Hit-to-Lead Studies for the Antimalarial Tetrahydroisoquinolone Carboxanilides
摘要:
Phenotypic whole-cell screening in erythrocytic cocultures of Plasmodium falciparum identified a series of dihydroisoquinolones that possessed potent antimalarial activity against multiple resistant strains of P. falciparum in vitro and show no cytotoxicity to mammalian cells. Systematic structure activity studies revealed relationships between potency and modifications at N-2, C-3, and C-4. Careful structure property relationship studies, coupled with studies of metabolism, addressed the poor aqueous solubility and metabolic vulnerability, as well as potential toxicological effects, inherent in the more potent primary screening hits such as 10b. Analogues 13h and 13i, with structural modifications at each site, were shown to possess excellent antimalarial activity in vivo. The (+)-(35,4S) enantiomer of 13i and similar analogues were identified as the more potent. On the basis of these studies, we have selected (+)-13i for further study as a preclinical candidate.
Hit-to-Lead Studies for the Antimalarial Tetrahydroisoquinolone Carboxanilides
摘要:
Phenotypic whole-cell screening in erythrocytic cocultures of Plasmodium falciparum identified a series of dihydroisoquinolones that possessed potent antimalarial activity against multiple resistant strains of P. falciparum in vitro and show no cytotoxicity to mammalian cells. Systematic structure activity studies revealed relationships between potency and modifications at N-2, C-3, and C-4. Careful structure property relationship studies, coupled with studies of metabolism, addressed the poor aqueous solubility and metabolic vulnerability, as well as potential toxicological effects, inherent in the more potent primary screening hits such as 10b. Analogues 13h and 13i, with structural modifications at each site, were shown to possess excellent antimalarial activity in vivo. The (+)-(35,4S) enantiomer of 13i and similar analogues were identified as the more potent. On the basis of these studies, we have selected (+)-13i for further study as a preclinical candidate.
Formation of 1,2,3,4-tetrahydro-2-pyridones by aza-annulation of imines with acrylate derivatives
作者:K. Paulvannan、John R. Stille
DOI:10.1021/jo00046a011
日期:1992.9
The aza-annulation of imines with activated acrylate derivatives was studied as a means of preparing the corresponding 1,2,3,4-tetrahydro-2-pyridones. Through the use of reagents known to facilitate the formation of amide bonds from carboxylic acids, several methods of activating the acrylate species were compared. The acrylate derivatives studied were acryloyl chloride and acrylic anhydride as well as acrylic acid activated by reaction with EtO2CCl, (PhO)2P(O)N3, or MCPI. Optimum annulation was obtained with imines derived from cyclohexanone to produce octahydro-2-quinolone products. The N-isobutylimine prepared from cyclopentanone also produced selective ring annulation to efficiently produce the corresponding bicyclic product, but the reaction with the imine of n-butanal produced lower yields of cyclic product. Ring formation was relatively unaffected by substituents at the a-position of the acrylate derivative, demonstrated by the use of methacrylate, but beta-substituents hindered the annulation process and, in turn, increased the amounts of byproduct resulting from only N-acylation of the imine. Increasing the steric bulk of the imine alkyl substituent produced the opposite effect; the relative amount of N-acylation compared to complete aza-annulation was diminished as the size of the substituent was increased. Mechanistic features of the reaction are discussed in terms of product distribution and competition experiments.