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An electrochemical C–H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemoselectivity is described; it uses inexpensive and readily available materials and represents a scalable allylic C–H oxidation that could be adopted in large-scale industrial settings without substantial environmental impact. Electrical allylic C–H oxidation Allylic C–H oxidation has been used widely in the syntheses of natural product variants, medicines and new materials. One disadvantage of the reaction is that it requires highly toxic reagents or expensive catalysts. In this manuscript, the authors describe an electrochemical alternative to conventional allylic oxidation. The new method utilizes inexpensive and readily available materials, has broad substrate scope, operational simplicity, and high chemoselectivity, all with minimal environmental impact. New methods and strategies for the direct functionalization of C–H bonds are beginning to reshape the field of retrosynthetic analysis, affecting the synthesis of natural products, medicines and materials 1 . The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C–H functionalization, owing to the utility of enones and allylic alcohols as versatile intermediates, and their prevalence in natural and unnatural materials 2 . Allylic oxidations have featured in hundreds of syntheses, including some natural product syntheses regarded as “classics” 3 . Despite many attempts to improve the efficiency and practicality of this transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium) 2 . These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. This oxidation strategy is therefore rarely used for large-scale synthetic applications, limiting the adoption of this retrosynthetic strategy by industrial scientists. Here we describe an electrochemical C–H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemoselectivity. It uses inexpensive and readily available materials, and represents a scalable allylic C–H oxidation (demonstrated on 100 grams), enabling the adoption of this C–H oxidation strategy in large-scale industrial settings without substantial environmental impact.

Direct C( sp 3 )–C( sp 2 ) bond formation under transition-metal-free conditions offers an atom-economical, inexpensive and environmentally benign alternative to traditional transition-metal-catalysed cross-coupling reactions. A new chemo- and regioselective coupling protocol between 3-aryl-substituted-1,1-diphenyl-2-azaallyl derivatives and vinyl bromides has been developed. This is the first transition-metal-free cross-coupling of azaallyls with vinyl bromide electrophiles and delivers allylic amines in excellent yields (up to 99%). This relatively simple and mild protocol offers a direct and practical strategy for the synthesis of high-value allylic amine building blocks that does not require the use of transition metals, special initiators or photoredox catalysts. Radical clock experiments, electron paramagnetic resonance studies and density functional theory calculations point to an unprecedented substrate-dependent coupling mechanism. Furthermore, an electron paramagnetic resonance signal was observed when the N -benzyl benzophenone ketimine was subjected to silylamide base, supporting the formation of radical species upon deprotonation. The unique mechanisms outlined herein could pave the way for new approaches to transition-metal-free C–C bond formations. Cross coupling under transition-metal-free conditions is an attractive and economic alternative to traditional transition-metal-catalysed methods. Metal-free coupling of azaallyls has now been demonstrated with vinyl bromide electrophiles, delivering allylic amines in excellent yields. Moreover, mechanistic evidence supports dual reaction pathways triggered by azaallyl anions and radicals.

The use of natural substance to ward off microbial infections has a long history. However, the large-scale production of natural extracts often reduces antibacterial potency, thus limiting practical applications. Here we present a strategy for converting natural organosulfur compounds into nano-iron sulfides that exhibit enhanced antibacterial activity. We show that compared to garlic-derived organosulfur compounds nano-iron sulfides exhibit an over 500-fold increase in antibacterial efficacy to kill several pathogenic and drug-resistant bacteria. Furthermore, our analysis reveals that hydrogen polysulfanes released from nano-iron sulfides possess potent bactericidal activity and the release of polysulfanes can be accelerated by the enzyme-like activity of nano-iron sulfides. Finally, we demonstrate that topical applications of nano-iron sulfides can effectively disrupt pathogenic biofilms on human teeth and accelerate infected-wound healing. Together, our approach to convert organosulfur compounds into inorganic polysulfides potentially provides an antibacterial alternative to combat bacterial infections. Garlic has a mild antibacterial activity due to its organosulfur content. Here, the authors develop an approach to convert natural organosulfur into iron-sulfur nanosheets, with significantly higher antibacterial activity that can be used against infections as well as biofilms.

The synthesis of valuable bioactive alicyclic amines containing variable substituents in multiple ring positions typically relies on multistep synthetic sequences that frequently require the introduction and subsequent removal of undesirable protecting groups. Although a vast number of studies have aimed to simplify access to such materials through the C–H bond functionalization of feedstock alicyclic amines, the simultaneous introduction of more than one substituent to unprotected amines has never been accomplished. Here we report an advance in C–H bond functionalization methodology that enables the introduction of up to three substituents in a single operation. Lithiated amines are first exposed to a ketone oxidant, generating transient imines that are subsequently converted to endocyclic 1-azaallyl anions, which can be processed further to furnish β-substituted, α,β-disubstituted, or α,β,α′-trisubstituted amines. This study highlights the unique utility of in situ-generated endocyclic 1-azaallyl anions, elusive intermediates in synthetic chemistry.The preparation of unprotected alicyclic amines containing variable substituents in multiple ring positions typically requires multistep synthetic sequences. Now, an advance in C–H bond functionalization methodology that enables the convenient preparation of elusive endocyclic 1-azaallyl anions allows the introduction of up to three substituents in a single operation.

There are many biologically active organic molecules that contain one or more nitrogen-containing moieties, and broadly applicable and efficient catalytic transformations that deliver them diastereoselectively and/or enantioselectively are much sought after. Various methods for enantioselective synthesis of α-secondary amines are available (for example, from additions to protected/activated aldimines), but those involving ketimines are much less common. There are no reported additions of carbon-based nucleophiles to unprotected/unactivated (or N–H) ketimines. Here, we report a catalytic, diastereo- and enantioselective three-component strategy for merging an N–H ketimine, a monosubstituted allene and B 2 (pin) 2 , affording products in up to 95% yield, >98% diastereoselectivity and >99:1 enantiomeric ratio. The utility of the approach is highlighted by synthesis of the tricyclic core of a class of compounds that have been shown to possess anti-Alzheimer activity. Stereochemical models developed with the aid of density functional theory calculations, which account for the observed trends and levels of enantioselectivity, are presented. Amines are commonly occurring units in many biologically active molecules. Now, a catalytic method has been developed that merges an unprotected/unactivated ketimine, a monosubstituted allene and a commercially available diboron reagent to afford versatile α-tertiary amines in up to 95% yield, >98% diastereomeric ratio and >99:1 enantiomeric ratio. The utility of this method was demonstrated through its application to the synthesis of the tricyclic core of a class of compounds with anti-Alzheimer activity.

Garlic is a vegetable with numerous pro-health properties, showing high antioxidant capacity, and cytotoxicity for various malignant cells. The inhibition of cell proliferation by garlic is mainly attributed to the organosulfur compounds (OSCs), but it is far from obvious which constituents of garlic indeed participate in the antioxidant and cytotoxic action of garlic extracts. This study aimed to obtain insight into this question by examining the antioxidant activity and cytotoxicity of six OSCs and five phenolics present in garlic. Three common assays of antioxidant activity were employed (ABTS● decolorization, DPPH● decolorization, and FRAP). Cytotoxicity of both classes of compounds to PEO1 and SKOV-3 ovarian cancer cells, and MRC-5 fibroblasts was compared. Negligible antioxidant activities of the studied OSCs (alliin, allicin, S-allyl-D-cysteine, allyl sulfide, diallyl disulfide, and diallyl trisulfide) were observed, excluding the possibility of any significant contribution of these compounds to the total antioxidant capacity (TAC) of garlic extracts estimated by the commonly used reductive assays. Comparable cytotoxic activities of OSCs and phenolics (caffeic, p-coumaric, ferulic, gallic acids, and quercetin) indicate that both classes of compounds may contribute to the cytotoxic action of garlic.

Diallyl trisulfide (DATS) is an organic sulfur compound derived from garlic (Allium sativum L). DATS is characterized by its oily and volatile nature, exhibiting insolubility in water and ethanol, while being miscible with ether. This property enhances its extraction process and expands its applicability across various fields. Recent studies have elucidated the diverse effects of DATS, demonstrating significant progress in healthcare, the food industry, and nanoformulation research. Research on DATS is currently limited, hindering a comprehensive understanding and appreciation of its possibilities for future development. This review offers an in-depth examination of the characteristics of DATS, highlighting the significant advancements and benefits achieved in the fields of drug metabolism, pharmacological effects, clinical trials, food chemistry applications, and nanoformulation research over the past two decades. In addition, this review examines the future prospects of DATS, emphasizing its current development status and challenges, while serving as a crucial reference for advancing research, application, and innovation in the field.

The aim of this study was to evaluate the chemical compounds of garlic essential oil (EO), and determine the antifungal efficacy of garlic EO and its major components, diallyl trisulfide and its nanoemulsions against wood-rotting fungi, Trametes hirsuta and Laetiporus sulphureus. GC-MS analysis revealed that the major constituents of garlic EO were diallyl trisulfide (39.79%), diallyl disulfide (32.91%), and diallyl sulfide (7.02%). In antifungal activity, the IC50 value of garlic EO against T. hirsuta and L. sulphureus were 137.3 and 44.6 μg/mL, respectively. Results from the antifungal tests demonstrated that the three major constituents were shown to have good antifungal activity, in which, diallyl trisulfide was the most effective against T. hirsuta and L. sulphureus, with the IC50 values of 56.1 and 31.6 μg/mL, respectively. The diallyl trisulfide nanoemulsions showed high antifungal efficacy against the examined wood-rotting fungi, and as the amount of diallyl trisulfide in the lipid phase increases, the antifungal efficacy of the nanoemulsions increases. These results showed that the nanoemulsions and normal emulsion of diallyl trisulfide have potential to develop into a natural wood preservative.

Currently, no safe vaccine against leishmaniasis is available. So far, different control strategies against numerous reservoir hosts and biological vectors have not been environment-friendly and feasible. Hence, employing medicinal components and conventional drugs could be a promising approach to developing novel therapeutic alternatives. This study aimed to explore diallyl sulfide (DAS), a dynamic constituent of garlic, alone and in a mixture with meglumine antimoniate (MAT as standard drug) using in vitro and animal model experiments against Leishmania major stages. The binding affinity of DAS and four major defense elements of the immune system (iNOS, IFN-ɣ, IL-12, and TNF-α) was used to predict the predominant binding mode for molecular docking configurations. Herein, we conducted a broad range of experiments to monitor and assess DAS and MAT potential treatment outcomes. DAS, combined with MAT, displayed no cytotoxicity and employed a powerful anti-leishmanial activity, notably against the clinical stage. The function mechanism involved immunomodulation through the induction of Th1 cytokine phenotypes, triggering a high apoptotic profile, reactive oxygen species (ROS) production, and antioxidant enzymes. This combination significantly decreased cutaneous lesion diameter and parasite load in BALB/c mice. The histopathological findings performed the infiltration of inflammatory cells associated with T-lymphocytes, particularly CD4+ phenotypes, as determined by biochemical markers in alleviating the amastigote stage and improving the pathological changes in L . major infected BALB/c mice. Therefore, DAS and MAT deserve further advanced therapeutic development and should be considered as possible candidates for treating volunteer cases with cutaneous leishmaniasis in designing an upcoming clinical trial.

Diallyl disulfide (DADS) and allyl methyl sulfide (AMS) have been known as a metabolic product of sulfur-containing foods, typically garlic. The odour of such organosulfur compounds following garlic ingestion is often considered as an unpleasant element. Although previous studies have identified the DADS and AMS associated with garlic breath, no study has been reported on the determination of both compounds emanating from human skin surface. This study aimed to demonstrate the effect of garlic ingestion on the dermal emissions of DADS and AMS using a passive flux sampler coupled with gas chromatography-mass spectrometry. Firstly, baseline levels were investigated for 30 healthy volunteers in their daily life. The results of 1 h-sampling at the forearm showed the emission fluxes of both compounds followed the lognormal distribution with a geometric mean of 0.18 ng cm −2 h −1 for DADS and 0.22 ng cm −2 h −1 for AMS. Subsequently, the garlic ingestion tests were conducted for selected volunteers. The emission flux of DADS increased just after grilled garlic ingestion and decreased gradually thereafter. In contrast, the dermal emission flux of AMS reached a peak at 30 min after ingestion, and then gradually decreased. This peak shift suggests AMS is relatively latent in the skin organs.