Isoamyl Nitrite Research Articles

ChemInform Abstract: Palladium-Catalyzed Acetoxylation of Cyclic Allyl Phosphonates in the Presence of Isopentyl Nitrite and Using Molecular Oxygen as Final Oxidant.

Abstract The palladium-catalyzed acetoxylation of cyclic dialkyl allyl phosphonates is effected using palladium chloride as catalyst, in the presence of isopentyl nitrite in acetic acid under an oxygen atmosphere. The proposed mechanism for the reaction involves a palladium nitro–nitroso redox couple.

Synthesis of azido arylselenides and azido aryldiselenides: a new class of selenium–nitrogen compounds

We present here our results of the efficient synthesis of azido arylselenides and azido aryldiselenides under mild conditions. Starting from nitrogen-substituted benzenes, we incorporated selenium atom at aromatic ring and obtained amino arylselenides and diselenides in satisfactory yields. Treatment of these compounds with iso-pentyl nitrite (i-C5H11ONO) and azido trimethylsilane (Me3SiN3) in THF affords a variety of azido arylselenides and diselenides in good to excellent yields.

Facile Synthesis of 2,3-Diacetoxyflavanones from 3-Aminoflavones

Abstract 3-Aminoflavone reacts with isopentyl nitrite in acetic acid to give 2,3-diacetoxyflavanone in good yield. 3-Aminoflavone, the starting material, is readily available, and this method is a powerful tool for the synthesis of 2,3-dihydroxyflavanone derivatives.

Sulfonation of ordered mesoporous carbon supported Pd catalysts for formic acid electrooxidation

A novel supporting material containing benzenesulfonic acid (BSA) groups and ordered mesoporous carbons (OMCs) was first prepared by in situ radical polymerization of 4-styrenesulfonate and isoamyl nitrite under ambient conditions. Then, Pd nanoparticles were deposited on as-produced OMCs (f-OMCs) by the NaBH 4 reduction method. The structure and nature of the resulting composites were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and nitrogen adsorption–desorption. The results show that BSA groups are created and the texture and surface chemistry are altered, whereas the ordered porous structure is maintained. The electrocatalytic properties of the Pd/f-OMCs catalysts for formic acid oxidation (HCOOH) have been investigated by cyclic voltammetry and chronoamperometry methods, and excellent electrocatalytic activity can be observed.

Photolysis of n-butyl nitrite and isoamyl nitrite at 355 nm: A time-resolved Fourier transform infrared emission spectroscopy and ab initio study

We report on the photodissociation dynamics study of n-butyl nitrite and isoamyl nitrite by means of time-resolved Fourier transform infrared (TR-FTIR) emission spectroscopy. The obtained TR-FTIR emission spectra of the nascent NO fragments produced in the 355 nm laser photolysis of the two alkyl nitrite species showed an almost identical rotational temperature and vibrational distributions of NO. In addition, a close resemblance between the two species was also found in the measured temporal profiles of the IR emission of NO and the recorded UV absorption spectra. The experimental results are consistent with our ab initio calculations using the time-dependent density functional theory at the B3LYP/6-311G(d,p) level, which indicate that the substitution of one of the two gamma-H atoms in n-C(4)H(9)ONO with a methyl group to form (CH(3))(2)C(3)H(5)ONO has only a minor effect on the photodissociation dynamics of the two molecules.

A facile access to [60]fullerene-fused δ-lactones: unexpected reaction pathway of benzenediazonium-2-carboxylates controlled by organic bases

The reaction of [60]fullerene with anthranilic acids and isoamyl nitrite in the presence of triethylamine unexpectedly afforded [60]fullerene-fused delta-lactones, which would be difficult to be prepared by other known methods; the organic base played a crucial role in the unusual reaction pathway.

Crystal Structure of 2,5-Dibenzoyl-4-iodoaniline

2,5-Dibenzoyl-1,4-diaminobenzene (1.0 g, 3.21 mmol) dissolved in ether (10 mL) was added to boron trifluoride etherate (1.6 mL, 12.85 mmol), followed by the addition of isoamyl nitrite (1.52 mL, 11.24 mmol). After the precipitate was isolated, it was added to a solution of sodium iodide (0.52 g, 3.53 mmol) and iodide (0.07 g, 0.32 mmol) in acetonitrile (20 mL). After 60 min, the mixture was poured into sodium thiosulfate aquation, extracted with dichloroethane, and dried over anhydrous magnesium sulfate. Finally, column chromatography (1:8, ethyl acetate/petroleum ether) gave the title compound (0.9 g, 66% yield). Its single crystal suitable for X-ray structural analysis was obtained by slowly evaporating from ethanol at room temperature for 10 days.A colorless crystal having dimensions of 0.10 ¥ 0.10 ¥ 0.05 mm

Formation of diazoate intermediate upon nitrous acid and nitric oxide treatment of 2′-deoxyadenosine

When 2′-deoxyadenosine was treated with HNO 2 or NO, a small amount of a previously unidentified product was formed. The product was also formed by the reaction of 2′-deoxyadenosine with isoamyl nitrite in tetrahydrofuran as a major product. The product was identified as a diazoate derivative of 2′-deoxyadenosine, a reaction intermediate. At the initial stage of the HNO 2 or NO reaction, the concentration of the diazoate was greater than or comparable to 2′-deoxyinosine, a deamination product of 2′-deoxyadenosine. The diazoate was fairly stable and decomposed with a half-life of 66 h at pH 7.4 and 37 °C. These results suggest that the diazoate can be formed in cellular nucleosides or DNA with biologically relevant dose of HNO 2 and NO.

A simple approach towards sulfonated multi-walled carbon nanotubes supported by Pd catalysts for methanol electro-oxidation

Functionalized benzenesulfonic groups were grafted onto the surface of multi-walled carbon nanotubes (MWCNTs) supported Pd catalysts in direct methanol fuel cells by a new and simple in situ radical polymerization of 4-styrenesulfonate and isoamyl nitrite. The resultant sulfonated MWCNTs-supported Pd catalysts (S-MWCNTs/Pd) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectrometry measurements. Electrochemical characterizations of S-MWCNTs/Pd catalysts for methanol electro-oxidation in alkaline solution were investigated by cyclic voltammetry techniques. These results showed that S-MWCNTs/Pd exhibited higher electrocatalytic activity, enhanced CO tolerance and better stable life than did that with the unsulfonated counterparts, mainly due to the easier access with methanol and well dispersed distribution of the S-MWCNTs/Pd catalysts in water. In addition, compared with traditional sulfonation of MWCNTs, this new approach is more advantageous to make small and uniform dispersion of Pd particles loaded onto the surfaces of sulfonated MWCNTs, indicating it is a simple, rapid, and efficient method to functionalize MWCNTs.

Aliphatic β-nitro alcohols for non-enzymatic collagen cross-linking of scleral tissue

The success of riboflavin photochemical cross-linking of the cornea in treating keratoconus and post-surgical keratectasia has prompted interest in cross-linking scleral tissue with a potential application to stabilize myopic progression. Applying an UVA light source to the sclera is difficult, particularly in the posterior region. An alternate pharmacologic approach to scleral cross-linking may be possible. The present study was undertaken in order to identify nitrite related compounds capable of inducing scleral tissue cross-linking and to gain information regarding the possible chemical mechanisms involved. 8 × 4 mm strips of porcine and human sclera were incubated in various concentrations of nitrite related agents (1–100 mM) at 37 °C. pH 7.4 was used for all experiments except those involving NaNO 2. Following a 24–96 h incubation period, the samples were tested for cross-linking effects using thermal shrinkage temperature ( T s) analysis. Several compounds were studied including NaNO 2, 2-nitroethanol, 2-nitro-1-propanol, 3-nitro-2-pentanol, 2-nitrophenol, 2-nitroethane, 2-aminoethanol, isopentyl nitrite, DPTA/NO, DETA/NO, and urea, a nitrous acid trap. The results indicate that short chain aliphatic β-nitro alcohols (2-nitroethanol, 2-nitro-1-propanol, and 3-nitro-2-pentanol) are particularly effective cross-linking agents at pH 7.4, showing both time and concentration dependent effects. Furthermore, nitrosation does not appear to induce tissue cross-linking. In conclusion, aliphatic β-nitro alcohols can cross-link scleral tissue at physiologic pH and temperature. Since β-nitro alcohols are known to have reasonable toxicity profiles, these agents could find utility as pharmacologic cross-linking agents for scleral thinning disease.

Effects of the addition of ethanol and cetane number improver on the combustion and emission characteristics of a compression ignition engine

Combustion and emission characteristics of a direct-injection diesel engine fuelled with diesel—ethanol blends were investigated. The results show that the ignition delay and the premixed combustion duration increase, while the diffusive combustion duration and the total combustion duration decrease with increase in the oxygen mass fraction in the blends. The addition of 0.2 per cent volume fraction of cetane number improver (isoamyl nitrite) could mean that the ignition delay and the premixed combustion duration of the fuel blends with 10vol% ethanol fraction recover to those of diesel fuel. Meanwhile, with the increase in the ethanol fraction in the fuel blends, the centre of the heat release curve moves closer to the top dead centre. The brake specific fuel consumption increases, while the diesel equivalent brake specific fuel consumption decreases with increase in the ethanol fraction. The exhaust smoke concentration increases and exhaust nitrogen oxide (NO x) concentration decreases on prolonging the fuel delivery advance angle for both diesel fuel and the blended fuels. For a specific fuel injection advance angle, the exhaust smoke concentration shows a large decrease and the exhaust NO x concentration a small decrease on ethanol addition.

Design and Evaluation ofS-Nitrosylated Human Serum Albumin as a Novel Anticancer Drug

In recent studies, the cytotoxic activity of NO has been investigated for its potential use in anticancer therapies. Nitrosated human serum albumin (NO-HSA) may act as a reservoir of NO in vivo. However, there are no published reports regarding the effects of NO-HSA on cancer. Therefore, the present study investigated the antitumor activity of NO-HSA. NO-HSA was prepared by incubating HSA, which had been sulfhydrylated using iminothiolane, with isopentyl nitrite (6.64 mol NO/mol HSA). Antitumor activity was examined in vitro using murine colon 26 carcinoma (C26) cells and in vivo using C26 tumor-bearing mice. Exposure to NO-HSA increased the production of reactive oxygen species in C26 cells. Flow cytometric analysis using rhodamine 123 showed that NO-HSA caused mitochondrial depolarization. Activation of caspase-3 and DNA fragmentation were observed in C26 cells after incubation with 100 muM NO-HSA for 24 h, and NO-HSA inhibited the growth of C26 cells in a concentration-dependent manner. The growth of C26 tumors in mice was significantly inhibited by administration of NO-HSA compared with saline and HSA treatment. Immunohistochemical analysis of tumor tissues demonstrated an increase in terminal deoxynucleotidyl transferase dUTP nickend labeling-positive cells in NO-HSA-treated mice, suggesting that inhibition of tumor growth by NO-HSA was mediated through induction of apoptosis. Biochemical parameters (such as serum creatinine, blood urea nitrogen, aspartate aminotransferase, and alanine aminotransferase) showed no significant differences among the three treatment groups, indicating that NO-HSA did not cause hepatic or renal damage. These results suggest that NO-HSA has the potential for chemopreventive and/or chemotherapeutic activity with few side effects.

Synthesis of α-oximinoketones under ultrasound irradiation

The reaction of 6-acylmethylphenanthridines with isoamyl nitrite results α-oximino-6-acylmethylphenanthridines in 73–95% yields in DMF under ultrasound irradiation. Compared with conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction time and higher yields.

Direct oxidation of cycloalkanes with molecular oxygen to dicarboxylic acids using isoamyl nitrite

Oxidation of cycloalkanes with molecular oxygen using isoamyl nitrite was examined under mild conditions. Cycloalkanes were easily oxidized with molecular oxygen to give the corresponding cycloalcohols, cycloalkanones and dicarboxylic acids at 120 °C or lower temperatures. The oxidation of the cycloalkanes was promoted by adding soluble Co and Mn ions.

Diazotisation of aromatic amines and solvolysis of diazonium salts in ethylene glycol ethers

Aniline and unhindered alkyl-substituted anilines undergo solvolysis in dioxane and DME saturated with dry hydrogen chloride on diazotisation with isoamyl nitrite to give 2-(2-chloroethoxy)ethyl aryl ethers and 2-methoxyethyl aryl ethers respectively in 36-47% yields. 2,6-Dialkyl-substituted anilines give the corresponding chloro compounds as the major product along with the aryl ethers in lower yields. Diazotisation of aniline in ethylene glycol and monomethyl ethers of ethylene glycol and diethylene glycol gave the corresponding alcoholysis products in low yields. The solvolysis of aniline did not occur on diazotisation in diethyl ether or THF.

A novel method for the synthesis of α-oximino-6-acylmethylphenanthridines under neutral conditions

A novel method is described for the synthesis of α-oximino-6-acylmethylphenanthridine derivatives (2a–g)B in good to excellent yields based on treatment of 6-acylmethylphenanthridines with isoamyl nitrite (IAN) in DMF without any added acid.

New Modular and Efficient Approach to 6-Substituted Pyridin-2-yl C-Nucleosides

A novel modular, efficient, and practical methodology of preparation of 6-substituted pyridin-2-yl C-nucleosides was developed. An addition of 2-lithio-6-bromopyridine 2b to TBDMS-protected 2-deoxyribonolactone 5 gave aduct 7 as an equilibrium mixture of anomeric hemiketals 1-(6-bromopyridin-2-yl)-1-hydroxynucleosides 7a,b and its open form 7c. Reduction of the adduct 7 with Et3SiH and BF3 x Et2O afforded the desired 6-bromonucleoside 8a as pure beta-anomer in a total yield of 32% over two steps from 5. Intermediate 8a was then subjected to a series of palladium catalyzed cross-coupling reactions and aminations to give a series of protected 1beta-(6-alkyl-, 6-aryl-, and 6-aminopyridin-2-yl)-2-deoxyribonucleosides 9. Catalytic hydrogenation of 8a gave an unsubstituted pyridine C-nucleoside, and diazotative oxodeamination of 6-aminopyridine nucleoside 9f by isopentyl nitrite in acetic acid gave 6-oxopyridine nucleoside 10i. Deprotection of silylated nucleosides 9 by Et3N.3HF gave a series of free C-nucleosides 10.

Formation of 1,2,5‐Oxadiazole, Isoxazole, Isothiazole, 1,2,3‐Triazole, and Pyrrole Rings from N‐(5,5‐Dimethyl‐3‐oxocyclohexenyl)‐S,S‐diphenylsulfilimine

Reactions of N‐(5,5‐dimethyl‐3‐oxocyclohexenyl)‐S,S‐diphenylsulfilimine, a kind of enaminone, with isopentyl nitrite, isocyanates, isothocyanates, benzenediazonium chloride, and 1,1,1‐trifluoro‐4‐ethoxy‐3‐buten‐2‐one gave 1,2,5‐oxadiazole, isoxazole, isothiazole, 1,2,3‐triazole, and pyrrole derivatives condensed with cyclohexane, respectively, in one pot.

Self-assembly of functionalized single-walled carbon nanotubes prepared from aryl diazonium compounds on Ag surfaces

Self-assembly of the sidewall functionalized single-walled carbon nanotubes (SWNTs) has been performed on Ag surfaces. The covalently functionalized SWNTs with benzoic acid moieties are prepared via diazonium reactions from 4-aminobenzoic acid and isoamyl nitrite. Raman, infrared, thermal gravimetric analysis (TGA) data, and solubility increase of SWNTs have indicated the modification of the sidewall of SWNTs. The functionalized SWNTs appeared to be assembled on Ag surfaces through the carboxylate group as evidenced from the emerging ν s(COO −) peak at ∼ 1380 cm − 1 .

Photodetachment of aryl moieties from covalently functionalized single-walled carbon nanotubes by UV laser irradiation

Photodetachment of aryl moieties from covalently functionalized SWNTs was studied by temperature-dependent and UV Raman spectroscopic tools. The sidewall functionalized SWNTs were prepared via diazonium reactions from 4-bromoaniline and isoamyl nitrite. I–V conductivity measurements were performed for the functionalized SWNTs, after purification from pristine SWNTs using their different solubility. Temperature dependent Raman data appeared to be in line with thermal gravimetric (TGA) data exhibiting removal of aryl moieties above 590 °C. Raman spectra of the functionalized SWNTs were examined using ultraviolet excitation at 244 nm (5.08 eV) and 325 nm (4.82 eV) as well as visible irradiation at 633 nm (1.96 eV). Our experimental results indicated that the disorder-induced D mode should change significantly, whereas the tangential G modes do not become different under UV irradiation. The D mode for the functionalized SWNTs was found weakly at ∼1410 cm−1 at a low power of UV irradiation, whereas it was observed strongly at ∼1310 cm−1 upon 633 nm irradiation. The attached aryl moieties appeared to be removed by UV irradiation as indicated from almost identical spectra with those of pristine SWNTs.