Novel renin inhibitors containing a non-peptide aminoalkanoyl moiety at P1-P1' position.

Six novel potential renin inhibitors have been designed and synthesized. All these inhibitors contained an unnatural aminoalkanoyl moiety at the central position P1- P1' of the molecule, which is attacked by renin. The moiety consists of pseudodipeptidic units, transition state analogues of a natural dipeptide of the parent substance: 4-amino-3-hydroxybutanoic acid (AHBA), 4-amino-5-(4-ethoxyphenyl)-3-hydroxypentanoic acid (AEPHPA), 4-amino-5-cyclohexyl-3-hydroxypentanoic acid (ACHPA) or 4-amino-3-hydroxynonanoic acid (AHNA). An unnatural moiety, 4-methoxyphenylalanylhistydyl (Phe(4-OMe)-His) has been introduced at the P3-P2 position of the obtained compounds. Five compounds contain isoamylamide of 6-aminohexanoic acid (epsilon-Ahx-laa) at the P2'-P3' position. One of designed inhibitors has been obtained in the form of an ethyl ester. The in vitro renin inhibitory activity of all synthesized compounds is contained within the range 10(-6) - 10(-8) M. The compound in the form of an ethyl ester has proven to be the most active (IC50 = 1.3 x 10(-8) M) but also susceptible to enzymatic degradation. The other five inhibitors were stable to chymotrypsin.

Synthesis and anticonvulsant activity of some amino acid derivatives. Part 3: Derivatives of Ala, Arg, Tzl, Gly and chi Abu.

Ten amino acid derivatives as antagonists of the excitatory amino acid (EAA) receptor and anticonvulsant activity have been designed. Five of these compounds supposed to show rather strong and five of them rather weak action as it was expected on the base of their hydrophobicity. All the compounds were synthesized and then evaluated in mice in the maximal electroshock seizure (MES) test, the subcutaneous Metrasol seizure threshold (scMet) test and the rotorod neurotoxicity (Tox) test. Four of the obtained compounds have shown high activity (three received class I and one class II) and six were classified in class III according to the classification of the Anticonvulsant Screening Project (ASP) of the Antiepileptic Drug Development Program (ADDP) of NINDS. One of the compounds classified in class I (10) was tested quantitatively following i.p. administration in mice. It has a MES ED50 = 29.05 b.w. and protective index (PI) of 3.77.

New renin inhibitors with hydrophilic C-terminus.

Four new peptide-based renin inhibitors, Boc-Phe(4-OMe)-MePhe-AHPPA-epsilon Ahx-EA (11), Boc-Phe(4-OMe)-MeLeu-AHP-PA-epsilon Ahx-EA (15), Boc-Phe(4-OMe)-MePhe-Sta-epsilon Ahx-EA (20) and Boc-Phe(4-OMe)-MeLeu-Sta-epsilon Ahx-EA (21) have been synthesized in search of structures with improved biological properties. They were designed as compounds with moderate hydrophobicity (5.28, 4.79, 4.79 and 4.30), respectively. All synthesized inhibitors were resistant to chymotrypsin activity, all were poorly soluble in buffers pH 2.0 and pH 7.4. The inhibitory potency of renin activity in vitro of 11, 15, 20 and 21 expressed as IC50 was 7.0 x 10(-4), 7.5 x 10(-5), 6.0 x 10(-4) and 2.5 x 10(-4) M/l, respectively.

Synthesis and anticonvulsant activity of some amino acid derivatives. Part 2: Derivatives of Gly, Ala, Leu, Pro, Trp, Phe(4 Cl), Ala(alpha-Me).

Fourteen amides of N-substituted natural and anatural amino acids have been designed and synthesized as potential anticonvulsants. They were evaluated in the maximal electroshock seizure (MES) test, the subcutaneous Metrazol seizure threshold (sc Met) test and the rotorod neurotoxicity (Tox) test. According to the classification of the Anticonvulsant Screening Project (ASP) of the Antiepileptic Drug Development Program (ADDP) eight of synthesized compounds received class I, two class II and four class III. One of the compounds classified in class I (18) was tested quantitatively after i.p. administration in mice. It showed MES ED50 = 67.41 mg/kg and protective index (PI) = 4.5. Conformational models of the synthesized compounds were compared to one another, as well as to models of some standard compounds.