[Stereochemistry of the reductive amination of 4-oxoproline derivatives with glycine esters].

An amination of 4-oxoproline derivatives with glycine methyl or benzyl ester and sodium cyanoborohydride led to the mixtures of corresponding diastereomeric 4-cis- and 4-trans-glycinoproline derivatives. We found that the ratio of diastereomers mainly depends on the structure of 4-oxoproline ester groups and, to a lesser extent, on the structure of N-acyl substituents. The best results were achieved with tert-butyl ester group; it ensured good yields of the amination products and the greatest prevalence of 4-cis-isomers.

[Synthesis isomeric 4-prolylamines and 4,4'-diprolylamines].

Starting from the previously described tert-butyl esters of 4-epimeric N-benzyloxycarbonyl-4-hydroxyprolines and N-benzyloxycarbonyl-4-trans- and 4-cis-trifluoroacetamidoproline tert-butyl esters, the corresponding un-protected 4-aminoprolines and a number of their partially protected derivatives were synthesized via the intermediate 4-O-mesyl and 4-azide derivatives. The reductive amination of N-benzyloxycarbonyl-4-oxoproline tert-butyl ester with ammonium acetate led to N-benzyloxycarbonyl-4-cis-4'-cis- and 4-cis-4'-trans-diprolinylamines. The 1H NMR and CD spectra of the synthesized compounds are described.

[Hydrolysis of primary amide groups in Asn/Gln-containing peptides].

Peptides Boc-Ala-Asn/Gln-OH and Boc-Asn/Gln-Ala-OH were saponified with barium hydroxide to corresponding Asp/Glu-containing peptides. Under the conditions of saponification, Boc-Asn-Ala-OH additionally afforded Boc-Asp-OH, isopeptide Boc-Asp(Ala)-OH, and Boc-NHSuc > Ala-OH, with the third being the key intermediate in these transformations. Boc-Asp(OMe)-Ala-OMe underwent similar transformations under treatment with diazomethane or triethylamine.

[Structural-functional characteristics of argiopine--the ion channel blockers from the spider Argiope lobata venom].

Argiopine, a compound capable of blocking the glutamate-activated ion channels in experiments with glutamatergic synapses of blowfly larvae, was isolated from the venom of spider Argiope lobata. Argiopine-receptor complex has KD 6,7 X 10(-7) M. The venom solution was treated with 60% ethanol, centrifuged and supernatant was subjected to reversed-phase HPLC in the acetonitrile concentration gradient.

[Attempt at mathematical prognosis of the effect of surgery in embolism of the main arteries, according to various clinico-biochemical indicators].

The possibility, in principle, of mathematical prognostication of the results of an operative intervention according to the initial clinicobiochemical indices is shown. The duration of ischemia, the blood serotonin level, and the severity of the atherosclerosis and cardiovascular insufficiency are the most significant of the studied indices influencing the outcome of operation for embolism of the major limb arteries.

[Chemical characteristics of the antibiotic, memomycin (LIA-0775)].

By its physico-chemical and biological properties memomycin was classified as belonging to the group of hydrostatin-nifimycin. Memomycin contained ester (or lactone) and amide, 7 C-methyl and 10-12 acetylating groups. Oxidation of the antibiotic with an excess of alkaline permanganate solution revealed the presence of an unbroken chain consisting at least of 8 methylen groups in the carbon skeleton of memomycin.