Versatile Synthesis of Free andN-Benzyloxycarbonyl-Protected 2,2-Disubstituted Taurines

Favorable Preclinical Pharmacological Profile of a Novel Antimalarial Pyrrolizidinylmethyl Derivative of 4-amino-7-chloroquinoline with Potent In Vitro and In Vivo Activities

The 4-aminoquinoline drugs, such as chloroquine (CQ), amodiaquine or piperaquine, are still commonly used for malaria treatment, either alone (CQ) or in combination with artemisinin derivatives. We previously described the excellent in vitro activity of a novel pyrrolizidinylmethyl derivative of 4-amino-7-chloroquinoline, named MG3, against P. falciparum drug-resistant parasites. Here, we report the optimized and safer synthesis of MG3, now suitable for a scale-up, and its additional in vitro and in vivo characterization. MG3 is active against a panel of P. vivax and P. falciparum field isolates, either alone or in combination with artemisinin derivatives. In vivo MG3 is orally active in the P. berghei, P. chabaudi, and P. yoelii models of rodent malaria with efficacy comparable, or better, than that of CQ and of other quinolines under development. The in vivo and in vitro ADME-Tox studies indicate that MG3 possesses a very good pre-clinical developability profile associated with an excellent oral bioavailability, and low toxicity in non-formal preclinical studies on rats, dogs, and non-human primates (NHP). In conclusion, the pharmacological profile of MG3 is in line with those obtained with CQ or the other quinolines in use and seems to possess all the requirements for a developmental candidate.

Synthesis of sulfonopeptides

Sulfonopeptides as the sulfur analogues of natural peptides have been widely used as enzyme inhibitors due to their tetrahedral sulfonamide moiety, which can mimic the transition-state analogues of hydrolysis of the ester and amide bonds. Synthetic methods of sulfonopeptides are reviewed. The synthetic methods of sulfonopeptides include the condensation of N-protected amino acid/peptide acids and 2-aminoalkanesulfonic acids, coupling of N-protected 2-aminoalkanesulfonyl chlorides and amino acid esters/peptide esters, sulfinylation of amino acid esters/peptide esters with N-protected 2-aminoalkanesulfinyl chlorides and subsequent oxidation, the alkylation of taurine-containing peptides, and the displacement of N-aminoacyl/peptidyl 2-aminoalkyl halides/methanesulfonates with sulfites. Hybrid sulfonophosphinopeptides are prepared through the Mannich-type reaction of N-protected 2-aminoalkanesulfonamides/peptidylsulfonamides, aldehydes, and aryldichlorophosphines/phosphorus trichloride followed by the aminolysis with amino acid/peptide esters or hydrolysis. The developed synthetic methods provide diverse synthetic routes for biologically important sulfonopeptides as the candidates of medicinal agents.

Versatile synthesis of α-substituted taurines from nitroolefins

A series of 1-substituted and 1,1-disubstituted taurines were synthesized from nitroolefins via the Michael addition with sodium ethylxanthate, oxidation with performic acid, and reduction with hydrogen in the presence of palladium on carbon powder. The current route is a versatile and salt-free method for synthesis of both aliphatic and aromatic 1-substituted and 1,1-disubstituted taurines.