win-54954 and disoxaril

A series of 1,2,4-oxadiazoles has been prepared as ester bioisosteres and tested against 15 human rhinovirus serotypes, and the MIC80, the concentration which inhibits 80% or 12 of the serotypes tested, was determined. Homologation of the alkyl group attached to the oxadiazole ring resulted in a reduction in activity with increased chain length. Introduction of hydrophilic groups in this position rendered the compounds inactive. Increasing the length of the side chain attached to the isoxazole ring resulted in an increase in activity. Replacement of the methyl with alkoxyalkyl substituents retained activity; however, introduction of a hydroxyl group on to the side chain reduced activity. Compound 8a, where both the isoxazole and oxadiazole rings were substituted with methyl groups, was one of the most active compounds in the series. A comparison was made between 8a and the two isomeric oxadiazoles 41 and 46, and an attempt was made to explain the difference in activity by examining electrostatic potential maps and by an energy profiling study. No conclusive results were obtained from these studies.

Topics: Antiviral Agents; Esters; HeLa Cells; Humans; Isoxazoles; Oxadiazoles; Rhinovirus

A series of tetrazole analogues of Win 54954, a broad-spectrum antipicornavirus compound, has been synthesized to address the acid lability of the oxazoline ring of this series of compounds. The results of X-ray crystallography studies of several members of the oxazoline series bound to human rhinovirus type 1A and 14 have been used to design compounds in the tetrazole series with a broad spectrum of activity. Compound 16b, which has a three-carbon linkage between the isoxazole and phenyl rings and a propyl chain extending from the isoxazole ring, exhibiting an MIC80 for 15 rhinovirus serotypes of 0.20 microM as compared to 0.40 microM for Win 54954. X-ray studies of 16b bound to human rhinovirus-14 show that the propyl side chain extends into a pore in the binding site with the possibility of hydrophobic interactions with a pocket formed by Leu106 and a portion of Ser107.

Topics: Amino Acid Sequence; Antiviral Agents; Binding Sites; Humans; Isoxazoles; Microbial Sensitivity Tests; Molecular Sequence Data; Picornaviridae; Rhinovirus; Structure-Activity Relationship; Tetrazoles

A series of conformationally restricted analogs of disoxaril has been synthesized and evaluated against human rhinovirus types (HRV) 14 and 1A. The sensitivity of these serotypes to this series varied and was dependent upon the length of the molecule as well as upon the flexibility of the aliphatic chain. Minimum energy conformations of these compounds were overlaid with the X-ray structure of a closely related analog 9 bound to the capsid protein of both HRV-14 and -1A and then modeled in the compound-binding site of both serotypes. A comparative sweep volume of these compounds about the isoxazole ring revealed an inaccessible region of space for the cis-olefin 8b, which is not the case for either the trans-olefin 8a or the acetylene 5. This region may be important to the binding of the compounds to the HRV-14 site particularly during entry into the pocket.

Topics: Antiviral Agents; Binding Sites; Humans; Isoxazoles; Models, Molecular; Rhinovirus; Structure-Activity Relationship

The binding affinities (Kds) and the rates of association and dissociation of members of a chemical class of antiviral compounds at their active sites in human rhinovirus type 14 (HRV-14) were determined. On the basis of analysis by LIGAND, a nonlinear curve-fitting program, of saturation binding experiments with HRV-14, the Kds for Win 52084, Win 56590, disoxaril (Win 51711), and Win 54954 were found to be 0.02, 0.02, 0.08, and 0.22 microM, respectively. The independently determined kinetic rates of association and dissociation resulted in calculated Kd values which were in agreement with the Kd values determined in saturation binding experiments. Scatchard plots of each of four compounds for the binding data indicated that approximately 40 to 60 molecules were bound per HRV-14 virion. Hill plots showed no evidence of cooperativity in binding. Furthermore, the antiviral activities (MICs in plaque reduction assays with HRV-14) for this limited series of compounds (n = 4) correlated well (r = 0.997) with the observed Kds. Likewise, the absence of detectable binding of Win 54954 to the drug-resistant mutant HRV-14 (Leu-1188) corresponded to a lack of antiviral activity. The positive relationship between the antiviral activities and the Kds that were determined may have implications for the molecular design of capsid-binding antirhinovirus drugs.

Topics: Antiviral Agents; Capsid; Cells, Cultured; Dose-Response Relationship, Drug; Half-Life; Humans; Isoxazoles; Kinetics; Microbial Sensitivity Tests; Rhinovirus

A number of 2,6-disubstituted analogues of disoxaril, a broad spectrum antipicornavirus agent, have been prepared and evaluated against several rhinovirus serotypes. A QSAR study revealed that the mean MIC (MIC) against five rhinovirus serotypes correlated well with log P. The 2,6-dichloro analogue, 15, was highly effective in vitro against rhinoviruses with an MIC80 of 0.3 microM, as well as against several enteroviruses, and was also effective in preventing paralysis in mice infected with coxsackievirus A-9.

Topics: Antiviral Agents; Coronaviridae; Humans; Isoxazoles; Oxazoles; Structure-Activity Relationship