Publications by authors named "Venkata Velvadapu"

A class of imidazoisoindole (III) heme-binding indoleamine-2,3-dioxygenase (IDO1) inhibitors were optimized via structure-based drug design into a series of tryptophan-2,3-dioxygenase (TDO)-selective inhibitors. Kynurenine pathway modulation was demonstrated , which enabled evaluation of TDO as a potential cancer immunotherapy target. As means of mitigating the risk of drug-drug interactions arising from cytochrome P450 inhibition, a novel property-based drug design parameter, herein referred to as the CYP Index, was implemented for the design of inhibitors with appreciable selectivity for TDO over CYP3A4.

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Article Synopsis
  • Epstein-Barr virus (EBV) is linked to 1-2% of human cancers, such as various lymphomas and gastric carcinoma, due to its persistent latent infection promoting tumor growth.
  • EBNA1, a viral protein present in all EBV-related tumors, is crucial for viral functions and presents a target for developing treatments.
  • Researchers have identified specific inhibitors that block EBNA1's DNA binding activity, showing effectiveness in lab models by suppressing tumor growth and altering important signaling pathways in nasopharyngeal carcinoma.
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Background And Purpose: Synthetic cathinones, commonly referred to as 'bath salts', are a group of amphetamine-like drugs gaining popularity worldwide. 4-Methylmethcathinone (mephedrone, MEPH) is the most commonly abused synthetic cathinone in the UK, and exerts its effects by acting as a substrate-type releaser at monoamine transporters. Similar to other cathinone-related compounds, MEPH has a chiral centre and exists stably as two enantiomers: R-mephedrone (R-MEPH) and S-mephedrone (S-MEPH).

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Novel sources of antibiotics are needed to address the serious threat of bacterial resistance. Accordingly, we have launched a structure-based drug design program featuring a desmethylation strategy wherein methyl groups have been replaced with hydrogens. Herein we report the total synthesis, molecular modeling, and biological evaluation of 4-desmethyl telithromycin (6), a novel desmethyl analogue of the third-generation ketolide antibiotic telithromycin (2) and our final analogue in this series.

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We have found that α-amino acid amide derivatives of 2-aminobenzothiazoles undergo a time-dependent, thermal rearrangement in which the amine group attacks the 2-position carbon of the thiazole ring to form a 5,5-spiro ring system. This is followed by sulfur leaving and air oxidation to the corresponding symmetrical disulfide. The isolated yields of such products are quite high (>70%) if there is conformational bias to further promote the intramolecular reaction such as for the 2-aminobenzothiazole amides derived from proline or 4-aminopiperidine-4-carboxylic acid.

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3-Chloro-4-(dichloromethyl)-5-hydroxy-5H-furan-2-one (Mutagen X, MX) was synthesized in six steps from commercially-available and inexpensive starting materials (27% overall yield). This synthesis enables the preparation of MX analogs and does not require the use of chlorine gas, as do previously reported methods.

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Novel sources of antibiotics are required to keep pace with the inevitable onset of bacterial resistance. Continuing with our macrolide desmethylation strategy as a source of new antibiotics, we report the total synthesis, molecular modeling and biological evaluation of 4,10-didesmethyl telithromycin (4), a novel desmethyl analogue of the 3rd-generation drug telithromycin (2). Telithromycin is an FDA-approved ketolide antibiotic derived from erythromycin (1).

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Dysfunction of the heterogeneous ribonucleoprotein TAR DNA binding protein 43 (TDP-43) is associated with neurodegeneration in diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Here we examine the effects of a series of 4-aminoquinolines with affinity for TDP-43 upon caspase-7-induced cleavage of TDP-43 and TDP-43 cellular function. These compounds were mixed inhibitors of biotinylated TG6 binding to TDP-43, binding to both free and occupied TDP-43.

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Novel sources of antibiotics are required to address the serious problem of antibiotic resistance. Telithromycin (2) is a third-generation macrolide antibiotic prepared from erythromycin (1) and used clinically since 2004. Herein we report the details of our efforts that ultimately led to the total synthesis of (-)-4,8,10-tridesmethyl telithromycin (3) wherein methyl groups have been replaced with hydrogens.

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There is an urgent need to discover new drugs to address the pressing problem of antibiotic-resistance. Macrolide antibiotics such as erythromycin (1) are safe, broad-spectrum antibiotics used in the clinic since 1954. Herein we report the synthesis and evaluation of 4,8,10-tridesmethyl telithromycin (3), a novel desmethyl analogue of the 3rd-generation drug telithromycin (2), which is a semisynthetic derivative of 1.

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Polysubstituted 2-carboxylate and 2-phosphonate pyrroles are prepared by aromatization of the corresponding 3-oxo 2-carboxylate and 2-phosphonate NH-pyrrolidines using air. Reaction of electrophiles with 3-oxo pyrrolidine dianions readily introduces substituents, regioselectively at C-4 in these pyrrolidines.

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A concise synthesis of d-desosamine has been accomplished in five steps and in 15% overall yield from methyl alpha-d-glucopyranoside. Desosamine was then transformed into two known 2-thiopyrimidinyl donors (Woodward and Tatsuta donors), each in two steps. Finally, analogues of methyl desosaminide at the C-3 position were prepared (3-pyrrolidino, 3-piperidino, 3-morpholino) from a common 2,3-anhydrosugar intermediate.

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