Search results
Search for "nitro" in Full Text gives 523 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction
Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34
- conditions tested. Similarly, the resolution of nitro aldehydes 16 and 17, prepared by Michael addition of nitromethane to α,β-unsaturated aldehydes (entries 16 and 17, Table 5), was tested, and the same results were obtained as in the cases of the malonate derivatives. These results indicate that dicarbonyl
- compounds are better leaving groups than diesters or nitro derivatives in this type of transformation. Another possible explanation is that Michael adducts other than 1,5-dicarbonyl compounds require more robust bases to shift the equilibrium toward the retro-Michael product. It is essential to highlight
The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation
Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27
Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones
Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26
- interaction of 2,3,3-trimethylindolenine with 3,5-di(tert-butyl)-1,2-benzoquinone leads to the formation of indolo[1,2-a]indoline derivatives [23], while the presence of a nitro group in 4,6-di(tert-butyl)-3-nitro-1,2-benzoquinone the reaction with 2,3,3-trimethylindolenine leads to an o-quinone ring
Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates
Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24
- compounds 5a, 5b, 6b, 6c, and 7a. Acknowledgements The physicochemical studies were performed on the equipment of Center for Collective Use ''Physical and chemical methods for the study of nitro compounds, coordination, biologically active substances and nanostructured materials'' at the Interdisciplinary
Facile one-pot reduction of β-nitrostyrenes to phenethylamines using sodium borohydride and copper(II) chloride
Beilstein J. Org. Chem. 2025, 21, 39–46, doi:10.3762/bjoc.21.4
- ]. One of the most studied and inexpensive routes to synthesize substituted phenethylamines focuses on the reduction of their α,β-unsaturated nitroalkene analogue (β-nitrostyrene), where both the double bond and the nitro group need to be reduced to deliver the corresponding primary amine. Their
- -nitrostyrene (4a), precursor of most of the hallucinogenic 2C-X family (Table 1). This method was also tested on other types of scaffolds to investigate its potential general applications and effects on other substituents. As sodium borohydride per se does not reduce ester nor nitro functionalities [15][16][17
- ][18][19][20][21][22][28][29], the presence of the copper salt results in overcoming this issue and leads to isolated yields above 90% (7–9) (Scheme 2). Therefore, the NaBH4/CuCl2 system was proved to work on aromatic ester, nitro, and α,β-unsaturated nitroalkene functionalities. Our work demonstrates
Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning
Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3
Synthesis, characterization, and photophysical properties of novel 9‑phenyl-9-phosphafluorene oxide derivatives
Beilstein J. Org. Chem. 2024, 20, 3299–3305, doi:10.3762/bjoc.20.274
- was achieved in 5 steps starting from commercially available 2-bromo-4-fluoro-1-nitrobenzene (1, Scheme 1 and Scheme 2). For the preparation of the key intermediate 5 (Scheme 1), self-coupling of 1 in the presence of copper followed by reduction of the nitro group generated diamine compound 3 (89
Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines
Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268
- evaluate the synthetic utility of this methodology, derivative 39e was reduced using BF3·OEt2 and Et3SiH leading to 41 in a good yield and moderate diastereoselectivity (Scheme 14). In 2017, Li’s group developed a chiral (DHQ)2PHAL-catalyzed [2 + 4] annulation reaction of cyclic 1-azadiene 14 with γ-nitro
- patterns and aryl R2 substituents led to the desired products. However, the presence of a cyclopropyl or isopropyl R2 substituent, led to a complex mixture of products (Scheme 15). In the mechanism proposed by the authors, (DHQ)2PHAL XIII provokes the deprotonation of the γ-nitro ketone at the α-position
- to the nitro group, resulting in the formation of an anionic nucleophilic specie A. The latter reacts with the cyclic 1-azadiene via stereoselective Michael addition, forming intermediate B, stabilized by π–π stacking interactions between the Ar group and the aromatic cyclic moiety of the 1-azadiene
Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling
Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265
- chromene (12) were tolerated. Benzylic azides were accommodated including those bearing nitro (2), iodo (3), and boronic ester groups (5, 21). Strained rings were effective including cubane (18) and bicyclopentane (20). While 18 and 20 were isolated in lower yield, no evidence of ring opening was observed
Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies
Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261
- as nitro or azide groups, rather than protected amines. Following the Ugi-4CR, the nitro or azide group is reduced to form the amine, leading to a condensation reaction that results in the formation of the benzodiazepine ring [55]. Pertejo et al. [61] described the diastereselective synthesis of 3
- -carboxamide-1,4-benzodiazepin-5-ones when enantiopure (S)-(−)-α-methylbenzylamine and arylglyoxals were used. Thus, a reversal of diastereoselectivity was observed depending on the cyclization methodology employed, the reduction of a nitro group or the Staudinger/aza-Wittig on azide derivatives. This
Advances in radical peroxidation with hydroperoxides
Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249
- the target product 181. With N-containing second fragment Mn(III)-catalyzed difunctionalization of alkenes 182 with TBHP and tert-butylnitrite to form β-peroxynitroalkanes 183 was developed (Scheme 57) [126]. tert-Butylnitrite was used as the precursor of the nitro group. The reaction proceeds under
Structure and thermal stability of phosphorus-iodonium ylids
Beilstein J. Org. Chem. 2024, 20, 2931–2939, doi:10.3762/bjoc.20.245
- charge on this substituent in the hypervalent bond. The long I–X distances (a = 2.758–4.165 Å) are indicative of ionic compounds, with the exception of the cyclic benziodoxolone 2, in which a covalent I–O bond is observed (a = 2.484 Å). We were unable to obtain a crystal structure of the ortho-nitro
- compound 1j. However, a previously reported crystal structure of ylid 3, which also contains an ortho-nitrobenzene substituent, suggests a pseudocyclic structure where the nitro group is coordinating to the iodine centre (a(I–ON) = 2.695 Å) [28], which we propose is likely to be the case in 1j as well. In
Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts
Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243
- -arylation of α-cyano-α-fluoroacetamides (9, R = CN), too. Aryl(mesityl)iodonium salts 6 (which are unsymmetrical diaryliodonium salts) were used as hypervalent iodine salts in both reactions. To achieve the C(sp3)-arylation of the α-nitro derivative of compounds 9 within 2 h to yield products 10, K2CO3 as
C–H Trifluoromethylthiolation of aldehyde hydrazones
Beilstein J. Org. Chem. 2024, 20, 2883–2890, doi:10.3762/bjoc.20.242
- being explained by a tedious purification. Interestingly, the methodology was successfully applied to the functionalization of aliphatic hydrazones 1s and 1t and even the hydrazone derived from citronellal 1u. The method was functional group-tolerant to various functional groups (nitro, CN, ester
Synthesis of fluoroalkenes and fluoroenynes via cross-coupling reactions using novel multihalogenated vinyl ethers
Beilstein J. Org. Chem. 2024, 20, 2691–2703, doi:10.3762/bjoc.20.226
- % yields (Table 3, entries 6–8). The reaction between 1a and 4j, which contains an electron-withdrawing nitro group, afforded 2j in 88% yield (Table 3, entry 9). Although p-hydroxyphenylboronic acid (4k) gave 2k in only 9% yield, m-aminophenylboronic acid (4l) provided 2l in high yield (Table 3, entries 10
- –Miyaura cross-coupling. The reaction of 1b or 1c, which had a m-methoxy or p-nitro group on the benzene ring, with 4a proceeded smoothly to furnish 2p or 2q in good yieds (Table 3, entries 15 and 16). A phenyl group could be introduced into 1d possessing an ester moiety in moderate yield, whereas the
- -naphthylacetylene (5g) provided the corresponding enynes (3b–g) in 43–92% yields (Table 4, entries 1–6). On the contrary, electron-withdrawing substituents such as chloro, trifluoromethyl and nitro groups resulted in low cross-coupling yields (3h–j) (Table 4, entries 7–9). p-Acetyl or p-formylphenylacetylene (5k or
Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments
Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202
- of complexes 5 and 8 do not contain any solvent molecules, while the unit cell of crystals 6·0.5CH3CN contains one acetonitrile molecule per two catechol molecules. The nitro-substituted pyridine group in 5 is disordered in two positions. The X-ray structure of catechol 5 is shown in Figure 1, and
- planes of the cycles corresponds to 5°). These pairs (Figure 3) are bound in a supramolecular chain along the 0c axis owing to two H-bonds between the OH group of catechol and the oxygen atom of nitro-group (O1–H1···O4B (1−x, 1−y, −1+z): the H1···O4 distance is 2.46(1) Å, the O1···O4 distance is 2.886(3
- of the electron-withdrawing nitro group. Some differences are observed in the electrochemical behavior of thiones 6–9 compared to thioethers 1–5. In the case of compounds 6–8 with a 1,3,4-oxadiazole-2-thione fragment, the oxidation potential of the first peak is shifted to the cathodic region
Electrochemical allylations in a deep eutectic solvent
Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189
- product, although in this case, reduction of the nitro group to an amino group was observed and the resulting 4-aminobenzaldehyde is likely too electron-rich to undergo allylation. The use of other halides was also explored (Table 3). Switching to allyl chloride (Table 3, entry 2) did result in partial
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
Other Beilstein-Institut Open Science Activities
