Visual Sensor Array for Multiple Aromatic Amines via Specific Ascorbic Acid Oxidase Mimic Triggered Schiff-Base Chemistry.

Redox nanozymes have exhibited various applications in recognizing environmental pollutants but not aromatic amines (a type of typical pollutant). Herein, with Cu2+ as a node and tryptophan (Trp) as a linker, Cu-Trp as a specific ascorbic acid oxidase mimic was synthesized, which could catalyze ascorbic acid (AA) oxidation to dehydroascorbic acid (DHAA). Alternatively, with other natural amino acids as linkers to synthesize Cu-based nanozymes, such catalytic performances are also observed. The as-produced DHAA could react with o-phenylenediamine (OPD) and its derivatives (2,3-naphthalene diamine (NDA), 4-nitro-o-phenylenediamine (4-NO2-OPD), 4-fluoro-o-phenylenediamine (4-F-OPD), 4-chloro-o-phenylenediamine(4-Cl-OPD), and 4-bromo-o-phenylenediamine(4-Br-OPD)) to form a Schiff base and emit fluorescence. Based on the results, with Cu-Trp + AA and Cu-Arg (with arginine (Arg) as a linker) + AA as two sensing channels and extracted red, green, and blue (RGB) values from emitted fluorescence as read-out signals, a visual sensor array was constructed to efficiently distinguish OPD, NDA, 4-NO2-OPD, 4-F-OPD, 4-Cl-OPD, and 4-Br-OPD as low as 10 µM. Such detecting performance was further confirmed through discriminating binary, ternary, quinary, and senary mixtures with various concentration ratios, recognizing 18 unknown samples, and even quantitatively analyzing single aromatic amine. Finally, the discriminating ability was further validated in environmental waters, providing an efficient assay for large-scale scanning levels of multiple aromatic amines.

Dual-Functionalized Mesoporous Silica Nanoparticles for Celecoxib Delivery: Amine Grafting and Imidazolyl PEI Gatekeepers for Enhanced Loading and Controlled Release with Reduced Toxicity.

The development of targeted drug delivery systems has been a pivotal area in nanomedicine, addressing challenges like low drug loading capacity, uncontrolled release, and systemic toxicity. This study aims to develop and evaluate dual-functionalized mesoporous silica nanoparticles (MSN) for targeted delivery of celecoxib, enhancing drug loading, achieving controlled release, and reducing systemic toxicity through amine grafting and imidazolyl polyethyleneimine (PEI) gatekeepers. MSN were synthesized using the sol-gel method and functionalized with (3-aminopropyl) triethoxysilane (APTES) to create amine-grafted MSN (MSN-NH2). Celecoxib was loaded into MSN-NH2, followed by conjugation of imidazole-functionalized PEI (IP) gatekeepers synthesized via carbodiimide coupling. Characterization was conducted using Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR). Drug loading capacity, entrapment efficiency, and in vitro drug release at pH 5.5 and 7.4 were evaluated. Cytotoxicity was assessed using the MTT assay on RAW 264.7 macrophages. The synthesized IP was confirmed by FTIR and 1H-NMR. Amine-grafted MSN demonstrated a celecoxib loading capacity of 12.91 ± 2.02%, 2.1 times higher than non-functionalized MSN. In vitro release studies showed pH-responsive behavior with significantly higher celecoxib release from MSN-NH2-celecoxib-IP at pH 5.5 compared to pH 7.4, achieving a 33% increase in release rate within 2 h. Cytotoxicity tests indicated significantly higher cell viability for IP-treated cells compared to PEI-treated cells, confirming reduced toxicity. The dual-functionalization of MSN with amine grafting and imidazolyl PEI gatekeepers enhances celecoxib loading and provides controlled pH-responsive drug release while reducing systemic toxicity. These findings highlight the potential of this advanced drug delivery system for targeted anti-inflammatory and anticancer therapies.

Nano-anticoagulant based on carrier-free low molecular weight heparin and octadecylamine with an albumin shuttling effect.

Low-molecular-weight heparin (LMWH), derived from unfractionated heparin (UFH), has enhanced anticoagulant efficacy, long duration of action, and extended half-life. Patients receiving LMWH for preventive therapies would strongly benefit from its long-term effects, however, achieving this is challenging. Here, we design and evaluate a nanoengineered LMWH and octadecylamine conjugate (LMHO) that can act for a long time while maintaining close to 97 ± 3% of LMWH activity via end-specific conjugation of the reducing end of LMWH. LMHO can self-assemble into nanoparticles with an average size of 105 ± 1.7 nm in water without any nanocarrier and can be combined with serum albumin, resulting in a lipid-based albumin shuttling effect. Such molecules can circulate in the bloodstream for 4-5 days. We corroborate the self-assembly capability of LMHO and its interaction with albumin through molecular dynamics (MD) simulations and transmission electron microscopy (TEM) analysis. This innovative approach to carrier-free polysaccharide delivery, enhanced by nanoengineered albumin shuttling, represents a promising platform to address limitations in conventional therapies.

α,ß-Desaturation and Formal ß-C(sp3)-H Fluorination of N-Substituted Amines: A Late-Stage Functionalization Strategy Enabled by Electrochemistry.

Incorporation of C(sp3)-F bonds in biologically active compounds is a common strategy employed in medicinal and agricultural chemistry to tune pharmacokinetic and pharmacodynamic properties. Due to the limited number of robust strategies for C(sp3)-H fluorination of complex molecules, time-consuming de novo syntheses of such fluorinated analogs are typically required, representing a major bottleneck in the drug discovery process. In this work, we present a general and operationally simple strategy for site-specific ß-C(sp3)-H fluorination of amine derivatives including carbamates, amides, and sulfonamides, which is compatible with a wide range of functional groups including N-heteroarenes. In this approach, an improved electrochemical Shono oxidation is used to set the site of functionalization via net α,ß-desaturation to access enamine derivatives. We further developed a series of new transformations of these enamine intermediates to synthesize a variety of ß-fluoro-α-functionalized structures, allowing efficient access to pertinent targets to accelerate drug discovery campaigns.

Development of modular polymeric nanoparticles for drug delivery using amine reactive chemistry.

Curcumin has been explored for its anti-cancer potential, but is severely limited by its hydrophobicity and sensitivity to light and water. In this study, poly (lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) were synthesized to encapsulate curcumin via single emulsion method to improve curcumin stability and bioavailability. The PLGA NPs were coated with oligomeric chitosan (COS) and RGD peptide (a peptide consisting of Arg-Gly-Asp) using amine-reactive chemistry (NHS and EDC). Both COS and RGD had been previously shown to accumulate and target many different types of cancer cells. NPs were characterised based on size distribution, zeta potential, and binding efficiency of RGD peptide. They were also evaluated on encapsulation efficiency, and stability, of curcumin within the NPs. OVCAR-3 cancer cells were treated with COS and RGD-coated PLGA NPs loaded with Coumarin-6 dye for fluorescent imaging of cell uptake. They were also treated with curcumin-loaded NPs to determine cytotoxicity and effectiveness of delivery. The NPs exhibited size distribution and zeta potential within expected values, though binding efficiency of RGD was low. Curcumin-loaded NPs showed significant increase in cytotoxicity over free (unencapsulated) curcumin, and void (empty) NPs, suggesting successful delivery of curcumin as an anti-cancer agent; the performance of COS and RGD coated NPs over bare PLGA NPs was inconclusive, however, optimization will be required to improve formulation during the coating steps. This method of NP synthesis serves as proof of concept for a modular solution to the development of various coated polymeric NPs for other drugs or applications.

Investigations on 5,6,7,8-tetrahydro-[1,2,4]triazolo[1,2-a]pyridazin-1-amines and related compounds: synthesis, chemical behaviour, structure elucidation and iNOS inhibitory activity.

The present work reports on the preparation of the hitherto unknown title compounds 5, with various synthetic routes described. The initially pursued concept of S-N exchange with varioius 1-substituted 3-methylsulfanyl-5,6,7,8-tetrahydro-1 H -[1,2,4]triazolo[1,2- a ]pyridazines 4 by using nitrogen nucleophiles was only marginally successful. The reactions proceeded slowly and the yields were low, mainly because of the pronounced formation of 5,6,7,8-tetrahydro-[1,2,4]triazolo[1,2- a ]pyridazin-1-imines 7 by oxidation of the heterocyclic amines 5 initially formed. The integration of the synthesis of 3-acylsulfanyl analogues with the more reactive leaving groups also failed. On the other hand, the cyclization of the hydrohalides of hexahydropyridazine-1-carboximidamide with aromatic aldehydes and some low molecular weight ketones gives significantly better results in the synthesis of the title compounds 5. The use of the hydrochloride 6b proved to be advantageous in comparison to the hydroiodide 6a because the yields were significantly better and the imines 7 formed at the same time only to a small extent. In addition, the starting compound 6b can be prepared in a single-step synthesis in very good yield from hexahydropyridazine hydrochloride 1 and cyanamide. The cyclization of N' -phenylhexahydropyridazine-1-carboximidamide hydrochloride 6c with substituted benzaldehydes gives the 3-aryl-substituted 2-phenyl-2,3,5,6,7,8-hexahydro -1H -[1,2,4]triazolo[1,2- a ] pyridazin-1-imines 8. In the context with the study of the reaction of hexahydropyridazine-1-carboximidamide hydroiodide 6a with cyclohexanone, the hexahydropyridazine-1-carboxamide 9 was specifically synthesized. This can be reacted with aromatic aldehydes to give the 5,6,7,8-tetrahydro-1 H -[1,2,4]triazolo[1,2- a ]pyridazin-1-ones 10 in very good yields. The results of the biological testing of representatives of the synthesized 5,6,7,8-tetrahydro-[1,2,4] triazolo[1,2-a]pyridazine-1-amines 5 show, in comparison to the already examined thions 3 and 3-methylsulfanyl derivatives 4, significantly less inducible nitric oxide synthase (iNOS) inhibitory activity.

Synthesis, Optimization and Molecular Self-Assembly Behavior of Alginate-g-Oleylamine Derivatives Based on Ugi Reaction for Hydrophobic Drug Delivery.

To achieve the optimal alginate-based oral formulation for delivery of hydrophobic drugs, on the basis of previous research, we further optimized the synthesis process parameters of alginate-g-oleylamine derivatives (Ugi-FOlT) and explored the effects of different degrees of substitution (DSs) on the molecular self-assembly properties of Ugi-FOlT, as well as the in vitro cytotoxicity and drug release behavior of Ugi-FOlT. The resultant Ugi-FOlT exhibited good amphiphilic properties with the critical micelle concentration (CMC) ranging from 0.043 mg/mL to 0.091 mg/mL, which decreased with the increase in the DS of Ugi-FOlT. Furthermore, Ugi-FOlT was able to self-assemble into spherical micellar aggregates in aqueous solution, whose sizes and zeta potentials with various DSs measured by dynamic light scattering (DLS) were in the range of 653 ± 25~710 ± 40 nm and -58.2 ± 1.92~-48.9 ± 2.86 mV, respectively. In addition, RAW 264.7 macrophages were used for MTT assay to evaluate the in vitro cytotoxicity of Ugi-FOlT in the range of 100~500 µg/mL, and the results indicated good cytocompatibility for Ugi-FOlT. Ugi-FOlT micellar aggregates with favorable stability also showed a certain sustained and pH-responsive release behavior for the hydrophobic drug ibuprofen (IBU). Meanwhile, it is feasible to control the drug release rate by regulating the DS of Ugi-FOlT. The influence of different DSs on the properties of Ugi-FOlT is helpful to fully understand the relationship between the micromolecular structure of Ugi-FOlT and its macroscopic properties.

Gabapentin-induced Multifocal Myoclonus.

BACKGROUND: Gabapentin is the most commonly preferred agent for neuropathic pain in general practice as it is usually well tolerated, but occasionally, its toxicity may occur at standard doses, especially in elderly individuals, even without any prior comorbidities. CASE: We present an elderly male with normal renal parameters, who was started on gabapentin for neuropathic pain. He developed multifocal myoclonus all over the body within few days after starting gabapentin and subsided completed after withdrawal of the drug. CONCLUSION: Acute hyperkinetic movement disorders such as multifocal or segmental myoclonus in elderly patients warrant a prompt review of recent drug history, especially gabapentin, even in the background of normal renal function.

Fabrication of multifunctional cotton fabrics with quaternized N-halamine endowing the synergetic rechargeable antibacterial, wound healing and self-cleaning performances.

Cotton has attracted considerable attention due to its functional characteristics. The focus of research on cotton has shifted in recent years towards designing multi-functional and modified media for cotton fibers, which can be firmly combined with textiles, giving them reusability and extending their service life. This study constructed a synergistic antibacterial layer of quaternary ammonium compounds (QACs) and N-halamine (Hals) using an in-situ free radical copolymerization method in water, named QACs/Hals@cotton-Cl. The route significantly increases the number of antibacterial active centers. FTIR, XPS, and SEM were used to systematically analyze the product's chemical structure, surface morphology, and other characteristics. The modified fabric's antibacterial efficiency, wound healing, renewability, and durability were also evaluated. The chlorinated modified cotton fabric could completely eradicate S. aureus and E. coli within 10 min. Compared with pure cotton, it notably promoted the healing rate of infected wounds in mice. The modification method imparted excellent hydrophobicity to the cotton fabric, with a contact angle exceeding 130°, making it easy to remove surface stains. After 30 days of regular storage and 24 h of UV irradiation, the active chlorine concentration (Cl+%) only decreased by 25 % and 39 %, respectively, and the reduced Cl+% was effectively recharged via simple re-chlorination. The hydrophobicity and antimicrobial properties of QACs/Hals@cotton-Cl remained stable even after 20 cycles of friction. This simple synthesis technique provides a convenient approach for the scalable fabrication of multifunctional and rechargeable antibacterial textiles, with potential applications in medical devices and personal hygiene protection.

Silk fibroin wetting stability film induced by polyamide-amine-epichlorohydrin (PAE) for intelligent sensing system.

Protein materials gain new functions and applicability through redesigns in protein structure and engineering confer. However, the application and development of proteins for use in flexible devices that fit in flexible devices that fit the surface of human skin is hindered by their poor wet stability. Here, we described the design of wet-stable materials based on the reconstruction of silk fibroin (SF). The combination of polyamide-amine-epichlorohydrin (PAE) was used as a traction rope to bring SF molecular chains closer to each other, to facilitate the self-assembly of SF through branching and lengthening of molecular chains, and change its crystalline structure. SF/PAE composite films that exhibited huge improvement in ductility and wet stability were combined with flexible SF substrates via patterning and ion sputtering to prepare flexible sensors. In addition, the SF/PAE sensing system equipped with a microprocessor and Bluetooth module enabled the real-time remote acquisition of human health signals such as vocal cords, joints, pulse and meridians. This reconfiguration of the SF structure will advance the systematic exploration of protein structures and the development of protein materials for intelligent device applications.

Preparative scale Achmatowicz and aza-Achmatowicz rearrangements catalyzed by Agrocybe aegerita unspecific peroxygenase.

The unspecific peroxygenase (UPO) from Agrocybe aegerita (rAaeUPO-PaDa-I-H) is an effective and practical biocatalyst for the oxidative expansion of furfuryl alcohols/amines on a preparative scale, using the Achmatowicz and aza-Achmatowicz reaction. The high activity and stability of the enzyme, which can be produced on a large scale as an air-stable lyophilised powder, renders it a versatile and scalable biocatalyst for the preparation of synthetically valuable 6-hydroxypyranones and dihydropiperidinones. In several cases, the biotransformation out-performed the analogous chemo-catalysed process, and operates under milder and greener reaction conditions.

Ex Situ Gaseous Reagent for Multicomponent Amine Bioconjugation.

We report a minimalist gaseous sulfonyl-chloride-derived reagent for multicomponent bioconjugation with amine, phenol, or aniline reagents to afford urea or carbamate products. With the utilization of a gas-phase reagent for a reaction mediated by metal ions, a variety of biologically relevant molecules, such as saccharide, poly(ethylene glycol), fluorophore, and affinity tag, can be efficiently cross-linked to the N terminus or lysine side-chain amines on natural polypeptides or proteins.

Structurally diverse zinc(II) complexes containing tripodal tetradentate phenoxido-amines with promising antiproliferative effects.

Structurally diverse zinc(II) complexes with tripodal tetradentate phenolic-amines of variable substituents in the phenol and amine moieties were synthesized and thoroughly characterized. The two dinuclear [Zn2(L1)2](ClO4)2·MeOH (1), [Zn2(L2)2](ClO4)2 (2), and four mononuclear [Zn(L3)(H2O)]·MeOH (3), [Zn(L4)] (4), [Zn(L5)] (5) and [Zn(L6)] (6) complexes revealed distorted octahedral, trigonal-bipyramidal or tetrahedral geometries. The free HL1 and H2L3-6 ligands, and complexes 1-6 were evaluated for in vitro cytotoxicity against human cancer cell lines (A2780, A2780R, PC-3 and 22Rv1) and normal healthy MRC-5 cells. Overall results revealed high-to-moderate cytotoxicity (with the best IC50 values for complex 6 ranging from 2.4 to 4.5 µM), which is however, significantly higher than that of the reference drug cisplatin. The moderately active complexes 1-4 showed considerable selectivity on A2780 cells (IC50 ≈ 16.3-19.5 µM) over MRC-5 ones (with IC50 >50 µM for 1, 2 and 4, and with IC50 >25 µM for 3). The complexes 1, 2, and 6 and the ligand H2L6 were chosen for subsequent deeper biological evaluations. Their time-resolved cellular uptake and other cellular effects in A2780 cells were studied, such as cell cycle profile, intracellular ROS production, induction of apoptosis and activation of caspases 3/7. Complexes 1 and 2 caused significant G0/G1 cell cycle arrest in A2780 cells and antioxidant effects at normal conditions. They showed only limited effects on cellular processes connected with cytotoxicity, i.e. induction of apoptosis, depletion of mitochondrial membrane potential, and autophagy. These findings can be at least partly attributed to the low ability of the complexes to enter the A2780 cells and the depression of metabolic activity of the target cancer cells.

Antibacterial and oral tissue effectiveness of a mouthwash with a novel active system of amine + zinc lactate + fluoride.

OBJECTIVES: Reflecting the need for an effective support for the daily oral hygiene routine of patients experiencing (symptoms of) gum inflammation, a new mouthwash has been developed containing an amine + zinc lactate + fluoride system. The in vitro efficacy of this product was assessed using traditional laboratory methods, as well as novel experimentation. MATERIALS AND METHODS: This mouthwash has been evaluated in a series of laboratory tests including two short interval kill tests (SIKTs), a 12-h (longer term) biofilm regrowth assay, a plaque glycolysis assay, and an aerobic, repeated exposure biofilm model, as well as tests for soft tissue uptake and LPS neutralization. RESULTS: Several laboratory studies demonstrate that a mouthwash containing an amine + zinc lactate + fluoride system provides short-term and long-term antibacterial activity. While the immediate efficacy of this formula has been shown to be driven by the presence of the amine, zinc lactate provides a long-term antibacterial effect, as well as is able to inhibit bacterial metabolism. CONCLUSIONS: This research provides the basis for understanding the mode of action of this new mouthwash formulation and explains the previously observed clinical efficacy of this formula against plaque and gingivitis.

Biocatalysis enables the scalable conversion of biobased furans into various furfurylamines.

Biobased furans have emerged as chemical building blocks for the development of materials because of their diverse scaffolds and as they can be directly prepared from sugars. However, selective, efficient, and cost-effective scalable conversion of biobased furans remains elusive. Here, we report a robust transaminase (TA) from Shimia marina (SMTA) that enables the scalable amination of biobased furanaldehydes with high activity and broad substrate specificity. Crystallographic and mutagenesis analyses provide mechanistic insights and a structural basis for understanding SMTA, which enables a higher substrate conversion. The enzymatic cascade process established in this study allows one-pot synthesis of 2,5-bis(aminomethyl)furan (BAMF) and 5-(aminomethyl)furan-2-carboxylic acid from 5-hydroxymethylfurfural. The biosynthesis of various furfurylamines, including a one-pot cascade reaction for BAMF generation using whole cells, demonstrates their practical application in the pharmaceutical and polymer industries.

[Development of Organocatalytic Reactions for the Synthesis of Natural Products and Pharmaceuticals].

This review describes novel organocatalytic methods for the enantioselective construction of spiroindans and spirochromans and the application of the methods to the total synthesis of natural products. We developed an intramolecular Friedel-Craftstype 1,4-addition in which the substrates were a resorcinol derivative and 2-cyclohexenone linked by an alkyl chain. The reaction proceeded smoothly in the presence of a cinchonidine-based primary amine (30 mol%) with water and p-bromophenol as additives. A variety of spiroindanes were obtained with high enantioselectivity under these conditions. The reaction was applied in the first total synthesis of the unusual proaporphine alkaloid (-)-misramine, which included the key steps of enantioselective spirocyclization and double reductive amination of the keto-aldehyde to form a piperidine ring toward the end of the synthesis. The total synthesis of misrametine was achieved by selective demethylation of the methoxy group from the precursor to misramine. Next, a method for highly enantioselective organocatalytic construction of spirochromans containing a tetrasubstituted stereocenter was developed. An intramolecular oxy-Michael addition was catalyzed by a bifunctional cinchona alkaloid thiourea catalyst. A variety of spirochroman compounds containing a tetrasubstituted stereocenter were obtained with excellent enantioselectivity of up to 99% enantiomeric excess. The reaction was applied to the asymmetric formal synthesis of (-)-(R)-cordiachromene.

A change in metal cation switches selectivity of a phospholipid sensor from phosphatidic acid to phosphatidylserine.

Phosphatidic acid and phosphatidylserine are anionic phospholipids with emerging signalling roles in cells. Determination of how phosphatidic acid and phosphatidylserine change location and quantity in cells over time requires selective fluorescent sensors that can distinguish these two anionic phospholipids. However, the design of such synthetic sensors that can selectively bind and respond to a single phospholipid within the complex membrane milieu remains challenging. In this work, we present a simple and robust strategy to control the selectivity of synthetic sensors for phosphatidic acid and phosphatidylserine. By changing the coordination metal of a dipicolylamine (DPA) ligand from Zn(II) to Ni(II) on the same synthetic sensor with a peptide backbone, we achieve a complete switch in selectivity from phosphatidic acid to phosphatidylserine in model lipid membranes. Furthermore, this strategy was largely unaffected by the choice and the position of the fluorophores. We envision that this strategy will provide a platform for the rational design of targeted synthetic phospholipid sensors to probe plasma and intracellular membranes.

Isothiocyanate intermediates facilitate divergent synthesis of N-heterocycles for DNA-encoded libraries.

The versatile reactivity of isothiocyanate intermediates enabled the diversity-oriented synthesis (DOS) of N-heterocycles in a DNA-compatible manner. We first reported a mild in situ conversion of DNA-conjugated amines to isothiocyanates. Subsequently, a set of diverse transformations was successfully developed to construct 2-thioxo-quinazolinones, 1,2,4-thiadiazoles, and 2-imino thiazolines. Finally, the feasibility of these approaches in constructing DELs was further demonstrated through enzymatic ligation and mock pool preparation. This study demonstrated the advantages of combining in situ conversion strategies with DOS, which effectively broadened the chemical and structural diversity of DELs.

In Situ Preparation of Chlorine-Regenerable Antimicrobial Polymer Molecular Sieve Membranes.

Microbial contamination has profoundly impacted human health, and the effective eradication of widespread microbial issues is essential for addressing serious hygiene concerns. Taking polystyrene (PS) membrane as an example, we herein developed report a robust strategy for the in situ preparation of chlorine-regenerable antimicrobial polymer molecular sieve membranes through combining post-crosslinking and nucleophilic substitution reaction. The cross-linking PS membranes underwent a reaction with 5,5-dimethylhydantoin (DMH), leading to the formation of polymeric N-halamine precursors (PS-DMH). These hydantoinyl groups within PS-DMH were then efficiently converted into biocidal N-halamine structures (PS-DMH-Cl) via a simple chlorination process. ATR-FTIR and XPS spectra were recorded to confirm the chemical composition of the as-prepared PS-DMH-Cl membranes. SEM analyses revealed that the chlorinated PS-DMH-Cl membranes displayed a rough surface with a multitude of humps. The effect of chlorination temperature and time on the oxidative chlorine content in the PS-DMH-Cl membranes was systematically studied. The antimicrobial assays demonstrated that the PS-DMH-Cl membranes could achieve a 6-log inactivation of E. coli and S. aureus within just 4 min of contact time. Additionally, the resulting PS-DMH-Cl membranes exhibited excellent stability and regenerability of the oxidative chlorine content.

Stereospecific Enzymatic Conversion of Boronic Acids to Amines.

Boronic acids and esters are highly regarded for their safety, unique reactivity, and versatility in synthesizing a wide range of small molecules, bioconjugates, and materials. They are not exploited in biocatalytic synthesis, however, because enzymes that can make, break, or modify carbon-boron bonds are rare. We wish to combine the advantages of boronic acids and esters for molecular assembly with biocatalysis, which offers the potential for unsurpassed selectivity and efficiency. Here, we introduce an engineered protoglobin nitrene transferase that catalyzes the new-to-nature amination of boronic acids using hydroxylamine. Initially targeting aryl boronic acids, we show that the engineered enzyme can produce a wide array of anilines with high yields and total turnover numbers (up to 99% yield and >4000 TTN), with water and boric acid as the only byproducts. We also demonstrate that the enzyme is effective with bench-stable boronic esters, which hydrolyze in situ to their corresponding boronic acids. Exploring the enzyme's capacity for enantioselective catalysis, we found that a racemic alkyl boronic ester affords an enantioenriched alkyl amine, a transformation not achieved with chemocatalysts. The formation of an exclusively unrearranged product during the amination of a boronic ester radical clock and the reaction's stereospecificity support a two-electron process akin to a 1,2-metallate shift mechanism. The developed transformation enables new biocatalytic routes for synthesizing chiral amines.