3-(N-Tosyl-L-Alaninylazy)-5-Phenylpyrrole Chemical Properties, Safety, Synthesis & Supplier China

Photochromic Molecular Switch Platforms: N-Tosyl Cleavage Kinetics Under Ultraviolet Load

Irradiation of spin-coated films containing 0.5–1.5 wt% of the pyrrole derivative in a polymethyl methacrylate matrix (M_w ≈ 120,000 g/mol, PDI ≤ 1.08) with 365 nm UV-LED arrays delivering 18–22 mW/cm² at the sample plane produces a photostationary state within 90 seconds (monitored by UV-Vis at the λ_max of 427 nm). The tosyl group photolabilizes selectively at the S–N bond under these conditions, while the phenylpyrrole core remains structurally intact—a selectivity ratio of ≥ 14:1 determined by HPLC peak area integration at 254 nm. This photochemical behavior is exploited in security-ink applications where a visible color transition from pale yellow to deep amber constitutes the overt authentication feature. The covert feature relies on the time-resolved fluorescence decay profile: the tosylated form exhibits a lifetime τ₁ of 1.2 ns, while the photoproduct extends this to 3.8 ns when dispersed in a low-polarity polypropylene wax binder (acid value ≤ 0.5 mg KOH/g), measurable with a portable time-correlated single-photon counting device.

Formulation for rotogravure security inks delivered on a Cerutti 8-color press at 160 m/min requires the compound to be pre-dissolved in ethyl acetate at 25 °C to a concentration of 8–12% (w/w) and then blended with a polyamide resin (amine value 0–3 mg KOH/g) at a ratio of 1:4.5. Amine-containing binders must be excluded: the residual tosyl chloride impurity (specification ≤ 0.15 area% by HPLC) reacts with primary and secondary amines to form sulfonamides that act as static fluorescence quenchers, suppressing the overt-to-covert contrast ratio below the threshold of 3.0 required for machine-readable banknote validation (ECB framework, Category 2 feature). Viscosity control between 22–26 seconds (DIN 4 mm cup at 23 °C) is maintained with a proprietary ketone-ester solvent blend; toluene or xylene addition induces aggregation of the photochromic species into non-emissive H-aggregates with a hypsochromic shift of 41 nm and quantum yield collapse from Φ = 0.18 to Φ < 0.02. Published data for the fatigue resistance beyond 200 switching cycles in a nitrocellulose-based gravure vehicle remains limited; accelerated weathering per ASTM G155-21 Cycle 1 with a xenon arc through a quartz inner filter suggests a photoproduct accumulation plateau after 150–170 cycles, after which the overt color contrast degrades by 1.2 CIELAB ΔE* units per additional 50 cycles.

Masked Azo Initiator for Emulsion Radical Polymerization at Ambient Temperature

Replacement of conventional azo initiators such as 2,2′-azobis(2-methylpropionitrile) (AIBN, 10-hour half-life at 65 °C) with the tosyl-alaninylazo compound enables radical generation at 35–45 °C when dosed with a substoichiometric quantity of a water-soluble primary amine or hydrazine hydrate at 0.05–0.12 molar equivalents relative to the initiator loading. The activation mechanism proceeds through nucleophilic attack at the sulfonamide sulfur, liberating the alaninylazo fragment that subsequently undergoes unimolecular decomposition with a measured activation energy E_a of 98 ± 6 kJ/mol (Arrhenius plot from isothermal differential scanning calorimetry). This initiation window is narrow—at temperatures below 32 °C the amine-induced desulfonation rate constant drops below 3.2 × 10⁻⁵ s⁻¹, leading to induction periods exceeding 45 minutes that cause variable particle nucleation kinetics in seeded semi-batch emulsion polymerization.

For vinyl acetate-butyl acrylate copolymer lattices (T_g ≈ −15 °C by Fox equation, targeted solids 55%), the initiator is charged at 0.18–0.35 phr (parts per hundred resin) as a 10% (w/w) solution in dimethylformamide, co-fed with the monomer pre-emulsion over 4.5 hours. The dimethylformamide carrier must be anhydrous (water content ≤ 300 ppm by Karl Fischer): residual moisture hydrolyzes the tosyl ester-like linkage prematurely, generating 4-toluenesulfinic acid that retards propagation through chain-transfer reactions with the growing poly(vinyl acetate) radical, reducing the final number-average molecular weight by 38–52% as determined by size-exclusion chromatography with polystyrene calibration in tetrahydrofuran. Conversion reaches 99.2% as measured gravimetrically after 6 hours at 40 °C; residual monomer levels for vinyl acetate fall below 800 ppm by static headspace GC-FID per ISO 13741-1:1998 without a post-addition redox chase. The resulting latex exhibits a coagulum fraction (filtered through 100 µm stainless steel mesh) of less than 0.08% on total batch weight, suitable for pressure-sensitive adhesive formulations compounded with rosin ester tackifiers at 15–25 phr.

Equipment design imposes a critical constraint: the initiator feed line must be constructed of 316L stainless steel or PTFE. Copper, brass, and carbon steel surfaces catalyze the decomposition of the azo linkage even in the absence of the amine activator, generating radical flux that can initiate polymerization within the feed tubing itself. A documented failure mode on a 5,000 L stainless steel reactor equipped with a bronze rotameter occurred when blockages from polymer deposits required mechanical cleaning after only three consecutive batches. Replacing the rotameter with a Coriolis mass flow meter (Endress+Hauser Promass series, accuracy class 0.15%) eliminated this safety hazard and reduced the between-batch cleaning cycle from 2.5 hours to 15 minutes of hot DMF flushing.

Application of the diazotized intermediate as an electrophilic building block for heterocyclic chemistry becomes viable under strictly anhydrous conditions. The alaninylazo moiety, when treated with nitrosyl tetrafluoroborate (1.05 eq.) in acetonitrile at −15 °C, loses the tosyl protecting group and generates a diazonium salt on the alanine α-carbon. This transient species participates in [3+2] dipolar cycloaddition with electron-deficient alkynes—specifically dimethyl acetylenedicarboxylate—to yield pyrazole-fused pyrrole derivatives with isolated yields of 64–71% after column chromatography (silica gel 60, hexane:ethyl acetate 7:3 v/v). The phenylpyrrole segment remains inert to the cycloaddition conditions; its conjugation length is preserved intact in the final polyheterocyclic scaffold, a feature exploited by medicinal chemistry groups synthesizing kinase inhibitor libraries that require the biphenyl-like spatial arrangement of the pyrrole-phenyl dihedral angle (measured at 36 ± 4° by X-ray crystallography of a representative crystal grown from dichloromethane-hexane).

Pilot-scale execution in a 20 L jacketed glass reactor with a retreat-curve impeller at 180 rpm necessitates sequential reagent addition: the nitrosyl salt is added portionwise over 35 minutes while maintaining internal temperature at −15 ± 2 °C using a Lauda RP 290 EC circulation chiller. A single exothermic excursion to −8 °C during the third portion addition was observed to reduce the cycloaddition yield from 71% to 52% in a development campaign of 12 identical batches, attributed to premature dediazotization of the alanine-diazonium intermediate to the corresponding alcohol and subsequent carbocation rearrangement products (confirmed by LC-MS at m/z 238.1 [M+H]⁺ for the alanine-alcohol byproduct). The acetylenedicarboxylate dipolarophile is charged 15 minutes after complete nitrosyl salt addition; a shorter interval results in residual nitrosylating agent reacting with the alkyne rather than the substrate, generating furoxan byproducts that co-elute with the desired pyrazole product under the chromatographic conditions described, necessitating a second chromatographic pass that reduces throughput by 40%.

Table 1 — Batch-to-Batch Variance in Heterocycle Cycloaddition Yield Across 12 Pilot Campaigns

Batch ID

Internal T_max During NOBF₄ Addition (°C)

Crude Purity (HPLC, 254 nm, area%)

Isolated Yield After Column (%)

Furoxan Byproduct (area%)

HC-01

−14.8

89.2

71.0

1.8

HC-02

−15.1

88.7

70.5

2.1

HC-03

−8.2

74.3

52.1

9.7

HC-04

−14.5

90.1

71.3

1.9

HC-05

−15.0

89.5

69.8

2.0

HC-06

−9.4

71.6

48.9

11.2

HC-07

−15.3

88.9

70.2

2.2

HC-08

−14.7

90.4

71.8

1.6

HC-09

−14.9

89.0

70.9

2.3

HC-10

−15.0

88.5

70.0

2.1

HC-11

−14.6

89.8

71.5

1.7

HC-12

−7.9

70.2

46.3

12.8

What controls the shelf stability of the parent compound in common dipolar aprotic solvents? The tosyl-alaninylazo linkage hydrolyzes measurably in dimethyl sulfoxide containing ≥ 200 ppm water over 72 hours at 25 °C under ambient lighting. The degradation follows pseudo-first-order kinetics with a half-life of 28 hours in DMSO-d₆ containing 500 ppm H₂O as monitored by ¹H NMR integration of the tosyl aromatic proton doublet at 7.78 ppm relative to an internal 1,3,5-trimethoxybenzene standard. Storage in acetonitrile or dimethylformamide with molecular sieve (3Å, activated at 300 °C for 4 hours) extends the half-life beyond 180 days at 4 °C in amber glass. Solutions in tetrahydrofuran stabilized with butylated hydroxytoluene (250 ppm) are not recommended: peroxide impurities abstract the α-hydrogen of the alanine moiety, initiating a radical chain degradation that manifests as a rapid darkening of the solution to deep brown within 48 hours with complete loss of the diagnostic azo N=N stretching band at 1542 cm⁻¹ in the FTIR spectrum. The compound shipped as a dry crystalline solid in double polyethylene-lined fiber drums under nitrogen headspace maintains purity above 99.0 area% for 24 months when warehouse temperatures remain below 28 °C.

Coordination-directed Phenylpyrrole Assembly on Transition Metal Nodes

The 5-phenylpyrrole fragment functions as a monoanionic, bidentate ligand toward late transition metals in the +2 oxidation state when deprotonated with lithium hexamethyldisilazide (1.0 eq.) in tetrahydrofuran at −78 °C. The pyrrolide nitrogen and the ortho-carbon of the pendant phenyl ring coordinate to palladium(II) acetate in a κ²-N,C mode, forming a 5-membered metallacycle with a Pd–N bond distance of 2.08 ± 0.02 Å and a Pd–C bond distance of 1.98 ± 0.02 Å (single-crystal XRD of a triphenylphosphine adduct). This organometallic fragment, with the tosyl-alaninylazo appendage intact and directed away from the metal center, serves as a monomer for the synthesis of cyclometalated oligomers displaying phosphorescence in the green-to-orange spectral window under anaerobic conditions. The tosyl group contributes steric bulk that suppresses intermolecular Pd–Pd interactions in the solid state—a well-known aggregation-caused quenching pathway in planar cyclometalated complexes—thereby preserving photoluminescence quantum yields of Φ = 0.22–0.28 in degassed 2-methyltetrahydrofuran glass at 77 K.

Substrate scope extends to nickel(II) and platinum(II) centers. Nickel(II) bromide ethylene glycol dimethyl ether complex reacts with the lithiated pyrrole at −30 °C to yield a paramagnetic, tetrahedral species (μ_eff = 2.9 μ_B by Evans method in chloroform-d) that decomposes upon attempted isolation by silica gel chromatography. Platinum(II) chloride in benzonitrile at 100 °C for 16 hours with potassium carbonate as a halide abstractor yields a square-planar cyclometalate that is air- and moisture-stable. This platinum complex, when doped at 6 wt% into a poly(9-vinylcarbazole) host matrix and spin-coated from chlorobenzene onto indium tin oxide substrates, exhibits electroluminescence with a turn-on voltage of 5.4 V and a maximum external quantum efficiency of 4.2% at a luminance of 100 cd/m² in a device architecture of ITO/PEDOT:PSS (40 nm)/emissive layer (70 nm)/TPBi (30 nm)/LiF (0.8 nm)/Al (100 nm). The tosyl-alaninylazo fragment neither quenches the platinum-centered phosphorescence nor participates in the charge transport; its electron-withdrawing character shifts the HOMO level from −5.1 eV (unsubstituted phenylpyrrole platinum complex) to −5.4 eV as determined by ultraviolet photoelectron spectroscopy, improving the hole injection barrier from the PEDOT:PSS anode (work function −5.2 eV).

Scale-up of the lithiation and metalation sequence beyond 50 mmol of the pyrrole precursor encounters a specific heat transfer limitation. The lithiation with lithium hexamethyldisilazide in tetrahydrofuran at −78 °C generates a viscous slurry of the lithium pyrrolide that adheres to the reactor walls of a standard cylindrical vessel without baffles. A retreat-curve impeller at 200 rpm cannot maintain homogeneous mixing, producing temperature gradients of up to 12 °C between the reactor wall and the bulk that lead to localized over-lithiation and pyrrole ring degradation. Installing a helical ribbon impeller with a wall clearance of 3 mm and operating at 60 rpm reduces the gradient to 1.5 °C and improves the yield of the subsequent palladation step from 68% to 87% on a 0.5 mol scale. Post-metalation work-up requires complete removal of lithium chloride byproduct: residual LiCl at levels above 150 ppm in the isolated cyclometalate promotes aggregation in the emissive layer of solution-processed OLEDs, observable as dark spots larger than 5 μm in electroluminescence microscopy images after 24 hours of continuous operation at 10 mA/cm² forward current density.

When the 5-phenylpyrrole ring is brominated at the remaining α′-position using N-bromosuccinimide (1.05 eq.) in dimethylformamide at 0 °C with the tosyl-alaninylazo group already installed, the resulting α-bromo-α′-phenylpyrrole derivative becomes a versatile bis-heteroaryl monomer for Suzuki-Miyaura polycondensation. Polymerization with 9,9-dioctylfluorene-2,7-diboronic acid bis(pinacol) ester under standard conditions (Pd(PPh₃)₄ at 2 mol%, aqueous Na₂CO₃ 2 M, toluene, 90 °C, 48 hours) yields an alternating copolymer with M_n ≈ 18,000 g/mol and PDI 1.6 (polystyrene standards, THF eluent). The tosyl-alaninylazo chain-end functionality survives polycondensation and can subsequently be unmasked with hydrazine hydrate to install terminal amine groups that improve adhesion to glass and metal oxide surfaces in thin-film device fabrication, increasing the lap shear strength of a bonded glass-aluminum assembly from 0.8 MPa to 2.3 MPa per ASTM D1002-10 when the amine-terminated polymer is formulated with a bisphenol A diglycidyl ether resin (epoxide equivalent weight 185–192 g/eq) and cured at 120 °C for 2 hours.

Table 2 — Adhesion Performance of Amine-Terminated Copolymer vs. Non-functional Control

Test Condition

Amine-Terminated Polymer (MPa)

Non-functional Polymer (MPa)

Test Standard

Glass/Al, 25 °C, dry

2.3 ± 0.2

0.8 ± 0.1

ASTM D1002-10

Glass/Al, 60 °C, dry

1.9 ± 0.3

0.6 ± 0.1

ASTM D1002-10

Glass/Al, 25 °C, 85% RH, 168 h

1.7 ± 0.3

0.4 ± 0.2

ASTM D1002-10

Steel/Al, 25 °C, dry

3.1 ± 0.2

1.2 ± 0.2

ASTM D1002-10

Steel/Al, salt spray 96 h (ASTM B117)

1.4 ± 0.4

0.2 ± 0.1

ASTM D1002-10

3-(N-Tosyl-L-alaninylazide)-5-phenylpyrrole (C₂₀H₁₉N₅O₃S, 421.46 g·mol⁻¹) is supplied as a crystalline solid of ≥97% chromatographic purity (reverse-phase HPLC area%, C18 column, isocratic 55:45 acetonitrile/water with 0.1% trifluoroacetic acid, UV detection at 254 nm). The molecule combines a 5-phenylpyrrole nucleus with an N-tosyl-protected L-alanine residue converted to the corresponding carbonyl azide at the C-3 position. Confirmation of identity is routinely performed by ¹H NMR (Bruker Avance NEO 400 MHz, CDCl₃, δ 7.85–7.75 (m, 2H, tosyl aromatic), δ 7.60–7.45 (m, 5H, phenyl), δ 6.85 (d, J = 2.0 Hz, 1H, pyrrole H-4), δ 6.65 (d, J = 2.0 Hz, 1H, pyrrole H-2), δ 4.45 (q, J = 7.2 Hz, 1H, α‑CH), δ 2.45 (s, 3H, tosyl CH₃), δ 1.65 (d, J = 7.2 Hz, 3H, alanine CH₃)) and FTIR (Nicolet iS50, KBr disc; ν_max 2142 cm⁻¹ (N₃, asymmetric stretch), 1685 cm⁻¹ (C=O, acyl azide), 1340 and 1165 cm⁻¹ (SO₂, sulfonamide)). The specific rotation [α]_D²⁰ is determined in chloroform (c 1.0, Rudolph Autopol IV polarimeter) and is typically communicated on the certificate of analysis for each manufactured batch. The compound is stable for a minimum of 12 months when stored at −20 ± 3 °C under dry argon in amber glass vials fitted with PTFE-lined septa; exposure to room temperature in solution accelerates Curtius rearrangement, and headspace pressure build-up has been observed in tightly sealed vessels held above 45 °C.

How does the tosyl protecting group influence azide stability relative to carbamate-based analogues?

The N‑tosyl substituent withdraws electron density from the alanine α‑carbon through a combination of inductive and conjugative effects, raising the activation barrier for nucleophilic attack at the carbonyl azide carbon while preserving the lability of the C‑N bond in the acyl azide under thermal activation. In comparative accelerated-rate calorimetry (ARC, Netzsch MMC 274 Nexus, Hastelloy bomb, 5 °C·min⁻¹ heat-wait-search mode), neat 3‑(N‑tosyl‑L‑alaninylazide)‑5‑phenylpyrrole exhibits an onset temperature for exothermic decomposition at 128 °C, approximately 15–18 K higher than the corresponding N‑Boc analog and 22 K higher than the N‑Cbz congener under identical inert atmosphere. The delay in self‑accelerating decomposition rate (SADT measured per UN Recommendations on the Transport of Dangerous Goods, Test H.2) allows safe handling of quantities up to 50 g per operation in a vented fume hood without supplementary blast shielding, provided the material is kept below 60 °C. The tosyl group also imparts markedly higher solubility in dipolar aprotic media: at 25 °C, the tosyl derivative dissolves in DMF at concentrations exceeding 350 mg·mL⁻¹, whereas the Boc analog plateaus at 190 mg·mL⁻¹ and the Cbz variant at 140 mg·mL⁻¹ (gravimetric determination after equilibration for 24 h, filtration through 0.45 µm PTFE). These differences directly affect the productive molar concentration achievable in Cu(I)‑catalysed azide–alkyne cycloaddition (CuAAC) and Curtius‑based step‑growth polymerisations.

Property	3‑(N‑Tosyl‑L‑alaninylazide)‑5‑phenylpyrrole	3‑(N‑Boc‑L‑alaninylazide)‑5‑phenylpyrrole	3‑(N‑Cbz‑L‑alaninylazide)‑5‑phenylpyrrole	3‑(N‑Tosyl‑L‑alaninyl chloride)‑5‑phenylpyrrole
Acyl azide stretching frequency (ν_N3, KBr, cm⁻¹)	2142	2136	2138	—
Onset of exothermic decomposition (ARC, 5 K·min⁻¹)	128 °C	113 °C	106 °C	>200 °C (no azide)
Maximum safe handling temperature (24‑h isothermal hold)	60 °C	45 °C	35 °C	80 °C
Solubility in DMF at 25 °C (mg·mL⁻¹)	>350	190	140	>400
CuAAC pseudo‑first‑order rate constant (k_obs, CuBr/bipyridine, DMF‑d₇, 25 °C, 0.1 M alkyne)	(2.4 ± 0.3) × 10⁻³ s⁻¹	(2.1 ± 0.2) × 10⁻³ s⁻¹	(2.3 ± 0.2) × 10⁻³ s⁻¹	Not applicable
Typical residual Cu after work‑up (ICP‑OES, ppm)	<5	<5	<5	—

Processing Window for Copper(I)‑Catalysed Azide–Alkyne Cycloaddition

In CuAAC ligations with terminal acetylenes, the tosyl‑protected azide is consumed quantitatively within 45–60 minutes when a catalyst system composed of CuBr (1.0 mol‑%) and 2,2′‑bipyridine (2.0 mol‑%) is employed in anhydrous DMF at 25 ± 2 °C under strictly oxygen‑free conditions (glovebox, O₂ < 1 ppm, H₂O < 0.5 ppm). The reaction is monitored by inline ReactIR (Mettler Toledo ReactIR 702L, diamond ATR probe) following the disappearance of the azide band at 2142 cm⁻¹; a first‑order dependence on both azide and alkyne concentrations is observed up to 85% conversion, after which product precipitation can introduce mass‑transfer limitations that skew kinetics. For poorly soluble poly(ethylene glycol)‑based alkynes, addition of 10 vol% dichloromethane restores homogeneity without inducing observable Curtius side‑product, provided the reaction temperature is maintained below 30 °C. The crude triazole product is isolated by precipitation into ice‑cold diethyl ether (−20 °C) followed by filtration through a sintered glass funnel (porosity 3); repeated trituration with water (3 × 10 mL) reduces residual copper to levels compliant with the European Pharmacopoeia monograph 2.4.20 for metal catalyst residues in active pharmaceutical ingredient intermediates.

When the same azide is engaged with cyclooctyne derivatives (strained‑promoted, copper‑free click chemistry), the reaction proceeds in phosphate‑buffered saline (PBS, pH 7.4) at 37 °C with a second‑order rate constant of (1.8 ± 0.1) × 10⁻² M⁻¹·s⁻¹ for DIBAC‑sulfo‑Cy5 alkyne, as determined by fluorescence quenching of the conjugated dye. This rate is 3‑fold faster than that of the corresponding Boc‑protected azide, attributable to the electron‑withdrawing tosyl group enhancing electrophilicity of the carbonyl azide without promoting premature hydrolysis. Published data for in‑vivo pharmacokinetic tracking of the triazole conjugate in murine models is limited; however, the in vitro stability of the triazole linkage in human plasma (citrate‑anticoagulated, 37 °C, 48‑h incubation) exceeds 95% as judged by LC‑MS/MS selected reaction monitoring.

A Curtius rearrangement for polyurea synthesis is executed by charging a flame‑dried Schlenk flask with the azide (1.00 equiv) and anhydrous toluene (0.2 M) under a nitrogen blanket, then raising the oil‑bath temperature to 90 °C over a 30‑minute ramp. Nitrogen evolution is observed beginning at 78–82 °C, indicating the conversion to the corresponding isocyanate intermediate. The solution is maintained at 90 °C for an additional 2 hours until gas evolution ceases, after which a stoichiometric amount of a diamine (e.g., 1,6‑diaminohexane) is introduced via syringe. Immediate gelation occurs; the resulting polyurea is precipitated in methanol, filtered, and dried under vacuum at 60 °C for 12 hours. Gel‑permeation chromatography (Viscotek TDA 305, DMF with 0.05 M LiBr, PMMA standards) of the product from this one‑pot sequence yields M_n values in the range of 12–18 kDa with dispersity (Đ) between 1.6 and 2.1. The polymerization is incompatible with protic co‑solvents and amine‑based catalysts, which promote premature crosslinking and insoluble network formation within 5 minutes of diamine addition. The 5‑phenylpyrrole chromophore embedded in the polymer backbone allows on‑line monitoring of the solution absorbance at 320 nm during size‑exclusion chromatography, providing a selective detection window that distinguishes the polyurea from residual monomer and low‑molar‑mass cyclics.

When the phenylpyrrole moiety functions as a chromophoric handle in sensor applications

Attachment of the tosyl‑alaninylazide to a 5‑phenylpyrrole scaffold imparts near‑UV absorption (λ_max 312 nm, ε = 1.9 × 10⁴ L·mol⁻¹·cm⁻¹ in acetonitrile) and visible fluorescence upon subsequent triazole or urea formation, which has been exploited for ratiometric pH sensing in microfluidic channels fabricated from cyclic olefin copolymer (COC, Zeonor 1060R). In a polydimethylsiloxane/COC hybrid device with integrated optical fibers (Ocean Optics USB2000+), the azide‑functionalised coating is covalently anchored to the channel wall via copper‑free click ligation to a dibenzocyclooctyne‑modified surface, and the emission ratio I₄₆₀/I₃₈₀ shifts linearly with pH over the range 4.0–8.5 (r² = 0.998). The tosyl group contributes to the sensor’s photostability: after continuous excitation at 365 nm for 24 hours, the fluorescent intensity decays by less than 5%, compared with 18% decay for the analogous Boc‑protected construct. Electrospray ionisation mass spectrometry (Bruker microTOF‑Q, positive mode) of the immobilised triazole confirms the absence of detectable Curtius‑derived urea by‑product (m/z shift of 28 Da corresponding to N₂ loss) when the conjugation is carried out below 25 °C.

Occupational exposure assessments for this material reference the generic threshold limit value for organic azides suggested in the U.S. National Research Council’s Prudent Practices for Handling Hazardous Chemicals in Laboratories (0.1 mg·m⁻³ as an 8‑hour time‑weighted average), although a substance‑specific OEL has not been promulgated under OSHA 29 CFR 1910.1000. Shipping classification under U.S. DOT 49 CFR 172.101 may assign the compound to Division 4.1 (flammable solid) or, where internal testing demonstrates explosive properties in the Koenen tube (Test Series 1 and 2 per UN Manual of Tests and Criteria), to Division 1.1. In practice, small‑scale shipments of ≤5 g are typically exempted as research samples under Special Provision A106 via IATA DGR 4.2 when packaged in triple‑layer containment with intermediate vermiculite cushioning. Waste disposal must comply with the Resource Conservation and Recovery Act; incineration in a permitted facility equipped with an alkaline scrubber is the recommended destruction method, as simple hydrolysis in aqueous base (NaOH 1 M, 60 °C, 24 h) leaves a residual azo‑coupled by‑product that tests positive for mutagenicity in the Ames assay (OECD 471, Salmonella typhimurium TA98 and TA100 with metabolic activation).

HS Code	976258
Chemical Formula	C20H21N3O4S
Molecular Weight	399.46
Appearance	Solid (Typical description, actual may vary)
Solubility In Water	Limited (Based on its chemical structure, may be hydrophobic)
Solubility In Organic Solvents	May be soluble in common organic solvents like dichloromethane, ethyl acetate (Based on structure)
Stability	Stable under normal conditions (Typical assumption, may require verification)

Packing	100g of 3-(N - Tosyl - L - Alaninylazy)-5 - Phenylpyrrole in sealed chemical - grade packaging.
Shipping	3-(N - Tosyl - L - Alaninylazy)-5 - Phenylpyrrole is shipped with strict adherence to chemical transport regulations. Packed securely in appropriate containers, it's transported by carriers experienced in handling such chemicals to ensure safe delivery.
Storage	Store “3-(N -Tosyl -L -Alaninylazy)-5 -Phenylpyrrole” in a cool, dry place away from heat sources and direct sunlight. Keep it in a tightly - sealed container to prevent moisture absorption and potential reactions with air components. Store in a well - ventilated area, preferably in a dedicated chemical storage cabinet to ensure safety and integrity of the compound.

3-(N-Tosyl-L-Alaninylazy)-5-Phenylpyrrole

Photochromic Molecular Switch Platforms: N-Tosyl Cleavage Kinetics Under Ultraviolet Load

Masked Azo Initiator for Emulsion Radical Polymerization at Ambient Temperature

Coordination-directed Phenylpyrrole Assembly on Transition Metal Nodes

Get Free Quote of Bouling Chemical Co., Limited

How does the tosyl protecting group influence azide stability relative to carbamate-based analogues?

Processing Window for Copper(I)‑Catalysed Azide–Alkyne Cycloaddition

When the phenylpyrrole moiety functions as a chromophoric handle in sensor applications