No abstract

A 2-amido benzo[ d]imidazole library has been constructed by solid-phase synthesis. The key step of this solid-phase synthesis involves the preparation of polymer-bound 2-amino benzo[ d]imidazole resin through desulfurative cyclization of thiourea resin using 2-chloro-1,3-dimethylimidazolinium chloride and N, N-diisopropylethylamine in dichloromethane (DCM), and the resin is then functionalized by acylation at the 2-amine position to afford 2-amidobenzo[ d]imidazole resin. In the case of 2-amidobenzo[ d]imidazole resin having a p-I or m-NO, the resin was further functionalized by Suzuki/Sonogashira-coupling ( p-I) and reduction to the primary amine ( m-NO) followed by acylation. Finally, the functionalized 2-amido-benzo[ d]imidazole resin was cleaved from the polymer support by treatment with a cocktail of trifluoroacetic acid and DCM. As a result, we obtained 2-amidobenzo[ d]imidazole analogues in high yield and good purities.

A novel solid-phase methodology has been developed for the synthesis of N-alkyl, N-acyl, and N-sulfonyl-2-aminobenzo[d]thiazole derivatives. The key step in this procedure involves the preparation of polymer-bound 2-aminobenzo[d]thiazole resins 5 by cyclization reaction of 2-iodophenyl thiourea resin 3. The resin-bound 2-iodophenyl thiourea 3 is produced by addition of 2-iodophenyl isothiocyanate 2 to the amine-terminated linker amide resin 1. These core skeleton 2-aminobenzo[d]thiazole resins 5 undergo functionalization reactions with various electrophiles, such as alkyl halides, acid chlorides, and sulfonyl chlorides to generate N-alkyl, N-acyl, and N-sulfonyl-2-aminobenzo[d]thiazole resins 6, 7, and 8, respectively. Finally, N-alkyl, N-acyl, and N-sulfonyl-2-aminobenzo[d]thiazole derivatives 9, 10, and 11 are then generated in good yields and purities by cleavage of the respective resins 6, 7, and 8 using trifluoroacetic acid (TFA) in dichloromethane (DCM).

A series of compounds containing both 1,3,4-oxadiazole and thiohydantoin were synthesized as a promising scaffold for application in medicinal chemistry. The key step of the synthesis is a microwave-assisted cyclization of semicarbazides possessing a thiohydantoin moiety at one of the acyl termini using POCl 3 as a dehydrating reagent. A wide range of semicarbazides were prepared through the substitution of hydrazides with an N-acylated thiohydantoin derived from the cyclization of the corresponding isothiocyanate with an amino acid and subsequent N-acylation of the resultant thiohydrantion. Consequently, the 58 number of 1,3,4-oxadiazole derivatives having a thiohydantoin substituent were prepared in good overall yields.

Novel N-(2,2 0 -disubstituted-2H-cromenyl)-N 0 N 00 -disubstituted guanidine derivatives were synthesized and evaluated as an S-nitrosoglutathion (GSNO) reductase inhibitor. The synthesized guanidine derivatives 1 and 2b showed high potency in an enzyme-based assay with recombinant GSNO reductase (IC 50 < 10 μM). Surface plasmon resonance measurement and molecular docking studies confirmed the direct interaction of compound 2b with GSNO reductase. The results provide valuable information for the design of inhibitors with better spectrum of activity toward GSNO reductase.