Site-selective amination and/or nitrilation via metal-free C(sp2)-C(sp3) cleavage of benzylic and allylic alcohols.

Benzylic/allylic alcohols are converted via site-selective C(sp2)-C(sp3) cleavage to value-added nitrogenous motifs, viz., anilines and/or nitriles as well as N-heterocycles, utilizing commercial hydroxylamine-O-sulfonic acid (HOSA) and Et3N in an operationally simple, one-pot process. Notably, cyclic benzylic/allylic alcohols undergo bis-functionalization with attendant increases in architectural complexity and step-economy.

Activation of GPR75 Signaling Pathway Contributes to the Effect of a 20-HETE Mimetic, 5,14-HEDGE, to Prevent Hypotensive and Tachycardic Responses to Lipopolysaccharide in a Rat Model of Septic Shock.

ABSTRACT: The orphan receptor, G protein-coupled receptor (GPR) 75, which has been shown to mediate various effects of 20-hydroxyeicosatetraenoic acid (20-HETE), is considered as a therapeutic target in the treatment of cardiovascular diseases in which changes in the production of 20-HETE play a key role in their pathogenesis. Our previous studies showed that 20-HETE mimetic, N -(20-hydroxyeicosa-5[Z],14[Z]-dienoyl)glycine (5,14-HEDGE), protects against vascular hyporeactivity, hypotension, tachycardia, and arterial inflammation induced by lipopolysaccharide (LPS) in rats. This study tested the hypothesis that the GPR75 signaling pathway mediates these effects of 5,14-HEDGE in response to systemic exposure to LPS. Mean arterial pressure reduced by 33 mm Hg, and heart rate increased by 102 beats/min at 4 hours following LPS injection. Coimmunoprecipitation studies demonstrated that (1) the dissociation of GPR75/Gα q/11 and GPR kinase interactor 1 (GIT1)/protein kinase C (PKC) α, the association of GPR75/GIT1, large conductance voltage and calcium-activated potassium subunit ß (MaxiKß)/PKCα, MaxiKß/proto-oncogene tyrosine-protein kinase (c-Src), and epidermal growth factor receptor (EGFR)/c-Src, MaxiKß, and EGFR tyrosine phosphorylation were decreased, and (2) the association of GIT1/c-Src was increased in the arterial tissues of rats treated with LPS. The LPS-induced changes were prevented by 5,14-HEDGE. N -[20-Hydroxyeicosa-6( Z ),15( Z )-dienoyl]glycine, a 20-HETE antagonist, reversed the effects of 5,14-HEDGE in the arterial tissues of LPS-treated rats. Thus, similar to 20-HETE, by binding to GPR75 and activating the Gα q/11 /PKCα/MaxiKß, GIT1/PKCα/MaxiKß, GIT1/c-Src/MaxiKß, and GIT1/c-Src/EGFR signaling pathways, 5,14-HEDGE may exert its protective effects against LPS-induced hypotension and tachycardia associated with vascular hyporeactivity and arterial inflammation.

EET Analog Treatment Improves Insulin Signaling in a Genetic Mouse Model of Insulin Resistance.

We previously showed that global deletion of the cytochrome P450 epoxygenase Cyp2c44, a major epoxyeicosatrienoic acid (EET) producing enzyme in mice, leads to impaired hepatic insulin signaling resulting in insulin resistance. This finding led us to investigate whether administration of a water soluble EET analog restores insulin signaling in vivo in Cyp2c44(-/-) mice and investigated the underlying mechanisms by which this effect is exerted. Cyp2c44(-/-) mice treated with the analog EET-A for 4 weeks improved fasting glucose and glucose tolerance compared to Cyp2c44(-/-) mice treated with vehicle alone. This beneficial effect was accompanied by enhanced hepatic insulin signaling, decreased expression of gluconeogenic genes and increased expression of glycogenic genes. Mechanistically, we show that insulin-stimulated phosphorylation of insulin receptor ß (IRß) is impaired in primary Cyp2c44(-/-) hepatocytes and this can be restored by cotreatment with EET-A and insulin. Plasma membrane fractionations of livers indicated that EET-A enhances the retention of IRß in membrane rich fractions, thus potentiating its activation. Altogether, EET analogs ameliorate insulin signaling in a genetic model of hepatic insulin resistance by stabilizing membrane-associated IRß and potentiating insulin signaling.

EET Analog Treatment Improves Insulin Signaling in a Genetic Mouse Model of Insulin Resistance.

We previously showed that global deletion of the cytochrome P450 epoxygenase Cyp2c44, a major epoxyeicosatrienoic acid (EET) producing enzyme in mice, leads to impaired hepatic insulin signaling resulting in insulin resistance. This finding led us to investigate whether administration of a water soluble EET analog restores insulin signaling in vivo in Cyp2c44(-/-) mice and investigated the underlying mechanisms by which this effect is exerted. Cyp2c44(-/-) mice treated with the analog EET-A for 4 weeks improved fasting glucose and glucose tolerance compared to Cyp2c44(-/-) mice treated with vehicle alone. This beneficial effect was accompanied by enhanced hepatic insulin signaling, decreased expression of gluconeogenic genes and increased expression of glycogenic genes. Mechanistically, we show that insulin-stimulated phosphorylation of insulin receptor ß (IRß) is impaired in primary Cyp2c44(-/-) hepatocytes and this can be restored by cotreatment with EET-A and insulin. Plasma membrane fractionations of livers indicated that EET-A enhances the retention of IRß in membrane rich fractions, thus potentiating its activation. Altogether, EET analogs ameliorate insulin signaling in a genetic model of hepatic insulin resistance by stabilizing membrane-associated IRß and potentiating insulin signaling.

Picolinate-Directed Arene meta-C-H Amination via FeCl3 Catalysis.

Direct C-H functionalization of aromatic compounds is a powerful tool for organic synthesis; however, differentiation among the ubiquitous and often chemically similar C-H bonds remains a significant challenge. Conflation with coordinating or directing groups incorporated into the intended substrate has helped address these limitations, although access to remote sites remains limited. Herein, we report an operationally simple and sustainable direct meta-selective H2N amination of benzylic and related aromatic picolinates under conditions mild enough to modify polyfunctional and late-stage molecules.

Cu(II)-Mediated N-H and N-Alkyl Aryl Amination and Olefin Aziridination.

Cu(II)-mediated direct NH2 and NH alkyl aryl aminations and olefin aziridinations are described. These room-temperature, one-pot, environmentally friendly procedures replace costly Rh2 catalysts and, in some instances, display important differences with comparable Rh2- and Fe-supported reactions.

Cu(OTf)2-catalyzed Beckmann Rearrangement of Ketones Using Hydroxylamine-O-sulfonic Acid (HOSA).

The Beckmann Rearrangement (BKR) of ketones to secondary amides often requires harsh reaction conditions that limit its practicality and scope. Herein, we describe the Cu(OTf)2-catalyzed BKR of ketones under mild reaction conditions using hydroxylamine-O-sulfonic acid (HOSA), a commercial water soluble aminating agent. This method is compatible with most functional groups and directly provides the desired amides in good to excellent yields.

Tunable Diastereoselective Desymmetrization of Cyclohexadienones Triggered by Copper-Catalyzed Three-Component Coupling Reaction.

Catalytic tandem diastereoselective desymmetrization of cyclohexadienone-containing 1,6-enynes has been achieved through copper-catalyzed [3 + 2]-cycloaddition followed by ketenimine formation and subsequent intramolecular conjugate addition. The cascade reaction provides cis-hydrobenzofurans in good yields with excellent diastereoselectivity. The exo- or endo-selectivity of bicyclic scaffolds depends on the selection of the base in the reaction. In addition, N-tethered bicyclic products further transformed into tricyclic compounds via intramolecular Michael addition.

The Ireland-Claisen rearrangement strategy towards the synthesis of the schizophrenia drug, (+)-asenapine.

(±)-Asenapine, sold in the market as Saphris/Sycrest for the treatment of bipolar disorders, is synthesized in an optically pure form involving an Ireland-Claisen rearrangement as the key step. This approach allows access to all diastereomers.