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At least 343 records · Page 19Linked to original sources
PubMed1984

[Substances with central nervous system activity. Derivatives of octahydro-1,4-dihydroxypyrrolo(1,2-a)pyrazine-6-carboxylic acids].

Compounds with potential activity on the Central Nervous System were prepared starting either from 2,5-diethoxycarbonylpyrrolidine or from N-benzyloxycarbonyl-2,5-pyrrolidinedicarboxylic acid anhydride. By the Arndt-Eistert reaction it was possible to obtain chain lengthening at position 6. The carboxy group was also successfully reduced to a hydroxymethyl group. The synthetic work was completed with the synthesis of some derivatives having a phenyl ring condensed at position 7 and 8. Some pharmacological data on the Central Nervous System depressant activity of the prepared compounds are also reported.

Aggression↗
PubMedDate not supplied

Studies on pyrazine derivatives. Part X. Synthesis and tuberculostatic activity of some 6-cyclamino-, 6-imidazolyl--and triazolylpyrazine-2-carboxylic acids derivatives.

The 6(2'-methylpiperidine-, 2',6'-dimethylmorpholino-, imidazolyl- and triazolyl)-2-cyanopyrazines were prepared from 2-cyano-6-chloropyrazine. The -CN group was then transformed into COOH, CONH2, CSNH2, CONHNH2, CONHOH and C(NOH)NH2 functions. All compounds obtained were of weak tuberculostatic activity. Comp. 13 was active against isoniazide, capreomycin and ethionamide resistent strains at the concentration range of 31.2--62.5 microgram/cm3.

Antitubercular Agents↗
PubMedDate not supplied

Studies on pyrazine derivatives. XXX. Synthesis of pyrazinylamino-1,3-diazacycloalkanes of potential circulatory activity.

A series of pyrazinylamino-1,3-diazacycloalkanes was obtained by reaction of the corresponding substituted aminopyrazines with aliphatic amines. Selected compounds were studied with respect to their potential circulatory activity. The effect on the blood pressure, isolated rat tail artery and heart atria, and an influence on the human blood platelet aggregation were investigated.

Amines↗
PubMed1998

Stability, blood partition, and protein binding of a chemoprotective agent, 2-(allylthio)pyrazine.

The stability of 2-AP, a chemoprotective agent, in various pH solutions and human gastric juice, the blood partition of 2-AP between plasma and blood cells, and the factors influencing the binding of 2-AP to 4% human serum albumin (HSA) were evaluated. 2-AP was stable in human gastric juice and pH solutions ranging from 1 to 12, however, 2-AP was unstable in pH 13 solution; the disappearance rate constant was 0.00759/h. 2-AP reached equilibrium rapidly between plasma and blood cells of rabbit blood. The equilibrium plasma/blood cells partition ratios were independent of initial rabbit blood concentrations of 2-AP, 1, 5, and 10 micrograms/ml; the values were in the range of 5.99-11.8. Binding of 2-AP to 4% HSA was dependent on HSA concentration, incubation temperature, 'the buffer' pH, and addition of acetylsalicylic acid. The binding of 2-AP was independent of buffers containing various concentrations of chloride ion, heparin, and alpha-1-acid glycoprotein.

Animals↗
PubMed2000

Novel regioselective hydroxylations of pyridine carboxylic acids at position C2 and pyrazine carboxylic acids at position C3.

We have previously described the isolation of the new bacterial species, Ralstonia/Burkholderia sp. strain DSM 6920, which grows with 6-methylnicotinate and regioselectively hydroxylates this substrate in the C2 position by the action of 6-methylnicotinate-2-oxidoreductase to yield 2-hydroxy-6-methylnicotinate (Tinschert et al. 1997). In the present study we show that this enzymatic activity can be used for the preparation of a series of hydroxylated heterocyclic carboxylic acid derivatives. The following products were obtained from the unhydroxylated educts by biotransformation using resting cells: 2-hydroxynicotinic acid, 2-hydroxy-6-methylnicotinic acid, 2-hydroxy-6-chloronicotinic acid, 2-hydroxy-5,6-dichloronicotinic acid, 3-hydroxypyrazine-2-carboxylic acid, 3-hydroxy-5-methylpyrazine-2-carboxylic acid and 3-hydroxy-5-chloropyrazine-2-carboxylic acid. Thus the respective educts were all regioselectively mono-hydroxylated at the carbon atom between the ring-nitrogen and the ring-carbon atom carrying the carboxyl group. In contrast to its relatively broad biotransformation abilities, the strain shows a limited heterocyclic nutritional spectrum. It could grow only with three of the seven transformed educts: 6-methylnicotinate, 2-hydroxy-6-methylnicotinate and 5-methylpyrazine-2-carboxylate. 2-Hydroxynicotinate, 2-hydroxy-6-chloronicotinate, 2-hydroxy-5,6-dichloronicotinate, 3-hydroxypyrazine-2-carboxylate and 3-hydroxy-5-chloropyrazine-2-carboxylate were not degraded by the strain. Therefore, unlike 6-methylnicotinate-2-oxidoreductase, which has a broad substrate spectrum, the second enzyme of the 6-methylnicotinate pathway seems to have a much more limited substrate range. Among 28 aromatic heterocyclic compounds tested as the sole source of carbon and energy, only pyridine-2,5-dicarboxylate was found as a further growth substrate, and this was degraded by a pathway which did not involve 6-methylnicotinate-2-oxidoreductase. To the best of our knowledge the microbial production of 2-hydroxy-6-chloronicotinic acid, 2-hydroxy-5,6-dichloronicotinic acid and 3-hydroxy-5-methylpyrazine-2-carboxylic acid have not been reported before. Strain DSM 6920 is so far the only known strain which allows the microbial production of both these compounds and 3-hydroxypyrazine-2-carboxylic acid and 3-hydroxy-5-chloroypyrazine-2-carboxylic acid.

Biotransformation↗