Mtb-Selective 5-Aminomethyl Oxazolidinone Prodrugs: Robust Potency and Potential Liabilities.

Linezolid is a drug with proven human antitubercular activity whose use is limited to highly drug-resistant patients because of its toxicity. This toxicity is related to its mechanism of action─linezolid inhibits protein synthesis in both bacteria and eukaryotic mitochondria. A highly selective and potent series of oxazolidinones, bearing a 5-aminomethyl moiety (in place of the typical 5-acetamidomethyl moiety of linezolid), was identified.

DNA-Dependent Binding of Nargenicin to DnaE1 Inhibits Replication in .

Natural products provide a rich source of potential antimicrobials for treating infectious diseases for which drug resistance has emerged. Foremost among these diseases is tuberculosis. Assessment of the antimycobacterial activity of nargenicin, a natural product that targets the replicative DNA polymerase of , revealed that it is a bactericidal genotoxin that induces a DNA damage response in () and inhibits growth by blocking the replicative DNA polymerase, DnaE1.

Novel oxazolidinone calcitonin gene-related peptide (CGRP) receptor antagonists for the acute treatment of migraine.

In our efforts to develop CGRP receptor antagonists as backups to MK-3207, 2, we employed a scaffold hopping approach to identify a series of novel oxazolidinone-based compounds. The development of a structurally diverse, potent (20, cAMP+HS IC50=0.67 nM), and selective compound (hERG IC50=19 μM) with favorable rodent pharmacokinetics (F=100%, t1/2=7h) is described.

Lessons from the Total Synthesis of (±) Phalarine: Insights Into the Mechanism of the Pictet-Spengler Reaction.

The furanobisindole alkaloid, phalarine, possesses a unique structural framework within the alkaloid family of natural products. Our laboratory recently disclosed the racemic total synthesis of phalarine, featuring an efficient azaspiroindolenine rearrangement; this achievement is revisited in detail. Upon completion of the first-generation total synthesis, we explored some interesting mechanism-level issues with regard to the key azaspiroindolenine rearrangement.

Total synthesis of enantiopure phalarine via a stereospecific Pictet-Spengler reaction: traceless transfer of chirality from L-tryptophan.

An appropriately constructed 2-substituted derivative of l-tryptophan undergoes conversion to a prephalarine structure in a single step. The reaction occurs in a diastereoselective fashion, leading shortly thereafter to the naturally occurring version of the alkaloid phalarine.

Total synthesis and evaluation of [Psi[CH2NH]Tpg4]vancomycin aglycon: reengineering vancomycin for dual D-Ala-D-Ala and D-Ala-D-Lac binding.

An effective synthesis of [Psi[CH(2)NH]Tpg(4)]vancomycin aglycon (5) is detailed in which the residue 4 amide carbonyl of vancomycin aglycon has been replaced with a methylene. This removal of a single atom was conducted to enhance binding to D-Ala-D-Lac, countering resistance endowed to bacteria that remodel their D-Ala-D-Ala peptidoglycan cell wall precursor by a similar single atom change (ester O for amide NH). Key elements of the approach include a synthesis of the modified vancomycin ABCD ring system featuring a reductive amination coupling of residues 4 and 5 for installation of the deep-seated amide modification, the first of two diaryl ether closures for formation of the modified CD ring system (76%, 2.

Total synthesis of the ristocetin aglycon.

The first total synthesis of the ristocetin aglycon is described employing a modular and highly convergent strategy. An effective 12-step (12% overall) synthesis of the ABCD ring system 3 from its amino acid subunits sequentially features an intramolecular aromatic nucleophilic substitution reaction for formation of the diaryl ether and closure of the 16-membered CD ring system (65%), a respectively diastereoselective (3:1, 86%) Suzuki coupling for installation of the AB biaryl linkage on which the atropisomer stereochemistry can be further thermally adjusted, and an effective macrolactamization (51%) for closure of the 12-membered AB ring system. A similarly effective 13-step (14% overall) synthesis of the 14-membered EFG ring system 4 was implemented employing a room-temperature intermolecular S(N)Ar reaction of an o-fluoronitroaromatic for formation of the FG diaryl ether (69%) and a key macrolactamization (92%) with formation of the amide linking residues 1 and 2.

Synthesis and evaluation of methyl ether derivatives of the vancomycin, teicoplanin, and ristocetin aglycon methyl esters.

A series of methyl ether derivatives of the vancomycin, teicoplanin, and ristocetin aglycon methyl esters was synthesized and their antimicrobial activity was established. These derivatives exhibit increased activity against VanB resistant strains of bacteria equipotent with that observed with sensitive bacteria.

Partitioning the loss in vancomycin binding affinity for D-Ala-D-Lac into lost H-bond and repulsive lone pair contributions.

The binding affinity of 4, which incorporates a methylene (CH2) in place of the key linking amide of Ac2-l-Lys-d-Ala-d-Ala, for vancomycin was compared with that of Ac2-l-Lys-d-Ala-d-Ala (3) and Ac2-l-Lys-d-Ala-d-Lac (5). The vancomycin affinity for 4 was approximately 10-fold less than that of 3, but 100-fold greater than that of 5. This suggests that the reduced binding affinity of 5 (4.

A new and improved method for deglycosidation of glycopeptide antibiotics exemplified with vancomycin, ristocetin, and ramoplanin.

A general method for the deglycosidation of glycopeptide antibiotics has been developed. Treatment of vancomycin, ristocetin, and ramoplanin with anhydrous HF results in efficient cleavage of the sugars to provide the corresponding aglycons in high yield.