Danoprevir: First Global Approval

Oxysulfonylation of Alkynes with Sodium Sulfinates to Access β-Keto Sulfones Catalyzed by BF3·OEt2

An efficient and operationally simple method for the synthesis of β-keto sulfones through the BF3·OEt2-promoted reaction of alkynes and sodium sulfinates is developed. With its facile and selective access to the targets, it features good functional group compatibility, mild conditions, easily available starting materials, and good yields. Notably, the reaction does not require metal catalysts or chemical reagents with pungent odors.

Transition metal-free C(sp3)-H selenation of β-ketosulfones

The installation of selenium groups has become an essential step across a number of industries such as agrochemicals, drug discovery, and materials. However, direct C(sp3)-H selenation, which is most atom economical, remains a formidable challenge, and only a few examples have been reported to date. In this article, we introduce the transition metal-free C(sp3)-H selenation with the easily available β-ketosulfones and diselenides as the material source. This benign protocol permits access to a broad spectrum of α-aryl(alkyl) seleno-β-ketosulfones in high yields with outstanding functional group compatibility. Distinct advantages of this protocol over all previous methods encompass the utilization of base and air as an oxidant, room temperature, and enhanced green chemistry matrices.

Hepatitis C: The Story of a Long Journey through First, Second, and Third Generation NS3/4A Peptidomimetic Inhibitors. What Did We Learn?

Hepatitis C viral (HCV) infection is the leading cause of liver failure and still represents a global health burden. Over the past decade, great advancements made HCV curable, and sustained viral remission significantly improved to more than 98%. Historical treatment with pegylated interferon alpha and ribavirin has been displaced by combinations of direct-acting antivirals. These regimens include drugs targeting different stages of the HCV life cycle. However, the emergence of viral resistance remains a big concern. The design of peptidomimetic inhibitors (PIs) able to fit and fill the conserved substrate envelope region within the active site helped avoid contact with the vulnerable sites of the most common resistance-associated substitutions Arg155, Ala156, and Asp168. Herein, we give an overview of HCV NS3 PIs discovered during the past decade, and we deeply discuss the rationale behind the structural optimization efforts essential to achieve pangenotypic activity.

Asymmetric Synthesis of US-FDA Approved Drugs over Five Years (2016–2020): A Recapitulation of Chirality

Chirality is a major theme in the design, discovery, and development of new drugs. Historically, pharmaceuticals have been synthesized as racemic mixtures. However, the enantiomeric forms of drug molecules have distinct biological properties. One enantiomer may be responsible for the desired therapeutic effect (eutomer), whereas the other may be inactive, interfere with the therapeutic form, or exhibit toxicity (distomer). Classical chemical synthesis usually leads to a racemic mixture unless stereospecific synthesis is employed. To meet the requirements of single-enantiomeric drugs, asymmetric synthesis has evolved at the forefront of drug discovery. Asymmetric synthesis involves the conversion of an achiral starting material into a chiral product. This review emphasizes the methods used for synthesizing FDA-approved chiral drugs during 2016–2020, with a special focus on asymmetric synthesis by means of chiral induction, resolution, or chiral pool.

Viral proteases as therapeutic targets

Some medically important viruses-including retroviruses, flaviviruses, coronaviruses, and herpesviruses-code for a protease, which is indispensable for viral maturation and pathogenesis. Viral protease inhibitors have become an important class of antiviral drugs. Development of the first-in-class viral protease inhibitor saquinavir, which targets HIV protease, started a new era in the treatment of chronic viral diseases. Combining several drugs that target different steps of the viral life cycle enables use of lower doses of individual drugs (and thereby reduction of potential side effects, which frequently occur during long term therapy) and reduces drug-resistance development. Currently, several HIV and HCV protease inhibitors are routinely used in clinical practice. In addition, a drug including an inhibitor of SARS-CoV-2 main protease, nirmatrelvir (co-administered with a pharmacokinetic booster ritonavir as Paxlovid®), was recently authorized for emergency use. This review summarizes the basic features of the proteases of human immunodeficiency virus (HIV), hepatitis C virus (HCV), and SARS-CoV-2 and discusses the properties of their inhibitors in clinical use, as well as development of compounds in the pipeline.

Current trends in diagnosis and treatment strategies of COVID-19 infection

Coronaviruses are terrifically precise and adapted towards specialized respiratory epithelial cells, observed in organ culture and human volunteers both. This virus is found to possess an unpredictable anti-viral T-cell response which in turn results in T-cell activation and finally apoptosis, leading to cytokine storm and collapse of the whole immune system. The present review provides comprehensive information regarding SARS-CoV-2 infection, mutant strains, and the impact of SARS-COV-2 on vital organs, the pathophysiology of the disease, diagnostic tests available, and possible treatments. It also includes all the vaccines developed so far throughout the world to control this pandemic. Until now, 18 vaccines have been approved by the WHO and further 22 vaccines are in the third trial. This study also provides up-to-date information regarding the drugs repurposed in clinical trials and the recent status of allopathic drugs along with its result. Although vaccines are available, specific treatment is not available for the disease. Furthermore, the effect of vaccines on new variants is a new area of research at this time. Therefore, a preventive attitude is the best approach to fight against this virus.

Pharmacokinetics, safety and tolerability of ravidasvir, with and without danoprevir/ritonavir, in healthy subjects

Ravidasvir (RDV) is a novel oral hepatitis C virus NS5A inhibitor. This study aimed to evaluate the pharmacokinetics and safety of RDV and the drug-drug interaction between RDV and ritonavir-boosted danoprevir (DNVr) in healthy adults. In 1^st study, healthy volunteers were administered oral single doses of 100, 200 and 300 mg RDV and 200 mg once daily for 7 days. The 2^nd study was randomized, double-blind and placebo-controlled sequential design (day 1 for 200 mg RDV alone, day 7 for 100 mg/100 mg DNVr, day 13 for 200 mg RDV plus 100mg/100mg DNVr, followed by RDV 200 mg once daily with DNVr 100mg/100mg twice daily for 10 days). The results showed that RDV exposure increased in a dose-proportional manner following a single dose with no evidence of accumulation with multiple doses. Co-administration with DNVr regimen (100 mg/100 mg, twice daily) resulted in a 2.92- and 1.99-fold increase in minimum plasma concentration at steady state (C_min,ss) and area under the concentration-time curve at steady state (AUC_τ) of RDV. With co-administration of RDV, maximum plasma concentration (C_max) and area under the concentration curve from zero to 12 h (AUC_0-12) of DNV increased 1.71-fold and 2.33-fold, respectively. We did not observe any significant changes in ritonavir exposure. Both single and multiple doses of RDV with or without DNVr were well tolerated. The favorable pharmacokinetic and safety results support ravidasvir's continued clinical development and treatment.

Molecular Docking and Virtual Screening Based Prediction of Drugs for COVID-19

AIMS

To predict potential drugs for COVID-19 by using molecular docking for virtual screening of drugs approved for other clinical applications.

BACKGROUND

SARS-CoV-2 is the betacoronavirus responsible for the COVID-19 pandemic. It was listed as a potential global health threat by the WHO due to high mortality, high basic reproduction number, and lack of clinically approved drugs and vaccines. The genome of the virus responsible for COVID-19 has been sequenced. In addition, the three-dimensional structure of the main protease has been determined experimentally.

OBJECTIVE

To identify potential drugs that can be repurposed for treatment of COVID-19 by using molecular docking based virtual screening of all approved drugs.

METHODS

A list of drugs approved for clinical use was obtained from the SuperDRUG2 database. The structure of the target in the apo form, as well as structures of several target-ligand complexes, were obtained from RCSB PDB. The structure of SARS-CoV-2 Mpro determined from X-ray diffraction data was used as the target. Data regarding drugs in clinical trials for COVID-19 was obtained from clinicaltrials.org. Input for molecular docking based virtual screening was prepared by using Obabel and customized python, bash, and awk scripts. Molecular docking calculations were carried out with Vina and SMINA, and the docked conformations were analyzed and visualized with PLIP, Pymol, and Rasmol.

RESULTS

Among the drugs that are being tested in clinical trials for COVID-19, Danoprevir and Darunavir were predicted to have the highest binding affinity for the Main protease (Mpro) target of SARS-CoV-2. Saquinavir and Beclabuvir were identified as the best novel candidates for COVID-19 therapy by using Virtual Screening of drugs approved for other clinical indications.

CONCLUSION

Protease inhibitors approved for treatment of other viral diseases have the potential to be repurposed for treatment of COVID-19.

Recent advances in the synthesis and applications of β-keto sulfones: new prospects for the synthesis of β-keto thiosulfones

This review mainly focuses on recent developments in the preparation of β-keto sulfones and their extensive synthetic applications. New prospects for the synthesis of β-keto thiosulfones have also been highlighted. Over the last decade, there has been exponential growth in the direct construction of β-keto sulfones using a wide variety of keto and sulfonyl precursors. Of note, the most promising photoredox transformations and electrochemical synthesis methods of β-keto sulfones are also presented. Moreover, β-keto sulfones are versatile building blocks in organic synthesis due to their three essential functional groups: sulfonyl, carbonyl, and active methylene moieties. The convenient preparation of β-keto sulfones allows the synthesis of many valuable carbocyclic and heterocyclic compounds, and the effortless removal of the sulfonyl moiety via transformations is supported. The chemistry of β-keto sulfones (2013 to present) can be divided into several sections based on the sulfonyl surrogates, and ubiquitous synthetic strategies were systematically outlined.

Oxidative Sulfonylation of Hydrazones Enabled by Synergistic Copper/Silver Catalysis

A copper/silver-cocatalyzed protocol for oxidative sulfonylation of hydrazones is demonstrated. A wide range of β-ketosulfones and N-acylsulfonamides are directly synthesized in moderate to good yields. Our work provides a viable method for scalable preparation of β-ketosulfone derivatives that have found wide applications in the pharmaceutical industry.

Pharmacological treatments of COVID-19

The viral infection due to the new coronavirus or coronavirus disease 2019 (COVID-19), which was reported for the first time in December 2019, was named by the World Health Organization (WHO) as Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV2), because of the very similar genome and also its related symptoms to SARS-CoV1. The ongoing COVID-19 pandemic with significant mortality, morbidity, and socioeconomic impact is considered by the WHO as a global public health emergency. Since there is no specific treatment available for SARS-CoV2 infection, and or COVID-19, several clinical and sub-clinical studies are currently undertaken to find a gold-standard therapeutic regimen with high efficacy and low side effect. Based on the published scientific evidence published to date, we summarized herein the effects of different potential therapies and up-to-date clinical trials. The review is intended to help readers aware of potentially effective COVID-19 treatment and provide useful references for future studies.

Existing antiviral options against SARS-CoV-2 replication in COVID-19 patients

COVID-19 caused by SARS-CoV-2, is an international concern. This infection requires urgent efforts to develop new antiviral compounds. To date, no specific drug in controlling this disease has been identified. Developing the new treatment is usually time consuming, therefore using the repurposing broad-spectrum antiviral drugs could be an effective strategy to respond immediately. In this review, a number of broad-spectrum antivirals with potential efficacy to inhibit the virus replication via targeting the virus spike protein (S protein), RNA-dependent RNA polymerase (RdRp), 3-chymotrypsin-like protease (3CLpro) and papain-like protease (PLpro) that are critical in the pathogenesis and life cycle of coronavirus, have been evaluated as possible treatment options against SARS-CoV-2 in COVID-19 patients.

SARS-CoV-2: A critical review of its history, pathogenesis, transmission, diagnosis and treatment

The outbreak of the deadly virus (novel coronavirus or Severe Acute Respiratory Syndrome Coronavirus-2) that emerged in December 2019, remained a controversial subject of intense speculations regarding its origin, became a worldwide health problem resulting in serious coronavirus disease 2019 (acronym COVID-19). The concern regarding this new viral strain "Severe Acute Respiratory Syndrome Coronavirus-2" (acronym SARS-CoV-2) and diseases it causes (COVID-19) is well deserved at all levels. The incidence of COVID-19 infection and infectious patients are increasing at a high rate. Coronaviruses (CoVs), enclosed positive-sense RNA viruses, are distinguished by club-like spikes extending from their surface, an exceptionally large genome of RNA, and a special mechanism for replication. Coronaviruses are associated with a broad variety of human and other animal diseases spanning from enteritis in cattle and pigs and upper chicken respiratory disease to extremely lethal human respiratory infections. With World Health Organization (WHO) declaring COVID-19 as pandemic, we deemed it necessary to provide a detailed review of coronaviruses discussing their history, current situation, coronavirus classification, pathogenesis, structure, mode of action, diagnosis and treatment, the effect of environmental factors, risk reduction and guidelines to understand the virus and develop ways to control it.

COVID-19 treatment: Much research and testing, but far, few magic bullets against SARS-CoV-2 coronavirus

The new virus of the of β-Coronaviruses genus, SARS-CoV-2, is the causative agent of coronavirus disease-2019 (COVID-19) and is winning a proverbial chess match against all players simultaneous, including physicians, clinicians, pathologists, doctors, scientists, economists, athletes and politicians. The COVID-19 outbreak has seriously threatened public health, killing the most vulnerable persons and causing general panic. To stop this disease, effective remedies (i.e., drugs, vaccines, personal protection elements, etc.) are urgently required. Unfortunately, no registered specific therapies (including antiviral therapies, immune-modulating agents and vaccines) are currently available to treat coronavirus infections, highlighting an urgent need for therapeutics targeting SARS-CoV-2. In this work, fourteen existing small molecule drugs or/and experimental drugs selected by experts and examined from the point of view of bioavailability via the Lipinski-Veber rules and assessment of their physicochemical descriptors. The aim of this study is to discover selected pattern similarities and peculiar characteristics that could be useful for antiviral drug optimization, drug combination or new antiviral agent design.

COVID-19 treatment: Much research and testing, but far, few magic bullets against SARS-CoV-2 coronavirus

The new virus of the of β-Coronaviruses genus, SARS-CoV-2, is the causative agent of coronavirus disease-2019 (COVID-19) and is winning a proverbial chess match against all players simultaneous, including physicians, clinicians, pathologists, doctors, scientists, economists, athletes and politicians. The COVID-19 outbreak has seriously threatened public health, killing the most vulnerable persons and causing general panic. To stop this disease, effective remedies (i.e., drugs, vaccines, personal protection elements, etc.) are urgently required. Unfortunately, no registered specific therapies (including antiviral therapies, immune-modulating agents and vaccines) are currently available to treat coronavirus infections, highlighting an urgent need for therapeutics targeting SARS-CoV-2. In this work, fourteen existing small molecule drugs or/and experimental drugs selected by experts and examined from the point of view of bioavailability via the Lipinski-Veber rules and assessment of their physicochemical descriptors. The aim of this study is to discover selected pattern similarities and peculiar characteristics that could be useful for antiviral drug optimization, drug combination or new antiviral agent design.

A narrative literature review on traditional medicine options for treatment of corona virus disease 2019 (COVID-19)

Coronavirus disease 2019 (COVID-19) as a life-threatening disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that is accounted as global public health concern. Treatment of COVID-19 is primarily supportive and the role of antiviral agents is yet to be established. However, there are no specific anti-COVID-19 drugs and vaccine until now. This review focuses on traditional medicine such as medicinal plant extracts as promising approaches against COVID-19. Chinese, Indian and Iranian traditional medicine, suggests some herbs for prevention, treatment and rehabilitation of the diseases including COVID-19. Although, inhibition of viral replication is considered as general mechanism of herbal extracts, however some studies demonstrated that traditional herbal extracts can interact with key viral proteins which are associated with virus virulence. Chinese, Indian and Iranian traditional medicine, suggests some herbs for prevention, treatment and rehabilitation of the diseases including COVID-19. However the beneficial effects of these traditional medicines and their clinical trials remained to be known. Herein, we reviewed the latest updates on traditional medicines proposed for treatment of COVID-19.

Is Antioxidant Therapy a Useful Complementary Measure for Covid-19 Treatment? An Algorithm for Its Application

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes the corona virus disease-19 which is accompanied by severe pneumonia, pulmonary alveolar collapses and which stops oxygen exchange. Viral transmissibility and pathogenesis depend on recognition by a receptor in the host, protease cleavage of the host membrane and fusion. SARS-CoV-2 binds to the angiotensin converting enzyme 2 receptor. Here, we discuss the general characteristics of the virus, its mechanism of action and the way in which the mechanism correlates with the comorbidities that increase the death rate. We also discuss the currently proposed therapeutic measures and propose the use of antioxidant drugs to help patients infected with the SARS-CoV-2. Oxidizing agents come from phagocytic leukocytes such as neutrophils, monocytes, macrophages and eosinophils that invade tissue. Free radicals promote cytotoxicity thus injuring cells. They also trigger the mechanism of inflammation by mediating the activation of NFkB and inducing the transcription of cytokine production genes. Release of cytokines enhances the inflammatory response. Oxidative stress is elevated during critical illnesses and contributes to organ failure. In corona virus disease-19 there is an intense inflammatory response known as a cytokine storm that could be mediated by oxidative stress. Although antioxidant therapy has not been tested in corona virus disease-19, the consequences of antioxidant therapy in sepsis, acute respiratory distress syndrome and acute lung injury are known. It improves oxygenation rates, glutathione levels and strengthens the immune response. It reduces mechanical ventilation time, the length of stay in the intensive care unit, multiple organ dysfunctions and the length of stay in the hospital and mortality rates in acute lung injury/acute respiratory distress syndrome and could thus help patients with corona virus disease-19.

Potential Repurposed Therapeutics and New Vaccines against COVID-19 and Their Clinical Status

SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), was first reported in Wuhan, China, in December 2019. Since then, the virus has stretched its grip to almost all the countries in the world, affecting millions of people and causing enormous casualties. The World Health Organization (WHO) declared COVID-19 a pandemic on March 11, 2019. As of June 12, 2020, almost 7.30 million people have already been infected globally, with 413,000 reported casualties. In the United States alone, 2.06 million people have been infected and 115,000 have succumbed to this pandemic. A multipronged approach has been launched toward combating this pandemic, with the main focus on exhaustive screening, developing efficacious therapies, and vaccines for long-term immunity. Several pharmaceutical companies in collaboration with various academic institutions and governmental organizations have started investigating new therapeutics and repurposing approved drugs so as to find fast and affordable treatments against this disease. The present communication is aimed at highlighting the efforts that are currently underway to treat or prevent SARS-CoV-2 infection, with details on the science, clinical status, and timeline for selected investigational drugs and vaccines. This article is going to be of immense help to the scientific community and researchers as it brings forth all the necessary clinical information of the most-talked-about therapeutics against SARS-CoV-2. All the details pertaining to the clinical status of each therapeutic candidate have been updated as of June 12, 2020.

Danoprevir for the Treatment of Hepatitis C Virus Infection: Design, Development, and Place in Therapy

On June 8, 2018, an NS3/4A protease inhibitor called danoprevir was approved in China to treat the infections of HCV genotype (GT) 1b – the most common HCV genotype worldwide. Based on phase 2 and 3 clinical trials, the 12-week regimen of ritonavir-boosted danoprevir (danoprevir/r) plus peginterferon alpha-2a and ribavirin offered 97.1% (200/206) of sustained virologic response at post-treatment week 12 (SVR12) in treatment-naïve non-cirrhotic patients infected with HCV genotype 1b. Adverse events such as anemia, fatigue, fever, and headache were associated with the inclusion of peginterferon alpha-2a and ribavirin in the danoprevir-based regimen. Moreover, drug resistance to danoprevir could be traced to amino acid substitutions (Q80K/R, R155K, D168A/E/H/N/T/V) near the drug-binding pocket of HCV NS3 protease. Despite its approval, the clinical use of danoprevir is currently limited to its combination with peginterferon alpha-2a and ribavirin, thereby driving its development towards interferon-free, ribavirin-free regimens with improved tolerability and adherence. In the foreseeable future, pan-genotypic direct-acting antivirals with better clinical efficacy and less adverse events will be available to treat HCV infections worldwide.

Tailor-Made Amino Acids and Fluorinated Motifs as Prominent Traits in Modern Pharmaceuticals

Structural analysis of modern pharmaceutical practices allows for the identification of two rapidly growing trends: the introduction of tailor-made amino acids and the exploitation of fluorinated motifs. Curiously, the former represents one of the most ubiquitous classes of naturally occurring compounds, whereas the latter is the most xenobiotic and comprised virtually entirely of man-made derivatives. Herein, 39 selected compounds, featuring both of these traits in the same molecule, are profiled. The total synthesis, source of the corresponding amino acids and fluorinated residues, and medicinal chemistry aspects and biological properties of the molecules are discussed.

An early assessment of the efficacy of medicines in the treatment of patients with COVID-19

Coronavirus infection 2019 is considered a modern challenge to the world community. In the absence of vaccines and antivirals, effective and safe medicines are an urgent request from the healthcare system. We have evaluated the medical technologies for COVID-19 which are being examined. The search was conducted on the СlinicalTrials.gov at the beginning of April 2020. As a result it was shown that the growth of new clinical trials in the world devoted to COVID-19 is growing by 65% per week. More often, interventional clinical trials of the II and III phases are carried out. Most studies are planned or conducted in Western Europe (n = 92), China (n = 79), and the United States (n = 51). Surrogate points are usually evaluated, such as: clinical recovery, symptom-based disease relief (fever, cough, diarrhea, myalgia, shortness of breath), lack of progression of shortness of breath, rate of artificial ventilation, rate of admission to the intensive care unit, etc. It is antimalarial drugs that are mainly studied. Currently, it is not possible to discuss the efficacy and safety of a drug in the treatment of COVID-19, as most studies have just begun. The therapeutic regimens proposed now in clinical recommendations have no evidence base, and the studies indicated in them are at best considered hypothesizing.

Clinical trials on drug repositioning for COVID-19 treatment

The World Health Organization (WHO) was informed on December 2019 about a coronavirus pneumonia outbreak in Wuhan, Hubei province (China). Subsequently, on March 12, 2020, 125,048 cases and 4,614 deaths were reported. Coronavirus is an enveloped RNA virus, from the genus Betacoronavirus, that is distributed in birds, humans, and other mammals. WHO has named the novel coronavirus disease as COVID-19. More than 80 clinical trials have been launched to test coronavirus treatment, including some drug repurposing or repositioning for COVID-19. Hence, we performed a search in March 2020 of the clinicaltrials.gov database. The eligibility criteria for the retrieved studies were: contain a clinicaltrials.gov base identifier number; describe the number of participants and the period for the study; describe the participants' clinical conditions; and utilize interventions with medicines already studied or approved for any other disease in patients infected with the novel coronavirus SARS-CoV-2 (2019-nCoV). It is essential to emphasize that this article only captured trials listed in the clinicaltrials.gov database. We identified 24 clinical trials, involving more than 20 medicines, such as human immunoglobulin, interferons, chloroquine, hydroxychloroquine, arbidol, remdesivir, favipiravir, lopinavir, ritonavir, oseltamivir, methylprednisolone, bevacizumab, and traditional Chinese medicines (TCM). Although drug repurposing has some limitations, repositioning clinical trials may represent an attractive strategy because they facilitate the discovery of new classes of medicines; they have lower costs and take less time to reach the market; and there are existing pharmaceutical supply chains for formulation and distribution.