Synthetic Strategy Research Articles

A facile synthetic strategy to simultaneously achieve ultra-wide PL redshift of carbon nanodots and their high selectivity and sensitivity for Mn2+ detection

This paper presents a straightforward synthesis strategy for N, S co-doped carbon nanodots (N, S-CDs), aiming to achieve CDs emitting ultra-wide redshifts while obtaining excellent metal ion detection performance. The N, S-CDs display excellent fluorescence (FL) emission independence regardless of the excitation wavelength or concentration. By introducing a single dopant thiourea, the FL emission of CDs was red-shifted from 445 to 575 nm (∼130 nm). The doped N and S elements are discovered to cause the introduction of defective energy levels and an elevation in oxidation on the surface of CDs, which could potentially be the crucial factor for the ultra-wide redshift of FL emission. Also, it is investigated that solvent engineering is essential for the redshift of the emission peak, which can also be an effective way to synthesize multicolor CDs. Furthermore, the N, S-CDs can be utilized for measuring the water content in methanol solvent based on their solvent effects. Additionally, N, S-CDs have the capability of detecting Mn2+ with high selectivity and sensitivity. The interaction of CDs with Mn2+ resulted in an obvious change in both the UV absorption spectrum and FL lifetime. To put it differently, the reaction mechanism between CDs and Mn2+ probably includes mixed processes of dynamic and static quenching. Zeta potential tests additionally indicate that the FL quenching is strongly correlated with the surface condition of CDs. The outcomes and discoveries offer a fresh and viable method for achieving the simultaneous production of long-wavelength glowing CDs and their analysis and detection of metal ions as fluorescent probes.

Enzymatic Synthesis of New Acetoacetate-Ursodeoxycholic Acid Hybrids as Potential Therapeutic Agents and Useful Synthetic Scaffolds as Well.

Ursodeoxycholic acid (UDCA) and acetoacetate are natural compounds present in the human intestine and blood, respectively. A number of studies highlighted that besides their well-known primary biological roles, both compounds possess the ability to influence a variety of cellular processes involved in the etiology of various diseases. These reasons suggested the potential of acetoacetate-UDCA hybrids as possible therapeutic agents and prompted us to develop a synthetic strategy to selectively derivatize the hydroxyl groups of the bile acid with acetoacetyl moieties. 3α-acetoacetoxy UDCA was obtained (60% isolated yield) via the regioselective transesterification of methyl acetoacetate with UDCA promoted by the Candida antarctica lipase B (CAL-B). 3α,7β-bis-acetoacetoxy UDCA was obtained instead by thermal condensation of methyl acetoacetate and UDCA (80% isolated yield). This bis-adduct was finally converted to the 7β-acetoacetoxy UDCA (82% isolated yield) via CAL-B catalyzed regioselective alcoholysis of the ester group on the 3α position. In order to demonstrate the value of the above new hybrids as UDCA-based scaffolds, 3α-acetoacetoxy UDCA was subjected to multicomponent Biginelli reaction with benzaldehyde and urea to obtain the corresponding 4-phenyl-3,4-dihydropyrimidin-2-(1H)-one derivative in 65% isolated yield.

Thioxanthone-TfOH complex (9-HTXTF) photoredox enabled reduction of sulfoxides

This study presents a photoredox-mediated reduction of sulfoxides, employing 9-HTXTF as photocatalyst and THF as an external reductant. Scope investigation revealed that diverse substrates, including those with electron-donating and electron-withdrawing groups, could be transformed into corresponding sulfides. Mechanistic insights suggest a cascade of events initiated by the excited state of 9-HTXTF, involving multiple single-electron reduction steps and proton transfers. This approach enriches the toolkit for sulfoxide reduction under photoredox catalysis as sustainable synthetic strategies.

Particle-Based Artificial Antigen-Presenting Cell Systems for T Cell Activation in Adoptive T Cell Therapy.

T cell-based adoptive cell therapy (ACT) has emerged as a promising treatment for various diseases, particularly cancers. Unlike other immunotherapy modalities, ACT involves directly transferring engineered T cells into patients to eradicate diseased cells; hence, it necessitates methods for effectively activating and expanding T cells in vitro. Artificial antigen-presenting cells (aAPCs) have been widely developed based on biomaterials, particularly micro- and nanoparticles, and functionalized with T cell stimulatory antibodies to closely mimic the natural T cell-APC interactions. Due to their vast clinical utility, aAPCs have been employed as an off-the-shelf technology for T cell activation in FDA-approved ACTs, and the development of aAPCs is constantly advancing with the emergence of aAPCs with more sophisticated designs and additional functionalities. Here, we review the recent advancements in particle-based aAPCs for T cell activation in ACTs. Following a brief introduction, we first describe the manufacturing processes of ACT products. Next, the design and synthetic strategies for micro- and nanoparticle-based aAPCs are discussed separately to emphasize their features, advantages, and limitations. Then, the impact of design parameters of aAPCs, such as size, shape, ligand density/mobility, and stiffness, on their functionality and biomedical performance is explored to provide deeper insights into the design concepts and principles for more efficient and safer aAPCs. The review concludes by discussing current challenges and proposing future perspectives for the development of more advanced aAPCs.

Innovative Arylimidazole-Fused Phytovirucides via Carbene-Catalyzed [3+4] Cycloaddition: Locking Viral Cell-To-Cell Movement by Out-Competing Virus Capsid-Host Interactions.

The control of potato virus Y (PVY) induced crop failure is a challengeable issue in agricultural chemistry. Although many anti-PVY agents are designed to focus on the functionally important coat protein (CP) of virus, how these drugs act on CP to inactivate viral pathogenicity, remains largely unknown. Herein, a PVY CP inhibitor -3j (S) is disclosed, which is accessed by developing unusually efficient (up to 99% yield) and chemo-selective (> 99:1 er in most cases) carbene-catalyzed [3+4] cycloaddition reactions. Compound -3j bears a unique arylimidazole-fused diazepine skeleton and shows chirality-preferred performance against PVY. In addition, -3j (S) as a mediator allows ARG191 (R191 ) of CP to be identified as a key amino acid site responsible for intercellular movement of virions. R191 is further demonstrated to be critical for the interaction between PVY CP and the plant functional protein NtCPIP, enabling virions to cross plasmodesmata. This key step can be significantly inhibited through bonding with the -3j (S) to further impair pathogenic behaviors involving systemic infection and particle assembly. The study reveals the in-depth mechanism of action of antiviral agents targeting PVY CP, and contributes to new drug structures and synthetic strategies for PVY management.

MOFs-derived Ni@ZrO2 catalyst for dry reforming of methane: Tunable metal-support interaction

Metal-support interaction (MSI) plays an important role in heterogeneous catalysis, that could be well regulated by many strategies. Here, Ni@ZrO2 catalysts were controllably synthesized by sacrificial Zr-MOFs template strategy, and were applied to the dry reforming of methane (DRM). Amongst, the Ni/ZrO2-B catalyst shows the best performance toward CH4 and CO2 conversion, H2/CO ratio, and stability, following by Ni/ZrO2-A and Ni/ZrO2C catalysts. The difference in catalytic performance should be ascribed to different synthetic strategy, resulting in different properties of Ni species and ZrO2 matrix, and interface interaction. It revealed that small Ni particles were benefit for CH4 activation, and strong MSI boosted CO2 activation, that could remain the Ni dispersion and thermal stability. This study is beneficial to the catalyst design in DRM reaction.

Reaction Paradigms that Leverage Cycloaddition and Ring Strain to Construction Bicyclic Aryl Bioisosteres from Bicyclo[1.1.0]butanes

AbstractWithin a medicinal chemist's toolbox, one of the most effective strategies to improve the overall properties of a biologically active compound is bioisosteric replacement. Ever since the first example of replacing benzene with a bicyclo[1.1.1]pentane (BCP) group was published in the late 1990s,[1] the medicinal chemistry community has continually been expanding the scope of such phenyl bioisosteric replacements. Recent interest from academia has focused on novel synthetic strategies to access C(sp3)‐rich bicyclic hydrocarbons with expanded ring sizes. Herein, we summarize some of these transformations and reveal that most rely on strain releasing cycloadditions with bicyclo[1.1.0]butane (BCB) and bicyclo[2.1.0]pentane (housane). We have organized this review based on the mechanism of such strain release strategies, namely, carbene cycloadditions, energy transfer photocatalyzed cycloadditions, electron transfer catalyzed cycloadditions, and polar cycloadditions.

New approaches for the synthesis of chromene and quinoline derivatives and their anti-proliferative, morphological studies

This work aimed to evaluate the anticancer potential of the novel 5,6,7,8-tetrahydro-4H-chromenes against selected six cancer cell lines together with the prostate cancer cell line PC-3. A novel series of substituted 5,6,7,8-tetrahydro-4H-chromenes were synthesized through feasible synthetic strategy. The synthetic schemes involve firstly the multi-component reactions of dimedone with the aromatic aldehydes and ethyl acetoacetate to produce the 5,6,7,8-tetrahydro-4H-chromenes derivatives. On the other hand, carrying the same reactions using NH4OAc produced the hexahydroquinoline compounds. Anti-proliferative evaluations and inhibitions for all synthesized compounds toward selected cancer cell lines were carried out and the results revealed that many of them exhibited high inhibitions. Morphology of A549 cell line by the effect of compounds 14f and 16c was performed.
 KEY WORDS: Anti-proliferative activity, Chromene derivatives, Morphology, Multi-component reactions
 Bull. Chem. Soc. Ethiop. 2024, 38(3), 775-798. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i3.18

Polyrotaxanated covalent organic frameworks based on β-cyclodextrin towards high-efficiency synergistic inactivation of bacterial pathogens

As an emerging artificial porous material, covalent organic frameworks (COFs) with customizable structure and function, have always been the focus of polymer science. Controllable fabrication of COFs with brand-new structure is the top priority for its development. Here, the ‘supramolecular binding’ strategy is developed as a simple but efficient method to prepare COFs with novel structures and functions. By this means, polymeric rotaxanes threaded COFs, denoted as Por-CD-COF, was facilely prepared via the combination of dynamic covalent imine-bond formation with supramolecular self-assembly, in which the polyrotaxane formed via inclusion of aromatic linker with bactericidal active β-cyclodextrin macrocycle (CD) was condensed with the photosensitive porphyrin via the combination of mechanical grinding and solvothermal synthesis. The formation of polyrotaxane could change the distance between layers, avoiding the quench of photoactivity caused by the severe aggregation of layered structure. Under the same molar amount of reaction monomers, the weight of the Por-CD-COF is approaching five times of the CD-free COF, which could greatly reduce the use of photoactive ingredients. Further experiments demonstrated the introduction of CDs could also significantly improve the biocompatibility. Impressively, this special porphyrin-involved CD-COF, displays excellent photo activity, which could act as an efficient broad spectrum antibacterial agents realizing the combinational action of cyclodextrin enhanced photothermal and photodynamic antimicrobial at an extremely low quality of the effective photosensitizer (Porphyrin). Meanwhile, even at the same dose of fungicide, the bactericidal effect of Por-CD-COF is far exceeding the CD-free therapeutic agent. This novel synthetic strategy allows the incorporation of mechanically interlocked CDs (MIMs) into the porous polymeric materials, providing an easy access to low-cost preparation of COFs for the specific applications.

A Domino Protocol toward High-performance Unsymmetrical Dibenzo[d,d']thieno[2,3-b;4,5-b']dithiophenes Semiconductors.

Unsymmetric organic semiconductors have many advantages such as good solubility, rich intermolecular interactions for potential various optoelectronic applications. However, their synthesis is more challenging due to intricate structures thus normally suffering tedious synthesis. Herein, we report a trisulfur radical anion (S3⋅-) triggered domino thienannulation strategy for the synthesis of dibenzo[d,d']thieno[2,3-b;4,5-b']dithiophenes (DBTDTs) using readily available 1-halo-2-ethynylbenzenes as starting materials. This domino protocol features no metal catalyst and the formation of six C-S and one C-C bonds in a one-pot reaction. Mechanistic study revealed a unique domino radical anion pathway. Single crystal structure analysis of unsymmetric DBTDT shows that its unique unsymmetric structure endows rich and multiple weak S⋅⋅⋅S interactions between molecules, which enables the large intermolecular transfer integrals of 86 meV and efficient charge transport performance with a carrier mobility of 1.52 cm2 V-1 s-1. This study provides a facile and highly efficient synthetic strategy for more high-performance unsymmetric organic semiconductors.

Flowered molybdenum base trimetallic oxide decorated by CdS nanorod construct S-scheme heterojunctions for efficient photocatalytic hydrogen evolution

Molybdenum-based metal oxide catalysts are attracting widespread attention in the field of photocatalysis due to their significant applications in addressing energy and environmental challenges. As a new three-dimensional molybdenum-based metal oxide photocatalyst, NaZn2(OH)(MoO4)2·H2O is highly promising as a semiconductor catalyst for enhancing photocatalytic performance, thanks to its ease of preparation and environmental friendliness. Herein, we prepared an S-scheme heterojunction photocatalyst composed of NaZn2(OH)(MoO4)2·H2O and CdS, which enabled efficient H2 production through photocatalysis, addressing issues associated with the rapid recombination rate of photogenerated carriers. The hydrogen generation yield of NZM/CdS-30 reached 5335 µmol g−1 h−1, approximately 30 and 953 times higher than those of CdS and NaZn2(OH)(MoO4)2·H2O, respectively. Moreover, we verified the mechanism through in-situ XPS analysis to elucidate the activity enhancement. Our research provides an innovative universal and effective synthetic strategy of design S-scheme heterojunction for hydrogen production from solar water splitting.

Synthesis of hydrophobic CuCl/LaA modified by butyltrichlorosilane towards enhanced CO adsorption under humid environment

Cuprous ion modified molecular sieves have been considered as promising CO adsorbents in gas separation or purification industry. However, it persists as a significant challenge to overcome the unfavorable effect of water vapor in the work environment on gas adsorption and separation. Herein, we propose a synthetic strategy using rare earth element La as an additive to form LaOLa coordination bonds followed by surface silanization treatment to construct a hydrophobic SiOSi barrier to significantly improve the stability of Cu+ under humid atmosphere. By successively introducing La3+ and Cu+ into zeolite 5A, CuCl/LaA adsorbents were prepared via ion exchange and solid dispersion methods. And then by silanization modification using toluene as solvent and butyltrichlorosilane (BTS) as hydrophobic agent, hydrophobic CuCl/LaA-BTS adsorbents were prepared. Dynamic adsorption investigation demonstrated that the as-prepared CuCl/LaA-BTS adsorbents possessed hydrophobic surface and consequently the adsorption capacity of CO was enhanced significantly under humid atmosphere. The CO adsorption breakthrough capacity over CuCl/LaA-BTS attained 0.34 mg/g, which was 5.7 times higher than that of zeolite 5A at 40 °C, atmospheric pressure and a relative humidity of RH = 55 %. Moreover, the CO adsorption capacity of CuCl/LaA-BTS retained 0.31 mg/g after four cycle regenerations. This work provides an effective and novel route for synthesizing highly stable cuprous ion modified zeolite adsorbents.

Rapid ion conduction enabled by synergism of oriented liquid crystals and Electron-Deficient boron atoms in multiblock copolymer electrolyte for advanced Solid-State Lithium-Ion battery

Liquid crystals (LCs) with characteristics of self-orientation have exhibited superiorities in construction of ordered ion channels for rapid Li-ion transport. Herein, reversible addition-fragmentation chain transfer (RAFT) polymerization is employed to synthesize a unique type of boron-containing LCs based ABCBA type multiblock copolymers for the first time. The composite block copolymer electrolytes (BCPEs) are fabricated by introducing the copolymer electrolytes into glass fiber separator via solution-casting method. Noteworthily, LCs can not only provide ordered ion channels for efficient ion conduction, but also ameliorate the mechanical strength. Meanwhile, the nitrile groups with high polarity from LCs are able to further facilitate lithium salt dissociation and reinforce electrochemical stability of the system. Crucially, boron elements with electron deficiency can anchor anions and adsorb impurities to endow BCPEs with boosted ion transport capability and sufficient electrochemical stability. Consequently, the well-designed electrolyte shows high ionic conductivity of 1.13 × 10−4 S cm−1 (30 °C), and broadened electrochemical stability window of 4.85 V. Impressively, the assembled Li/LiFePO4 cells and even Li/LiMnxFe1-xPO4 high-voltage cells exhibit remarkable performances. This work provides a synthetic strategy of structure-controlled polymer electrolyte matrix and illustrates that the BCPEs are definitely a category of satisfactory electrolyte candidate for high-performance solid-state lithium-ion batteries.

Enriched supercapacitive performance of electrochemically tailored β-Co(OH)2/CoOOH nanodiscs from sacrificial Co3(PO4)2·4H2O microbelts

Electrochemically induced structural reconstruction process of metal precursors into their corresponding metal hydroxides/(oxy)hydroxides is developed as an ingenious strategy towards preparing efficient electrode material. However, the influence of electrochemical activation on the charge storage ability of electrode material is barely explored. Herein, we have utilized a synthetic strategy (solvothermal reaction in water:ethanol mixture) to prepare Co3(PO4)2·4H2O microbelts and subsequently applied the electrochemical bulk reconstruction process in 1 M KOH electrolyte. A thorough physical and electrochemical characterization unveil that the electrode material is converted into redox active site rich β-Co(OH)2/CoOOH nanodiscs via etching of lattice anionic PO43− moieties. The material possesses a specific capacitance of 386 F g−1at a current density of 0.25 A g−1. Additionally, a hybrid device constructed with β-Co(OH)2/CoOOH nanodiscs and activated charcoal (AC) as positive and negative electrodes has achieved a high energy density of 13.33 Wh Kg−1at a power density of 400 W kg−1. Further, the device displayed a good capacitance retention of 93 % (columbic efficiency ~98 %) up to 10,000 cycles. The improved charge storage of reconstructed material with abundant redox active sites could be attributed to the facile diffusion of electrolyte ions into the bulk of the material.

A Domino Protocol toward High‐performance Unsymmetrical Dibenzo[d,d′]thieno[2,3‐b;4,5‐b′]dithiophenes Semiconductors

AbstractUnsymmetric organic semiconductors have many advantages such as good solubility, rich intermolecular interactions for potential various optoelectronic applications. However, their synthesis is more challenging due to intricate structures thus normally suffering tedious synthesis. Herein, we report a trisulfur radical anion (S3⋅−) triggered domino thienannulation strategy for the synthesis of dibenzo[d,d′]thieno[2,3‐b;4,5‐b′]dithiophenes (DBTDTs) using readily available 1‐halo‐2‐ethynylbenzenes as starting materials. This domino protocol features no metal catalyst and the formation of six C−S and one C−C bonds in a one‐pot reaction. Mechanistic study revealed a unique domino radical anion pathway. Single crystal structure analysis of unsymmetric DBTDT shows that its unique unsymmetric structure endows rich and multiple weak S⋅⋅⋅S interactions between molecules, which enables the large intermolecular transfer integrals of 86 meV and efficient charge transport performance with a carrier mobility of 1.52 cm2 V−1 s−1. This study provides a facile and highly efficient synthetic strategy for more high‐performance unsymmetric organic semiconductors.

Structural Motifs in Covalent Organic Frameworks for Photocatalysis

AbstractCovalent organic frameworks (COFs) attract significant attention due to their ordered, crystalline, porous, metal‐free, and predictable structures. These unique characteristics offer great opportunities for the diffusion and transmission of photogenerated charges during photocatalysis. Currently, a considerable number of COFs are used as metal‐free organic semiconductor photocatalysts. This review aims to understand the relationships between the structure and photocatalysis performance of COFs and provides in‐depth insight into the synthetic strategy to improve photocatalysis performance. Subsequently, the review focuses on the structural motif of COFs in sustainable photocatalytic hydrogen evolution, carbon dioxide reduction, hydrogen peroxide generation, and organic compound transformations. Last, in conjunction with the significant progress achieved and the challenges yet to be overcome, a candid discussion is undertaken regarding the challenges and opportunities in the field of COF photocatalysis, accompanied by the presentation of potential research avenues and future directions. This review seeks to provide readers with a comprehensive understanding of the pivotal role of COFs in the field of photocatalysis, to offer robust guidance for the innovative utilization of COFs in future sustainable photocatalysis.

Intra-nanoparticle plasmonic nanogap based spatial-confinement SERS analysis of polypeptides

Sensing and characterizing water-soluble polypeptides are essential in various biological applications. However, detecting polypeptides using Surface-Enhanced Raman Scattering (SERS) remains a challenge due to the dominance of aromatic amino acid residues and backbones in the signal, which hinders the detection of non-aromatic amino acid residues. Herein, intra-nanoparticle plasmonic nanogap were designed by etching the Ag shell in Au@AgNPs (i.e., obtaining AuAg cores) with chlorauric acid under mild conditions, at the same time forming the outermost Au shell and the void between the AuAg cores and the Au shell (AuAg@void@Au). By varying the Ag to added chloroauric acid molar ratios, we pioneered a simple, controllable, and general synthetic strategy to form interlayer-free nanoparticles with tunable Au shell thickness, achieving precise regulation of electric field enhancement within the intra-nanogap. As validation, two polypeptide molecules, bacitracin and insulin B, were successfully synchronously encapsulated and spatial-confined in the intra-nanogap for sensing. Compared with concentrated 50 nm AuNPs and Au@AgNPs as SERS substrates, our simultaneous detection method improved the sensitivity of the assay while benefiting to obtain more comprehensive characteristic peaks of polypeptides. The synthetic strategy of confining analytes while fabricating plasmonic nanostructures enables the diffusion of target molecules into the nanogap in a highly specific and sensitive manner, providing the majority of the functionality required to achieve peptide detection or sequencing without the hassle of labeling.

A Review on the Synthetic Methods towards Benzothienobenzothiophenes.

Benzothienobenzothiophenes (BTBTs) are a class of heteroacenes for which two distinct isomers have been identified depending on the locations of the fused benzothiophene motifs. Benzothienobenzothiophenes represent a class of heteroacenes demonstrating remarkable electronic properties that make them prominent in the realm of organic semiconductors. The structure of BTBTs, incorporating two sulfur atoms, contributes to their unique electronic characteristics, including narrow bandgaps and effective charge transport pathways. These compounds have gained attention for their high charge carrier mobility, making them desirable candidates for application in organic field-effect transistors (OFETs) and other electronic devices. Researchers have explored various synthetic strategies to design and tailor the properties of BTBT derivatives, leading to advancements in the development of high-performance organic semiconductors. Various synthetic techniques for benzothienobenzothiophenes have been reported in the literature including multistep synthesis, tandem transformations, electrochemical synthesis, and annulations. This review investigates the generality of each synthetic methodology by highlighting its benefits and drawbacks, and it analyses all synthetic approaches described for the creation of the two isomers. For the advantage of the readers, we have delved upon every mechanism of the reactions that are known. Finally, we have also summarized the synthetic methodologies that are used for making benzothienobenzothiophene analogues for material applications.

Understanding of ZnO‐Catalyzed Polyurethane Synthesis from Bisurea for Further Exploration of One‐Pot Synthesis and Property Evaluation Thereof

AbstractZnO is considered to be a good catalyst for the synthesis of polyurethanes (PUs) by alcoholysis of bisureas (BUs). ZnO tends to form Zn(NCO)2(NH3)2 in the presence of urea at high temperature, so does it in the alcoholysis of BUs. Here, attempt is made to understand the role Zn(NCO)2(NH3)2 plays in the alcoholysis of BUs. A loading of Zn(NCO)2(NH3)2 at 5 mol% is found to be sufficient to catalyze the polymerization and the reaction time is greatly cut from 40 h (catalyzed by ZnO) to 26 h, with similar chemical structures and properties. The tensile strength, elongation at break, and toughness for PU–Zn‐5 can reach 43.8 MPa, 330%, and 94.0 J cm−3, respectively. One‐pot synthetic strategy is then further introduced to improve the efficiency of the polymerization. Zn(NCO)2(NH3)2, BU, and PU can be synthesized in one‐pot, by adding ZnO, urea, diamine, LiBr, and diol sequentially. The feasibility of this one‐pot method is verified, indicated by the similar reaction time, chemical structures, molecular weight, thermal and mechanical properties. This one‐pot synthetic strategy offers an efficient way to synthesize PUs directly and simply from urea, diamines, and diols, which is beneficial for improving the molecular diversity of PUs.

Design, synthesis, in silico, and in vitro evaluation of novel benzyloxybenzene substituted (S)-α-amino amide derivatives as cholinesterases and monoaminoxidases inhibitor.

In this study, a series of novel benzyloxybenzene substituted (S)-α-amino acid methyl esters and their amide derivatives were synthesized and evaluated for their inhibitory actions against acetylcholinesterase(AChE), butyrylcholinesterase(BChE), monoamine oxidase A(MAO-A), and monoamine oxidase B(MAO-B). The synthetic strategy was based on starting from benzyl bromide (5) and 4-hydroxybenzaldehyde (6). The reaction of 5 and 6 in the presence of K2 CO3 gave benzyloxybenzaldehyde 7. Benzyloxybenzene substituted (S)-α-amino acid methyl esters 11, 12, 13, (±)-19, and (±)-20 were obtained from the reaction of L-amino acid methyl esters with benzyloxybenzaldehyde (7) followed by in situ reduction with NaBH4 . The reaction of (S)-11, (S)-12, 13, (±)-19, and (±)-20 with excess ammonia gave amides (S)-14, (S)-15, 16, (±)-21, and (±)-22. The in vitro inhibitory activities of compounds against MAO-A,MAO-B, AChE, and BChEwere investigated. Within the α-amino acid methyl ester series, 13 (21.32 ± 0.338 µM) showed selectivity by inhibiting the MAO-B better than MAO-A. 13 emerged as the most active member of this series, exhibiting a 12-fold selectivity for MAO-B. 14 (4.501 ± 0.295 µM) demonstrated a pronounced selectivity for MAO-A over MAO-B, with a selectivity ratio of 110-fold. In addition, it was determined that compound 15 (95.65 ± 3.09 µM) had high selectivity for BChE inhibition. 21was demonstrated the most potent inhibition (18.36 ± 1.36 µM) against AChE.