Design of Potent and Proteolytically Stable Biaryl-Stapled GLP-1R/GIPR Peptide Dual Agonists.

Recent clinical trials have revealed that the chimeric peptide hormones simultaneously activating glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) demonstrate superior efficacy in glycemic control and body weight reduction, better than those activating the GLP-1R alone. However, the linear peptide-based GLP-1R/GIPR dual agonists are susceptible to proteolytic cleavage by common digestive enzymes present in the gastrointestinal tract and thus not suitable for oral administration. Here, we report the design and synthesis of biaryl-stapled peptides, with and without fatty diacid attachment, that showed potent GLP-1R/GIPR dual agonist activities. Compared to a linear peptide dual agonist and semaglutide, the biaryl-stapled peptides displayed drastically improved proteolytic stability against the common digestive enzymes. Furthermore, two stapled peptides showed excellent efficacy in an oral glucose tolerance test in mice, owing to their potent receptor activity in vitro and good pharmacokinetics exposure upon subcutaneous injection. By exploring a more comprehensive set of biaryl staplers, we expect that this stapling method could facilitate the design of the stapled peptide-based dual agonists suitable for oral administration.

Unsymmetrical 1,1-Bisboryl Species: Valuable Building Blocks in Synthesis.

Unsymmetrical 1,1-bis(boryl)alkanes and alkenes are organo-bismetallic equivalents, which are synthetically important because they allow for sequential selective transformations of C-B bonds. We reviewed the synthesis and chemical reactivity of 1,1-bis(boryl)alkanes and alkenes to provide information for the synthetic community. In the first part of this review, we disclose the synthesis and chemical reactivity of unsymmetrical 1,1-bisborylalkanes. In the second part, we describe the synthesis and chemical reactivity of unsymmetrical 1,1-bis(boryl)alkenes.

α-Borylalkyl radicals: their distinctive reactivity in modern organic synthesis.

Organoborons are extremely important for synthetic organic chemistry; they can serve as advanced intermediates for a variety of transformations. Such a well-known transformation involves the loss of the boron moiety, creating alkyl radicals. Although these originally developed protocols for alkyl radical generation remain in active use today, in recent years their α-boryl carbon-centred radicals have been joined by a new array of radical generation strategies that offer a unique reactivity to forge a wider diversity of organoborons that often operate under mild and benign conditions. Herein, we will highlight the stability and reactivity of α-borylalkyl radicals and their remarkably recent advances in order to further utilise them for C-C and C-heteroatom bond formation. Their use for this purpose has been reported over the last decade in an attempt to guide the synthetic community. Various transition-metal and metal-free methods for their generation are presented, and more advanced photoredox approaches are discussed, mainly for the period of 2009-2019.

Enantioselective, Organocatalytic, Dissymmetric 1,4- and 1,2-Addition of Malononitrile to a Keto-bisenone Followed by an Oxa-Michael Addition Cascade.

An unprecedented enantioselective dissymmetric 1,4- and 1,2-addition of malononitrile to a keto-bisenone followed by an oxa-Michael addition cascade to trap the in situ generated unstable tertiary alcohol have been developed. The quinine-derived amino-squaramide bifunctional organocatalyst worked efficiently and provides the oxa-spiro-[4,4]-nonanes in good yields and excellent diastereo- and enantioselectivities (up to 99:1 dr and 99% ee). Notably, a complete chemoselective addition of a methylene unit to an aliphatic-tethered enone over the aromatic-tethered enone was observed.

Stereoselective Desymmetrization of gem-Diborylalkanes by "Trifluorination".

An efficient and general method for the chemoselective synthesis of unsymmetrical gem-diborylalkanes is reported. This method is based on a late-stage desymmetrization through nucleophilic "trifluorination", providing chiral gem-diborylalkanes bearing a trifluoroborate group. The reaction offers a highly modular and diastereoselective approach towards the synthesis of gem-diborylcyclopropanes. The utility of the gem-diborylalkane building blocks was demonstrated by selective post-functionalization of the trifluoroborate group. These functionalizations include inter- and intra- Pd-catalyzed Suzuki-Miyaura coupling reactions.

Enantioselective Synthesis of Cyclohexadienone Containing Spiroketals via DyKat Ketalization/oxa-Michael Addition Cascade.

An oxidative dearomatization of phenol followed by a dynamic kinetic (DyKat) ketalization/oxa-Michael addition cascade using cinchona alkaloid-based chiral bifunctional amino-squaramide catalysts is reported. A broad array of sterically hindered [5,5]-spiroketals attached to a cyclohexadienone moiety in spiro-fashion is synthesized in an enantiopure form. Further, the methodology was optimized and extended to the corresponding benzannulated [5,5]-spiroketals attached to a cyclohexadienone moiety in spiro-fashion. In general, good yields and excellent diastereoselectivies and enantioselectivities (up to 20:1 dr and up to 99% ee) were obtained.

Nitrile-assisted oxidation over oxidative-annulation: Pd-catalyzed α,ß-dehydrogenation of α-cinnamyl ß-keto nitriles.

A palladium-catalyzed oxidation reaction is disclosed where the nitrile functionality on the substrate simply changes the course of the reaction. Our previous finding showed that using the Pd(ii)-catalyst in the presence of benzoquinone as an oxidant, 2-cinnamyl-1,3-dicarbonyls provides functionalized furans via oxidative cyclization. When a nitrile group is replaced with one of the carbonyl functionalities of the same substrate, the oxidative cyclization was completely suppressed; instead, the oxidation at the α,ß-position occurred to provide α,ß,γ,δ-diene containing ß-keto nitriles.

Catalyst-free Synthesis of 6-Hydroxy Indoles via the Condensation of Carboxymethyl Cyclohexadienones and Amines.

An efficient catalyst-free synthesis of 6-hydroxy indoles from carboxymethyl cyclohexadienones and primary amines has been developed. The aza-Michael addition of the in situ formed enamine, generated through the condensation of carboxymethyl unit of the substrates with an external amine, to cyclohexadienone moiety followed by rearomatization reaction to provide such indoles. Anilines, aliphatic amines, α-chiral aliphatic amines, or even ammonia were used as amine counterpart. Some of the cyclohexadienones gave 6-amino indoles instead of 6-hydroxy indoles using the Re2O7 catalyst. Various post methodological transformations were performed to explore the synthetic utility of the synthesized hydroxy indoles.

Organocatalytic, Enantioselective Synthesis of Cyclohexadienone Containing Hindered Spirocyclic Ethers through an Oxidative Dearomatization/Oxa-Michael Addition Sequence.

An unprecedented enantioselective oxa-Michael reaction of α-tertiary alcohols using cinchona-alkaloid-based chiral bifunctional squaramide catalysts is reported. An oxidative dearomatization of phenol followed by an enantioselective oxa-Michael addition sequence provided a broad array of chiral sterically hindered tetrahydrofurans and tetrahydropyrans attached to a cyclohexadienone moiety in spiro fashion. In general, good yields and excellent enantioselectivities (up to 99 %) were observed. The chiral oxo-cycles obtained have easily been transformed into chromans without disturbing the enantioselectivity.

Potential Risks and Mitigation Strategies Before the Conduct of a Clinical Trial: An Industry Perspective.

Conduct of clinical trials has undergone substantial changes over the last two decades. Newer markets, evolving guidelines and documentation and high cost involved in conducting the trials have led pharmaceutical companies to prepare a risk mitigation plan. Extensive monitoring of potential risks is an essential element of clinical trials which helps to ensure quality and integrity of a clinical investigation. Every clinical trial has pre (before the trial), conduct and post phase. This article which has been developed as a result of extensive research at ground level by a reputed pharmaceutical company to identify the potential stages of risks that could affect the overall quality and safety of a trial and its outcome during the pre-phase of trial (the stage of the trial where the study design is being planned before initiation of the clinical trial). It includes risks associated with basic study concept, protocol design, Confidential Disclosure Agreement (CDA) and Clinical Trial Authorization (CTA) application signing, vendors of central drug laboratory, site and investigator selection, Clinical Research Coordinator (CRC) meet, Informed Consent Form (ICF), Case Report Form (CRF)/ Status Report Form (SRF) preparation, Ethics Committee (EC) submission, etc. have been highlighted. The risk based mitigation strategy (to develop an effective risk monitoring plan before staring a clinical trial) has also been suggested by authors. A well-tailored and integrated plan, recognition of potential risks and their mitigation strategy can result in the pre exclusion or end to end solution of all the risks associated with pre- phase of clinical trials.

Palladium-Catalyzed Oxidative Cycloisomerization of 2-Cinnamyl-1,3-Dicarbonyls: Synthesis of Functionalized 2-Benzyl Furans.

A new palladium-catalyzed intramolecular oxidative cycloisomerization of readily available starting materials, 2-cinnamyl-1,3-dicarbonyls, has been demonstrated for the creation of structurally diverse 2-benzyl furans. The cycloisomerization occurs by a regioselective 5-exo-trig pathway. The reaction shows a broad substrate scope with good to excellent yields. Furthermore, a one-pot procedure has been executed by using readily available cinnamyl alcohols and 1,3-diketones.

Intramolecular rearrangement of α-azidoperoxides: an efficient synthesis of tert-butyl esters.

An unprecedented intramolecular rearrangement of α-azidoperoxides, promoted by simple organic base to provide tert-butyl esters, has been presented. Further, a one-pot methodology consisting of in situ generation of the α-azidoperoxides from corresponding aldehydes followed by base-promoted rearrangement to obtain the desired ester has also been executed. Relevant mechanistic studies, to provide the proof for intramolecular alkoxy transfer, are investigated.

Transition metal-free generation of N-unsubstituted imines from benzyl azides: synthesis of N-unsubstituted homoallylic amines.

An efficient transition metal-free approach for the generation of N-unsubstituted imines from azides followed by trapping with allyl nucleophile to provide N-unsubstituted homoallylic amines has been described. Although catalytic KO(t)Bu in DMSO is sufficient to allow imine generation, stoichiometric KO(t)Bu is essential in THF. Further, an enantio- and diastereoselective synthesis of homoallylic amines from benzyl azide has also been exemplified.

NRAS mutations in de novo acute leukemia: prevalence and clinical significance.

The activating mutations of the Ras gene or other abnormalities in Ras signaling pathway lead to uncontrolled growth factor-independent proliferation of hematopoietic progenitors. Oncogenic mutations in NRAS gene have been observed with variable prevalence in hematopoietic malignancies. In the present study, NRAS mutations were detected using bidirectional sequencing in 264 acute leukemia cases--129 acute lymphocytic leukemia (ALL) and 135 acute myeloid leukemia (AML) and 245 age- and gender-matched controls. Missense mutation was observed only in the 12th codon of NRAS gene in 4.7% of AML and 3.16% of ALL cases. The presence of NRAS mutation did not significantly influence blast % and lactate dehydrogenase (LDH) levels in AML patients. When the data were analyzed with respect to clinical variables, the total leukocyte count was elevated for mutation positive group, compared to negative group. In AML patients with NRAS mutations, 60% failed to achieve complete remission (CR), as compared to 34.8% in mutation negative group. These results indicated that NRAS mutations might confer poor drug response. In AML, disease free survival (DFS) in NRAS mutation positive group was lesser, compared to mutation negative group (9.5 months vs. 11.68 months). In ALL patients, DFS of NRAS mutation positive group was lesser than mutation negative group (9.2 months vs. 27.5 months). The CR rate was also lower for mutation-positive patients group, compared to mutation-negative group. In conclusion, these results suggested that presence of NRAS mutation at 12th codon was associated with poor response and poorer DFS in both ALL and AML.

Congenital gluteus maximus contracture syndrome--a case report with review of imaging findings.

Although the clinical features of gluteus maximus contracture syndrome have been frequently described, imaging features have been seldom described. Most commonly reported cases are those following intramuscular injection in the gluteal region although congenital contracture is an uncommon but important occurrence. This condition has most often been reported in children of school going age. These patients often present with difficulty in squatting, limitation of hip motion or specific deformities and often require surgical correction. We describe the plain radiography, ultrasonography (USG) and magnetic resonance imaging (MRI) features of this condition in a patient with no previous known history of intramuscular injections.

Cerebral venous thrombosis in ulcerative colitis.

Ulcerative colitis has been reported to show hyper coagulation leading to peripheral and rarely central thrombosis. A 35-year-old female was admitted with chief complaints of increased frequency of bloody diarrhea, abdominal pain, and weight loss for 2 months. The patient was diagnosed to have ulcerative colitis after sigmoidoscopy and biopsy and she was started on treatment. Two days later, the patient developed headache and seizures. Magnetic resonance imaging of brain showed cerebral venous thrombosis with venous infarcts. A high index of clinical suspicion is needed to diagnose this uncommon condition so that appropriate treatment can be initiated.

Lead-induced Hepatotoxicity and Evaluation of Certain Anti-stress Adaptogens in Poultry.

A total of 225 day-old sexed male broiler chicks (Vencobb strain) were divided randomly into 15 groups consisting of 15 chicks in each group to study the toxicity of lead on hepatocytes. Group 1 was maintained on basal diet, group 2 on polyherbal formulation (PHF; stressroak), group 3 on shilajith, group 4 on amla and group 5 on vit E + Se. Group 6 was maintained on lead for 6 weeks and group 7 on lead for 4 weeks and subsequently on basal diet without lead for the remaining 2 weeks. Groups 8, 9, 10 and 11 were given lead along with PHF, shilajith, amla and vit E + Se, respectively, throughout 6 weeks. Groups 12, 13, 14 and 15 were given lead containing diet for the first 4 weeks and subsequently treated with PHF, shilajith, amla and vit E + Se, respectively, for the remaining 2 weeks. The activity of alanine transaminase (ALT) was significantly (P<0.05) increased in the toxic control groups at the end of 4(th) week as compared to group 1. However, following treatment, there was a significant (P<0.05) reversal in groups 12-15. The activity of Na(+)/K(+)-ATPase, Ca(2+)ATPase, Mg(2+)ATPase and CYP(450) was significantly (P<0.05) reduced in the liver of toxic control groups 6 and 7 as compared to groups1 through 5, which had the maximum activity of all the groups. Groups 8 through 15 revealed a significant (P<0.05) increase in the activity of these hepatocytic enzymes. The histological sections of the liver in lead toxic control (group 6) showed moderate focal lymphoid aggregates in liver, whereas the lesions were mild to moderate in treated groups and there were no observable lesions in plain control groups. The study revealed protective effect of PHF (stressroak), shilajith, amla and vit E + Se in lead-induced hepatocytic damage.

Chiral separation of Frovatriptan isomers by HPLC using amylose based chiral stationary phase.

A stereospecific HPLC method for separation of Frovatriptan enantiomers in bulk drug and pharmaceutical formulations was developed and validated on a normal-phase amylose derivertized chiral column. The effects of the organic modifiers namely 2-propanol, ethanol and diethyl amine (DEA) in the mobile phase were optimized to obtain the best enantiomeric separation. Calibration curves were linear over the range of 200-6150 ng/mL, with a regression coefficient (R(2)) of 0.9998. The limit of detection (LOD) and limit of quantification (LOQ) were 65 ng/mL and 200 ng/mL, respectively. The method was accurate and precise and suitable for the intended purpose. Analysis results were compared with the results obtained by using a validated chiral CE method and found to be in very good agreement. This method can be successfully applied to the enantiomeric purity analysis of Frovatriptan in pharmaceutical bulk drug samples and formulations.

Modulation of cardiovascular remodeling with statins: fact or fiction?

The concept of cardiac remodeling implies a complex mixture of myocardial ischemia, and increased wall stress that results in molecular, cellular and interstitial changes in the heart. Clinically, cardiac remodeling is manifested as a change in size, shape and function of the heart. Morphologically the key feature of remodeling is myocyte hypertrophy, myocyte loss from necrosis or apoptosis, as well as interstitial cell growth especially fibroblast proliferation leading to myocardial fibrosis. Cardiac remodeling is influenced by hemodynamic load, neurohumoral activation, and other factors that can further affect the remodeling process. Despite advances in the management of heart failure, morbidity and mortality still present major health care issues in these patients. Statins (HMG Coenzyme A reductase inhibitors) play a key role in the management of ischemic heart disease. Recent studies indicate that statins may modulate cardiac remodeling by affecting signals that cause fibroblast growth, and myocyte hypertrophy and loss. In this paper we review the mechanisms of cardiac remodeling and the mechanisms of potential beneficial effects of statins on cardiac remodeling.