Effects of Cannabidiol, ∆9-Tetrahydrocannabinol, and WIN 55-212-22 on the Viability of Canine and Human Non-Hodgkin Lymphoma Cell Lines.

In our previous study, we demonstrated the impact of overexpression of CB1 and CB2 cannabinoid receptors and the inhibitory effect of endocannabinoids (2-arachidonoylglycerol (2-AG) and Anandamide (AEA)) on canine (Canis lupus familiaris) and human (Homo sapiens) non-Hodgkin lymphoma (NHL) cell lines' viability compared to cells treated with a vehicle. The purpose of this study was to demonstrate the anti-cancer effects of the phytocannabinoids, cannabidiol (CBD) and ∆9-tetrahydrocannabinol (THC), and the synthetic cannabinoid WIN 55-212-22 (WIN) in canine and human lymphoma cell lines and to compare their inhibitory effect to that of endocannabinoids. We used malignant canine B-cell lymphoma (BCL) (1771 and CLB-L1) and T-cell lymphoma (TCL) (CL-1) cell lines, and human BCL cell line (RAMOS). Our cell viability assay results demonstrated, compared to the controls, a biphasic effect (concentration range from 0.5 µM to 50 µM) with a significant reduction in cancer viability for both phytocannabinoids and the synthetic cannabinoid. However, the decrease in cell viability in the TCL CL-1 line was limited to CBD. The results of the biochemical analysis using the 1771 BCL cell line revealed a significant increase in markers of oxidative stress, inflammation, and apoptosis, and a decrease in markers of mitochondrial function in cells treated with the exogenous cannabinoids compared to the control. Based on the IC50 values, CBD was the most potent phytocannabinoid in reducing lymphoma cell viability in 1771, Ramos, and CL-1. Previously, we demonstrated the endocannabinoid AEA to be more potent than 2-AG. Our study suggests that future studies should use CBD and AEA for further cannabinoid testing as they might reduce tumor burden in malignant NHL of canines and humans.

The Mechanism of Inhibition of Mycobacterial (p)ppGpp Synthetases by a Synthetic Analog of Erogorgiaene.

The synthesis of (p)ppGpp alarmones plays a vital role in the regulation of metabolism suppression, growth rate control, virulence, bacterial persistence, and biofilm formation. The (p)ppGpp alarmones are synthesized by proteins of the RelA/SpoT homolog (RSH) superfamily, including long bifunctional RSH proteins and small alarmone synthetases. Here, we investigated enzyme kinetics and dose-dependent enzyme inhibition to elucidate the mechanism of 4-(4,7-dimethyl-1,2,3,4-tetrahydronaphthalen-1-yl)pentanoic acid (DMNP) action on the (p)ppGpp synthetases RelMsm and RelZ from Mycolicibacterium smegmatis and RelMtb from Mycobacterium tuberculosis. DMNP was found to inhibit the activity of RelMtb. According to the enzyme kinetics analysis, DMNP acts as a noncompetitive inhibitor of RelMsm and RelZ. Based on the results of molecular docking, the DMNP-binding site is located in the proximity of the synthetase domain active site. This study might help in the development of alarmone synthetase inhibitors, which includes relacin and its derivatives, as well as DMNP - a synthetic analog of the marine coral metabolite erogorgiaene. Unlike conventional antibiotics, alarmone synthetase inhibitors target metabolic pathways linked to the bacterial stringent response. Although these pathways are not essential for bacteria, they regulate the development of adaptation mechanisms. Combining conventional antibiotics that target actively growing cells with compounds that impede bacterial adaptation may address challenges associated with antimicrobial resistance and bacterial persistence.

A dual-targeting antifungal is effective against multidrug-resistant human fungal pathogens.

Drug-resistant fungal infections pose a significant threat to human health. Dual-targeting compounds, which have multiple targets on a single pathogen, offer an effective approach to combat drug-resistant pathogens, although ensuring potent activity and high selectivity remains a challenge. Here we propose a dual-targeting strategy for designing antifungal compounds. We incorporate DNA-binding naphthalene groups as the hydrophobic moieties into the host defence peptide-mimicking poly(2-oxazoline)s. This resulted in a compound, (Gly0.8Nap0.2)20, which targets both the fungal membrane and DNA. This compound kills clinical strains of multidrug-resistant fungi including Candida spp., Cryptococcus neoformans, Cryptococcus gattii and Aspergillus fumigatus. (Gly0.8Nap0.2)20 shows superior performance compared with amphotericin B by showing not only potent antifungal activities but also high antifungal selectivity. The compound also does not induce antimicrobial resistance. Moreover, (Gly0.8Nap0.2)20 exhibits promising in vivo therapeutic activities against drug-resistant Candida albicans in mouse models of skin abrasion, corneal infection and systemic infection. This study shows that dual-targeting antifungal compounds may be effective in combating drug-resistant fungal pathogens and mitigating fungal resistance.

Isolation of undescribed cladosporols and spirobisnaphthalenes from a plant pathogen Cladosporium cladosporioides F-10-2-A.

Two undescribed cladosporol derivatives, cladosporols J-K (1-2), and three previously unreported spirobisnaphthalenes, urnucratins D-F (3-5), as well as eleven known cladosporols (6-16), were characterized from Cladosporium cladosporioides (Cladosporiaceae), a common plant pathogen isolated from the skin of Chinese toad. Cladosporols J-K (1-2) with a single double bond have been rarely reported, while urnucratins D-F (3-5) featured an unusual benzoquinone bisnaphthospiroether skeleton, contributing to an expanding category of undiscovered natural products. Their structures and absolute configurations were determined using extensive spectroscopic methods, including NMR, HRESIMS analyses, X-ray single crystal diffraction, as well as through experimental ECD analyses. Biological assays revealed that compounds 1 and 2 exhibited inhibitory activity against A549 cells, with IC50 values of 30.11 ± 3.29 and 34.32 ± 2.66 µM, respectively.

Discriminative stimulus properties of Cannabis sativa terpenes in rats.

Cannabis is a pharmacologically complex plant consisting of hundreds of potentially active compounds. One class of compounds present in cannabis that has received little attention are terpenes. Traditionally thought to impart aroma and flavor to cannabis, it has become increasingly recognized that terpenes might exert therapeutic effects themselves. Several recent reports have also indicated terpenes might behave as cannabinoid type 1 (CB1) receptor agonists. This study aimed to investigate whether several terpenes present in cannabis produce discriminative stimulus effects similar to or enhance the effects of Δ 9 -tetrahydrocannabinol (THC). Subsequent experiments explored other potential cannabimimetic effects of these terpenes. Rats were trained to discriminate THC from vehicle while responding under a fixed-ratio 10 schedule of food presentation. Substitution testing was performed with the CB receptor agonist JWH-018 and the terpenes linalool, limonene, γ-terpinene and α-humulene alone. Terpenes were also studied in combination with THC. Finally, THC and terpenes were tested in the tetrad assay to screen for CB1-receptor agonist-like effects. THC and JWH-018 dose-dependently produced responding on the THC-paired lever. When administered alone, none of the terpenes produced responding predominantly on the THC-paired lever. When administered in combination with THC, none of the terpenes enhanced the potency of THC, and in the case of α-humulene, decreased the potency of THC to produce responding on the THC-paired lever. While THC produced effects in all four tetrad components, none of the terpenes produced effects in all four components. Therefore, the terpenes examined in this report do not have effects consistent with CB1 receptor agonist properties in the brain.

A derivative of trihydroxynaphthalenone and a pyrone metabolite from the endophytic fungus Talaromyces purpurpgenus.

A newly discovered trihydroxynaphthalenone derivative, epoxynaphthalenone (1) involving the condensation of ortho-hydroxyl groups into an epoxy structure, and a novel pyrone metabolite characterized as pyroneaceacid (2), were extracted from Talaromyces purpurpgenus, an endophytic fungus residing in Rhododendron molle. The structures of these compounds were elucidated through a comprehensive analysis of their NMR and HRESIMS data. The determination of absolute configurations was accomplished using electronic circular dichroism (ECD) calculations and CD spectra. Notably, these recently identified metabolites exhibited a moderate inhibitory activity against xanthine oxidase (XOD).

NPS-2143 inhibit glioma progression by suppressing autophagy through mediating AKT-mTOR pathway.

Gliomas are the most common tumours in the central nervous system. In the present study, we aimed to find a promising anti-glioma compound and investigate the underlying molecular mechanism. Glioma cells were subjected to the 50 candidate compounds at a final concentration of 10 µM for 72 h, and CCK-8 was used to evaluate their cytotoxicity. NPS-2143, an antagonist of calcium-sensing receptor (CASR), was selected for further study due to its potent cytotoxicity to glioma cells. Our results showed that NPS-2143 could inhibit the proliferation of glioma cells and induce G1 phase cell cycle arrest. Meanwhile, NPS-2143 could induce glioma cell apoptosis by increasing the caspase-3/6/9 activity. NPS-2143 impaired the immigration and invasion ability of glioma cells by regulating the epithelial-mesenchymal transition process. Mechanically, NPS-2143 could inhibit autophagy by mediating the AKT-mTOR pathway. Bioinformatic analysis showed that the prognosis of glioma patients with low expression of CASR mRNA was better than those with high expression of CASR mRNA. Gene set enrichment analysis showed that CASR was associated with cell adhesion molecules and lysosomes in glioma. The nude mice xenograft model showed NPS-2143 could suppress glioma growth in vivo. In conclusion, NPS-2143 can suppress the glioma progression by inhibiting autophagy.

Discovery of novel dihydronaphthalene-imidazole ligands as potential inhibitors of Staphylococcus aureus multidrug resistant NorA efflux pump: A combination of experimental and in silico molecular docking studies.

Overexpression of the efflux pump is a predominant mechanism by which bacteria show antimicrobial resistance (AMR) and leads to the global emergence of multidrug resistance (MDR). In this work, the inhibitory potential of library of dihydronapthyl scaffold-based imidazole derivatives having structural resemblances with some known efflux pump inhibitors (EPI) were designed, synthesized and evaluated against efflux pump inhibitor against overexpressing bacterial strains to study the synergistic effect of compounds and antibiotics. Out of 15 compounds, four compounds (Dz-1, Dz-3, Dz-7, and Dz-8) were found to be highly active. DZ-3 modulated the MIC of ciprofloxacin, erythromycin, and tetracycline by 128-fold each against 1199B, XU212 and RN4220 strains of S. aureus respectively. DZ-3 also potentiated tetracycline by 64-fold in E. coli AG100 strain. DZ-7 modulated the MIC of both tetracycline and erythromycin 128-fold each in S. aureus XU212 and S. aureus RN4220 strains. DZ-1 and DZ-8 showed the moderate reduction in MIC of tetracycline in E. coli AG100 only by 16-fold and 8-fold, respectively. DZ-3 was found to be the potential inhibitor of NorA as determined by ethidium bromide efflux inhibition and accumulation studies employing NorA overexpressing strain SA-1199B. DZ-3 displayed EPI activity at non-cytotoxic concentration to human cells and did not possess any antibacterial activity. Furthermore, molecular docking studies of DZ-3 was carried out in order to understand the possible binding sites of DZ-3 with the active site of the protein. These studies indicate that dihydronaphthalene scaffolds could serve as valuable cores for the development of promising EPIs.

Bibenzyl and naphthalene derivatives from Dendrobium chrysanthum and their anti-hepatic-steatosis activities.

In this study, 16 new compounds, six bibenzyls (1-6) and 10 naphthalenes (7-13), including three pairs of naphthalene enantiomers and three known compounds (14-16), were isolated from Dendrobium chrysanthum. Structurally, compounds 1-5 are previously undescribed dimeric bibenzyls, uniquely linked by unusual carbon bonds. The structures of the compounds were determined using spectroscopy and X-ray crystallography. The screening results indicated that 1, 2, and 5 showed remarkable lipid-lowering activities in FFA-induced HepG2 cells, with EC50 values ranging from 3.13 to 6.57 µM. Moreover, 1, 2, and 5 significantly decreased both the mRNA and protein levels of the target SREBP-1c, and 5 also reduced PPARα mRNA and protein levels. Therefore, 1, 2, and 5 are potential drugs against hepatic steatosis by targeting PPARα or SREBP-1c.

Chitosan-sulfonic acid-catalyzed green synthesis of naphthalene-based azines as potential anticancer agents.

Aim: This study focuses on advancing green chemistry in anticancer drug discovery, particularly through the synthesis of azine derivatives with a naphthalene core using CS-SO3H as a catalyst. Methods: Novel benzaldazine and ketazine derivatives were synthesized using (E)-(naphthalen-1-ylmethylene)hydrazine and various carbonyl compounds. The methods employed included thermal and grinding techniques, utilizing CS-SO3H as an eco-friendly and cost-effective catalyst. Results: The approach resulted in high yields, short reaction times and demonstrated catalyst reusability. Cytotoxicity tests highlighted compounds 3b, 11 and 13 as potent against the HEPG2-1. Conclusion: This study successfully aligns with the objectives of eco-conscious drug development in organic chemistry. Molecular docking and in silico studies further indicate the potential of these ligands as antitumor medicines, with favorable oral bioavailability properties.

In vitro determination of the combination of ciclopirox and terbinafine in the treatment of dermatophytosis.

INTRODUCTION: The cases of dermatophytosis are increasing and they are associated with a higher number of therapeutic failures leading the doctor to prescribe combinations of antifungals as therapy. The objective was to evaluate the interaction of terbinafine and ciclopirox, the most commonly antifungals used in the clinic, in dermatophyte isolates. METHODOLOGY: The minimum inhibitory concentrations (MIC) of ciclopirox and terbinafine were determined by the broth microdilution method according CLSI and the checkerboard assay was used to evaluate the interaction between the antifungal agents. RESULTS: For terbinafine the mic50 was 0.125 ug/mL and mic90 was 0.250 ug/mL. For ciclopirox the values were 2.0 ug/mL for mic50 and 4.0 ug/mL for mic90. No synergistic interaction was observed for the dermatophyte isolates tested. CONCLUSION: These results suggest that the use of terbinafine in combination with ciclopirox, which is widely used in the clinic, may not be a good choice for the treatment of onychomycosis.

Identification of novel human CC chemokine receptor 8 (CCR8) antagonists via the synthesis of naphthalene amide and sulfonamide isosteres.

The human CC chemokine receptor 8 (CCR8) has been extensively pursued as target for the treatment of various inflammatory disorders. More recently, the importance of CCR8 in the tumor microenvironment has been demonstrated, spurring the interest in CCR8 antagonism as therapeutic strategy in immuno-oncology. On a previously described naphthalene sulfonamide with CCR8 antagonistic properties, the concept of isosterism was applied, leading to the discovery of novel CCR8 antagonists with IC50 values in the nM range in both the CCL1 competition binding and CCR8 calcium mobilization assay. The excellent CCR8 antagonistic activity of the most potent congeners was rationalized by homology molecular modeling.

Structure-based design and synthesis of sulfonylureas as novel NLRP3 inhibitors for Alzheimer's disease.

Alzheimer's disease (AD) remains an incurable neurodegenerative condition that poses a threat to humanity. Immune signaling in the brain, particularly the NLR family pyrin domain containing 3 (NLRP3), is currently targeted for AD treatment. Based on the crystal structure of the NACHT domain of NLRP3 and its renowned inhibitor MCC950, we designed and synthesized nineteen sulfonylurea compounds and evaluated their capacity to inhibit caspase-1 and interleukin-1ß (IL-1ß). Of these, nine were selected for measuring their IC50 for caspase-1 and cytotoxicity analysis. Finally, three compounds were chosen to assess their inhibitory effect on IL-1ß in mice. The results showed that compound 5m had a superior ability to reduce IL-1ß levels in the brain compared to MCC950 at a lower dosing concentration, indicating that 5m has the potential to penetrate the blood-brain barrier (BBB) and inhibit inflammation both in vitro and in vivo. Docking studies of compound 5m on NLRP3 revealed a binding mode similar to MCC950. These findings suggest that compound 5m holds promise as an NLRP3 inhibitor for AD treatment.

Naphthalene Diimide-Tetraazacycloalkane Conjugates Are G-Quadruplex-Based HIV-1 Inhibitors with a Dual Mode of Action.

Human immunodeficiency virus 1 (HIV-1) therapeutic regimens consist of three or more drugs targeting different steps of the viral life cycle to limit the emergence of viral resistance. In line with the multitargeting strategy, here we conjugated a naphthalene diimide (NDI) moiety with a tetraazacycloalkane to obtain novel naphthalene diimide (NDI)-tetraazacycloalkane conjugates. The NDI inhibits the HIV-1 promoter activity by binding to LTR G-quadruplexes, and the tetraazacycloalkane mimics AMD3100, which blocks HIV entry into cells by interfering with the CXCR4 coreceptor. We synthesized, purified, and tested the metal-free NDI-tetraazacycloalkane conjugate and the two derived metal-organic complexes (MOCs) that incorporate Cu2+ and Zn2+. The NDI-MOCs showed enhanced binding to LTR G4s as assessed by FRET and CD assays in vitro. They also showed enhanced activity in cells where they dose-dependently reduced LTR promoter activity and inhibited viral entry only of the HIV-1 strain that exploited the CXCR4 coreceptor. The time of addition assay confirmed the dual targeting at the different HIV-1 steps. Our results indicate that the NDI-MOC conjugates can simultaneously inhibit viral entry, by targeting the CXCR4 coreceptor, and LTR promoter activity, by stabilizing the LTR G-quadruplexes. The approach of combining multiple targets in a single compound may streamline treatment regimens and improve the overall patient outcomes.

Thiazolobenzamide-Naphthalene Hybrids as Potent Anticancer agents compared to Doxorubicin: Design, Synthesis, SAR, In-silico and Toxicity Analysis.

In order to determine whether thiazolobenzamide molecules connected to naphthalene could inhibit the growth of three different tumor cell lines, MCF7 (breast carcinoma), A549 (pulmonary carcinoma), and DU145 (prostatic adenocarcinoma) a novel series of ten molecules, designated TA 1-10, was designed, synthesized, and tested. Among these compounds, TA7 showed promising results against cell lines, especially showing exceptional efficacy against breast cancer. Antioxidant activity tests consistently showed the best performance from the TA7 molecule. Furthermore, when a dose of 50 to 500 mg/kg of the total mass of rats is given, the most effective chemical, TA7, did not exhibit any harmful effects during acute oral toxicity tests. The biochemical indicators (SGOT and SGPT) for hepatotoxicity associated with compound TA7 were found to be fairly similar to those of the control group. The findings from molecular docking, XP visualization, and MM-GBSA dG binding investigations are in agreement with the outcomes of in-vitro tests of antioxidant and anticancer capabilities. TA7 was the most effective compound among those that were docked; it bound free energy and had adequate properties for metabolism (biochemical processes), distribution (dispersion), absorption (assimilation), and excretion (elimination). This study found that the TA7 molecule, a thiazole ring system derivative connected to naphthalene, is to be a promising and possible anticancer agent and its efficacy may be further explored in clinical studies.

Prior selection of itraconazole in the treatment of recalcitrant Trichophyton indotineae infection: Real-world results from retrospective analysis.

BACKGROUND: The number of terbinafine-resistant Trichophyton indotineae is increasing in recent years while the treatment is still a matter to discuss. OBJECTIVES: To explore the best therapeutic approach, we present real-world treatment of T. indotineae infection by analysing publicly available data. METHODS: We have reviewed all published articles, mainly including case reports and case series, on the drug-resistant T. mentagrophytes complex by using the key search terms to search the databases. RESULTS: We enrolled 25 articles from 14 countries, including 203 times of treatment information for 113 patients. The cure rate of itraconazole 200 mg per day at the fourth, eighth and the twelfth week were 27.27%, 48.48% and 54.55%, respectively, which was significantly higher than terbinafine 250 mg per day (8.77%, 24.56% and 28.07%) and even 500 mg/d terbinafine. Griseofulvin 500-1000 mg for 2-6 months may be effective while fluconazole had no record of successful treatment. Voriconazole and ravuconazole had potential therapeutic efficacy. Topical therapy alone showed limited therapeutic efficacy, but the combination with oral antifungals can be alternative. CONCLUSION: Oral itraconazole 200 mg per day for 4-8 weeks was the most effective treatment out of these commonly used antifungal drugs, and can be prior selection.

Structural modification of C2-substituents on 1,4-bis(arylsulfonamido)benzene or naphthalene-N,N'-diacetic acid derivatives as potent inhibitors of the Keap1-Nrf2 protein-protein interaction.

The Keap1-Nrf2-ARE signaling pathway is an attractive therapeutic target for the prevention and treatment of oxidative stress-associated diseases by activating the cellular expression of cytoprotective enzymes and proteins. Small molecule inhibitors can directly disrupt the Keap1-Nrf2 protein-protein interaction (PPI), resulting in elevated levels of Nrf2 protein and subsequent stimulation of related antioxidant responses. Previously, we found that 1,4-bis(arylsulfonamido)benzene or naphthalene-N,N'-diacetic acid derivatives with an ether type C2-substituent on the benzene or naphthalene core exhibited potent inhibitory activities with IC50's in the submicromolar or nanomolar range. We here describe a more detailed structure-activity relationship study around the C2 substituents containing various polar linkers shedding new insight on their binding interactions with the Keap1 Kelch domain. The key observation from our findings is that the substituents at the C2-position of the benzene or naphthalene scaffold impact their inhibitory potencies in biochemical assays as well as activities in cell culture. The biochemical FP and TR-FRET assays revealed that the naphthalene derivatives 17b and 18 with an additional carboxylate at the C2 were the most active inhibitors against Keap1-Nrf2 PPI. In the cell-based assay, the two compounds were shown to be potent Nrf2 activators of the transcription of the Nrf2-dependent genes, such as HMOX2, GSTM3, and NQO1.

Exploring the Antioxidant Potency of New Naphthalene-Based Chalcone Derivatives: Design, Synthesis, Antioxidant Evaluation, Docking Study, DFT Calculations.

Naphthalene-based chalcone derivative was successfully synthesized through the condensation of 2,4-dichlorobenzaldehyde with 2-acetylnaphthalene. This chalcone, denoted as compound 1, demonstrated a versatile reactivity upon treatment with both nitrogen and carbon nucleophiles, and yielded diverse heterocyclic scaffolds such as pyrazoline, thiazole, pyrimidine, pyran, and pyridine derivatives. The pyrazoline aldehyde derivative 7 was further derivatized to produce the hydrazide-hydrazone 13, namely, (1H-pyrazol-1-yl)methylene)acetohydrazide, which was exploited to synthesize derivatives of 2-oxo-2H-chromene-3-carbohydrazide 14, 2-(4-oxo-4,5-dihydrothiazol-2-yl)acetohydrazide 15, and 3-(4-nitrophenyl)acrylohydrazide 16. All the newly synthesized compounds were characterized by melting point, elemental analysis, as well as FT-IR, 1 H-NMR and mass spectroscopy. Furthermore, these heterocyclic derivatives were screened for their antioxidant capacities using the DPPH radical assay. The results showed that compounds 5 and 10 are the most potent antioxidants with IC50 values 178, 177(µM), respectively. comparable to that of ascorbic acid which has IC50 value 148. Meanwhile, compounds 2, 12, 13, 14, 15, and 16 exhibited moderate antioxidant activities with IC50 values ranged from 266 to 291(µM). Thus, these heterocycles could emerge as promising antioxidant drugs for the treatment of oxidative stress-related diseases. Finally, molecular docking was conducted to study the binding affinity for the most potent antioxidant compounds 5, 10, and ascorbic acid inside the active pocket of Human Peroxiredoxin 5 (1HD2). DFT calculations and global descriptors were calculated for the most potent compounds to correlate the relation between chemical structure and reactivity.

The Influence of Chirality on the ß-Amino-Acid Naphthalenediimides/G-Quadruplex DNA Interaction.

G-quadruplexes (G4s) have been identified as a potential alternative chemotherapy target. A series of eight ß-amino acid derived naphthalenediimides (NDI) were screened against a series of oncogenic G4 sequences: c-KIT1, h-TELO, and TBA. Three sets of enantiomers were investigated to further our understanding of the effect of point chirality on G4 stabilisation. Enantioselective binding behaviour was observed with both c-KIT1 and h-TELO. Docking studies using GNINA and UV-vis titrations were employed to better understand this selective binding behaviour.

Exploring novel HIV-1 reverse transcriptase inhibitors with drug-resistant mutants: A double mutant surprise.

HIV-1 reverse transcriptase (RT) remains a key target for HIV drug development. As successful management of the disease requires lifelong treatment, the emergence of resistance mutations is inevitable, making development of new RT inhibitors, which remain effective against resistant variants crucial. To this end, previous computationally guided drug design efforts have resulted in catechol diether compounds, which inhibit wildtype RT with picomolar affinities and appear to be promising preclinical candidates. To confirm that these compounds remain potent against Y181C, a widespread mutation conferring resistance to first generation inhibitors, they were screened against the HIV-1 N119 clinical isolate, reported as a Y181C single mutant. In comparison to a molecular clone with the same mutation, N119 appears less susceptible to inhibition by our preclinical candidate compounds. A more detailed sequencing effort determined that N119 was misidentified and carries V106A in combination with Y181C. While both indolizine and naphthalene substituted catechol diethers are potent against the classical Y181C single mutant, the addition of V106A confers more resistance against the indolizine derivatives than the naphthalene derivatives. Crystal structures presented in this study highlight key features of the naphthyl group, which allow these compounds to remain potent in the double mutant, including stronger interactions with F227 and less reliance on V106 for stabilization of the ethoxy-uracil ring, which makes critical hydrogen bonds with other residues in the binding pocket.