The synthesis of baclofen and GABOB via Rh(II) catalyzed intramolecular C–H insertion of α-diazoacetamides

In silico structure-based design of GABAB receptor agonists using a combination of docking and QSAR

The study of γ-aminobutyric acid B receptor (GABA_B ) activation is of great interest for several brain disorders. The search of new GABA_B receptor agonists has been carried out by many research groups. As a result, Baclofen has become the prototypical GABA_B receptor agonist. However, several attempts have been made to modify its structure to generate derivatives with improved activity. In this work, we carried out a theoretical and computational study for a wide range of GABA_B receptor agonists reported in the literature. Molecular docking and QSAR techniques were combined by using the interaction energies of the agonists with the key residues of GABA_B receptor, as molecular descriptors for the QSAR construction. The resulting mathematical model suggests that the activity of GABA_B receptor agonists is influenced by three factors: their shape and molecular size (PW5 and PJI2), their constitutional features (E_LUMO and T(N…O)) and the energy interaction with GABA_B receptor (E_TRP278 ). This model was validated by the QUIK, REDUNDANCY and OVERFITTING rules, and its predicted ability was tasted by the Q_LOO , Q_ASYM , R 0 2 and r m 2 rules. Finally, six new compounds are proposed (35-40) with high potential to be used as GABA_B receptor agonists.

Synthesis, antimycobacterial activity and influence on mycobacterial InhA and PknB of 12-membered cyclodepsipeptides

In recent years, several small natural cyclopeptides and cyclodepsipeptides were reported to have antimycobacterial activity. Following this lead, a synthetic pathway was developed for a small series of 12-membered ring compounds with one amide and two ester bonds (cyclotridepsipeptides). Within the series, the ring system proved to be necessary for growth inhibition of Mycobacterium smegmatis and Mycobacterium tuberculosis in the low micromolar range. Open-chain precursors and analogues were inactive. The compounds modulated autophosphorylation of the mycobacterial protein kinase B (PknB). PknB inhibitors were active at µM concentration against mycobacteria while inducers were inactive. PknB regulates the activity of the mycobacterial reductase InhA, the target of isoniazid. The activity of the series against Mycobacterium bovis BCG InhA overexpressing strains was indistinguishable from that of the parental strain suggesting that they do not inhibit InhA. All substances were not cytotoxic (HeLa > 5 µg/ml) and did not show any significant antiproliferative effect (HUVEC > 5 µg/ml; K-562 > 5 µg/ml). Within the scope of this study, the molecular target of this new type of small cyclodepsipeptide was not identified, but the data suggest interaction with PknB or other kinases may partly cause the activity.

Organic chemistry. Strain-release amination

To optimize drug candidates, modern medicinal chemists are increasingly turning to an unconventional structural motif: small, strained ring systems. However, the difficulty of introducing substituents such as bicyclo[1.1.1]pentanes, azetidines, or cyclobutanes often outweighs the challenge of synthesizing the parent scaffold itself. Thus, there is an urgent need for general methods to rapidly and directly append such groups onto core scaffolds. Here we report a general strategy to harness the embedded potential energy of effectively spring-loaded C-C and C-N bonds with the most oft-encountered nucleophiles in pharmaceutical chemistry, amines. Strain-release amination can diversify a range of substrates with a multitude of desirable bioisosteres at both the early and late stages of a synthesis. The technique has also been applied to peptide labeling and bioconjugation.

One pot domino reaction accessing γ-nitroesters: synthesis of GABA derivatives

γ-Nitroesters are synthesized by the one pot domino process. GABA derivatives phenibut and baclofen were readily accessed.

Asymmetric Synthesis of Highly Substituted γ-Amino Acids from Allyltitanium Sulfoximines

[structure: see text]. Asymmetric syntheses of the highly substituted protected gamma-amino acids 10a, 10b, 18, and 21 have been developed starting from the allyltitanium sulfoximines V and VI, respectively, and furan-2-carbaldehyde.