A high-titer scalable Chinese hamster ovary transient expression platform for production of biotherapeutics.

Transient gene expression (TGE) in Chinese hamster ovary (CHO) cells offers a route to accelerate biologics development by delivering material weeks to months earlier than what is possible with conventional cell line development. However, low productivity, inconsistent product quality profiles, and scalability challenges have prevented its broader adoption. In this study, we develop a scalable CHO-based TGE system achieving 1.

Characterization of TAP Ambr 250 disposable bioreactors, as a reliable scale-down model for biologics process development.

Demands for development of biological therapies is rapidly increasing, as is the drive to reduce time to patient. In order to speed up development, the disposable Automated Microscale Bioreactor (Ambr 250) system is increasingly gaining interest due to its advantages, including highly automated control, high throughput capacity, and short turnaround time. Traditional early stage upstream process development conducted in 2 - 5 L bench-top bioreactors requires high foot-print, and running cost.

A Scalable Total Synthesis of (-)-Nakadomarin A.

The convergent total synthesis of the manzamine alkaloid (-)-nakadomarin A (1) is described. The retrosynthetic analysis recognized spirocycle 3, assembled via an organocatalyst-promoted Michael addition/cyclization between bicyclic lactam 4 and furan aldehyde 5, both accessible from achiral starting materials and on a multigram scale. Lactam 4 is assembled through an S2'/reduction/Staudinger/retro-aza-Claisen sequence on scale.

Synthesis of quaternary α-amino acid-based arginase inhibitors via the Ugi reaction.

The Ugi reaction has been successfully applied to the synthesis of novel arginase inhibitors. In an effort to decrease conformational flexibility of the previously reported series of 2-amino-6-boronohexanoic acid (ABH) analogs 1, we designed and synthesized a series of compounds, 2, in which a piperidine ring is linked directly to a quaternary amino acid center. Further improvement of in vitro activity was achieved by adding two carbon bridge in the piperidine ring, that is, tropane analogs 11.

Discovery of (R)-2-amino-6-borono-2-(2-(piperidin-1-yl)ethyl)hexanoic acid and congeners as highly potent inhibitors of human arginases I and II for treatment of myocardial reperfusion injury.

Recent efforts to identify treatments for myocardial ischemia reperfusion injury have resulted in the discovery of a novel series of highly potent α,α-disubstituted amino acid-based arginase inhibitors. The lead candidate, (R)-2-amino-6-borono-2-(2-(piperidin-1-yl)ethyl)hexanoic acid, compound 9, inhibits human arginases I and II with IC50s of 223 and 509 nM, respectively, and is active in a recombinant cellular assay overexpressing human arginase I (CHO cells). It is 28% orally bioavailable and significantly reduces the infarct size in a rat model of myocardial ischemia/reperfusion injury.

2-Substituted-2-amino-6-boronohexanoic acids as arginase inhibitors.

Substitution at the alpha center of the known human arginase inhibitor 2-amino-6-boronohexanoic acid (ABH) is acceptable in the active site pockets of both human arginase I and arginase II. In particular, substituents with a tertiary amine linked via a two carbon chain show improved inhibitory potency for both enzyme isoforms. This potency improvement can be rationalized by X-ray crystallography, which shows a water-mediated contact between the basic nitrogen and the carboxylic acid side chain of Asp200, which is situated at the mouth of the active site pocket of arginase II (Asp181 in arginase I).

Diels-Alder reactions of cyclic isoimidium salts.

Diels-Alder reactions of cyclic isoimidium salts are described. The corresponding cycloadducts are obtained with high regio- and stereoselectivity. The use of homochiral cyclic isoimidium salts delivers cycloadducts with excellent diastereoselectivity (>99:1) that can be efficiently converted to enantiomerically pure lactones.

Synthetic and mechanistic studies of the aza-retro-Claisen rearrangement. A facile route to medium ring nitrogen heterocycles.

An efficient synthesis of medium-sized heterocyclic rings was achieved using a one-pot aza-Wittig/retro-aza-Claisen sequence of vinyl cyclobutanecarboxaldehydes derived from simple allylic carbonates. The use of various Staudinger reagents in the aza-Wittig reaction allows for a variety of N-substituted products to be obtained. The rearrangement is under thermodynamic control driven by relief of the cyclobutane ring strain and resonance stabilization of the resulting vinylogous amide/sulfonamide.

The design and synthesis of human branched-chain amino acid aminotransferase inhibitors for treatment of neurodegenerative diseases.

The inhibition of the cytosolic isoenzyme BCAT that is expressed specifically in neuronal tissue is likely to be useful for the treatment of neurodegenerative and other neurological disorders where glutamatergic mechanisms are implicated. Compound 2 exhibited an IC50 of 0.8 microM in the hBCATc assays; it is an active and selective inhibitor.