126109-42-0

A new non-hydrolyzable phosphotyrosine analogue, L-F4Pmp and its N-Fmoc protected derivative were prepared by using an enantioselective synthetic pathway with camphor sultam as chiral auxiliary. The side chain pKa2 (6.9) of L-F4

The L-type amino acid transporter 1 (LAT1, SLC7A5) transports essential amino acids across the blood-brain barrier (BBB) and into cancer cells. To utilize LAT1 for drug delivery, potent amino acid promoieties are desired, as prodrugs must compete with millimolar concentrations of endogenous amino acids. To better understand ligand-transporter interactions that could improve potency, we developed structural LAT1 models to guide the design of substituted analogues of phenylalanine and histidine. Furthermore, we evaluated the structure-activity relationship (SAR) for both enantiomers of naturally occurring LAT1 substrates. Analogues were tested in cis-inhibition and trans-stimulation cell assays to determine potency and uptake rate. Surprisingly, LAT1 can transport amino acid-like substrates with wide-ranging polarities including those containing ionizable substituents. Additionally, the rate of LAT1 transport was generally nonstereoselective even though enantiomers likely exhibit different binding modes. Our findings have broad implications to the development of new treatments for brain disorders and cancer.

In the present work the scope of D-hydantoinase enzyme application was increased towards new racemic (R,S)-5-benzylhydantoin derivatives. Five new substrates for the D-hydantoinase (R,S)-5-(3′-carboxybenzyl)hydantoin, (R,S)-5-(4′-carboxybenzyl)hydantoin, (R,S)-5-(2′-carbomethoxybenzyl) hydantoin, (R,S)-5-(3′-carbomethoxybenzyl)hydantoin and (R,S)-5-(4′(4-ethoxycarboxy)propoxybenzyl)hydantoin were synthesised and converted using a two-step hydantoinase process into their corresponding D-phenylalanine derivatives. In this study two D-hydantoinases from Vigna angularis (adzuki bean) obtained from commercial sources were used: pure, isolated directly from Vigna angularis (V.a.D-HYD) 494 U/g and immobilised, recombinant, cloned and expressed in Escherichia coli (rD-HYD) 53.1 U/g. The results obtained showed that the examined enzymes catalysed hydrolysis of all new substrates into their corresponding N-carbamoyl-D-phenylalanine derivatives. High enantiomeric purities of the resulting D-phenylalanine derivatives were also determined. However, very low conversion yields of (R,S)-5-(3′- carboxybenzyl)hydantoin and (R,S)-5-(2′-carbomethoxybenzyl)hydantoin to corresponding N-carbamoyl-D amino acid were observed. Three D-phenylalanine derivatives: 4-carboxy-D-phenylalanine, 3-carbomethoxy-D-phenylalanine and 4-carbopropoxy-D-phenylalanine were obtained and isolated from the reaction mixtures using ion-exchange chromatography.

The synthesis of a new bifunctional ligand 1-(p- carboxybenzyl)-N,N'-bis-[1,1-dimethyl-1-(p- methoxybenzylthio)ethyl]ethylenediamine-N,N'-diacetic acid, di-t- butyl ester (1, nbi6ss) is described. It consists of a carboxybenzyl group substituted on a carb