Mimicking Nature in Reshaping the Triterpene Skeleton: Synthesis of a Class of Unnatural Oleanane Derivatives.

The possibility of duplicating the efficiency and selectivity of natural processes under laboratory conditions remains a significant challenge for organic chemists. In this letter, we demonstrated that it is possible to introduce pinpoint modifications and to reshape the terpene skeleton of easily available oleananes in a biomimetic fashion. Furthermore, aromatization of the A ring of the triterpene system is reported here for the first time, mimicking what occurs exclusively in nature in sediments.

Optimization of Steroid Photochemistry and Its Application in the Synthesis of 5,6-Dihydro-Ophiopogonol A.

The photoreactivity of steroids represented a hot topic in the middle of the last century and in this project, we "rediscover" it through the exploration of the photochemical behavior of Δ-3-keto-steroids. In terms of number of products obtained, the photochemistry of Δ-3-keto-steroids is less complicated than that of Δ-3-keto- and Δ-3-keto-steroids, furnishing an efficient and tunable method to remodel the classic steroid 6/6/6/5 ring system. In this scenario, this approach can represent a simple strategy to interconvert a class of easily available steroids to another difficult-to-access from natural sources.

The Impact of a Quinone Scaffold on Thermo-TRPs Modulation by Dimethylheptyl Phytocannabinoids.

Phytocannabinoids (pCBs) from represent an important class of bioactive molecules, potentially useful for the treatment of a wide range of diseases. Their efficacy is due to their ability to interact with multiple targets of the endocannabinoid system, including the thermosensitive transient receptor potential (Thermo-TRPs), namely TRPV1-4, TRPA1, and TRPM8 channels. Previously, we demonstrated a shift in selectivity toward TRPA1 in the activity profile of the main pCBs, that is, CBD, ∆-THC, CBG, CBC, and CBN, by swapping the pentyl chain with the α,α-dimethylheptyl (DMH) one.

Stereoselective Shi-type epoxidation with 3-oxo-4,6--benzylidene pyranoside catalysts: unveiling the role of carbohydrate skeletons.

Asymmetric epoxidation represents a hot topic in organic synthesis. In recent years, organocatalysts based on sugar skeletons have been exploited in asymmetric epoxidation to achieve enantiomeric pure epoxides. In this work, two different endocyclic ketones derived from glucose and galactose protected with a 4,6--benzylidene group have been prepared and exploited for Shi-type epoxidation.

Novel Skeletal Rearrangements of the Tigliane Diterpenoid Core.

To investigate the role of the secondary 5-hydroxy group in the activity of the anticancer drug tigilanol tiglate () (Stelfonta), oxidation of this epoxytigliane diterpenoid from the Australian rainforest plant was attempted. Eventually, 5-dehydrotigilanol tiglate () proved too unstable to be characterized in terms of biological activity and, therefore, was not a suitable tool compound for bioactivity studies. On the other hand, a series of remarkable skeletal rearrangements associated with the presence of a 5-keto group were discovered during its synthesis, including a dismutative ring expansion of ring A and a mechanistically unprecedented dyotropic substituent swap around the C-4/C-10 bond.

Iodine-triphenylphosphine triggers an easy one-pot alpha stereoselective dehydrative glycosylation on hemiacetalic benzylated glycosyl donors.

The discovery of new glycosylation reactions is still a major challenge in carbohydrate chemistry. Traditional glycosylation reactions require the preparation of sugar donors with anomeric active or latent leaving groups. Dehydrative glycosylation is a fascinating alternative that enables the direct formation of the glycosidic bond from the hemiacetal, eliminating the need for (sometimes unstable) leaving groups, and allowing to reduce reaction, work-up, and purification times.

Identification of a Novel Curcumin Derivative Influencing Notch Pathway and DNA Damage as a Potential Therapeutic Agent in T-ALL.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy considered curable by modern clinical management. Nevertheless, the prognosis for T-ALL high-risk cases or patients with relapsed and refractory disease is still dismal. Therefore, there is a keen interest in developing more efficient and less toxic therapeutic approaches.

Cannabinol: History, Syntheses, and Biological Profile of the Greatest "Minor" Cannabinoid.

Cannabis ( L.) is an outstanding source of bioactive natural products, with more than 150 different phytocannabinoids isolated throughout the decades; however, studies of their bioactivity have historically concentrated on the so-called "big four" [∆-THC (), CBD (), CBG () and CBC ()]. Among the remaining products, which have traditionally been referred to as "minor cannabinoids", cannabinol (CBN, ) stands out for its important repercussions and implications on the global scientific landscape.

Drug affinity-responsive target stability unveils filamins as biological targets for artemetin, an anti-cancer flavonoid.

Artemetin is a valuable 5-hydroxy-3,6,7,3',4'-pentamethoxyflavone present in many different medicinal plants with very good oral bioavailability and drug-likeness values, owing to numerous bioactivities, such as anti-inflammatory and anti-cancer ones. Here, a multi-disciplinary plan has been settled and applied for identifying the artemetin target(s) to inspect its mechanism of action, based on drug affinity-responsive target stability and targeted limited proteolysis. Both approaches point to the disclosure of filamins A and B as direct artemetin targets in HeLa cell lysates, also giving detailed insights into the ligand/protein-binding sites.

Rotational constriction of curcuminoids impacts 5-lipoxygenase and mPGES-1 inhibition and evokes a lipid mediator class switch in macrophages.

Polypharmacological targeting of lipid mediator networks offers potential for efficient and safe anti-inflammatory therapy. Because of the diversity of its biological targets, curcumin (1a) has been viewed as a privileged structure for bioactivity or, alternatively, as a pan-assay interference (PAIN) compound. Curcumin has actually few high-affinity targets, the most remarkable ones being 5-lipoxygenase (5-LOX) and microsomal prostaglandin E synthase (mPGES)-1.

Pyrazole-Curcumin Suppresses Cardiomyocyte Hypertrophy by Disrupting the CDK9/CyclinT1 Complex.

The intrinsic histone acetyltransferase (HAT), p300, has an important role in the development and progression of heart failure. Curcumin (CUR), a natural p300-specific HAT inhibitor, suppresses hypertrophic responses and prevents deterioration of left-ventricular systolic function in heart-failure models. However, few structure-activity relationship studies on cardiomyocyte hypertrophy using CUR have been conducted.

The synthetic triterpenoids CDDO-TFEA and CDDO-Me, but not CDDO, promote nuclear exclusion of BACH1 impairing its activity.

The transcription factor BACH1 is a potential therapeutic target for a variety of chronic conditions linked to oxidative stress and inflammation, as well as cancer metastasis. However, only a few BACH1 degraders/inhibitors have been described. BACH1 is a transcriptional repressor of heme oxygenase 1 (HMOX1), which is positively regulated by transcription factor NRF2 and is highly inducible by derivatives of the synthetic oleanane triterpenoid 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO).

Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation.

Historically, plants have represented an invaluable source of compounds with complex structures and interesting pharmacological profiles [...

Betulinic Acid Hydroxamate is Neuroprotective and Induces Protein Phosphatase 2A-Dependent HIF-1α Stabilization and Post-transcriptional Dephosphorylation of Prolyl Hydrolase 2.

Huntington's disease (HD) is a neurodegenerative disorder characterized by unwanted choreatic movements, behavioral and psychiatric disturbances, and dementia. The activation of the hypoxic response pathway through the pharmacological inhibition of hypoxia-inducing factor (HIF) prolyl-hydroxylases (PHDs) is a promising approach for neurodegenerative diseases, including HD. Herein, we have studied the mechanism of action of the compound Betulinic acid hydroxamate (BAH), a hypoximimetic derivative of betulinic acid, and its efficacy against striatal neurodegeneration using complementary approaches.

Icilio Guareschi and his amazing "1897 reaction".

Organic chemistry honors Icilio Guareschi (1847-1918) with three eponymic reactions, the best known ones being the Guareschi synthesis of pyridones and the Guareschi-Lustgarten reaction. A third Guareschi reaction, the so-called "Guareschi 1897 reaction", is one of the most unusual reactions in organic chemistry, involving the radical-mediated paradoxical aerobic generation of hydrocarbons in near-neutral water solution. A discussion of the mechanism of this amazing reaction, the only metal-free process that generates hydrocarbons, and the implications of the approach in biology and geosciences mirrors the multifaceted scientific personality of the discoverer.

Biomimetic Approaches to the Synthesis of Natural Disesquiterpenoids: An Update.

Natural disesquiterpenoids represent a small group of secondary metabolites characterized by complex molecular scaffolds and interesting pharmacological profiles. In the last decade, more than 400 new disesquiterpenoids have been discovered and fully characterized, pointing out once more the "" of nature in the design of new compounds. The perfect blend of complex and unique architectures and biological activity has made sesquiterpene dimers an attractive and challenging synthetic target, inspiring organic chemists to find new and biomimetic approaches to replicate the efficiency and the selectivity of natural processes under laboratory conditions.

Betulinic acid hydroxamate prevents colonic inflammation and fibrosis in murine models of inflammatory bowel disease.

Intestinal fibrosis is a common complication of inflammatory bowel disease (IBD) and is defined as an excessive accumulation of scar tissue in the intestinal wall. Intestinal fibrosis occurs in both forms of IBD: ulcerative colitis and Crohn's disease. Small-molecule inhibitors targeting hypoxia-inducing factor (HIF) prolyl-hydroxylases are promising for the development of novel antifibrotic therapies in IBD.

The Oxidation of Phytocannabinoids to Cannabinoquinoids.

Spurred by a growing interest in cannabidiolquinone (CBDQ, HU-313, ) as a degradation marker and alledged hepatotoxic metabolite of cannabidiol (CBD, ), we performed a systematic study on the oxidation of CBD () to CBDQ () under a variety of experimental conditions (base-catalyzed aerobic oxidation, oxidation with metals, oxidation with hypervalent iodine reagents). The best results in terms of reproducibility and scalability were obtained with λ-periodinanes (Dess-Martin periodinane, 1-hydroxy-1λ,2-benziodoxole-1,3-dione (IBX), and SIBX, a stabilized, nonexplosive version of IBX). With these reagents, the oxidative dimerization that plagues the reaction under basic aerobic conditions was completely suppressed.

Crystal structure of Haemophilus influenzae 3-isopropylmalate dehydrogenase (LeuB) in complex with the inhibitor O-isobutenyl oxalylhydroxamate.

3-isopropylmalate dehydrogenases (LeuB) belong to the leucine biosynthetic pathway and catalyze the irreversible oxidative decarboxylation of 3IPM to 2-ketoisocaproate that is finally converted into leucine by a branched-chain aminotransferase. Since leucine is an essential amino acid for humans, and it is also vital for the growth of many pathogenic bacteria, the enzymes belonging to this pathway can be considered as potential target sites for designing of a new class of antibacterial agents. We have determined the crystal structure of the Haemophilus influenzae LeuB in complex with the cofactor NAD and the inhibitor O-IbOHA, at 2.

The dimerization of -tetrahydrocannabinolic acid A (THCA-A).

The renewed interest in dimeric salicylates as broad-spectrum anti-inflammatory and anti-diabetic agents provided a rationale to investigate the dimerization of the substituted salicylate -tetrahydrocannabinolic acid (THCA-A, ) as a strategy to solve its instability to decarboxylation and to generate analogues and/or pro-drugs of this native pre-cannabinoid. Activation of the carboxylic group with the DCC-HOBt-DMAP protocol afforded a high yield of the OBt ester , that was next converted into the highly crystalline di-depsidic dimer upon treatment with DMAP. The mono-depsidic dimer was also formed when the reaction was carried out with partially decarboxylated THCA-A samples.