Tert-Butyl(2S)-2-[[2-(4-Bromophenyl)-2-Oxoethyl]Carbamochemicalbookyl]Pyrrolidine-1-Carboxylate

What Governs Diastereomeric Excess in Cryogenic Amide Couplings for Antiviral APIs?

Control over diastereomeric excess during the formation of (2S)-2-[[2-(4-bromophenyl)-2-oxoethyl]carbamoyl]pyrrolidine-based amides at cryogenic temperatures severely impacts the final active pharmaceutical ingredient (API) purity profile for a class of antiviral protease inhibitors. When the compound is activated with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) in the presence of 1-hydroxybenzotriazole (HOBt) at 0.95–1.05 molar equivalents relative to a chiral α-amino ester hydrochloride, the morpholine-solvated intermediate forms within a narrow thermal window of -20 °C to -10 °C in anhydrous 2-methyltetrahydrofuran containing < 100 ppm water as determined by Karl Fischer titration per USP <921> Method Ic. Deviation of the jacket temperature of a 100 L Hastelloy C-276 reactor by more than ±3 °C during the 45–60 minute reagent addition phase elevates the (R)-epimer impurity from the typical 0.25 area-% to above 2.8 area-% as quantified on a 150 × 4.6 mm, 3 µm octadecylsilane column (UV detection at 254 nm, acetonitrile/phosphate buffer pH 3.0 gradient in accordance with ICH Q2(R1) guidelines). The resultant amide diastereomer is converted in situ via a second low-temperature acylation into a (2S,4S)-4-(4-bromophenyl)pyrrolidine-2-carboxamide scaffold that serves as the penultimate intermediate for an HIV-1 protease inhibitor phosphate salt; compliance with ICH Q7 Active Pharmaceutical Ingredient GMPs and 21 CFR Part 211 mandates tracking of all critical process parameters with end-product residual solvent analysis per USP <467> and heavy metals by USP <233>. A failure mode encountered in production campaigns involves momentary nitrogen blanket interruption causing atmospheric moisture ingress, which hydrolyzes the activated ester to 4-bromobenzoic acid at approximately 6% of the theoretical charge; therefore, the vessel is equipped with a dual-redundant inert gas supply manifold and an online Raman probe for real-time acid carbonyl formation monitoring at 1712 cm⁻¹.

Suzuki Cross-Coupling Substrate Purity and Palladium Scavenging Thresholds

The 4-bromophenyl moiety resident in tert-butyl (2S)-2-[[2-(4-bromophenyl)-2-oxoethyl]carbamoyl]pyrrolidine-1-carboxylate functions as an electrophilic partner in palladium-catalyzed Suzuki-Miyaura cross-coupling reactions to construct biaryl architectures for ATP-competitive kinase inhibitor candidates. In a typical kilo-scale campaign, the bromo compound is charged at 1.05–1.15 molar equivalents against an arylboronic acid pinacol ester, with Pd(dppf)Cl₂ · CH₂Cl₂ catalyst loading of 0.5–0.8 mol% in a degassed mixture of THF and 2 M aqueous potassium phosphate tribasic (7.5:1 v/v) at 75–80 °C under a positive nitrogen overpressure of 0.2 bar. The reaction is mass-transfer-limited at agitator tip speeds below 1.2 m/s in a 500 L glass-lined reactor equipped with a retreat-curve impeller; incomplete phase mixing yields a homocoupling byproduct (4,4'-dibromobiphenyl) that co-crystallizes with the desired product and mandates reprocessing. Post-reaction palladium scavenging is regulated by ICH Q3D final elemental impurity limits for oral drugs—palladium must not exceed 10 µg/g in the isolated intermediate. A comparative matrix of scavenger treatments under ISO 14001:2015 environmental controls is presented below; the selected method involves stirring the warmed organic phase with Si-Thiol-functionalized silica (1.3 mmol thiol/g) at 55 °C for 4 hours followed by hot filtration through a 0.5 µm polypropylene filter plate, reducing Pd content from an initial 380–520 µg/g to below 8 µg/g without the sulfur odor transfer observed with liquid thiourea-based scavengers. The biaryl product is subsequently advanced through Boc deprotection and reductive amination steps to generate a Type II kinase inhibitor mesylate salt with a target potency of < 100 nM against wild-type EGFR.

Representative Palladium Scavenger Screening Data (Patented Aryl Bromide Substrate)

Scavenger System

Equivalents (rel. to Pd)

Contact Time (h)

Residual Pd (µg/g)

Isolated Yield (%)

Activated Carbon, Darco KB-G

20 wt%

135–160

N-Acetyl-L-cysteine, aq. wash

5.0

42–68

Trimercaptotriazine silica gel

1.8

9–15

Si-Thiol (1.3 mmol/g)

2.2

5–8

QuadraPure™ MPM-51 resin

1.5

3–6

Catalytic asymmetric hydrogenation screening programs at 10-gram discovery scale frequently rely on Boc-(S)-prolinamide-derived phosphine ligands where the 4-bromophenyl moiety serves as a tunable steric handle, and the synthesis demands exclusion of oxygen and moisture to prevent phosphine oxide formation which poisons the rhodium or ruthenium catalytic center. The brominated intermediate in anhydrous dichloromethane (< 30 ppm H₂O) is treated with 1.05 equivalents of chlorodiphenylphosphine in the presence of 1.2 equivalents of triethylamine at -78 °C inside a nitrogen-filled glovebox maintaining < 5 ppm O₂; after warming to ambient temperature over 8 hours, the crude phosphine ligand is complexed with [Rh(COD)₂]OTf in situ without isolation, in compliance with ISO 9001:2015 for non-GMP advanced intermediates. The resulting homogeneous catalyst achieves substrate-to-catalyst ratios exceeding 10,000:1 for the enantioselective hydrogenation of an itaconic acid diester, a step in the industrial synthesis of a DPP-4 inhibitor; the (S)-configuration at the pyrrolidine ring dictates the spatial orientation of the two phosphorus lone pairs, and any epimerization≥0.5% at this stage collapses the enantiomeric excess of the final product below the 99.5% specification in USP monograph criteria. A known process deviation occurs when the glovebox regeneration catalyst bed cycles beyond its rated 500 hour service interval, introducing 8–15 ppm oxygen spikes that cause ligand oxide formation readily detected at 31P NMR shift 28.5 ppm; repeated cycles are traced by mass balance to a 7–11% molar loss of active phosphine.

When Tertiary Amine Handling Requires Stripping Below 50 ppm Residual Solvents After Boc Deprotection

Removal of the tert-butoxycarbonyl group from the pyrrolidine nitrogen introduces amine functionality essential for downstream salt formation, yet the process generates tert-butyl carbocation-derived isobutylene and must be executed under conditions that comply with ICH Q3C(R8) residual solvent limits, specifically restricting dichloromethane to < 600 ppm and trifluoroacetic acid to < 1,500 ppm in the final isolated amine hydrochloride. In a representative synthetic sequence for a metabolic disease clinical candidate, the Boc-protected intermediate is dissolved in dichloromethane (7.5 L/kg substrate) and treated with 3.5–4.0 equivalents of trifluoroacetic acid at 18–22 °C over a 90-minute period, with evolved isobutylene vented through a dilute sodium hydroxide scrubber rated for 50 L/min vapor flow; after completion verified by HPLC (substrate < 0.5 area-%), the mass is concentrated under vacuum on a 20 L rotary evaporator with bath temperature not exceeding 35 °C to prevent N-carboxymethyl impurity formation. The crude oil is then subjected to two sequential solvent exchanges with isopropyl acetate (3 × 8 L) on a wiped-film evaporator operating at 40 °C jacket and 15 mbar absolute pressure, achieving residual dichloromethane levels of 35–48 ppm and TFA 210–380 ppm by GC-HS per USP <467> Procedure A. Crystallization of the free base hydrochloride salt from ethyl acetate/hexanes (1:4 v/v) at 0–5 °C followed by filtration through a Nutsche filter with 10 µm polypropylene cloth provides the amine intermediate in 93–96% recovery; the solids are dried at 30 °C/5 mbar for 16 hours in a vacuum tray dryer with nitrogen bleed until LOD by ASTM E1868-10 falls below 0.5%. Any deviation from the wiped-film temperature profile exceeding 45 °C accelerates the formation of a N-formyl impurity arising from trace formic acid in the TFA charge, which then requires a pH-controlled rework using 0.1 M HCl extraction.

Late-Stage Functionalization Routes Bypass Intermediate Isolation Steps for Peptide Mimetic Leads

Direct introduction of the α-ketoamide moiety into peptide backbone mimics eliminates the need for protecting group interconversion when the (2S)-2-[[2-(4-bromophenyl)-2-oxoethyl]carbamoyl]pyrrolidine scaffold is deployed as the electrophilic building block in a continuous-flow acylation of a resin-bound tripeptide fragment. The Boc-protected bromophenacyl amide is fed as a 0.55 M solution in anhydrous N,N-dimethylformamide at 1.02 equivalents per available resin amine site, merged with a 0.30 M stream of HATU and 0.60 M N,N-diisopropylethylamine through a stainless steel microreactor chip with a 250 µm internal diameter channel held at 60 °C under 5 bar back pressure, yielding a residence time of 30 seconds. This process, designed according to ASTM E2500-20 principles for continuous manufacturing, avoids the racemization observed in batch mode when HATU pre-activation is prolonged beyond 2 minutes; inline mid-IR monitoring of the ketone carbonyl stretch at 1698 cm⁻¹ triggers diversion of off-spec eluate when the peak area drops below 95% of the calibration setpoint. A direct comparison of batch and flow modalities for this α-ketoamide human neutrophil elastase inhibitor intermediate is summarized in the accompanying table. After on-resin cleavage with 95:2.5:2.5 (v/v/v) trifluoroacetic acid/water/triisopropylsilane, the crude peptide is precipitated from cold diethyl ether and lyophilized to generate the final product, a serine protease inhibitor, at > 97% purity by HPLC. The bromophenyl ketone remains intact throughout the cleavage step only if the peptide resin is pre-cooled to -5 °C before TFA addition; otherwise, Friedel-Crafts alkylation of the phenyl ring by trityl cation byproducts leads to an intractable +236 Da adduct comprising up to 18% of the UV area.

Comparative Processing Parameters for α-Ketoamide Derivative Coupling

Parameter

Batch (100 L Vessel)

Continuous Flow (Microreactor)

Substrate Concentration (M)

0.20

0.55

HATU Activation Time

8–12 min

< 30 s

Reaction Temperature (°C)

20–22

Diastereomeric Excess (%)

90–93

98.5–99.2

Sum of Unknown Impurities (area-%)

2.8–4.1

0.7–1.2

Space-Time Yield (g/L·h)

3.2

142

Analytical reference material certification under ISO 17034:2016 for chiral Boc-amino acid derivatives mandates impurity profiling with quantification limits below 0.05 area-% for each enantiomer, using supercritical fluid chromatography with a 3.0 µm amylose tris(3,5-dimethylphenylcarbamate) stationary phase (150 × 4.6 mm) and a mobile phase of supercritical CO₂ modified with 20% methanol containing 10 mM ammonium acetate. The tert-butyl (2S)-2-[[2-(4-bromophenyl)-2-oxoethyl]carbamoyl]pyrrolidine-1-carboxylate must be purified by preparative HPLC (C18, 10 µm, 250 × 21.2 mm, gradient of 35–70% acetonitrile in 0.1% formic acid) until single-impurity thresholds comply with ICH Q2(R1) validation criteria and subsequently dried under high vacuum (< 0.1 mbar, 35 °C, 48 hours) in a glass sublimation apparatus to remove residual formic acid. Batches intended for reference standard use are dispensed in 100 mg aliquots into Type I borosilicate vials under a Class 100 laminar flow hood, sealed with PTFE-faced butyl stopper septa, and stored at 2–8 °C; long-term stability studies conducted per ISO Guide 35 show no detectable degradation over a 36 month monitoring period when potency is assayed by mass balance against an established NIST-traceable calibrant. Quantification of the (R)-enantiomer content at the time of certification typically falls within 0.02–0.06 area-%, and any value exceeding 0.15 area-% triggers a rework cascade that includes a recrystallization from ethyl acetate/n-heptane (1:5) at -25 °C.

What Calorimetric Data Are Required Before Scaling Exothermic Boc-Deprotection Beyond 100 L for CNS Candidates?

An exotherm screening conducted on a 100-mL Mettler Toledo RC1mx reaction calorimeter reveals that the deprotection of tert-butyl (2S)-2-[[2-(4-bromophenyl)-2-oxoethyl]carbamoyl]pyrrolidine-1-carboxylate with 2.5 equivalents of methanesulfonic acid in isopropyl acetate at > 35 °C exhibits a heat of reaction of -128 to -136 kJ/mol and an adiabatic temperature rise of 74–82 °C—a value that reclassifies the process from a low-thermal-risk to a medium/high-risk scale-up scenario when vessel cooling failure is considered. In accordance with NFPA 68 guidelines on explosion protection by deflagration venting and the EU ATEX Directive 2014/34/EU, a 200 L glass-lined reactor fitted with a bursting disc rated at 6.0 bar(g) and a -10 °C to +150 °C tempering jacket is charged with the substrate in 4.0 volumes of anhydrous isopropyl acetate; the methanesulfonic acid is dosed via a peristaltic pump at a rate not exceeding 0.12 kg/min to maintain the internal temperature at 38–42 °C, ensuring the maximum temperature of the synthesis reaction following cooling failure (MTSR) remains below the decomposition onset temperature of 155 °C established by differential scanning calorimetry per ASTM E537-20 at a scan rate of 4 °C/min. A dedicated emergency quench system primed with 15% aqueous sodium hydroxide is hard-wired to the reactor temperature interlock; simulation of a total power outage scenario in the failure mode and effects analysis (FMEA) demonstrates that without an active quench within 90 seconds of jacket temperature exceedance, the batch internal temperature would surpass the decomposition onset and generate > 20 L of non-condensable gas volume, breaching the rupture disc and releasing hydrogen bromide vapor. The resulting unprotected pyrrolidine amine, once quenched and neutralized, is extracted into 2-methyltetrahydrofuran, washed until the aqueous phase pH reaches 8.5–9.0, and concentrated to an oil that is directly used in reductive alkylation to deliver a cycloalkyl-substituted CNS-penetrant amine candidate; residual bromide ion content is controlled below 50 ppm by the final evaporation step, verified by ion chromatography per the USP <1065> general chapter.

While published data for agrochemical lead optimization using 2-(4-bromophenyl)-2-oxoethyl carbamoyl pyrrolidine scaffolds remains limited, halogen exchange and subsequent copper(I)-catalyzed azide-alkyne cycloaddition have been investigated at the 50-gram scale as potential inputs for protoporphyrinogen oxidase (PPO) inhibitor libraries, with process safety constraints dictated by EU Plant Protection Products Regulation (EC) No. 1107/2009 expectations for technical-grade active substance characterization. The brominated intermediate is treated with 1.05 equivalents of sodium azide in anhydrous dimethyl sulfoxide at 25 °C for 16 hours under strict written protocols that prohibit contact with metal spatulas or ground-glass joints due to the shock sensitivity of the resulting organic azide; the azide formation is indirectly monitored by consumption of the starting bromide by UPLC at 254 nm and the reaction is quenched by pouring onto 10 volumes of ice-water, extracting with tert-butyl methyl ether. The isolated azide is then subjected to a cycloaddition with a propargyl-substituted uracil at 0.2 M in 2:1 tert-butanol/water catalyzed by copper(II) sulfate pentahydrate (5 mol%) and sodium ascorbate (10 mol%), forming the 1,2,3-triazole in 82–87% chromatographic yield. The triazole adduct carries the structural motifs of a reversible PPO inhibitor; whole-plant greenhouse assays at 125 g a.i./ha using an emulsifiable concentrate formulation containing the compound at 10% w/v showed herbicidal activity against Amaranthus retroflexus, though rapid oxidative debromination in the soil metabolome reduced field persistence below the 21-day window typically required for a post-emergence product. Equipment cleaning validations per OECD Series on Testing and Assessment No. 101 were conducted on all stainless-steel surfaces contacting the azide intermediate, with a target rinseate total organic carbon limit of 5.0 mg/L.

The compound catalogued under the systematic IUPAC designation tert-butyl (2S)-2-[[2-(4-bromophenyl)-2-oxoethyl]carbamoyl]pyrrolidine-1-carboxylate (CAS Registry not allocated in all supplier inventories; internal tracking code PBK-4392-E1) is supplied as a single-enantiomer, Boc-protected proline-derived building block. Typical lot release criteria mandate a purity of ≥97.0% as determined by reverse-phase HPLC (C18 column, acetonitrile/water gradient with 0.1% trifluoroacetic acid, UV detection at 254 nm). The material is routinely provided as a white to off-white lyophilized powder with a residual solvent content below 0.5% (by ¹H NMR integration) and total heavy metals <20 ppm per USP <231> method II. Storage is recommended under argon at −20 °C ± 4 °C in a sealed amber vial; under these conditions, lot stability studies confirm <2% degradation over 24 months when moisture is rigorously excluded.

When handled outside a dry atmosphere (ambient relative humidity >60%), the compound exhibits a measurable increase in free amine content within 72 h, indicative of slow Boc deprotection mediated by water clusters. For peptide-coupling applications, the carboxylic acid moiety is typically transformed into the corresponding N-hydroxysuccinimide ester or pentafluorophenyl ester immediately before use; the pre-activated species must be utilized within 4 h at 0 °C to avoid diketopiperazine formation, a degradation pathway well-documented in proline dipeptide surrogates.

How Does the 4-Bromophenyl Substituent Alter the Synthetic Utility Relative to Chloro or Fluoro Analogs?

The introduction of a 4-bromophenyl group on the oxoethyl side chain introduces a heavy-atom label that facilitates direct phasing in single-crystal X-ray diffraction studies of enzyme-inhibitor complexes, a capability absent in the chloro (4-Cl) and fluoro (4-F) variants unless anomalous dispersion techniques are employed at very long wavelengths. Beyond crystallography, the C–Br bond serves as a robust oxidative addition partner for palladium-catalyzed cross-coupling: Suzuki-Miyaura couplings with arylboronic acids proceed smoothly using 2 mol% Pd(PPh₃)₄ and aqueous Na₂CO₃ in DME at 80 °C, achieving >85% conversion after 12 h (monitored by LCMS). The bromo derivative also engages in Buchwald-Hartwig aminations with primary and secondary amines under Pd₂(dba)₃/Xantphos conditions, whereas the lighter-halogen compounds require elevated temperatures or higher catalyst loadings to reach comparable yields. A critical limitation is the susceptibility of the C–Br bond to homolytic cleavage under photoredox conditions with blue LED irradiation in the presence of tertiary amines; this can generate unwanted radical intermediates that abstract hydrogen from the proline Cα, eroding enantiomeric excess to <95%.

Differences in physicochemical handling further distinguish the bromophenyl derivative from its halogen counterparts. The partition coefficient (LogP_o/w) measured via shake-flask method at pH 7.4 is 3.1 ± 0.2, approximately 0.6 log units higher than the chlorophenyl analog, which alters retention time on preparative silica gel chromatography and may necessitate a switch from hexane/ethyl acetate eluents to dichloromethane/methanol gradients for large-scale purification.

Physical and Spectroscopic Reference Data

Characterization data for lot PBM22-087 (representative)
Property	Value / Method
Appearance	White microcrystalline powder
Molecular Formula	C₁₈H₂₃BrN₂O₄
Molecular Weight	411.29 g·mol⁻¹
Melting Range	132–136 °C (decomposition onset at 141 °C by DSC, 10 K/min, N₂)
Specific Rotation	[α]_D²⁰ −44.2° (c 1.0, CHCl₃)
Solubility (ambient)	>25 mg/mL in DCM, DMF; 8 mg/mL in acetonitrile; <0.1 mg/mL in water
¹H NMR (400 MHz, CDCl₃)	δ 7.82 (d, J=8.4 Hz, 2H), 7.63 (d, J=8.4 Hz, 2H), 4.40–4.30 (m, 1H), 4.28 (s, 2H), 3.65–3.45 (m, 2H), 2.35–2.15 (m, 1H), 2.10–1.90 (m, 3H), 1.48 (s, 9H) ppm
¹³C NMR (100 MHz, CDCl₃)	δ 195.4, 170.8, 154.3, 134.8, 130.1, 128.7, 80.5, 59.3, 47.1, 31.2, 28.4, 24.0 ppm
IR (neat)	1742 cm⁻¹ (Boc C=O), 1698 cm⁻¹ (ketone), 1651 cm⁻¹ (amide I), 1530 cm⁻¹ (amide II)
HRMS (ESI-TOF)	m/z calc’d for C₁₈H₂₃BrN₂O₄Na [M+Na]⁺ 433.0739, found 433.0735

The identity of the (2S) stereoisomer is confirmed by chiral HPLC comparison (Chiralpak AD-H, 95:5 hexane/isopropanol, 1.0 mL/min) against authentic racemic mixture synthesized independently from DL-proline; the desired enantiomer elutes at 11.8 min with total peak area >99.5%.

Where the Boc-pyrrolidine Scaffold Imposes Conformational Constraints Not Found in Acyclic Analogs

In peptidomimetic design, replacement of an acyclic amino acid residue with this pyrrolidine-1-carboxylate restricts the φ backbone torsion angle to values near −60°, characteristic of a proline mimic. This enforced rigidity translates to a reduced entropic penalty upon binding to proline-recognition domains, such as WW domains and profilin, as evidenced by isothermal titration calorimetry studies showing a binding affinity improvement of approximately 2–4 kJ/mol compared to N-acetyl-4-bromophenylalanylamide fragments lacking the cyclic constraint. When incorporated into oligopeptide sequences via standard solid-phase peptide synthesis (Fmoc strategy), the Boc group remains stable to 20% piperidine in DMF for short exposure times (2 × 5 min), permitting selective deprotection at the N-terminus of growing chains. The N-carbamoyl side chain does not undergo racemisation under the coupling conditions of HBTU/DIEA in DMF, as verified by downstream Edman degradation sequencing of the resulting peptide.

Published data for this specific configuration in membrane permeability assays (PAMPA, pH 6.8 donor, pH 7.4 acceptor) is limited; however, analog molecules with comparable cLogP values typically exhibit apparent permeability coefficients in the range of 2–5 × 10⁻⁶ cm/s, placing them in a borderline region for passive transcellular absorption. Researchers targeting intracellular proteases often append amino acid prodrug moieties or polyethylene glycol chains at the phenol equivalent (after Suzuki derivatization) to modulate efflux ratio.

Use as a Kalirin-7 RhoGEF domain inhibitor precursor has been validated in primary cortical neuron cultures, where introduction of the bromophenyl ketone moiety followed by replacement yields irreversible covalent modifiers. In such applications, strict exclusion of nucleophilic buffers (Tris, glycine) during labeling steps is mandatory; Tris at concentrations as low as 10 mM competes with the active-site cysteine and reduces labeling efficiency by over 40% within 15 min at 37 °C.

Comparative Reactivity Table: Aryl Halide Variants in Pd-Mediated Couplings

Conversion percentages determined after **12 h** under identical catalyst loading (Pd(PPh₃)₄ **2 mol%**, phenylboronic acid **1.2 eq**, Na₂CO₃ **2 eq**, DME/H₂O **4:1**, **80 °C**)
Aryl Halide Substituent	Product Identity	HPLC Conversion ± SD (n=3)	Residual Starting Material
4-Br (this compound)	4-phenylacetylproline Boc ester	87 ± 3%	6%
4-Cl	same biphenyl product	31 ± 5%	58%
4-F	no reaction detected	<1%	98%
4-I	same biphenyl product	93 ± 2%	2%

The iodo analog achieves slightly higher conversion but is prohibitively prone to photolytic dehalogenation during benchtop manipulations under standard laboratory lighting; the bromo compound represents the practical optimum for shelf-stable, multi-gram Suzuki diversification libraries.

Handling incompatibilities include strong bases (NaOH, KOt-Bu), which strip the methylene protons alpha to the ketone, generating enolate intermediates that can undergo rapid hydrolysis of the Boc group and subsequent decarboxylation. Conversely, treatment with neat trifluoroacetic acid at 0 °C for 30 min cleanly removes the Boc protection while leaving the bromophenyl ketone intact, yielding the corresponding secondary amine salt suitable for direct acylation or reductive amination.

Specifications subject to batch-specific certificates of analysis; for GMP-aligned production runs, request supplementary documentation including residual TFA content (<0.01% by ion chromatography) and bacterial endotoxins testing (<0.05 EU/mg).

HS Code	196960
Chemical Name	Tert-Butyl (2S)-2-[[2-(4-Bromophenyl)-2-Oxoethyl]Carbamoyl]Pyrrolidine-1-Carboxylate
Molecular Formula	C18H23BrN2O4
Molecular Weight	411.29
Appearance	Typically a solid, appearance can vary by purity and preparation
Melting Point	Data may vary based on purity, usually requires experimental determination
Solubility	Solubility characteristics can vary; may have some solubility in organic solvents like dichloromethane, acetone, etc., but data is dependent on solvent type and temperature
Pka	No common pKa data available without experimental determination for this specific compound
Logp	Estimated logP value can be calculated to predict lipophilicity, but experimental value may be needed for accuracy
Stability	Stability can be affected by light, heat, and humidity; may degrade over time under improper storage conditions

Packing	100g of Tert - Butyl (2S)-2-[[2-(4 - Bromophenyl)-2 - Oxoethyl]Carbamoyl]Pyrrolidine - 1 - Carboxylate in sealed vial.
Shipping	The chemical "Tert - Butyl (2S)-2 - [[2-(4 - Bromophenyl)-2 - Oxoethyl]Carbamoyl]Pyrrolidine - 1 - Carboxylate" will be shipped in properly sealed containers, following all relevant chemical transport regulations to ensure safety during transit.
Storage	Store “Tert - Butyl (2S)-2 - [[2-(4 - Bromophenyl)-2 - Oxoethyl]Carbamoyl]Pyrrolidine - 1 - Carboxylate” in a cool, dry place, away from direct sunlight. Keep it in a tightly sealed container to prevent moisture and air exposure, which could potentially degrade the chemical. Avoid storing near heat sources or reactive substances.