191997-97-4Relevant academic research and scientific papers
Synthesis of pseudoxazolones and their inhibition of the 3C cysteine proteinases from hepatitis A virus and human rhinovirus-14
Ramtohul, Yeeman K.,Martin, Nathaniel I.,Silkin, Lara,James, Michael N. G.,Vederas, John C.
, p. 1351 - 1359 (2007/10/03)
The hepatitis A virus (HAV) and human rhinovirus (HRV) are important pathogens that belong to the picornavirus family. All picornaviruses have a 3C proteinase that processes an initially biosynthesised precursor protein and is crucial for viral maturation and replication. Monophenyl and diphenyl pseudoxazolones were prepared by cyclisation-elimination of N-α-chloroacyl amino acids or by condensation of p-substituted benzamides with glyoxylic acid followed by dehydrative cyclisation. Such pseudoxazolones are good time-dependent inhibitors of the HAV and HRV 3C proteinases with IC50 values in the micromolar range. Mechanistic insights into the mode of inhibition of the pseudoxazolones were obtained from mass spectrometry and gHMQC NMR spectroscopy of the HAV 3C enzyme-inhibitor complex using a pseudoxazolone labelled at the α-carbon with 13C, 13b(α-13C). The results indicate that HAV 3C proteinase was inactivated via the formation of a thioether bond by nucleophilic attack of the enzyme thiolate at the imine position of the pseudoxazolone 13b(α-13C).
Synthesis of Chiral Bicyclic Bis-lactam Components for the Controlled Self-Assembly of Hydrogen-Bonded Arrays
Brienne, Marie-Josephe,Gabard, Jacqueline,Leclercq, Martine,Lehn, Jean-Marie,Cheve, Michel
, p. 856 - 875 (2007/10/03)
The chiral biyclic bis-lactams of structures 3 and 4 were synthesized from the key intermediate 2′b, the N,N′-bis(4-methoxybenzyl) derivative of 2 (X = MeO) (Scheme 6). The synthesis of this intermediate involved two key steps: 1) a double condensation of glyoxylic acid/anisamide (= oxoacetic acid/4-methoxybenzamide) adduct 11c with veratrole (1,2-dimethoxybenzene; 10) allowed the introduction of two glycine units at the 4,5-positions of the veratrole ring to give 18c (Schemes 3 and 4); 2) in order to circumvent the hydrolysis of 4-methoxybenzoyl protective groups which proved to be unfeasible, these groups were transformed into 4-methoxybenzyl groups through a sequence involving thiocarbonylation followed by reduction (Scheme 5). Thereafter, the double intramolecular cyclization of the resulting diamino diester 22c proceeded easily to afford 2′b. This intermediate may be transformed via the tetrol 2′g or the diol 2′h into the N-protected derivatives of 2 (X = OR) and of 3 (X = OCOR). Cleavage of the 4-alkoxybenzyl groups was achieved by ceric ammonium nitrate. However, when the aromatic ring bore ether functions (N-protected 2), this normal reaction was accompanied by the oxidative ring cleavage to give the diene-diester structure 4 (Schemes 5 and 6).
