogenation side reactions that become pronounced above 85 °C. The downstream process begins with the coupling in a 50 L glass-lined reactor using Pd(dba)₂/SPhos under a strictly oxygen-free nitrogen sweep; after phase separation and flash chromatography on silica gel (eluent: n-heptane/ethyl acetate 9:1), the crude product undergoes gradient train sublimation at 1.2×10⁻⁶ Torr with a source zone temperature ramp of 220→310 °C over 18 hours. Operators have recorded batch failures when the aqueous phase pH drifted below 9.5 due to boronic acid protodeboronation, leading to an unreacted bromoaryl impurity that co-sublimes and causes a 300–500 mV increase in driving voltage in the final single-charge device stack. The terminal product is a hole-transport host incorporated at 15–25 wt% doping into a green phosphorescent emissive layer, which is integrated into top-emission AMOLED panels for automotive dashboard displays and augmented-reality waveguides. The entire supply chain operates under EU REACH (EC) No 1907/2006 and the RoHS 2011/65/EU annex III exemption 7(c)-I, with each shipment accompanied by a certificate of analysis documenting bromide ion content below 50 ppm via combustion ion chromatography per EN 14582:2016.

When dopant-free HTLs leverage the electron-rich pyrrole core in perovskite photovoltaics

Perovskite solar cell architectures migrating away from lithium bis(trifluoromethanesulfonyl)imide-doped spiro-OMeTAD increasingly employ alternative hole-transport layer (HTL) molecules built around an N-(3,5-disubstituted phenyl)pyrrole donor block, for which 1-(3-bromophenyl)-1H-pyrrole provides the mono-brominated entry point. Adherence to IEC 61215-1:2021 (Section 4.11 thermal cycling) and ISO 11358-1:2022 decomposition kinetics imposes a volatile matter specification of <0.03% as determined by Karl Fischer titration and DSC oxidation induction time exceeding 45 minutes at 200 °C under 3.5 MPa oxygen (ASTM E2009-08(2014)e1). In the synthetic route, the bromoaryl-pyrrole reactant is introduced at a molar ratio of 1.00:1.00 with a dibrominated carbazole-diphenylamine acceptor via microwave-assisted Buchwald–Hartwig coupling, where precise stoichiometric control is critical because residual free bromide above 0.1 mol% accelerates silver electrode corrosion in damp-heat testing. The manufacturing workflow proceeds in a 20 L Hastelloy reactor charged with Pd₂(dba)₃/XPhos, sodium tert-butoxide, and anhydrous toluene; the reaction mass is quenched with 5% aqueous NH₄Cl, passed through a 0.5 µm bag filter containing Celite 545, and subjected to two rounds of anti-solvent precipitation from dichloromethane into methanol. A notable scale-up pitfall is the formation of a viscous triarylamine tar when the exotherm during base addition exceeds 35 °C, requiring jacketed cooling with a temperature delta of ΔT ≤ 8 °C. The purified HTL material is dissolved in chlorobenzene at 6 mg·mL⁻¹ and dynamically spin-coated onto a formamidinium lead iodide absorber, yielding a device with stabilized power conversion efficiency that passes 1000-hour maximum-power-point tracking under continuous 1-sun illumination. The end product is a glass-encapsulated n-i-p minimodule (aperture area 100 cm²) utilized in building-integrated photovoltaic facades, classified under EN 50583-1:2016.

Why are batch-to-batch viscosity shifts in Stille polymerization traced back to the bromoaryl monomer purity?

Near-infrared (NIR) organic photodetector (OPD) arrays fabricated via donor–acceptor conjugated copolymers exemplify a polymerization application where 1-(3-bromophenyl)-1H-pyrrole functions as the electron-donating co-monomer, alternating with a diketopyrrolopyrrole (DPP) acceptor via Stille cross-coupling. Stringent lot-release criteria align with ISO 11357-2:2020 glass transition temperature window (T_g = 115–125 °C) and size-exclusion chromatography against polystyrene standards, requiring the monomer to exhibit number-average molecular weight reproducibility within ±5% across consecutive batches. The monomer is loaded at a precisely equimolar ratio with a bis(trimethylstannyl)-DPP derivative; even a 0.5 mol% deviation arising from residual inorganic bromide in the pyrrole monomer causes a 12–18% drop in weight-average molecular weight (M_w) due to chain termination, which manifests as a measurable reduction in solution viscosity from the target 1.8 dL·g⁻¹ to below 1.2 dL·g⁻¹ (chlorobenzene, 30 °C). The downstream process is executed in a 10 L jacketed glass vessel with an anchor stirrer under refluxing chlorobenzene (132 °C) using Pd₂(dba)₃/tris(2-tolyl)phosphine and copper iodide as a co-catalyst; molecular weight is controlled by phenyl bromide end-capping after 48 hours, followed by precipitation into methanol and sequential Soxhlet extraction with acetone, hexane, and chloroform to remove oligomers below M_n = 8000 Da. A critical process boundary is the exclusion of atmospheric moisture to levels below 10 ppm in the solvent, as stannane protiodestannylation generates homocoupled DPP defects that act as charge traps, increasing dark current density by an order of magnitude. The terminal thin-film device—a monolithic OPD array with a 50 µm pixel pitch—is integrated into pulse oximeter sensor modules classified under ISO 80601-2-61:2017, delivering specific detectivity above 1×10¹² Jones at 940 nm. Full compliance requires the monomer manufacturer to declare heavy metal content via EPA Method 6020A and to certify that no dibenzofuran-like byproducts exceed the reporting limit of 0.01%.

Synthesizing the pyrrolo[2,3-d]pyrimidine hinge-binding motif for kinase-targeted programs

In the discovery chemistry supply chain of reversible ATP-competitive kinase inhibitors, the annulation of a pyrrolo[2,3-d]pyrimidine core requires a 3-bromoaryl substituent at the N-1 position, and 1-(3-bromophenyl)-1H-pyrrole is employed as the direct precursor to a diverse array of 7-azaindole analogs. Pharmaceutical intermediate shipments must be accompanied by a full-elemental screening report in accordance with ICH Q3D Guideline for Elemental Impurities, with special attention to palladium (<10 µg/g), nickel (<5 µg/g), and copper (<50 µg/g) as residual catalyst metals; mutagenic impurity risk assessment follows the ICH M7(R2) framework, requiring Ames test data for the isolated intermediates if daily intake projections exceed the threshold of toxicological concern. The compound is typically charged into the registered intermediate synthesis at 1.00 equivalent relative to a protected 4-chloropyrrolopyrimidine in a Buchwald–Hartwig amination performed in anhydrous 2-methyltetrahydrofuran at 65 °C for 16–20 hours under an argon atmosphere. Post-reaction workup involves filtration through a 0.2 µm inline PTFE membrane, aqueous EDTA scrubbing to chelate leached metals, and crystallization from ethanol/water (7:3 v/v) with controlled cooling from 60 °C to 2 °C at a rate of 0.3 °C/min; crystals are dried in a vacuum tray dryer at 40 °C/5 mbar until moisture content falls below 0.2% (Karl Fischer). A documented operational constraint is the incompatibility of the bromoaryl-pyrrole with strong bases such as lithium diisopropylamide at temperatures above −20 °C, where ring-opening of the pyrrole moiety generates 4-aminobut-2-enal derivatives that contaminate the desired product. The final active pharmaceutical ingredient, after deprotection and salt formation, is formulated as a 25 mg immediate-release tablet with hydroxypropyl methylcellulose matrix, intended for clinical evaluation under an investigational new drug application referencing FDA 21 CFR Part 312. Each delivered batch of the bromoaryl intermediate is labeled with a retest date of 24 months when stored at 2–8 °C in amber glass under nitrogen.

Discovery-phase optimization of novel acaricidal and lepidopteran-active pyrrole derivatives frequently utilizes 1-(3-bromophenyl)-1H-pyrrole as a late-stage diversification handle, enabling the parallel synthesis of focused compound libraries through C–C or C–N bond formation at the bromine site without deactivating the electron-rich pyrrole ring. Agrochemical good laboratory practice standards require compliance with OECD Guideline 301B for ready biodegradability screening of any intermediate discharged into wastewater, and process impurities are profiled against the FAO/WHO Joint Meeting on Pesticide Specifications manual (Section 6.8) for unidentified peaks not exceeding 0.15% relative area. In a typical synthetic route to a pyrazole-carboxamide–pyrrole hybrid acaricide, the bromide is fed into the Suzuki coupling at 1.02–1.05 equivalents with respect to a furylethylboronic acid pinacol ester, using the sustainable solvent 2-methyltetrahydrofuran and a Pd(OAc)₂/butyl-di-1-adamantylphosphine catalyst system pre-activated at 45 °C; residual palladium in the crude active ingredient is scavenged by treatment with 1.5 wt% of 3-mercaptopropyl-functionalized silica gel, bringing levels below 20 ppm. Downstream formulation of the active compound into a 240 g/L suspension concentrate involves wet-milling with a 0.3–0.5 mm yttria-stabilized zirconia bead charge in a horizontal agitated media mill until the particle size distribution reaches D₉₀ < 3 µm (laser diffraction, ISO 13320:2020). Processing bottlenecks have been documented when the crude active ingredient exhibits a melting point depression greater than 4 °C compared to reference, indicating insufficient removal of the dehalogenated byproduct, which subsequently co-crystallizes during milling and causes nozzle clogging in the Dyno-Mill circulation loop. The finished suspension concentrate is packaged in 1 L HDPE containers with a tamper-evident seal and distributed for field trials under an experimental use permit, with a shelf-life target of 2 years at ambient storage conditions per CIPAC MT 46.3 accelerated stability protocol.

A microporous paradigm: crosslinking via C–N or C–C bonds in conjugated polymer networks

Conjugated microporous polymers (CMPs) engineered for post-combustion CO₂ capture utilize 1-(3-bromophenyl)-1H-pyrrole as a tri-functionalizable node in Yamamoto-type dehalogenation polycondensation, generating highly crosslinked networks with intrinsic ultramic porosity. The nitrogen- and bromine-rich monomer enables simultaneous C–C bond formation at the bromophenyl position and potential oxidative coupling at the pyrrole α-positions when reaction conditions are tuned for double activation. Surface area conformance is tested according to ISO 9277:2010 BET nitrogen adsorption at 77 K, with an acceptance window of 1120–1350 m²·g⁻¹, while the pore size distribution must show a mode below 0.7 nm verified by non-local density functional theory analysis. In the polymerization feed, the bromoaryl-pyrrole monomer constitutes 50 mol% of the total aromatic halide content, combined with 50 mol% of 1,3,5-tribromobenzene to adjust crosslink density; the solid-state molar ratio of residual bromine to total halogen is tracked by X-ray photoelectron spectroscopy and must fall below 5 atom% to avoid quenching of CO₂-philic amine sites. The production protocol is executed in a 2 L jacketed pressure reactor rated for 10 bar, charged with anhydrous DMF, Ni(COD)₂, 2,2′-bipyridine, and 1,5-cyclooctadiene, heated to 85 °C for 72 hours; the resulting black precipitate is collected by centrifugation at 8000 rpm, washed sequentially with hot THF, hydrochloric acid (1 M), and deionized water, then subjected to supercritical CO₂ drying at 40 °C/100 bar to preserve the micropore architecture. An observed operational boundary is the exotherm upon catalyst injection, which must be controlled to ΔT ≤ 6 °C to prevent nickel particle aggregation and the formation of non-porous graphitic domains, as evidenced by a loss of 40–50% of BET surface area in uncontrolled batches. The final CMP powder is packed into 316L stainless steel adsorption columns of 100 mm internal diameter for a pilot-scale temperature swing adsorption skid operating at 0.5 bar feed pressure, demonstrating a CO₂/N₂ selectivity exceeding 45:1 under simulated flue gas conditions (15 vol% CO₂, 85 vol% N₂, 25 °C). All off-gassed volatiles from the drying step are monitored for compliance with EU Industrial Emissions Directive 2010/75/EU, and the spent nickel catalyst is recycled through a licensed precious metal refinery.