4-Hydroxy-1(2H)-isoquinolone-3-carboxamides synthesis and properties

Synthesis of novel acceptor substrates for the dolichyl phosphate mannose synthase from yeast

Dolichols are polyisoprenoid lipid components of mammalian membranes consisting of an average of 20 head-to-tail linked isoprene units of which the first isoprene is fully saturated. The unusual size of these lipids is intriguing and poses questions about the role of dolichol structure in biological processes. In order to probe structure and function we have synthesised potential dolichyl analogues that retain only the first two isoprene units and carry a second functional group within the terminal lipid chain. Such analogues were evaluated as substrates for a key enzyme in the dolichyl-dependent pathway of glycan biosynthesis, dolichyl phosphate mannose (Dol-P-Man) synthase. It was shown that some functional groups, including labels such as biotin, could be tolerated. When the synthetic analogues were attached to a solid support they were still substrates for the Dol-P-Man system and thus allowed the enzymatic solid-phase synthesis of glycolipids.

Novel inhibitors of plasminogen activator inhibitor-1: development of new templates from diketopiperazines

Several isoquinoline-based templates were identified from the studies of the conformational effects of the diketopiperazine structures for PAI-1 inhibition. Moderate to good activity was retained with the elimination of unattractive characteristics in the diketopiperazine template.

Discovery of new inhibitors of aldose reductase from molecular docking and database screening

Aldose reductase (ALR2) is a target enzyme for the treatment of diabetic complications. Owing to the limited number of currently available drugs for the treatment of diabetic complications, the discovery of new inhibitors of ALR2 that can potentially be optimized as drugs appears highly desirable. In this study, a molecular docking analysis of the structures of more than 127,000 organic compounds contained in the National Cancer Institute database was performed to find and score molecules that are complementary to ALR2. Besides retrieving several carboxylic acid derivatives, which are known to generally inhibit aldose reductase, docking proposed other families of putative inhibitors such as sulfonic acids, nitro-derivatives, sulfonamides and carbonyl derivatives. Twenty-five compounds, chosen as the highest-scoring representatives of each of these families, were tested as aldose reductase inhibitors. Five of them were found to inhibit aldose reductase in the micromolar range. For these active compounds, selectivity with respect to the closely-related aldehyde reductase was determined by measuring the corresponding inhibitory activities. The structures of the complexes between the new lead inhibitors and aldose reductase, here refined with molecular mechanics and molecular dynamics calculations, suggest that new pharmacophoric groups can bind aldose reductase very efficiently. In the case of the family of the nitro-derivative inhibitors, a class of particularly interesting compounds, a round of optimizations was performed with the synthesis and biological evaluation of a series of derivatives aimed at testing the proposed binding mode and at improving interaction with active site residues. Starting from a hit compound having an IC(50) of 42 microM, the most potent compound synthesized showed a 10-fold increase in inhibitory activity and 10-fold selectivity with respect to ALR1, and structure--activity relationships of the designed compounds were in agreement with the proposed mode of binding at the active site.

Synthesis and anticonvulsant activity of N,N-phthaloyl derivatives of central nervous system inhibitory amino acids

In order to study the influence of the length of the amino acid chain of N,N-phthaloyl-amino acid amides as analogues of the former anticonvulsant taltrimide on the seizure-antagonizing activity glycine, beta-alanine and gamma-aminobutyric acid (GABA) derivatives were synthesized. The corresponding taurine derivatives were also included. Generally, the glycine-derived amides showed a higher activity than the beta-alanine and GABA derivatives in the maximal electroshock seizure (MES) test in mice upon intraperitoneal administration. The activity was comparable to the respective taurine derivatives. The N,N-phthaloyl-glycine amides were also active in the MES test upon oral administration to rats. No significant activity was noted in the seizure threshold test with subcutaneous pentylene-tetrazole. The ED50 of N,N-phthaloyl-glycine ethyl amide (4b) in the MES test upon intraperitoneal administration to mice was 19.1 mg/kg. On a molar basis this activity is comparable to the activity of phenytoin with little toxicity in the rotorod test. In conclusion, N,N-phthaloyl-glycine amides might represent promising antiepileptic drugs.