Synthesis and Antimalarial Activity of Some New 1,2-Dioxolane Derivatives

The synthesis of 1,2-dioxolane derivatives in two different acetophenone series, as simplified models of natural coumarins is described. 2-Acetyl-3-acetoxy-4-(3-hydroperoxy-3-methylbut-1-enyl)phenyl acetate and 2-acetyl-5-acetoxy-4-(3-hydroperoxy-3-methylbut-1-enyl) phenyl acetate synthons are used as precursors to these structures. In vitro antimalarial activity of the 1,2-dioxolane derivatives has been investigated.     

Protective Effects of Some Creatine Derivatives in Brain Tissue Anoxia

Some derivatives more lipophylic than creatine, thus theoretically being capable to better cross the blood–brain barrier, were studied for their protective effect in mouse hippocampal slices. We found that N-amidino-piperidine is harmful to brain tissue, and that phosphocreatine is ineffective. Creatine, creatine–Mg-complex (acetate) and phosphocreatine–Mg-complex (acetate) increased the latency to population spike disappearance during anoxia. Creatine and creatine–Mg-complex (acetate) also increased the latency of anoxic depolarization, while the delay induced by phosphocreatine–Mg-complex (acetate) was of borderline significance (P = 0.056). Phosphocreatine–Mg-complex (acetate) significantly reduced neuronal hyperexcitability during anoxia, an effect that no other compound (including creatine itself) showed. For all parameters except reduced hyperexcitability the effects statistically correlated with tissue levels of creatine or phosphocreatine. Summing up, exogenous phosphocreatine and N-amidino piperidine are not useful for brain protection, while chelates of both creatine and phosphocreatine do replicate some of the known protective effects of creatine. In addition, phosphocreatine–Mg-complex (acetate) also reduced neuronal hyperexcitability during anoxia.     

Synthesis and Antimicrobial Activity of Some New Coumarin and Dicoumarol Derivatives

Russian Journal of Bioorganic Chemistry - Phase transfer catalysis reaction of 4-hydroxy-6-methyl-2H-chromen-2-one with alkyl halides afforded C4 oxygen alkylation products of 2H-chromen-2-one...     

Synthesis of Some New Thiourea Derivatives and Their Influence on Biological and Genetic Effects of Gamma Rays*

The synthesis of the new radioprotective compounds ATB (I, 2-allylthioureidobenzoic acid), PTB (II, 2-phenylthioureidobenzoic acid), A-2-PTU (III, N-allyl-N"-2-pyridylthiourea), and P-2-PTU (IV, N-phenyl-N"-2-pyridylthiourea) and their influence on biological and genetic effects of gamma rays was studied. In result of investigations it must be noted that PTB displayed radioprotective effect as a result of which more plants in M₁ germination and survive in M₂ of the induced mutations is increased. The cytological analysis reveals that the studied substance (PTB) decreases chromosome aberration in meristem cells of pea roots almost twice as a result of postirradiation treatment. The effect of A-2-PTU in the experiments with peas greatly depends on the dose of irradiation, i.e., on the degree of damaging of the processes of cell restoration and the possibility of their partial restoration after the treatment with the protector. The results obtained suggest that chemical compounds of N,N"-disubstituted thiourea group (A-2-PTU and P-2-PTU) exert strong radioprotective effect in the experiments with peas. This is of great importance to modern radiobiology and radiation mutagenesis and also to protect hereditary structures against radiation.     

Synthesis and Taste of Some Dihydrochalcone Glycosides

Hesperetin-7-β-maltoside (V), -7-β-cellobioside (VI) and -7-β-lactoside (VII) were prepared by the coupling of hesperetin with the α-acetobromo derivatives of the appropriate disaccharides, followed by saponification. V was showed to be as sweet as glucose.

Naringenindihydrochalcone-4′-β-sophoroside (VIII), -4′-[β-d-glucosyl (1→2) β-d-galactoside] (IX) and also hesperetindihydrochalcone-4′-β-kojibioside (X), -4′-β-maltoside (XI), -4′-β-cellobioside (XII) and -4′-β-lactoside (XIII) were prepared by the catalytic reduction of the appropriate flavanone-7-β-glycosides in alkaline medium.

Their relative sweetness values were discussed in comparison with dihydrochalcones of naringin and neohesperidin.     

Effects of Some Benzimidazole Derivatives on Electrical Activity in Molluscan Neurons

We studied the effects of application of bemitil, 2-ethylbenzimidazole hydrochloride, and 2-methyl benzimidazole hydrochloride in 10^-5 and 10^-4 M concentration on identified molluscan neurons. It was found that the agents exert clear neurotropic effect, which, as we assume, are determined by their influence on different types of ion channels.     

Synthesis and Characterization of Some New N-Glycosides of Pyridine-2,6-bis-Carboxamides Derivatives

A series of novel pyridine-bridged 2,6-bis-carboxamide N-β-glycosides and Schiff's bases has been prepared starting from 2,6-bis-carboxamide pyridine hydrazide, which on treatment with appropriate monosaccharides, aromatic or heterocyclic aldehydes, and indoline-2,3-dione derivatives afforded the corresponding sugar hydrazones and pyridine-bridged 2,6-bis-carboxamide Schiff's bases.     

Structure and Taste of Some Analogs of Naringin

The structures of acidic oligosaccharides synthesized by a transglycosylation reaction by Bacillus circulans β-galactosidase, using lactose as the galactosyl donor, and N-acetylneuraminic acid (NeuAc) and glucuronic acid (GlcUA) as the acceptors were investigated. Acidic oligosaccharides thus synthesized were purified by anion exchange chromatography and charcoal chromatography. The MS and NMR studies indicated that the acidic oligosaccharides from NeuAc were Galβ-(1→8)-NeuAc, Galβ-(1→9)-NeuAc, and Galβ-(1→3)-Galβ-(1→8)-NeuAc, and those from GlcUA were Galβ-(1→3)-GlcUA and Galβ-(1→4)-Galβ-(1→3)-GlcUA. These are novel acidic galactooligosaccharides.     

Some Active Derivatives of Penicillin

The antibacterial activities of a number of amide derivatives of penicillin against both penicillin-sensitive and penicillin-resistant cultures were determined. Several of them were found to possess significant inhibitory activity against certain gram-positive bacteria. The amides, although resistant to the destructive action of beta-lactamase, did not protect G in competitive experiments. One derivative, the O-benzylhydroxamide of penicillin G, was active against six or eight penicillin-resistant strains of Staphylococcus aureus (minimal inhibitory concentration, 0.2 mug/ml or less), but was found to have only a minimal in vivo activity against mouse Streptococcus infections.     

Synthesis of Some Isocoumarin Derivatives

An alkaline κ-carrageenase, Cgk-K142, was found in the culture broth of a deep-sea bacterium, Pseudoalteromonas tetraodonis JAM-K142. A gene for the enzyme was cloned and expressed. Purified recombinant Cgk-K142 (rCgk-K142) showed an optimal pH of about 8.8 in glycine-NaOH buffer at 30 °C and of about 8.0 in MOPS buffer at 50 °C. The optimal temperature for the enzyme was 55 °C at pH 8.0. rCgk-K142 was unstable, but λ- and ι-carrageenans, non-degradative substrate homologs, extensively enhanced its stability. The nucleotide sequence of the gene for Cgk-K142 comprised 1,194 bp, and the deduced amino acid sequence (397 amino acids) showed a high level of similarity to the κ-carrageenase of P. carrageenovora, with 94% identity. Another gene for a κ-carrageenase-like protein was found downstream of the gene for Cgk-K142. The nucleotide sequence of that gene consisted of 966 bp (321 amino acids), and it showed the highest similarity, at 64% identity, to protein CgkB of P. carrageenovora, which has been reported as an incomplete 57-amino acid sequence.     

Synthesis of Some New N-Substituted Imidazole Derivatives and Their In Vitro Antibacterial Investigation

Russian Journal of Bioorganic Chemistry - Here we reported the synthesis of N-substituted imidazole derivatives (VIa–o) that involves Suzuki coupling reaction between...     

Synthesis and Antiproliferative Activity of Some New Coumarin Derivatives Derived from 8-Hydroxycoumarin

Russian Journal of Bioorganic Chemistry - A new series of coumarin-derived molecules have been synthesized and evaluated for their anticancer activity against human hepatocellular liver carcinoma...     

Herbicidal Activity of Some Pyridazine Derivatives

Pre-emergent herbicidal activities of various 3-halo-6-phenoxypyridazines, with or without nitro groups on their benzene rings, and 3-anilino-6-phenoxypyridazines were examined along with those of related compounds. Among them, 3-bromo-6-(2′-phenylphenoxy)-, 3-chloro-6-(3′-nitrophenoxy)- and 3-chloro-6-anilino-pyridazines showed rather high herbicidal effects to radish and millet. On the other hand, some pyridazine derivatives especially 3-anilino-6-benzyloxy- and 3-(3′-chloroanilino)-6-phenoxy-pyridazines promoted shoot growth of millet.     

Herbicidal Activity of Some Pyridazine Derivatives

3-Phenoxypyridazines and related compounds were evaluated their pre-emergence activities. Of these, 3-phenoxy-, 3-(2-methylphenoxy)-, and 3-(2-ethylphenoxy)-pyridazines (III, IV and VII) showed powerful effects on barnyardgrass and spikerush, whereas they gave no injury on rice plants. Furthermore, susceptibility of various kinds of cultivated plants as well as of weeds to III and IV were examined. Growth regulating activity of III was compared with that of maleic hydrazide.     

Herbicidal Activity of Some Pyridazine Derivatives

Herbicidal activity of some 50 pyridazyl ethers was evaluated. Among them, 3-chloro-6-(2-phenylphenoxy)-, 3-chloro-6-(2,6-dichlorophenoxy)-, 3-chloro-6-(3-methoxyphenoxy)- and 3-chloro-6-(4-methoxyphenoxy)-pyridazines showed conspicuous effectiveness on radish and millet in pre-emergence test, whereas postemergent activity of the compounds tested was not so remarkable in general. Relationships between herbicidal activity and chemical structure are discussed.     

The Synthesis and Antiviral Activity of Some New S-Adenosyl-L-homocysteine Derivatives and Their Nucleoside Precursors

Abstract

S-Adenosyl-L-homocysteine (SAH) and some of its analogues are potent inhibitors of transmethylation reactions catalysed by S-adenosyl methionine dependent methyltransferases.¹     

Enantiospecific Synthesis of Carbocyclic Aminoimidazole Carboxamide Ribonucleotide (C-AICAR), Succinoaminoimidazole Carboxamide Ribonucleotide (C-SAICAR), and a New Intermediate for SAICAR Analogs

Abstract

The (-)-enantiomer of the carbocyclic analogs of aminoimidazole carboxamide ribonucleotide (C-AICAR¹, 7), and succinoaminoimidazole carboxamide ribonucleotide (C-SAICAR, 14) have been prepared. En route, a new intermediate (19) for the preparation of SAICAR analogs was developed.