The Morita-Baylis-Hillman adducts bearing a nitroxyl moiety were synthesized from 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl and aliphatic, aryl and heterocyclic aldehydes.
The reactions of 3-isoselenocyanato-2,2,5,5-tetramethylpyrrolidine-1-oxyl, 3-isoselenocyanatomethyl-2,2,5,5-tetramethyl-3-pyrrolidine-1-oxyl, and ...4-isoselenocyanato-2,2,6,6-tetramethylpiperidine-1-oxyl with selected amines and alcohols give the corresponding novel nitroxyl selenoureas and selenocarbamates, all bearing a nitroxyl moiety. Synthesized selenoureas and selenocarbamates show significant activity against pathogenic fungi and bacteria. In contrast to piperidine nitroxides, pyrrolidine, five-membered nitroxyl selenoureas and selenocarbamates show excellent antifungal and antibacterial activity against pathogenic fungi and bacteria, respectively.
Cinnamic acid derivatives bearing a nitroxyl moiety (2,2,6,6-tetramethyl-1-oxyl-4-piperidyl 3-E-aryl acrylates) were synthesized in 30-100% yield using a Mizoroki-Heck cross-coupling reaction between ...4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl and iodobenzene derivatives in the presence of palladium(II) acetate coordinated with a tri(o-tolyl)phosphine ligand immobilized in a polyurea matrix.
The antifungal activity of nitroxyl radicals—derivatives of 2,2,6,6-tetramethylpiperidine-1-oxyl with reactive substituents 4-isothiocyanato-, 4-isocyano-, and 4-isoselenocyanato- and of N-formyl-, ...N-thioformyl-, N-selenoformyl-derivatives of 2,2,6,6-tetramethylpiperidine was investigated. Those of the above compounds, which contain a sulfur or selenium atom are the most active against four fungus plant patogens: Botrytiscinerea, Fusariumculmorum, Phytophthoracactorum, Rhizoctoniasolani. 4-Isoselenocyanato-2,2,6,6-tetramethylpiperidine-1-oxyl proved to be the most active compound.
A new idea for the modification of a carboxylic group in phenoxyacetic herbicides is proposed. Common herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid ...(MCPA), and their chalcogen analogs (arylthio and arylselenyl fragments instead of a phenoxy one) were used as carboxylic components in the tricomponent Passerini reaction. Cyclohexyl isocyanide and 4-isocyano-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO-NC) were used as isocyanides. Acetone, acetaldehyde and formaldehyde were used as carbonyl components. Passerini adducts
4a
–
4L
were obtained in yields of 32–59%. The structures of the Passerini adducts were determined using spectroscopic methods: MS, HR MS,
1
H NMR,
13
C NMR,
77
Se NMR (if appropriate) and IR spectra (MS, HR MS, IR for the nitroxides
4k
and
4L
). The herbicidal activity of the Passerini adducts synthesized (
4a
–
4L
) was tested against ten weed species (at 2 kg/ha using 2,4-D and MCPA as a control). 100% herbicidal post-emergent activity was reported for
4i
,
4j
,
4k
,
4L
a weed black mustard (
Brassica nigra
), for
4k
,
4L
weeds pale smartweed (
Polygonum lapathifolium
) and fathen (
Chenopodium album
), as well as for
4k
(weeds common poppy (
Papaver rhoeas
) and gallant soldier (
Galinsoga parviflora
)). The fungistatic activity of the Passerini adducts synthesized (
4a
–
4L
) was tested against six phytopathogenic fungi species (at 200 mg/L and procymidone as a control). The tested compounds showed a weak activity (% of inhibition) against:
Alternaria alternata:
4g
(47),
4i
(26),
4j
(26),
4k
(50),
Botrytis cinerea
4g
(38),
Fusarium culmorum
4g
(44),
Phytophthora cactorum
4i
(35),
4j
(35),
4k
(30)
, Rhizoctonia solani
4g
(30),
4i
(24),
Phytophthora infestans
4g
(29),
4i
(34),
4j
(28),
4k
(46).
Graphical abstract
The purpose of this study was to explore the possibility of replacing an expensive yeast extract contained in the fermentation medium for D-lactic acid (D-LA, R-lactic acid) biosynthesis with an ...alternative nitrogen source. The screening studies were conducted under stationary conditions and showed that pea seed hydrolysate was the most beneficial substrate in the process of D-LA biosynthesis by the strain Sporolactobacillus laevolacticus DSM 442 among the used inorganic and organic nitrogen sources, waste materials, food and agricultural products. After 96 h, 75.5 g/L D-LA was obtained in batch cultures in a medium containing pea seed hydrolysate, with an average productivity of 0.79 g/L/h, yield of 75.5%, and optical purity of 99.4%. In batch cultures fed once, in a medium with an analogous composition, 122.6 g/L D-LA was obtained after 120 h, and the average yield, productivity and optical purity were 87.6%, 1.021 g/L/h, and 99.6%, respectively. Moreover, the amount of D-LA obtained in the fermentation medium enriched with the above-mentioned cheap agricultural product was similar to the amounts obtained in the medium containing yeast extract in both stationary and bioreactor cultures. Our research shows that hydrolyzed pea seeds, which belong to the legume family, may be a promising nitrogen source for the production of D-LA on an industrial scale.
Glyphosate is the most heavily applied among pesticides in the world, and thus human exposure to this substance continues to increase. WHO changed classification of glyphosate to probably ...cancerogenic to humans, thus there is urgent need to assess in detail genotoxic mechanism of its action. We have assessed the effect of glyphosate, its formulation (Roundup 360 PLUS) and its main metabolite (aminomethylphosphonic acid, AMPA) in the concentration range from 1 to 1000 μM on DNA damage in human peripheral blood mononuclear cells (PBMCs). The cells were incubated for 24 h. The compounds studied and formulation induced DNA single and double strand-breaks and caused purines and pyrimidines oxidation. None of compounds examined was capable of creating adducts with DNA, while those substances increased ROS (including •OH) level in PBMCs. Roundup 360 PLUS caused damage to DNA even at 5 μM, while glyphosate and particularly AMPA induced DNA lesions from the concentration of 250 μM and 500 μM, respectively. DNA damage induced by glyphosate and its derivatives increased in order: AMPA, glyphosate, Roundup 360 PLUS. We may conclude that observed changes were not associated with direct interaction of xenobiotics studied with DNA, but the most probably they occurred through ROS–mediated effects.
•Glyphosate, Roundup 360 PLUS and AMPA induced DNA single and double strand-breaks.•The compounds studied caused purines and pyrimidines oxidation.•Glyphosate, Roundup and AMPA increased ROS level in PBMCs.•Glyphosate and Roundup increased .•OH level in peripheral blood mononuclear cells.•The compounds examined were not capable of creating adducts with DNA.
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