Regioisomeric 3-, 4- and 5-aminomethyl isoxazoles: synthesis and muscarinic activity

Structure-Based Design of MptpB Inhibitors That Reduce Multidrug-Resistant Mycobacterium tuberculosis Survival and Infection Burden in Vivo

Mycobacterium tuberculosis protein-tyrosine-phosphatase B (MptpB) is a secreted virulence factor that subverts antimicrobial activity in the host. We report here the structure-based design of selective MptpB inhibitors that reduce survival of multidrug-resistant tuberculosis strains in macrophages and enhance killing efficacy by first-line antibiotics. Monotherapy with an orally bioavailable MptpB inhibitor reduces infection burden in acute and chronic guinea pig models and improves the overall pathology. Our findings provide a new paradigm for tuberculosis treatment.

Substituent effect study on experimental ¹³C NMR chemical shifts of (3-(substituted phenyl)-cis-4,5-dihydroisoxazole-4,5-diyl)bis(methylene)diacetate derivatives

Eleven novel (3-(substituted phenyl)-cis-4,5-dihydroisoxazole-4,5-diyl)bis(methylene) diacetate derivatives were synthesized in the present study. These dihydroisoxazole derivatives were characterized by IR, (1)H NMR, (13)C NMR and elemental analyses. Their (13)C NMR spectra were measured in Deuterochloroform (CDCl3). The correlation analysis for the substituent-induced chemical shift (SCS) with Hammett substituent constant (σ), inductive substituent constant (σI), different of resonance substituent constants (σR, σR(o)) and Swain-Lupton substituent parameters (F, R) were performed using SSP (single substituent parameter), and DSP (dual substituent parameter) methods, as well as single and multiple regression analysis. From the result of regression analysis, the effect of substituent on the (13)C NMR chemical shifts was explained.

Design and synthesis of N¹,N⁵-bis[4-(5-alkyl-1,2,4-oxadiazol-3-yl)phenyl]glutaramides as potential antifungal prodrugs

A facile three step synthesis of a group of N1,N5-bis[4-(5-alkyl-1,2,4-oxadiazol-3-yl)phenyl]glutaramides, N1,N5-bis[4-(1,2,4-oxadiazol-3-yl)phenyl]glutaramide and N1,N5-bis[4-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)phenyl]glutaramide is described. These products are designed to function as masked bis-amidine prodrugs of a promising N1,N5-bis[4-(N'-(carbamimidoyl)phenyl]glutaramide antifungal lead.

Synthetic Utility of Epoxides for Chiral Functionalization of Isoxazoles

The lithio-anion of isoxazole 2 was found to ring open propylene oxide in good yields with complete regioselectivity. Vinylic and benzylic epoxides were utilized as key examples of electrophiles and found to produce a mixture of regioisomeric adducts. Additionally, the use of chiral epoxides was explored, and absolute configuration was determined by X-ray crystallography to prove that nucleophilic attack at the benzylic carbon of (R)-styrene oxide proceeds with 100% inversion at the benzylic carbon to afford the (S)-alcohol (4b).