N-nitro Group Research Articles

Isolation and identification of a novel bacterium, Pseudomonas sp. ZyL-01, involved in the biodegradation of CL-20

Hexanitrohexaazaisowurtzitane (CL-20) is a compound with a polycyclic cage and an N-nitro group that has been shown to play an unfavorable role in environmental fate, biosafety, and physical health. The aim of this study was to isolate the microbial community and to identify a single microbial strain that can degrade CL-20 with desirable efficiency. Metagenomic sequencing methods were performed to investigate the dynamic changes in the composition of the community diversity. The most varied genus among the microbial community was Pseudomonas, which increased from 1.46% to 44.63% during the period of incubation (MC0–MC4). Furthermore, the new strain was isolated and identified from the activated sludge by bacterial morphological and 16s rRNA sequencing analyses. The CL-20 concentrations decreased by 75.21 μg/mL and 74.02 μg/mL in 48 h by MC4 and Pseudomonas sp. ZyL-01, respectively. Moreover, ZyL-01 could decompose 98% CL-20 of the real effluent in 14 day’s incubation with the glucose as carbon source. Finally, a draft genome sequence was obtained to predict possible degrading enzymes involved in the biodegradation of CL-20. Specifically, 330 genes that are involved in energy production and conversion were annotated by Gene Ontology functional enrichment analysis, and some of these candidates may encode enzymes that are responsible for CL-20 degradation. In summary, our studies indicate that microbes might be a valuable biological resource for the treatment of environmental contamination caused by CL-20 and that Pseudomonas sp. ZyL-01 might be a promising candidate for eradicating CL-20 to achieve a more biosafe environment and improve public health.

Synthesis of 5-Alkynyl Substituted 2'-Arabinosyl 2'-Halogenated Uridine Nucleosides.

This unit describes the detailed preparation of 5-alkynyl-2'-halogenated arabinosyl uridine nucleosides (2'-halo-ara-EdU) from uridine. These compounds were synthesized as prospective chemical probes for the detection of DNA synthesis in proliferating cells. Currently, this is the only synthetic methodology reported to access these compounds. The key to success of the synthetic approach was to employ a 3-N-nitro-protecting group to stabilize the required 2'-triflate nucleoside precursor toward nucleophilic substitution. Several synthetic challenges were overcome to accommodate the combination of a 5-alkyne and 3-N-nitro functional group, including facile introduction and removal of the N-nitro group, and removal of the sugar acetyl groups under acidic conditions. © 2019 by John Wiley & Sons, Inc.

Stereoselective Synthesis of Highly Functionalized Arabinosyl Nucleosides through Application of an N-Nitro Protecting Group.

2'-Deoxy-2',5-disubstituted arabinosyl uridine derivatives bearing a halogen (Cl, Br or I) at C2' and an ethynyl group at C5 have been synthesized in 6 steps from 2',3',5'-tri- O-acetyl-5-iodo-uridine in overall yields of 61% (compound 3, Cl), 47% (compound 4, Br), and 19% (compound 5, I). Stabilization of a 2'- O-triflyl leaving group intermediate to overcome spontaneous intramolecular 2,2'-anhydro uridine formation was pivotal to the synthesis. Specifically, to favor SN2 reaction with a halogen nucleophile over intramolecular cyclization, the nucleophilicity of O-2 oxygen was reduced by incorporation of an adjacent electron withdrawing nitro substituent at N-3. The introduction of the 3- N-nitro group proceeded rapidly (nitronium trifluoroacetate, 1 min) and in quantitative yield. A one-pot method to remove the 3- N-nitro group by reductive nitration (zinc metal in acetic acid, 5 min) and the silyl protecting groups of the alkyne and 3',5' hydroxyls (fluoride reagent, 16 h) was established as the final synthetic step. This application of the 3- N-nitro protecting group addresses the significant shortfalls of the conventional approach to synthesis of 2' modified nucleosides, wherein condensation of a 2' modified sugar fragment with a pyrimidine base provides poor stereocontrol of N-glycosylation, low yields and incompatibility with 2' iodo sugars.

Biodegradation and mineralization of isotopically labeled TNT and RDX in anaerobic marine sediments.

The lack of knowledge on the fate of explosive compounds 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), particularly in marine ecosystems, constrains the application of bioremediation techniques in explosive-contaminated coastal sites. The authors present a comparative study on anaerobic biodegradation and mineralization of 15 N-nitro group isotopically labeled TNT and RDX in organic carbon-rich, fine-grained marine sediment with native microbial assemblages. Separate sediment slurry experiments were carried out for TNT and RDX at 23°C for 16 d. Dissolved and sediment-sorbed fractions of parent and transformation products, isotopic compositions of sediment, and mineralization products of the dissolved inorganic N pool (15 NH4+ ,15 NO3- ,15 NO2- , and 15 N2 ) were measured. The rate of TNT removal from the aqueous phase was faster (0.75 h-1 ) than that of RDX (0.37 h-1 ), and 15 N accumulation in sediment was higher in the TNT (13%) than the RDX (2%) microcosms. Mono-amino-dinitrotoluenes were identified as intermediate biodegradation products of TNT. Two percent of the total spiked TNT-N is mineralized to dissolved inorganic N through 2 different pathways: denitration as well as deamination and formation of NH4+ , facilitated by iron and sulfate reducing bacteria in the sediments. The majority of the spiked TNT-N (85%) is in unidentified pools by day 16. Hexahydro-1,3,5-trinitro-1,3,5-triazine (10%) biodegrades to nitroso derivatives, whereas 13% of RDX-N in nitro groups is mineralized to dissolved inorganic N anaerobically by the end of the experiment. The primary identified mineralization end product of RDX (40%) is NH4+ , generated through either deamination or mono-denitration, followed by ring breakdown. A reasonable production of N2 gas (13%) was seen in the RDX system but not in the TNT system. Sixty-eight percent of the total spiked RDX-N is in an unidentified pool by day 16 and may include unquantified mineralization products dissolved in water. Environ Toxicol Chem 2017;36:1170-1180. © 2016 SETAC.

Novel 1,1-diphenylhydrazine derivatives of benzofurazan and their dimerization

In a quest for novel persistent free radicals, two products were obtained from the reaction between 1,1-diphenylhydrazine and 4-chloro-7-nitrobenzofurazan: the expected 1-(4nitrobenzofurazan-7-yl)-2,2-diphenyl-hydrazine 3 formed via an SNAr process, and the unexpected 4,7-benzofurazandione-(bis-1,1-diphenylhydrazone) 4 formed from 3 by a further ipso substitution and dehydrogenation. Oxidation of 3 with solid PbO2 or solid KMnO4 at room temperature affords during the first few minutes a persistent mono-nitro-hydrazyl free radical 6, which reacts with NO2 and forms another persistent hydrazyl free radical 7 having two nitro groups. Two blue dimeric compounds, 11 and 13, were obtained by dimerisation of 6 and 7 respectively, and loss of N2O4, and their structures were determined by mass spectrometry and NMR spectra. Additionally, single crystal X-ray diffraction was used to ascertain the structures of compounds 4 and 13. Other novel derivatives were prepared either by N-alkylation of 3 with General Papers ARKIVOC 2011 (xi) 198-221 Page 199 ARKAT-USA, Inc. methyl iodide, which afforded compound 5, or by homolytic nitration of 3 with gaseous NO2 which yielded the 4,7-dinitrobenzofurazan derivative 8. When gaseous NO2 was used in a similar reaction, only one N-nitro group was present in the product 7. Persistent free radicals were obtained from 4, 11, or 13 with KMnO4. Cyclic voltammograms for 3 and 8 as well as electronic absorption spectra for all new compounds 3, 4, 5, 8, 11, and 13 are discussed.

Nitropyrazoles 14. Synthesis of 1,3,4-trinitropyrazole and its behavior in the nucleophilic substitution reactions. General method of synthesis of 5-substituted 3,4-dinitropyrazoles

For the first time pyrazole containing three nitro groups in the pyrazole cycle, viz., 1,3,4-tri-nitropyrazole, was obtained by N-nitration of 3,4-dinitropyrazole. 1,3,4-Trinitropyrazole enters the cine-substitution reaction of N-nitro group under the action of 0-, N-, and C-nucleophyls under mild conditions. Thus, general method of synthesis of 5-substituted 3,4-dinitropyrazoles containing free NH fragment was worked out.

Synthesis and Rearrangement of 2‐(N‐Methyl‐N‐nitroamino)‐4‐phenylthiazole.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Neonicotinoid insecticides: reduction and cleavage of imidacloprid nitroimine substituent by liver microsomal and cytosolic enzymes.

The major insecticide imidacloprid (IMI) is known to be metabolized by human cytochrome P450 3A4 with NADPH by imidazolidine hydroxylation and dehydrogenation to give 5-hydroxy-imidacloprid and the olefin, respectively, and by nitroimine reduction and cleavage to yield the nitrosoimine, guanidine, and urea derivatives. More extensive metabolism by human or rabbit liver microsomes with NADPH or rabbit liver cytosol without added cofactor reduces the IMI N-nitro group to an N-amino substituent, i.e., the corresponding hydrazone. A major metabolite on incubation of IMI in the human microsome-NADPH system is tentatively assigned by LC/MS as a 1,2,4-triazol-3-one derived from the hydrazone; the same product is obtained on reaction of the hydrazone with ethyl chloroformate. The hydrazone and proposed triazolone are considered here together (referred to as the hydrazone) for quantitation. Only a portion of the microsomal reduction and cleavage of the nitroimine substituent is attributable to a CYP450 enzyme. The cytosolic enzyme conversion to the hydrazone is inhibited by added cofactors (NAD > NADH > NADP > NADPH) and enhanced by an argon instead of an air atmosphere. The responsible cytosolic enzyme(s) does not appear to be DT-diaphorase (which is inhibited by several neonicotinoids), aldose reductase, aldehyde reductase, or xanthine oxidase. However, the cytosolic metabolism of IMI is inhibited by several aldo-keto-reductase inhibitors (i.e., alrestatin, EBPC, Ponalrestat, phenobarbital, and quercetin). Other neonicotinoids with nitroimine, nitrosoimine, and nitromethylene substituents are probably also metabolized by "neonicotinoid nitro reductase(s)" since they serve as competitive substrates for [(3)H]IMI metabolism.

Theoretical investigation of four conformations of HNIW by B3LYP method

The density function theory method has been used to study the geometry and electronic structure of hexanitrohexaazaisowurtzitane (HNIW). Four conformations of HNIW were obtained. Full geometry optimization, calculation of vibrational frequency, and NBO analyses for the four conformations of HNIW were performed at the B3LYP/6-31G ∗∗ level. The geometry and electronic structures of four conformations were analyzed. The C–C bond linking two five-membered rings and the boat-shaped six-membered ring are important factors in stabilizing the molecular skeleton. The N–N bonds in N-nitro group are possibly more easily broken than the other bonds. The spatial orientation of NO 2 has some influence on the molecular structure and energy.

Structure and properties of N-methyl-N-(4-pyridyl)-nitramine and 1,4-dihydro-1-methyl-4-nitriminopyridine

The molecular structure and spectral properties of N-methyl-N-(4-pyridyl)-nitramine (1) and 1,4-dihydro-1-methyl-4-nitriminopyridine (3) were investigated by the X-ray diffraction, FTIR, nuclear magnetic resonance (NMR) methods and DFT theoretical calculations. N-methyl-N-(4-pyridyl)-nitramine (1) crystallises in the orthorhombic Pbca space group. It is composed of two planar fragments; nitramino (N2O2) group and the pirydyl ring. These two groups are twisted at about 70° with respect to each other, along the Ar–N bond. On the contrary, in compound 3, they are coplanar to each other. Twist of the nitramino group in 1 with respect to the pirydyl ring leads to a significant increase in C–N bond length ca. 0.07Å in comparison to the analogous bond in the nitrimine 3. The true nitramines, like 1, give strong bands in the infrared spectra, in the regions 1252–1276 and 1488–1563cm−1. In the spectra of nitrimine 3, the frequencies characteristic of the N-nitro group, appear at 1245–1255 and 1420–1450cm−1. The proton and carbon NMR spectra of 3 indicate that the ortho positions of the ring, in the liquid state, are magnetically equivalent, due to the fast rotation along the CN bond, which was formally a double bond. The nitramine 1 rearranges to 4-(N-methylamino)-3-nitropyridine, in 95% sulphuric acid, whereas the nitrimine 3 cannot rearrange in any way. The difference in the susceptibility towards rearrangement was explained by the electron deficient character of the migration terminus, i.e. the pyridine ring (3a).

Acidity and basicity of primary N‐phenylnitramines: catalytic effect of protons on the nitramine rearrangement

AbstractPara‐substituted N‐phenylnitramines were prepared either by oxidation of diazonium salts or by nitration under alkaline or acidic conditions. Isotopic [15N‐NO2] labelling indicated that the bands characteristic of the N‐nitro group appear in the 1318–1323 and 1585–1607 cm−1 regions. In the nitrogen NMR spectra, the nitramino group gives two resonances at −193 ± 3 (NH) and −32 ± 3 ppm (NO2). The chemical shifts in proton and carbon NMR spectra are predictable, based on increments and the additivity rule. The spectral data indicate the lack of conjugation between the nitramino group and another substituent bound to the ring. It seems to contradict the well‐known fact that substituents strongly (ρ = 4) influence the rate of nitramine rearrangement. The acidities of primary N‐phenylnitramines (3.77 < pKA < 5.62) are similar to those of benzoic acids and weakly dependent (ρ = 1) on the electronic character of a substituent. Based on the analogy with benzoic acids, it has been calculated that basicities of nitramines (pKB ≈ 21) are extremely low. Consequently, addition of protons to an intact nitramine molecule, as the preliminary step of the rearrangement, seems to be improbable. Migration of the N‐nitro group precedes protonation; the latter process facilitates transformation of intermediates into stable final products. Copyright © 2001 John Wiley & Sons, Ltd.

A study of solvent polarity and hydrogen bonding effects on the nitrogen NMR shieldings of N-nitramines and ab initio calculations of the nitrogen shieldings of C-nitro, N-nitro and O-nitro systems

High-precision nitrogen NMR shieldings, bulk susceptibility corrected, are reported for dimethylnitramine ( 1) and diethylnitramine ( 2) in a variety of solvents which represent a wide range of solvent properties from the point of view of polarity as well as hydrogen bond donor and acceptor strength. The observed range of solvent-induced nitrogen shielding variations of 1 and 2 is significant for the amino-type nitrogens, up to about 10 ppm, and originates essentially from the deshielding effect of the increasing polarity of solvent. On the other side, the nitro nitrogens reveal a very weak and rather chaotic response to solvent effects, within about 2 ppm. This is in a sharp contrast with the behavior of the nitrogen shieldings of C-nitro and O-nitro groups where solvent effects induce variations within at least 6 ppm which follow a regular pattern of enhanced magnetic deshielding with increasing polarity involved. This apparent insensitivity of the N-nitro group shielding to solvent effects seems to stem from the cancellation of opposite effects, the shielding effect of the electron charge migration to the nitro group upon increasing solvent polarity, and the deshielding effect produced by the flattening of the pyramidal arrangement of bonds at the amino nitrogen with the increasing polarity of the medium. Ab initio quantum-mechanical calculations using the GIAO/ B3 PW91/6-311++ G ∗∗ approach and geometry optimizations employing the same basis set and density functionals show an excellent linear correlation with the experimental data and reproduce not only major changes but also most of the subtle variations in the experimental nitrogen shieldings of the nitro systems as a whole.

Structure and properties of some nitro derivatives of N-methyl-N-phenylnitramine

Ten mono-, di- and tri-nitro derivatives of N-methyl-N-phenylnitramine were prepared and investigated using spectral and electrooptical methods. Three of them, viz. N-(2, 5-dinitrophenyl)-N-methylnitramine (monoclinic, P21/c, a=8.248(2), b=11.655(2), c=10.404(2)Å,β=102.57(2)°), N-(2,3-dinitrophenyl)-N-methylnitramine (monoclinic, P21/c, a=9.224(2), b=7.222(2), c=15.458(4)Å,β=101.08(2)°)) and N-(3,5-dinitrophenyl)-N-methylnitramine (monoclinic, P21/n, a=9.814(2), b=12.000(2), c=8.865(2)Å,β=114.94(2)°) were examined by the X-ray diffraction method. The nitramino group is nearly planar with the short N(7)–N(8) bond and strongly electron deficient N(8) atom. The nitramino group is twisted vs. the aromatic ring, there is no conjugation between the nitro and nitramino groups across the ring. The nitramino group is an electron withdrawing substituent due to the inductive effect. The number and positions of the Ar-nitro groups have no influence on the N-nitro group. Its migration ability cannot be explained in terms of the interaction between the migration origin and the ring substituents.

4-(N-Methylnitramino)pyridine 1-oxide

In the title compound, C 6 H 7 N 3 O 3 , the NNO 2 group is twisted ca 59° from the planar pyridine ring. The nitramino group is almost planar, with the N7 atom diverging 0.15 A from the C4-N8-C11 plane. The lone pair on N7 is included into the N-nitro group π-electron system resulting in two independent sets of multicenter π-orbitals. Significant anisotropy of the temperature dependence of thermal expansion is observed in the range 90-300 K.

C-Nucleoside studies-15: Synthesis of 3-β-D-arabinofuranosylpyrazoles and the D-arabinofuranosyl analogue of formycin

A synthesis of 7-amino-3-(β -D-arabinofuranosyl)pyrazolo[ 4 3- d]pyrimidine ( 13), the D-arabino analogue of formycin ( 1), from D-mannose is described. 1-(2,4-Dinitrophenyl)-3-(penta- O-acetyl-D- manno-pentahydroxypentyl)pyrazole was converted into the 4-nitro-derivative 18 in 90% yield using trifluoroacetyl nitrate. In four steps 18 was transformed into the 3-β-D-arabinofuranosylpyrazole 12 which gave the N-nitro derivative 24 in two further stages. Cine-substitution of the N-nitro group in 24 by cyanide ion was followed by elaboration of the pyrimidine ring to give 13. All the reactions proceeded with complete regio and stereoselectivity.