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Search for "nitro" in Full Text gives 531 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
O,S,Se-containing Biginelli products based on cyclic β-ketosulfone and their postfunctionalization
Beilstein J. Org. Chem. 2024, 20, 2143–2151, doi:10.3762/bjoc.20.184
- derivatives 3–7 using SwissADME (http://www.swissadme.ch) [44], ProTox 3.0 (https://tox-new.charite.de) [45], and MolPredictX (https://www.molpredictx.ufpb.br) [46] free online software. Considering ADMET [47] and other crucial properties, we found that all compounds (except for the nitro derivative 2e) do
Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps
Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178
- process with hydrazine hydrate to give 3,5-substituted pyrazoles 136 (Scheme 47) [150]. Notably, nitro groups are reduced to amines due to the reductive conditions. Furthermore, neither aliphatic hydroxyiminoyl chlorides nor internal alkynes are competent substrates in this transformation. Palladium
Diastereoselective synthesis of highly substituted cyclohexanones and tetrahydrochromene-4-ones via conjugate addition of curcumins to arylidenemalonates
Beilstein J. Org. Chem. 2024, 20, 2016–2023, doi:10.3762/bjoc.20.177
- (55–75%) with excellent diastereoselectivity (Table 2, entries 1–3). At the same time, the corresponding triple Michael adducts 4a–c were also formed as minor products (12–36%). There was no reaction with ortho-nitro-substituted arylidenemalonate 2d under the optimized conditions which is attributable
Allostreptopyrroles A–E, β-alkylpyrrole derivatives from an actinomycete Allostreptomyces sp. RD068384
Beilstein J. Org. Chem. 2024, 20, 1981–1987, doi:10.3762/bjoc.20.174
- 2-nitro congeners, nitropyrrolins [14] and heronapyrroles [15], bearing a farnesyl chain at the C4 position. Pyrroloterpenes are proposed to be of mixed biogenesis, elaborated from an aromatic pyrrole moiety and a terpenoid chain [15]. Prodigiosin, a major metabolite of Serratia, is another example
Electrochemical radical cation aza-Wacker cyclizations
Beilstein J. Org. Chem. 2024, 20, 1900–1905, doi:10.3762/bjoc.20.165
- compatible to give the respective five-membered pyrrolidines, except for that possessing a 2-nitro group 7. As discussed later with cyclic voltammetric studies, the electron density in the aryl rings does not seem to have a significant impact on the reaction. While benzyl sulfonamide 8 was productive under
Harnessing unprotected deactivated amines and arylglyoxals in the Ugi reaction for the synthesis of fused complex nitrogen heterocycles
Beilstein J. Org. Chem. 2024, 20, 1758–1766, doi:10.3762/bjoc.20.154
- chromatography column, while the more eco-friendly second strategy needs an additional stage for the reduction of the nitro group on the Ugi adduct. In order to find a more efficient synthesis, we thought that the second nitrogen in the diazepine nucleus could be incorporated without the need of surrogates or
- more complex systems, we explored post-condensation reactions on the 2-nitrobenzylamine and 3-bromopropylamine derivatives. Thus, we carried out the reduction of the nitro group on derivatives 5b and 5h employing tin(II) chloride and chlorhydric acid in boiling n-butanol (120 °C), conditions previously
- [29], through post-condensation reactions. Following the methodology previously described in our group [30], the reduction of the nitro group on indole and pyrrole derivatives 9f,g,l–o (Scheme 9, Table 5) employing tin(II) chloride under acidic conditions in boiling n-butanol (120 °C) afforded the
Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor
Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139
- compound 7r′, in which the benzene ring was hydrogenated. Substrates with chloro groups produced the dechlorinated products (7t and 7u). Unfortunately, during the electrolysis of quinolines with cyano (6v), formyl (6w and 6x), nitro (6y), and amino (6z) groups, the flow path was clogged probably due to the
- conditions, and the nitro group was selectively reduced. The addition of an acid was also effective in reducing quinolines to 1,2,3,4-tetrahydroquinolines. In the presence a catalytic amount of PTSA, various 1,2,3,4-tetrahydroquinolines were obtained. Although a stoichiometric amount of PTSA was required
Benzylic C(sp3)–H fluorination
Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137
- have been used to effect the transformation of benzylic C(sp3)–H to C(sp3)–F bonds [22]. Shreeve and co-workers reported the use of KOH or n-BuLi to deprotonate acidic protons at benzylic positions adjacent to electron-withdrawing nitro or nitrile groups, respectively, generating benzylic anions that
- in good yield. The requirement of adjacent to nitro or nitrile groups limits the scope of this approach. Furthermore, the use of strong bases, particularly n-BuLi, prevents the application of this methodology on any substrate bearing sensitive functional groups. An analogous method for
- monofluorination of tertiary benzylic C(sp3)–H bonds adjacent to nitro groups was reported by Loghmani-Khouzani and co-workers in 2006, in which ammonium acetate and Selectfluor were employed under sonochemical conditions to effect the fluorination (Figure 3) [35]. The authors noted that the use of sonochemistry
Tetrabutylammonium iodide-catalyzed oxidative α-azidation of β-ketocarbonyl compounds using sodium azide
Beilstein J. Org. Chem. 2024, 20, 1510–1517, doi:10.3762/bjoc.20.135
- observed intermediate formation of the α-iodinated β-ketoester 3 as well (vide supra), which suggests an analogous mechanistic scenario as for the azidation (compare with Scheme 3). However, it should also be stated that the α-nitro products 10 were found to be not too stable, undergoing some unspecific
Domino reactions of chromones with activated carbonyl compounds
Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108
- (70 and 83%) were obtained for a 3-nitro- and a 3,5-dinitrophenyl group, presumably due to the electron-withdrawing character of the nitro groups and an enhanced electrophilicity. A moderate yield (49%) was obtained for the phenyl derivative. 1,3-Diphenylacetone Similarly, reaction of 1,3
- yields (up to 74%) were obtained for products containing nitro groups. 3-(2-Nitrobenzoyl)chromones Dimethyl acetone-1,3-dicarboxylate A completely different result was obtained when chromones containing a 2-nitrobenzoyl group were employed. The reaction of dimethyl acetone-1,3-dicarboxylate (3) with 3-(2
- applications have been developed. In the future, it will be interesting also to study reactions of 3-nitrochromone with carbonyl compounds. In this context, biological properties of the products will be interesting, as the nitro group can be transformed to the biologically important amino group. Structures of
The Ugi4CR as effective tool to access promising anticancer isatin-based α-acetamide carboxamide oxindole hybrids
Beilstein J. Org. Chem. 2024, 20, 1213–1220, doi:10.3762/bjoc.20.104
- structure–activity relationships derived from the GI50 values. The presence of a nitro group at the furan moiety enhanced the activity (8d > 8m). Presumably, the nitro group made 8d the most potent analogue bearing an aromatic amide (8c, 8e, 8g, 8i, 8l–n). For the aliphatic amides, the most potent
Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction
Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99
- ], Reformatsky reaction [65], azalactone synthesis [66], nitro reduction [67][68], epoxide rearrangement, thiourea guanylation, and others [69][70]. In this article, we describe a simple and direct protocol for the preparation of indanones through a classical Nazarov reaction catalyzed by bismuth(III) triflate
Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer
Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98
- , hydroaminomethylation, reduction of nitriles and nitro compounds or through reductive amination of carbonyl derivatives [26][27][28][29][30]. However, for example, cross-coupling reactions with alkyl or aryl halides generate considerable amounts of waste (Scheme 2A). Even though many different approaches exist for
- )phosphine ligand (PN3P) (Mn3) and studied N-methylation reactions in the presence of t-BuOK (20 mol %) at 120 °C for 24 h in toluene [36]. This catalytic system tolerated various functional groups, including nitro, ester, amide, and ketones and gave moderate to good yields (42–98%) of the mono-N-methylated
- moderate-to-high yields with aliphatic and aromatic alcohols (Scheme 18). In addition, this protocol allowed for the synthesis of indole through an intramolecular reaction and a resveratrol-derived amine. However, this catalytic method did not tolerate some functional groups such as nitro, ester, and
Mild and efficient synthesis and base-promoted rearrangement of novel isoxazolo[4,5-b]pyridines
Beilstein J. Org. Chem. 2024, 20, 1069–1075, doi:10.3762/bjoc.20.94
- the basis of readily available 2-chloro-3-nitropyridines via the intramolecular nucleophilic substitution of the nitro group as a key step. The previously unknown base-promoted Boulton–Katritzky rearrangement of isoxazolo[4,5-b]pyridine-3-carbaldehyde arylhydrazones into 3-hydroxy-2-(2-aryl[1,2,3
- ]triazol-4-yl)pyridines was observed. Keywords: aromatic nitro compounds; Boulton–Katritzky rearrangement; isoxazolo[4,5-b]pyridines; nucleophilic substitution; 1,2,3-triazoles; Introduction Nitrogen heterocycles represent a very important class of organic compounds that has found application in various
- isoxazolo[4,5-b]pyridine core synthesis have been summarized in a microreview [22]. Here, we wish to report an efficient method for the synthesis of isoxazolo[4,5-b]pyridines bearing electron-withdrawing groups (EWG) at positions 3 and 6 starting from readily available 2-chloro-3-nitro-6-R-pyridines as
Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions
Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90
- prepared through the oxidation of iodoarenes with NaBO3·4H2O [34], AcOOH [35], mCPBA [36], and NaClO·5H2O [37] in the presence of acetic acid. The reaction of (diacetoxyiodo)arenes bearing electron-donating (methyl (1b), methoxy (1c), and phenyl (1d)) and electron-withdrawing (methyl ester (1e), nitro (1f
Carbonylative synthesis and functionalization of indoles
Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87
- reductive elimination and the generated Pd(0) species gets oxidated by the oxygen to the active Pd(II) species (Scheme 7). Synthesis of indoles by metal-catalyzed reductive cyclization reaction of organic nitro compounds with carbon monoxide as reductant In the last 60 years, the metal-catalyzed
- carbonylative reduction approach of organic nitro compounds has been used for the synthesis of important industrial and pharmaceutical compounds such as indoles. In 1986, Cenini et al. reported a new synthetic method for indoles that involved 2-nitrostyrene derivatives. The reaction took place under drastic
- byproducts (Scheme 10) [23]. Two years later they developed two Pd-catalyzed reductive N-heteroannulations for the synthesis of fused indoles [24] and indoles isolated from two species of European Basidiomycetes [25] starting from suitably functionalized nitro compounds. Both in the first case and in the
Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles
Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84
- 4bo (o-phenoxy and o-bromo group, respectively), the er dropped considerably. Finally, a strong electron-withdrawing group in the ortho position such as nitro (4bn) was met with a decrease in yield (66%), but with a higher er. During the development of the scope, the hemiaminal ethers (Heck–Matsuda
Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins
Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76
- explored the reactivity of ortho-functionalized diaryliodonium salts containing electron-withdrawing groups (EWGs) such as fluorine and nitro groups [29][30]. These ortho-substituted diaryliodonium salts undergo selective benzocyclizations and arylocyclizations with aromatic acids, leading to 3,4
- group (such as a nitro group) in the para position was reacted, the corresponding product could not be obtained, but instead the O-arylated product 3at was obtained (Table 2, entry 19). Apart from naphthol, we also tested substituted phenols under the standard conditions. The corresponding products of
Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria
Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75
- carcinogenicity [3][4][5][6][7][8]. Biotic and abiotic degradation of cyclic nitramines often produce linear nitramine byproducts. For example, degradation of RDX and HMX by microbes or alkaline hydrolysis forms the linear nitramine 4-nitro-2,4-diazabutanal (NDAB) [9][10][11][12]. Linear nitramines are also
- formation of propionate 3-nitronate (P3N) as a conjugate base (Scheme 2) [39]. It is P3N that directly reacts with a cysteine in the ICL1 active site, forming a thiohydroxamate adduct that inhibits ICL1 turnover [40]. Additionally, the nitronate form of nitro acids has been proposed to behave as a
- transition analog of carboxylate groups, resulting in nitro compounds also acting as tight-binding reversible inhibitors [42]. Deprotonation of NNG also results in formation of the corresponding nitronate, albeit with a pKa of 6.6 [24], far lower than that for 3-NP (Scheme 2). Therefore, a much larger
Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles
Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36
Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines
Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34
- (31), is formed between the nitro and imino groups of the N-aryl ring. The compounds 4a–h intensely absorb light in the spectral range of 400–550 nm, with maxima at 439–459 nm, ε = 20600–37100 M−1⋅cm−1 (Figure 3 and Table 1). The introduction of an amino group into the p-position of the N-phenyl
Synthesis of spiropyridazine-benzosultams by the [4 + 2] annulation reaction of 3-substituted benzoisothiazole 1,1-dioxides with 1,2-diaza-1,3-dienes
Beilstein J. Org. Chem. 2024, 20, 280–286, doi:10.3762/bjoc.20.29
- yields than electron-donating groups (Scheme 2, 3aa–af). Remarkably, the nitro group gave the corresponding product 3ag in 94% yield. It was found that electron-donating groups afforded relatively higher dr values than electron-withdrawing groups (Scheme 2, 3aa–af). The effect of the R4 group was also
Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination
Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24
- quinolines, at the benzene ring, and the resulting nitro compounds could potentially be subjected to further transformations, including nucleophilic substitution of nitro groups. Indeed, under the action of a small excess of the nitrating mixture, dipyridoacenaphthene 5 undergoes double nitration at
- several minutes with a good yield (Scheme 4). The spectral data fully confirmed the purity and asymmetric structure of product 11. It should be emphasized that the isolation and purification of nitro compounds 10 and 11 is complicated by their low solubility in traditional organic solvents, sensitivity to
- sunlight (especially on adsorbents), and basic dipolar solvents (DMSO, for example, causes rather rapid degradation) [23]. Note that nitro derivatives 10 or 11 are not formed when base 5 is kept in nitric acid (25 °C, excess of 65% HNO3, 24 h) which returns the starting compound unchanged. After that step
Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions
Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11
- -wavelength absorption bands with maxima in a range from λmax = 333 nm for the ethyl-substituted compound 2f to λmax = 394 nm for the nitro-substituted derivative 2a (Figure 1A, Supporting Information File 1, Table S1). As compared with the absorption maximum of the parent compound at λmax = 330 nm [20], the
- derivatives 2b–g showed a slight bathochromic shift mostly in the range of λmax = 333–360 nm, whereas for the nitro-substituted compound 2a a stronger red shift of the absorption maximum was observed, presumably caused by the strong electron-withdrawing property of the nitro group resulting in a more
- an exception, the irradiation of the nitro-substituted styrylpyridine derivative 2a in MeCN or H2O led to disappearance of the long-wavelength absorption maximum with no formation of a distinct new band (Figure 2A), which usually indicates photoinduced decomposition. This observation is in agreement
N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction
Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136
- , resulting in glutarimides with a heterocyclic fragment at the α-position 1a–e – structures in demand for the design of CRBN ligands and immunomodulatory drugs. In compound 6n, catalytic hydrogenation was used to reduce the nitro group, resulting in the production of a benzotriazole analog of pomalidomide
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