Formal synthesis of (-)-kendomycin featuring a Prins-cyclization to construct the macrocycle.

The kendomycin skeleton was prepared by a highly convergent strategy in which the benzofuran fragment and the acyclic iodide fragment were prepared by standard methods and joined using a Suzuki coupling. The distinctive reaction in our approach was an intramolecular Prins cyclization that assembles the macrocyclic ring in good yield. Modeling studies demonstrate that the acyclic chain is predisposed for macrocycle formation. Ultimately, the product was correlated with one of Lee's advanced intermediates for a formal total synthesis of kendomycin.

Rapid stereocontrolled assembly of the fully substituted C-aryl glycoside of kendomycin with a Prins cyclization: a formal synthesis.

Prins cyclization using an electron-rich benzaldehyde and a homoallylic alcohol efficiently delivered the fully substituted C-aryl tetrahydropyranoside of kendomycin.

Discovery of Selective Small Molecule Inhibitors of Monoacylglycerol Acyltransferase 3.

Inhibition of triacylglycerol (TAG) biosynthetic enzymes has been suggested as a promising strategy to treat insulin resistance, diabetes, dyslipidemia, and hepatic steatosis. Monoacylglycerol acyltransferase 3 (MGAT3) is an integral membrane enzyme that catalyzes the acylation of both monoacylglycerol (MAG) and diacylglycerol (DAG) to generate DAG and TAG, respectively. Herein, we report the discovery and characterization of the first selective small molecule inhibitors of MGAT3. Isoindoline-5-sulfonamide (6f, PF-06471553) selectively inhibits MGAT3 with high in vitro potency and cell efficacy. Because the gene encoding MGAT3 (MOGAT3) is found only in higher mammals and humans, but not in rodents, a transgenic mouse model expressing the complete human MOGAT3 was used to characterize the effects of 6f in vivo. In the presence of a combination of diacylglycerol acyltransferases 1 and 2 (DGAT1 and DGAT2) inhibitors, an oral administration of 6f exhibited inhibition of the incorporation of deuterium-labeled glycerol into TAG in this mouse model. The availability of a potent and selective chemical tool and a humanized mouse model described in this report should facilitate further dissection of the physiological function of MGAT3 and its role in lipid homeostasis.

Synthesis of sulfones from organozinc reagents, DABSO, and alkyl halides.

Organozinc reagents react with the SO2 surrogate DABSO, and the resulting zinc sulfinate salts are alkylated in situ to afford sulfones. This transformation has a broad scope and is compatible with a wide range of structural motifs of medicinal chemistry relevance including nitrile, secondary carbamates, and nitrogen-containing heterocycles.

Design and synthesis of diazatricyclodecane agonists of the G-protein-coupled receptor 119.

A series of GPR119 agonists based on a 2,6-diazatricyclo[3.3.1.1∼3,7∼]decane ring system is described. Also provided is a detailed account of the development of a multigram scale synthesis of the diazatricyclic ring system, which was achieved using a Hofmann-Löffler-Freytag reaction as the key step. The basis for the use of this complex framework lies in an attempt to constrain one end of the molecule in the "agonist conformation" as was previously described for 3-oxa-7-aza-bicyclo[3.3.1]nonanes. Optimization of carbamate analogues of the diazatricylic compounds led to the identification of 32i as a potent agonist of the GPR119 receptor with low unbound human liver microsomal clearance. The use of an agonist response weighted ligand lipophilic efficiency (LLE) termed AgLLE is discussed along with the issues of applying efficiency measures to agonist programs. Ultimately, solubility limited absorption and poor exposure reduced further interest in these molecules.

Spirolactam-based acetyl-CoA carboxylase inhibitors: toward improved metabolic stability of a chromanone lead structure.

Acetyl-CoA carboxylase (ACC) catalyzes the rate-determining step in de novo lipogenesis and plays a crucial role in the regulation of fatty acid oxidation. Alterations in lipid metabolism are believed to contribute to insulin resistance; thus inhibition of ACC offers a promising option for intervention in type 2 diabetes mellitus. Herein we disclose a series of ACC inhibitors based on a spirocyclic pyrazololactam core. The lactam series has improved chemical and metabolic stability relative to our previously reported pyrazoloketone series, while retaining potent inhibition of ACC1 and ACC2. Optimization of the pyrazole and amide substituents led to quinoline amide 21, which was advanced to preclinical development.

Indolynes as electrophilic indole surrogates: fundamental reactivity and synthetic applications.

A mild method to access a variety of substituted indole derivatives has been developed. The strategy relies on the generation of highly reactive indolyne intermediates, which function as electrophilic indole surrogates.

Piperazinyl CCR1 antagonists--optimization of human liver microsome stability.

The synthesis, biological activity, and pharmacokinetic profile of CCR1 antagonists are described.

Bond insertion, complexation, and penetration pathways of vapor-deposited aluminum atoms with HO- and CH(3)O-terminated organic monolayers.

The interaction of vapor-deposited Al atoms with self-assembled monolayers (SAMs) of HS-(CH(2))(16)-X (X = -OH and -OCH(3)) chemisorbed at polycrystalline Au[111] surfaces was studied using time-of-flight secondary-ion mass spectrometry, X-ray photoelectron spectroscopy, and infrared reflectance spectroscopy. Whereas quantum chemical theory calculations show that Al insertion into the C-C, C-H, C-O, and O-H bonds is favorable energetically, it is observed that deposited Al inserts only with the OH SAM to form an -O-Al-H product. This reaction appears to cease prior to complete -OH consumption, and is followed by formation of a few overlayers of a nonmetallic type of phase and finally deposition of a metallic film. In contrast, for the OCH(3) SAM, the deposited Al atoms partition along two parallel paths: nucleation and growth of an overlayer metal film, and penetration through the OCH(3) SAM to the monolayer/Au interface region. By considering a previous observation that a CH(3) terminal group favors penetration as the dominant initial process, and using theory calculations of Al-molecule interaction energies, we suggest that the competition between the penetration and overlayer film nucleation channels is regulated by small differences in the Al-SAM terminal group interaction energies. These results demonstrate the highly subtle effects of surface structure and composition on the nucleation and growth of metal films on organic surfaces and point to a new perspective on organometallic and metal-solvent interactions.