PMC

F_o–F_c omit map of inhibitor 21 (green mesh) contoured at 3σ.

General structure of macrocyclic inhibitor (I)

View of the F_o–F_c omit map for inhibitor 13 (green mesh) contoured at 3σ

Hydrogen bond interactions (dashed lines) between inhibitor 21 and NV 3CL protease.

View of the m-chlorophenyl of inhibitor 13 which is positioned in a hydrophobic pocket of NV 3CLpro.

Electrostatic surface representation of NVPro showing the aliphatic chain of inhibitor 21 positioned in a hydrophobic S₄ pocket.

Hydrogen bond interactions (dashed lines) between NV 3CLpro and inhibitor 13. Contacts to water molecules are indicated by the solid lines

Two views showing the electrostatic surface representation NV 3CLpro binding site of inhibitor 13. A) View of the active site and B) the m-chlorophenyl group in the hydrophobic S₄ pocket. View is rotated counterclockwise approximately 90° about the vertical axis relative to panel A.

Surface representation of NV 3CL protease with bound inhibitor 21 site and with neighboring residues colored yellow (nonpolar), cyan (polar), and white (weakly polar). A) View of the inhibitor in the S₁/S₂ pocket and B) the S₄ pocket. View is rotated counterclockwise approximately 90° about the vertical axis relative to panel A.

The synthesis of inhibitors 11–21 by coupling compounds 3a–k () with compound 6a () to yield acyclic compounds 7a–k (). The reaction sequence outlined in is flexible and permits ready manipulation of the ring size using appropriate alkenyl Grignard reagents. Furthermore, the nature of the P₂ residue (R₂) could be readily manipulated by reacting intermediates 1a–f () with an appropriate amino acid ester isocyanate 4a–d (). Ring closure using a metathesis reaction furnished compounds 8a–k which, upon sequential catalytic hydrogenation, reduction with lithium borohydride, and Dess-Martin periodinane oxidation yielded aldehydes 11–21. With the exception of compounds 14 and 36, these were obtained as diastereomeric mixtures. Aldehydes 23–24 having an unsaturated linker were synthesized in an analogous manner (). Aldehyde bisulfite adducts 25–29 and α-ketoamide 31 were synthesized as shown in . Finally, coupling of intermediate 3c with 6b () followed by further elaboration of the product yielded aldehyde 36 ().

The synthesis of inhibitors 11–21 by coupling compounds 3a–k () with compound 6a () to yield acyclic compounds 7a–k (). The reaction sequence outlined in is flexible and permits ready manipulation of the ring size using appropriate alkenyl Grignard reagents. Furthermore, the nature of the P₂ residue (R₂) could be readily manipulated by reacting intermediates 1a–f () with an appropriate amino acid ester isocyanate 4a–d (). Ring closure using a metathesis reaction furnished compounds 8a–k which, upon sequential catalytic hydrogenation, reduction with lithium borohydride, and Dess-Martin periodinane oxidation yielded aldehydes 11–21. With the exception of compounds 14 and 36, these were obtained as diastereomeric mixtures. Aldehydes 23–24 having an unsaturated linker were synthesized in an analogous manner (). Aldehyde bisulfite adducts 25–29 and α-ketoamide 31 were synthesized as shown in . Finally, coupling of intermediate 3c with 6b () followed by further elaboration of the product yielded aldehyde 36 ().

The synthesis of inhibitors 11–21 by coupling compounds 3a–k () with compound 6a () to yield acyclic compounds 7a–k (). The reaction sequence outlined in is flexible and permits ready manipulation of the ring size using appropriate alkenyl Grignard reagents. Furthermore, the nature of the P₂ residue (R₂) could be readily manipulated by reacting intermediates 1a–f () with an appropriate amino acid ester isocyanate 4a–d (). Ring closure using a metathesis reaction furnished compounds 8a–k which, upon sequential catalytic hydrogenation, reduction with lithium borohydride, and Dess-Martin periodinane oxidation yielded aldehydes 11–21. With the exception of compounds 14 and 36, these were obtained as diastereomeric mixtures. Aldehydes 23–24 having an unsaturated linker were synthesized in an analogous manner (). Aldehyde bisulfite adducts 25–29 and α-ketoamide 31 were synthesized as shown in . Finally, coupling of intermediate 3c with 6b () followed by further elaboration of the product yielded aldehyde 36 ().

The synthesis of inhibitors 11–21 by coupling compounds 3a–k () with compound 6a () to yield acyclic compounds 7a–k (). The reaction sequence outlined in is flexible and permits ready manipulation of the ring size using appropriate alkenyl Grignard reagents. Furthermore, the nature of the P₂ residue (R₂) could be readily manipulated by reacting intermediates 1a–f () with an appropriate amino acid ester isocyanate 4a–d (). Ring closure using a metathesis reaction furnished compounds 8a–k which, upon sequential catalytic hydrogenation, reduction with lithium borohydride, and Dess-Martin periodinane oxidation yielded aldehydes 11–21. With the exception of compounds 14 and 36, these were obtained as diastereomeric mixtures. Aldehydes 23–24 having an unsaturated linker were synthesized in an analogous manner (). Aldehyde bisulfite adducts 25–29 and α-ketoamide 31 were synthesized as shown in . Finally, coupling of intermediate 3c with 6b () followed by further elaboration of the product yielded aldehyde 36 ().

The synthesis of inhibitors 11–21 by coupling compounds 3a–k () with compound 6a () to yield acyclic compounds 7a–k (). The reaction sequence outlined in is flexible and permits ready manipulation of the ring size using appropriate alkenyl Grignard reagents. Furthermore, the nature of the P₂ residue (R₂) could be readily manipulated by reacting intermediates 1a–f () with an appropriate amino acid ester isocyanate 4a–d (). Ring closure using a metathesis reaction furnished compounds 8a–k which, upon sequential catalytic hydrogenation, reduction with lithium borohydride, and Dess-Martin periodinane oxidation yielded aldehydes 11–21. With the exception of compounds 14 and 36, these were obtained as diastereomeric mixtures. Aldehydes 23–24 having an unsaturated linker were synthesized in an analogous manner (). Aldehyde bisulfite adducts 25–29 and α-ketoamide 31 were synthesized as shown in . Finally, coupling of intermediate 3c with 6b () followed by further elaboration of the product yielded aldehyde 36 ().

The synthesis of inhibitors 11–21 by coupling compounds 3a–k () with compound 6a () to yield acyclic compounds 7a–k (). The reaction sequence outlined in is flexible and permits ready manipulation of the ring size using appropriate alkenyl Grignard reagents. Furthermore, the nature of the P₂ residue (R₂) could be readily manipulated by reacting intermediates 1a–f () with an appropriate amino acid ester isocyanate 4a–d (). Ring closure using a metathesis reaction furnished compounds 8a–k which, upon sequential catalytic hydrogenation, reduction with lithium borohydride, and Dess-Martin periodinane oxidation yielded aldehydes 11–21. With the exception of compounds 14 and 36, these were obtained as diastereomeric mixtures. Aldehydes 23–24 having an unsaturated linker were synthesized in an analogous manner (). Aldehyde bisulfite adducts 25–29 and α-ketoamide 31 were synthesized as shown in . Finally, coupling of intermediate 3c with 6b () followed by further elaboration of the product yielded aldehyde 36 ().