3-Nitro-benzo-nitrile

The crystal structure of 3-nitrobenzonitrile, C7H4N2O2, was elucidated by low-temperature single-crystal X-ray diffraction. The compound crystallizes in the Sohncke space group P21 and features two mol-ecules in the unit cell. Aromatic π-π stacking leads to stacks of mol-ecules in the [100] direction. The absolute structure was established from anomalous dispersion.

8(meso)-Pyridyl-BODIPYs: Effects of 2,6-Substitution with Electron-Withdrawing Nitro, Chloro, and Methoxycarbonyl Groups

The introduction of electron-withdrawing groups on 8(meso)-pyridyl-BODIPYs tends to increase the fluorescence quantum yields of this type of compound due to the decrease in electronic charge density on the BODIPY core. A new series of 8(meso)-pyridyl-BODIPYs bearing a 2-, 3-, or 4-pyridyl group was synthesized and functionalized with nitro and chlorine groups at the 2,6-positions. The 2,6-methoxycarbonyl-8-pyridyl-BODIPYs analogs were also synthesized by condensation of 2,4-dimethyl-3-methoxycarbonyl-pyrrole with 2-, 3-, or 4-formylpyridine followed by oxidation and boron complexation. The structures and spectroscopic properties of the new series of 8(meso)-pyridyl-BODIPYs were investigated both experimentally and computationally. The BODIPYs bearing 2,6-methoxycarbonyl groups showed enhanced relative fluorescence quantum yields in polar organic solvents due to their electron-withdrawing effect. However, the introduction of a single nitro group significantly quenched the fluorescence of the BODIPYs and caused hypsochromic shifts in the absorption and emission bands. The introduction of a chloro substituent partially restored the fluorescence of the mono-nitro-BODIPYs and induced significant bathochromic shifts.

An Efficient Synthesis of 2-CF3-3-Benzylindoles

The reaction of α-CF₃-β-(2-nitroaryl) enamines with benzaldehydes afforded effectively α,β-diaryl-CF₃-enones having nitro group. Subsequent reduction of nitro group by NH₄HCO₂-Pd/C system initiated intramolecular cyclization to give 2-CF₃-3-benzylindoles. Target products can be prepared in up to quantitative yields. Broad synthetic scope of the reaction was shown. Probable mechanism of indole formation is proposed.

Crystal structures of three functionalized chalcones: 4'-di-methyl-amino-3-nitro-chalcone, 3-di-methyl-amino-3'-nitrochalcone and 3'-nitro-chalcone

The structure of three functionalized chalcones (1,3-di-aryl-prop-2-en-1-ones), containing combinations of nitro and di-methyl-amino functional groups, are presented, namely, 1-[4-(di-methyl-amino)-phen-yl]-3-(3-nitro-phen-yl)prop-2-en-1-one, C₁₇H₁₆N₂O₃, Gp8m, 3-[3-(di-methyl-amino)-phen-yl]-1-(3-nitro-phen-yl)prop-2-en-1-one, C₁₇H₁₆N₂O₃, Hm7m and 1-(3-nitro-phen-yl)-3-phenyl-prop-2-en-1-one, C₁₅H₁₁NO₃, Hm1-. Each of the mol-ecules contains bonding motifs seen in previously solved crystal structures of functionalized chalcones, adding to the large dataset available for these small organic mol-ecules. The structures of all three of the title compounds contain similar bonding motifs, resulting in two-dimensional planes of mol-ecules formed via C-H⋯O hydrogen-bonding inter-actions involving the nitro- and ketone groups. The structure of Hm1- is very similar to the crystal structure of a previously solved isomer [Jing (2009 ▸). Acta Cryst. E65, o2510].

Stereoselective Four-Component Synthesis of Functionalized 2,3-Dihydro-4-Nitropyrroles

We report a metal-free and stereoselective four-component reaction between α-ketoamides, amines, aromatic aldehydes and β-nitroalkenes or β-pivaloxy-nitroalkanes to obtain 2,3-dihydro-4-nitropyrroles functionalized in every position. The heterocycles accessible using this reaction may have utility in the synthesis of pharmacologically active compounds.

Recent Progress in Nitro-Promoted Direct Functionalization of Pyridones and Quinolones

Nitro group is one of the most important functional groups in organic syntheses because its strongly electron-withdrawing ability activates the scaffold, facilitating the reaction with nucleophilic reagents or the Diels-Alder reaction. In this review, recent progress in the nitro-promoted direct functionalization of pyridones and quinolones is highlighted to complement previous reviews.

Novel Anthranilic Diamide Scaffolds Containing N-Substituted Phenylpyrazole as Potential Ryanodine Receptor Activators

To discover potent insecticides targeting ryanodine receptors (RyRs), a series of novel anthranilic diamides analogues (12a-12u) containing N-substituted phenylpyrazole were designed and synthesized. These compounds were characterized by (1)H NMR, (13)C NMR, and HRMS, and the structure of compound 12u was confirmed by X-ray diffraction. Their insecticidal activities indicated that these compounds displayed moderate to excellent activities. In particular, 12i showed 100 and 37% larvicidal activities against oriental armyworm (Mythimna separata) at 0.25 and 0.05 mg L(-1), equivalent to that of chlorantraniliprole (100%, 0.25 mg L(-1); and 33%, 0.05 mg L(-1)). The activity of 12i against diamondback moth (Plutella xylostella) was 95% at 0.05 mg L(-1), whereas the control was 100% at 0.05 mg L(-1). The calcium-imaging technique experiment results showed that the effects of 12i on the intracellular calcium ion concentration ([Ca(2+)]i) in neurons were concentration-dependent. After the central neurons of Helicoverpa armigera were dyed by loading with fluo-5N and treated with 12i, the free calcium released in endoplasmic reticulum indicated the target of compound 12i is RyRs or IP3Rs. The activation of RyRs by natural ryanodine completely blocked the calcium release induced by 12i, which indicated that RyRs in the central neurons of H. armigera third-instar larvae is the possible target of compound 12i.

Sequential Diels-Alder/[3,3]-sigmatropic rearrangement reactions of β-nitrostyrene with 3-methyl-1,3-pentadiene

The tin(IV)-catalyzed reaction of β-nitrostyrene with (E)-3-methyl-1,3-pentadiene in toluene afforded two major nitronic ester cycloadducts in 27% and 29% yield that arise from the reaction at the less substituted diene double bond. Also present were four cycloadducts from the reaction at the higher substituted diene double bond, two of which were the formal cycloadducts of (Z)-3-methyl-1,3-pentadiene. A Friedel–Crafts alkylation product from the reaction of the diene, β-nitrostyrene, and toluene was also obtained in 10% yield. The tin(IV)-catalyzed reaction of β-nitrostyrene with (Z)-3-methyl-1,3-pentadiene in dichloromethane afforded four nitronic ester cycloadducts all derived from the reaction at the higher substituted double bond. One cycloadduct was isolated in 45% yield and two others are formal adducts of the E-isomer of the diene. The product formation in these reactions is consistent with a stepwise mechanism involving a zwitterionic intermediate. The initially isolated nitronic ester cycloadducts underwent tin(IV)-catalyzed interconversion, presumably via zwitterion intermediates. Cycloadducts derived from the reaction at the less substituted double bond of (E)-3-methyl-1,3-pentadiene underwent a [3,3]-sigmatropic rearrangement on heating to afford 4-nitrocyclohexenes. Cycloadducts derived from the reaction at the higher substituted diene double bond of either diene failed to undergo a thermal rearrangement. Rates and success of the rearrangement are consistent with a concerted mechanism possessing a dipolar transition state. An initial assessment of substituent effects on the rearrangement process is presented.

A Novel Mechanism for Nitric Oxide Production in Nitroalkyl Radicals that Circumvents Nitro-Nitrite Isomerization

In this study, we present a novel mechanism for NO loss from nitroalkyl radicals that circumvents the traditional higher-energy nitro-nitrite isomerization. We characterize the intrinsic reaction coordinate at the B3LYP/6-311++g(3df,2p) level of theory and calculate the transition-state energies using the G4 composite method; the subsequent dynamics en route to the highly exothermic NO + acetone product channel proceeds through a three-membered ring intermediate. Crossed laser-molecular beam scattering experiments on the 2-nitro-2-propyl radical confirm the importance of this new mechanism in determining the product branching.