Publications by authors named "Hanbiao Yang"

The ubiquity and persistence of organophosphate esters (OPEs) and heavy metal (HMs) pose global environmental risks. This study explored tris(2-chloroisopropyl)phosphate (TCPP) biomineralization coupled to lead (Pb) biostabilization driven by denitrifying bacteria (DNB). The domesticated DNB achieved synergistic bioremoval of TCPP and Pb in the batch bioreactor (efficiency: 98 %).

View Article and Find Full Text PDF

The hypoxia-inducible factor 2α (HIF-2α) is a key oncogenic driver in clear cell renal cell carcinoma (ccRCC). Our first HIF-2α inhibitor PT2385 demonstrated promising proof of concept clinical activity in heavily pretreated advanced ccRCC patients. However, PT2385 was restricted by variable and dose-limited pharmacokinetics resulting from extensive metabolism of PT2385 to its glucuronide metabolite.

View Article and Find Full Text PDF

HIF-2α, a member of the HIF family of transcription factors, is a key oncogenic driver in cancers such as clear cell renal cell carcinoma (ccRCC). A signature feature of these cancers is the overaccumulation of HIF-2α protein, often by inactivation of the E3 ligase VHL (von Hippel-Lindau). Herein we disclose our structure based drug design (SBDD) approach that culminated in the identification of PT2385, the first HIF-2α antagonist to enter clinical trials.

View Article and Find Full Text PDF

More than 90% of clear cell renal cell carcinomas (ccRCC) exhibit inactivation of the von Hippel-Lindau (pVHL) tumor suppressor, establishing it as the major underlying cause of this malignancy. pVHL inactivation results in stabilization of the hypoxia-inducible transcription factors, HIF1α and HIF2α, leading to expression of a genetic program essential for the initiation and progression of ccRCC. Herein, we describe the potent, selective, and orally active small-molecule inhibitor PT2385 as a specific antagonist of HIF2α that allosterically blocks its dimerization with the HIF1α/2α transcriptional dimerization partner ARNT/HIF1β.

View Article and Find Full Text PDF

Potent imidazopyridine-based inhibitors of fatty acid synthase (FASN) are described. The compounds are shown to have antiviral (HCV replicon) activities that track with their biochemical activities. The most potent analogue (compound 19) also inhibits rat FASN and inhibits de novo palmitate synthesis in vitro (cell-based) as well as in vivo.

View Article and Find Full Text PDF

Bryostatins, a family of structurally complicated macrolides, exhibit an exceptional range of biological activities. The limited availability and structural complexity of these molecules makes development of an efficient total synthesis particularly important. This article describes our initial efforts towards the total synthesis of bryostatins, in which chemoselective and atom-economical methods for the stereoselective assembly of the ring C subunit were developed.

View Article and Find Full Text PDF

Herein, we report the synthesis of novel ring-expanded bryostatin analogues. By carefully modifying the substrate, a selective and high-yielding Ru-catalyzed tandem enyne coupling/Michael addition was employed to construct the northern fragment. Ring-closing metathesis was utilized to form the 31-membered ring macrocycle of the analogue.

View Article and Find Full Text PDF

This article describes chemoselective and atom-economic methods for the stereoselective assembly of the ring A and B subunits of bryostatins. A Ru-catalyzed tandem alkene-alkyne coupling/Michael addition reaction was developed and applied to the synthesis of bryostatin ring B. We explored an acetylide-mediated epoxide-opening/6-exo-dig cyclization route to access the bryostatin ring A, although ring A was eventually furnished through an acid-catalyzed tandem transketalization/ketalization sequence.

View Article and Find Full Text PDF

Conformational modeling has been successfully applied to the design of cyclic bioisosteres used to replace a conformationally rigid amide bond in a series of thiophene carboxylate inhibitors of HCV NS5B polymerase. Select compounds were equipotent with the original amide series. Single-point mutant binding studies, in combination with inhibition structure-activity relationships, suggest this new series interacts at the Thumb-II domain of NS5B.

View Article and Find Full Text PDF

Importance Of The Field: The HIV/AIDS epidemic and the resultant therapeutic efforts have continued to evolve over the last several years. The continued challenges in vaccine development, the growing longevity of the patient population and the emergence of resistant strains to current highly active antiretroviral therapy necessitate the development of new, effective therapeutics which target novel mechanism of actions. CCR5, a member of the GPCR superfamily, plays a key role as a co-receptor during the HIV viral entry process.

View Article and Find Full Text PDF

Replacement of the cyclic carbamate in our previously disclosed 1-oxa-3,9-diazaspiro[5.5]undecan-2-one template led to the discovery of two novel series of 3,9-diazaspiro[5.5]undecane and undeca-2-one CCR5 antagonists.

View Article and Find Full Text PDF

We describe robust chemical approaches toward putative CCR5 scaffolds designed in our laboratories. Evaluation of analogues in the (125)I-[MIP-1beta] binding and Ba-L-HOS antiviral assays resulted in the discovery of 64 and 68 in the 4,4-disubstitited piperidine class H, both potent CCR5 ligands (pIC 50 = 8.30 and 9.

View Article and Find Full Text PDF

A ring expanded bryostatin analogue was synthesized by utilizing a Ru-catalyzed tandem tetrahydropyran formation, a Pd-catalyzed tandem dihydropyran formation, and a ring-closing metathesis (RCM) as key steps. The analogue possesses potent anti-tumor activity against the NCI-ADR cancer cell line with an IC of 123 nM.

View Article and Find Full Text PDF

Design, syntheses, and testing of new, fullerene-wheeled single molecular nanomachines, namely, nanocars and nanotrucks, are presented. These nanovehicles are composed of three basic components that include spherical fullerene wheels, freely rotating alkynyl axles, and a molecular chassis. The use of spherical wheels based on C60 and freely rotating axles based on alkynes permits directed nanoscale rolling of the molecular structure on gold surfaces.

View Article and Find Full Text PDF

[reaction: see text] A Ru-catalyzed tandem alkyne-enone coupling/Michael addition reaction is reported. It provides an efficient, atom-economic entry to 4-methylene-2,6-cis-tetrahydropyrans from simple, readily available homopropargylic alcohols and beta,gamma-unsaturated enones in good yields. Further functionalization of the resultant vinylsilane leads to the synthesis of either geometrically defined trisubstituted alkene exocyclic to the 2,6-cis-dihydropyran.

View Article and Find Full Text PDF

Novel strategies are developed for an efficient formal synthesis of (-)-mycalamide A. The left-hand side (-)-7-benzoylpederic acid is synthesized from (2S,3S)-2,3-epoxybutane. The key features include a highly regioselective Ru-catalyzed alkene-alkyne coupling reaction and a novel way to control the challenging C(7) stereocenter.

View Article and Find Full Text PDF

We have developed a new approach to prodrugs, which utilizes a pH-induced intramolecular O-->N migration of an acyloxy group in carbonate moiety to a free amino moiety at neutral pH. This method is exemplified by facile rearrangement of highly water-soluble prodrug 3 to carbamate 4, a close analogue of HIV-1 protease inhibitor Amprenavir. The O-->N acyloxy migration is unprecedented in the context of prodrugs and it enables a high atom economy due to recycling of the 'pro' moiety.

View Article and Find Full Text PDF

This review addresses key pharmacology and virology issues relevant in discovery and development of CCR5 antagonists as anti-HIV drugs, such as target validation, receptor internalization, allosterism, viral resistance and tropism. Recent progress in the discovery and development of CCR5 antagonists, SAR and clinical status are reviewed. Finally, modeling-based structure of CCR5 is discussed in the context of a small-molecule antagonism of the CCR5 receptor.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Notice

Message: fwrite(): Write of 34 bytes failed with errno=28 No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 272

Backtrace:

A PHP Error was encountered

Severity: Warning

Message: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions)

Filename: Unknown

Line Number: 0

Backtrace: