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A kinetic study of the nitrosation of the aminoacids proline, sarcosine and 4-hydroxyproline using 2-ethoxyethyl nitrite as nitrosating agent has been carried out. The mechanism proposed is considerably different from that found when studying this kind of reactions in acid media.

Oxidations of hemoglobin in oxygen-saturated and deoxygenated media by 10 structurally variant alkyl nitrites have been examined in kinetic detail. Pronounced structural influences on rate constants, whose values span a range of 80 in oxidations of both oxy- and deoxyhemoglobin, have been observed. tert-Butyl nitrite provides the slowest oxidation rate that for deoxyhemoglobin terminates after only half of the available iron(II) heme units have been oxidized. Activation parameters have been determined for oxidations of oxyhemoglobin and deoxyhemoglobin by ethyl, isopropyl, and neopentyl nitrites from kinetic evaluation of these reactions as a function of temperature. The differences in free energies of activation (delta G) between hemoglobin R and T states range from 1.8 to 2.9 kcal/mol for the three alkyl nitrites examined. The composite data portray alkyl nitrite oxidations as inner sphere electron transfer processes whose kinetic characteristics reflect the ligand binding properties of hemoglobin. A sulfhydryl-induced alkyl nitrite oxidation of oxyhemoglobin that is most pronounced in oxygen-saturated media has been observed, and its cause has been traced to nitrosyl exchange of alkyl nitrites with the beta-93 cysteine sulfhydryl group of hemoglobin.

Les temps de relaxation pour la conversion intramoleculaire (syn⇄anti) des alkylnitrites est mesuree par spectroscopie RMN dynamique en solution et a l'etat gazeux. Cinetique

A method for determining small amounts of methanol and ethanol in aqueous solutions based on a combination of stripping and gas chromatographic techniques, has been developed. By the reaction with alkali nitrite the alcohols are quantitatively converted into the corresponding volatile alkyl nitrites which are transferred to a liquid nitrogen sampling loop and after a instantaneous evaporation analysed by gas chromatography. Amounts of approximately 1 μg of the individual alcohols can be estimated in sample volumes of about 5 ml.

The rate of decomposition of s-butyl nitrite (SBN) has been studied in the absence (130–160°C) and presence (160–200°C) of NO. Under the former conditions, for low concentrations of SBN (6 × 10−5 − 10−4M) and small extents of reaction (∼1.5%), the first-order homogeneous rates of acetaldehyde (AcH) formation are a direct measure of reaction (1) since k3c » k2(NO): . Unlike t-butyl nitrite (TBN), d(AcH)/dt is independent of added CF4 (∼0.9 atm). Thus k3c is always » k2 (NO) over this pressure range. Large amounts of NO (∼0.9 atm) (130–160°C) completely suppress AcH formation. k1 = 1016.2–40.9/θ sec−1. Since (E1 + RT) and ΔH°1 are identical, within experimental error, both may be equated with D(s-BuO-NO) = 41.5 ± 0.8 kcal/mol and E2 = 0 ± 0.8 kcal/mol. The thermochemistry leads to the result ΔH°f (s-) = − 16.6 ± 0.8 kcal/mol. From ΔS°1 and A1, k2 is calculated to be 1010.4M−1 · sec−1, identical to that for TBN. From an independent observation that k6/k2 = 0.26 ± 0.01 independent of temperature, , we find E6 = 0 ± 1 kcal/mol and k6 = 109.8M−1 · sec−1. Under the conditions first cited, methyl ethyl ketone (MEK) is also a product of the reaction, the rate of which becomes measurable at extents of conversion >2%. However, this rate is ∼0.1 that of AcH formation. Although MEK formation is affected by the ratio S/V for different reaction vessels, in a spherical reaction vessel, this MEK arises as the result of an essentially homogeneous first-order 4-centre elimination of HNO. ; k5 = 1012.8–35.8/θ sec−1. Sec-butyl alcohol (SBA), formed at a rate comparable to MEK, is thought to arise via the hydrolysis of SBN, the water being formed from HNO. The rate of disappearance of SBN, that is, d(MEK + SBA + AcH)/dt, is given by kglobal = 1015.7–39.6/θ sec−1. In NO (∼1 atm) the rate of formation of MEK was about twice that in the absence of NO, whereas the SBA was greatly reduced. This reaction was also affected by the ratio S/V of different reaction vessels. It was again concluded that in a spherical reaction vessel, the rate of MEK formation was essentially homogeneous and first order. This rate is given by kobs = 1012.9–35.4/θ sec−1, very similar to k5. However, although it is clear that the rate of formation of MEK is doubled in the presence of NO, the value for kobs makes it difficult to associate this extra MEK with the disproportionation of s- and NO: s-. NO at temperatures of 130–160°C completely suppresses AcH formation. AcH reappears at higher temperatures (165–200°C), enabling k3c to be determined. Ignoring reaction (6), d(AcH)/dt = k1k3 (SBN)/[k3c + k2(NO)]; k3c = 1014.8–15.3/θ sec−1. Inclusion of reaction (6) into the mechanism makes very little difference to the result. Reaction (3c) is expected to be a pressure-dependent process.

1. The polymerization of methyl methacrylate, inhibited by NO, was investigated. The weak inhibiting action of NO is due to an interaction between the monomer and inhibitor, leading to the formation of a nitronitroso derivative of methyl methacrylate. The latter was isolated and identified. 2. An analogous effect of deactivation of inhibitors in the interaction with the monomer is also observed in the polymerization of methyl methacrylate in the presence of alkyl nitrites as a result of the formation of an alkyl nitrite-methyl methacrylate molecular complex.

The pyrolysis behaviour of ethyl, n -propyl, n -butyl and iso -butyl nitrite at low pressures was investigated in the temperature range 150–510°C, using a field ionization mass spectrometer. The three pyrolysis steps (loss of NO to form an alkoxy radical, loss of CH 2 O to form an alkyl radical, and loss of an olefine to form a secondary alkyl radical or hydrogen) could be readily identified. The alkoxy radicals can be identified only indirectly via secondary reactions on the surface of the field ionization emitter, while alkyl radicals undergo surface reactions to a lesser extent and thus can be identified directly. The proportion of free alkyl radicals increases with increasing chain length and branching of the alkyl nitrite, while the optimum temperature for formation of alkyl radicals decreases correspondingly. The results not only give information on the pyrolysis behaviour of alkyl nitrites but also shed light on the reactions of alkoxy and alkyl radicals on the surface of a field ionization emitter.

Although our pyrolytic studies of five alkyl nitrites (RONO) have shown that it is possible to determine precise, acceptable values for k1: we have been uncertain about the mechanism for the first order production of nitroxyl from primary and secondary nitrites. Nitroxyl could arise either from the direct elimination process (5) or from the disproportionation of the alkoxyl radical concerned and nitric oxide: Thus kexp = k5 or k1k6/[k2 + k6]. If the route is reaction (6), Eexp should be identical to E1, since the ratio k6/k2 is temperature independent. We preferred the elimination process because Eexp < E1 and Aexp was in agreement with transition-state calculations for such elimination processes. This study was concerned with the pyrolyses of ethyl and i-propyl nitrites in the presence of nitric oxide. The results show that nitroxyl is produced via the disproportionation of the alkoxyl radical and nitric oxide, as originally suggested by Levy. This is supported by the wealth of particularly photochemical data in the literature. Our and other previous spuriously low Arrhenius parameters are attributed to heterogeneous effects.

Cinetique d'hydrolyse des nitrites d'alkyle. Echange de nitrosyle avec des alcools. Preparation de nitrites et de thionitrites d'alkyle

The usually quoted expression for the second order rate constant, for a unimolecular reaction at the low pressure limit, is valid only for strictly irreversible processes. Its application to isomerization reactions (which are to some extent reversible) is demonstrably in error; corrected expressions have been published. Attention is directed to intramolecular conversions over low barriers, for which the inappropriateness of the unidirectional expression becomes obvious. For such isomerizations we propose a model which incorporates only operationally observable states, so that an essential conceptual ambiguity is avoided. Use of this model is illustrated for the syn⇄anti conversions of methyl nitrite, derived from a gas phase NMR coalescence curve (Mc:Tc). The present data suggest that during isomerization the alkyl nitrites may not be completely ergodic on a time scale of 10−9 s. A regional phase‐space model is proposed which has the appropriate formalism to account for this behavior.

N-Methyl-N-nitrosotoluene-p-sulphonamide (MNTS) reacts readily with the thiolate anion of cysteine and some of its derivatives, in aqueous ethanol, to give the corresponding S-nitroso species. The measured second order rate constant k2 increases with pH, and the experimental points lie close to the S-shaped curve calculated for reaction via the thiolate anion. The pKa values for SH ionisation were calculated from the experimental results, and gave figures generally in good agreement with the literature. There is no evidence of reaction via the thiol RSH, or of any reaction, under these conditions, with less powerful nucleophiles including amines, alcohols and an enol. There was no evidence of S-nitrosation of cysteine using dimethylnitrosamine, nitrosoproline or nitrososarcosine. The results are consistent with a direct transfer of the nitroso group to the sulphur atom of the thiolate anion. The results are compared with similar reactions of alkyl nitrites.

5-Amino-1-aryl-1H-pyrazole-4-carboxylate esters are converted to the corresponding desamino, chloro, bromo, iodo, and methylthio esters by processes involving nonaqueous diazotization. Diazotizing agents are alkyl nitrites except in the case of chlorine where nitrosyl chloride is used. Evidence is presented that the latter reagent leads to the formation of cationic rather than radical intermediates.

The mass spectrometry of alkyl nitrites and alkyl nitrates with chemical ionization using methane and isobutane as reagent gases produces quasi-molecular ions, (M+1)+ and/or (M−1)+. These ions have maximum abundance for lower nitrates and nitrites. The chemical ionization mass spectrometry, in conjunction with gas chromatography, can be used for quantitative estimation of alkyl nitrates and nitrites in very low amounts.

The A → X system fluorescence spectra of CH3O and C2H5O have been obtained following the 193 nm photolysis of methyl and ethyl nitrites. These species are produced in highly rotationally and vibrationally excited states. The OO band is at 31530 cm−1 for CH3O and at 29200 cm−1 for C2H5O. The collision-free fluorescence lifetimes of the A state are independent of the levels of the CO stretching vibrational mode and are measured to be 2.2 μs for CH3O and 1.8 μs for C2H5O. The quenching rate constants by the parent molecules show a little increase with the levels of the CO stretching vibrational mode. The vibrational distribution in the photofragments is discussed using statistical models.

The gas-phase chemistry of Co/sup +/ and ions of the type Co(ligand)/sub n//sup +/ with a series of nitroalkanes is presented. Also, for comparison, reactions of methyl nitrite and 1-butyl nitrite are included. The Co/sup +/ ion reacts with nitroalkanes by inserting into C-H, C-C, C-N, and N-O bonds. Many nitroalkane products can be best explained via a nitrite-like intermediate-possibly indicating a metal-induced nitro-to-nitrite isomerization. Collision-induced dissociation analysis of (i) primary reaction products and (ii) products of subsequent reactions is used to suggest production structures. With ligands present on the metal, dramatic changes of reactivity are observed. While nitroalkanes react by simple ligand displacement with Co(ligand)/sub n//sup +/ typical of monofunctional alkanes, alkyl nitrites exhibit a much richer chemistry, more typical of multifunctional organic molecules.

In strongly aqueous acid solution (±)-2-acetylamina-2-carboxy-l,1-dimethylethyl thionitrite (RSNO) undergoes denitrosation to give the corresponding thiol. The reaction is reversible and normally lies well over on the side of the thionitrite, but can proceed in the denitrosation direction in the presence of traps for free nitrous acid such as added sodium azide or sulphamic acid. At sufficiently high trap concentration to ensure complete irreversibility, the reaction was found to be first-order in RSNO and acid-catalysed; the observed reaction rate constant is approximately proportional to hO. Catalysis was observed by Cl–, Br–, SCN–, and SC(NH2)2 and the second-order rate constants were 4.6 × 10–3, 13.0 × 10–3, 34 × 10–3, and 27 × 10–3 l mol–1 s–1, respectively. The order of reactivity is as expected with the exception of that of thiourea. N-Methyl-4-nitroaniline was converted quantitatively to the corresponding nitrosamine by RSNO, but in the presence of added sodium azide, no nitrosamine was detected, this shows that RSNO like nitrosamines generally and alkyl nitrites, acts as a nitrosating agent towards amines etc., under these experimental conditions, by prior hydrolysis or via nitrosyl halide etc. formation. A kinetic analysis has enabled the reactivity of the nitrous acid traps hydrazoic acid and sulphamic acid to he established quantitatively.

Several new sulfonyl or sulfonyl derivativives, thionitrates (RSNO2), sulfonyl nitrites (RSO2NO), were successfully isolated by treating corresponding thiols and sulfinic acids with dinitrogen tetraoxide (N2O4). Spectroscopic data of both stable and many rather unstable compounds were determined and compared with those of corresponding alkyl nitrites (RONO) or alkyl nitrates (RONO2). Chemical reactivities of these uncommon, novel S-nitroso and S-nitro compounds were investigated.

Treatment of species formed by deprotonation with t-BuOK in THF with alkyl nitrites or NOBF4 of (η5-cyclopentadienyl-η6-areneiron) cations bearing methylene methyl or methyne substituents at the arene is studied. Only in the case of methylene are cationic oximes obtained, and the nature of the nitrosing agent is discussed. Oximes are transformed into the corresponding ketones by acidic hydrolysis with aqueous HF. Cathodic reduction on mercury of oxime and ketone complexes gives respectively their primary amines and secondary alcohols.

The reactions of human hemoglobin and sperm whale myoglobin with ethyl nitrite under aerobic conditions have been examined in kinetic detail. Ethyl nitrite converts two equivalents of oxyhemoglobin or oxymyoglobin to their oxidized counterparts with concurrent production of one equivalent each of molecular oxygen, nitrate ion, and ethyl alcohol. Inverse first order kinetic dependence on the concentration of molecular oxygen has been observed and is interpreted by a mechanism in which oxygen dissociation from the oxyhemoprotein occurs prior to rate-limiting oxidation by ethyl nitrite. The rate constant for ethyl nitrite oxidation of hemoglobin from which the fourth oxygen has dissociated is calculated to be 45 times greater than the corresponding rate constant for oxidation of deoxyhemoglobin. This rate enhancement is proposed to be a reflection of the oxidative susceptibility of the R and T conformational states of hemoglobin. Results obtained for the oxidation of myoglobin confirm this interpretation as do kinetic data for hemoglobin and myoglobin oxidations by iron(III) and copper(II) complexes. The effects of organic phosphates on rates for hemoglobin oxidations are interpreted in terms of oxidation inhibition by molecular oxygen.

The oxidation of nine alkyl nitrites to the corresponding carbonyl compounds in yields of 76–96% by dimethyl sulfoxide (DMSO) is described; since oxidation with DMSO is very selective this method can be used to obtain aldehydes or ketones from alcohols which include other labile functional groups such as alkene, alkyne and aldehyde.

Reactions of various arylamines with either t-butyl thionitrite, t-butyl thionitrate, or p-toluenesulfonyl nitrite in the presence of anhydrous copper(II) halides under mild conditions gave corresponding aryl halides in good yields. This reaction in the presence of such olefins as acrylonitrile, styrene, and acrylic acid gave the corresponding 2-aryl-1-haloethanes as the main products. t-Butyl thionitrite, t-butyl thionitrate, and p-toluenesulfonyl nitrite were found to be better deaminative reagents than alkyl nitrites or alkyl nitrates due to their weak sulfur–nitrogen bonds.

Both positive and negative ion-molecule reactions of alkyl nitrites have been examined using the techniques of ion cyclotron resonance spectroscopy. In the case of positive ion-molecule reactions a variety of NO + transfer and hydride abstraction reactions dominate the ion chemistry. In all of the nitrites reaction sequences lead to the production of relatively stable nitrito alkyl cations. The negative ion-molecule reactions are characterized by NO 2 - production by nucleophilic displacement reactions and enolate formation via proton transfer and loss of NO. The proton affinities of each of the nitrites studied have been determined and compared to the gas phase basicities of the corresponding alcohols.

The rate of decomposition of isopropyl nitrite (IPN) has been studied in a static system over the temperature range of 130–160°C. For low concentrations of IPN (1–5 × 10−5M), but with a high total pressure of CF4 (∼0.9 atm) and small extents of reaction (∼1%), the first-order rates of acetaldehyde (AcH) formation are a direct measure of reaction (1), since k3 » k2(NO): Addition of large amounts of NO (∼0.9 atm) in place of CF4 almost completely suppressed AcH formation. Addition of large amounts of isobutane – t-BuH – (∼0.9 atm) in place of CF4 at 160°C resulted in decreasing the AcH by 25%. Thus 25% of were trapped by the t-BuH (4): The result of adding either NO or t-BuH shows that reaction (1) is the only route for the production of AcH. The rate constant for reaction (1) is given by k1 = 1016.2±0.4–41.0±0.8/θ sec−1. Since (E1 + RT) and ΔH°1 are identical, within experimental error, both may be equated with D(i-PrO-NO) = 41.6 ± 0.8 kcal/mol and E2 = 0 ± 0.8 kcal/mol. The thermochemistry leads to the result that From ΔS°1 and A1, k2 is calculated to be 1010.5±0.4M−1·sec−1. From an independent observation that k6/k2 = 0.19 ± 0.03 independent of temperature we find E6 = 0 ± 1 kcal/mol and k6 = 109.8+0.4M−;1·sec−1: In addition to AcH, acetone (M2K) and isopropyl alcohol (IPA) are produced in approximately equal amounts. The rate of M2K formation is markedly affected by the ratio S/V of different reaction vessels. It is concluded that the M2K arises as the result of a heterogeneous elimination of HNO from IPN. In a spherical reaction vessel the first-order rate of M2K formation is given by k5 = 109.4–27.0/θ sec−1: IPA is thought to arise via the hydrolysis of IPN, the water being formed from HNO. This elimination process explains previous erroneous results for IPN.

Decyl nitrite was found to be an effective substitute for aliphatic aldehydes in the light producing reactions of bacterial luciferase. Two other aldehyde analogs, decyl formate and decyl formamide, were inactive. A kinetic isotope effect of 1.7 was found for 1- 2 H-dodecanal in comparison to dodecanal. These results support a Baeyer-Villiger type mechanism for bioluminescence proposed previously. Alkyl nitrites may be useful in the study of other enzymic reactions involving aldehyde substrates.

Nuclear magnetic resonance (NMR) was employed for the conclusive identification of isoamyl nitrite and isobutyl nitrite in street drugs.

Reaction of 2-acetyl-substituted thiophenes and furans with alkyl nitrites in the presence of the corresponding aliphatic alcohols and hydrochloric acid leads to the formation of linear acetals of thienyl- and furylglyoxals, whose structure was established by IR, UV, NMR spectroscopy, and mass spectrometry methods. The main paths of the dissociation of the molecules under electron impact were established.

The alkyl nitrites, C2H5ONO, n-C3H7ONO, n-C4H9ONO, and i-C4H9ONO were photolyzed at 23°C in the presence of 15NO at 366-nm incident radiation. The quantum yields of the corresponding isotopically-enriched alkyl nitrites were measured by mass spectrometry. The results indicated that only part of the absorption leads to photodecomposition. The remainder forms an electronically excited state which isotopically exchanges with 15NO. The indicated reactions of the electronically excited state RONO*, are where k3/k2 = 0.50 ± 0.10, 0.62 ± 0.20, 0.42 ± 0.06, and 0.24 ± 0.03 torr, and that k2a/k2 = 1.0, 1.0, 0.64 ± 0.04, and 0.56 ± 0.03, respectively, for C2H5ONO, n-C3H7ONO, n-C4H9ONO, and i-C4H9ONO.

The (M — 3)− ions in the negative chemical ionization spectra of alcohols in an ICR spectrometer are shown to arise from pyrolysis of the neutral alcohol on various hot surfaces in the instrument. Carbonyl compounds are formed, followed by deprotonation. Similar reactions are observed for alkyl nitrites and peroxides.

t -Butyl nitrite, n -butyl nitrite, and isoamyl nitrite were irradiated in the 225–227 nm, 208 nm, and 450–455 nm wavelength regions. The resulting mass spectra at different laser intensities, as well as those obtained by electron impact (EI), were compared. The ion fragmentation pattern is strongly dependent on the wavelength but shows similarities for the different nitrites at the same wavelength. The fragmentation obtained by EI is different from that obtained via laser excitation. Mechanisms for the laser-induced fragmentation process are suggested and discussed.

When the AIDS epidemic was in its earliest stages, and prior to identification of HIV as the etiological factor, the use of volatile nitrites by the male homosexual community to enhance sexual activities appeared to have a significant role in this disease. Preliminary observations indicated that that portion of the male homosexual community which developed Kaposi's sarcoma were also heavy nitrite users. These nitrites had been demonstrated to be mutagenic in bacteria and thus it was postulated that they could be responsible for the appearance of the sarcoma. To evaluate further the genotoxic activity of these chemicals, six nitrites, including those most commonly used by homosexuals for sexual gratification, were selected for testing in the mouse lymphoma TK {plus minus} and Salmonell typhimurium mutagenicity assays. One chemical, n-amyl nitrite, was negative in the mouse lymphoma assay, while the other five chemicals, n-butyl, isobutyl, iso-amyl, sec-butyl, and n-propyl nitrite, were positive. All six compounds were positive in the Salmonella assay. The mutagenic and known toxic effects of these chemicals remain a concern because a large population of teenagers and young adults continue to abuse these substances.

t-Butyl thionitrate have been found to be an excellent diazotizing reagent of arylamines in aprotic nonpolar media, affording eventually such products as aryl chlorides, aryl bromides, aryl iodides, biphenyls, and aryl methyl sulfides in the presence of CCl4, CHBr3, I2, benzene, and dimethyl disulfide, respectively, via extrusion of N2.

The decomposition of N-methyl-N-nitrosotoluene-p-sulphonamide (MNTS) has been studied in basic and neutral water–alcohol mixtures. In alkaline media and when OH– was the nucleophile, the known hydrolysis reaction in which OH– attacks the SO2 group was observed; this reaction was first order in both OH– and MNTS. In the presence of ammonia, hydroxylamine, hydrazine, or primary, secondary or tertiary amines, a transnitrosation reaction took place in which the additional nucleophiles attacked the nitrogen atom of the MNTS NO group; this reaction was first order in both MNTS and free amine. In particular, MNTS proved to be as efficient as some alkyl nitrites for the nitrosation of secondary amines in neutral or alkaline media, in which conventional nitrosating agents do not exist. Similar reaction rates were observed for the more basic tertiary amines (which gave NO2– among the final products). Primary amines underwent rather slower reactions, with the exception of hydroxylamine and hydrazine, the nucleophilic nature of which is increased by the α effect. We discuss the relative reactivities of the various amines in terms of their basicity and vertical ionization potentials, and we report the effect of the proportion of alcohol in the medium on the rates of both hydrolysis and transnitrosation reactions.

It is shown that it is possible to obtain good data for the rate constant for the decomposition of alkoxy radicals [RO] by using nitric oxide as a radical trap. Two experimental systems have been used. The first system involves the use of dialkyl peroxides [(RO)2] as thermal sources of alkoxy radicals. The peroxide concentration was ∼10−4M, nitric oxide ∼2 × 10−4M, and the extent of reaction was ∼10%. The total pressure was altered using carbon tetrafluoride as an inert gas. The mechanism is Hence R2/R3 = k2[NO]/k3. Our previous studies show that k2 lies in the range 1010.3±0.2M−1·sec−1. The second system employs alkyl nitrites [RONO] as a thermal source of alkoxy radicals. The experimental conditions are very similar, except that we chose to use an atmosphere of nitric oxide for initial experiments. If anything nitric oxide appears to be superior to carbon tetrafluoride as an energy transfer agent. The mechanism is Hence R3 = k1'k3[RONO]/(k3 + k2 + k6 [NO]). Results are given for R = t-Am, s-Bu, t-Bu, i-Pr, Et, and Me. In addition the first unequivocal evidence is given for the pressure dependence of k3 when R = t-Bu. The implications for atmospheric chemistry and combustion are also discussed.

Durch Umsetzung von primaren oder sekundaren Bromalkanen und 2-Bromcarbonylverbindungen mit Tetraalkylammoniumnitriten 1 in Dichlormethan oder Acetonitril bei -50 bis 200C erhalt man die Nitroverbindungen 2, 5 und 7. Das Nitroalkan/Alkylnitrit-Verhaltnis (2/3) in verschiedenen Losungsmitteln wird an der Umsetzung von 1-Bromheptan mit dem Salz 1auntersucht. 1,1'-(1,3-Phenylen)dipyrrolidin (6) eignet sich zum Abfangen der Alkylnitrite 3. Synthesis of Nitro Compounds from Tetraalkylammonium Nitrites Primary or secondary bromoalkanes and 2-bromo carbonyl compounds give the nitro derivatives 2, 5 and 7 on reaction with tetraalkylammonium nitrites 1 in dichloromethane or acetonitrile at -50 to 200C. The ratio of nitroalkane and alkyl nitrite (2/3) in the reaction of 1-bromoheptane with the salt 1a in various solvents is investigated. 1,1'-(1,3-Phenylene)dipyrrolidine (6) is a good scavenger for alkyl nitrites.

Thiols, such as glutathione and cysteine, are mutagenic in the Ames test, using Salmonella typhimurium strain TA 100 and rat kidney S-9 preparation [Glatt et al. Science220, (1983)]. Formation of thiyl free radicals, RS., has been implicated in this effect. We have prepared thionitrite (nitrosylmercaptan) derivatives of glutathione and other thiols. These unstable derivatives decompose by homolysis, yielding RS. radicals. Glutathione thionitrite is mutagenic to strains TA 100 and TA 102, in the absence of activation by mammalian S-9 preparations. We suggest that this mutagenicity is evidence for the role of thiyl free radicals as biological reactive intermediates. Since alkyl nitrites readily convert thiols to thionitrites, our findings have implications for the toxicology of nitrosating drugs, such as amyl nitrite.

The heats of formation of C3 and C4 alkyl nitrites (RONO) have been determined via their heats of combustion by bomb calorimetry, thereby providing a complete set of values of ΔHof for C1-C4 alkyl nitrites. The experimental values are in excellent agreement with values derived from group additivity rules. For branched compounds these calculations involve corrections for gauche interactions. In these cases, the gauche interactions are reflected in the activation energies E1 determined by recent kinetic studies, required for breaking the RO-NO bond. The heats of formation of the alkoxy radicals involved together with ΔHof(NO) = 21.6 kcal/mole leads to the result D(RO-NO) = 41.5 ± 1 kcal/mole. The concordance between D(thermochemical) and D(kinetic), unlike previous kinetic studies, implies that E2 = 0 ± 1 kcal/mole.

The main primary photochemical process for alkyl nitrites is fission to nitric oxide and alkoxy radicals, a proportion of which may be sufficiently excited to decompose spontaneously. The photolysis of t-butyl, of isopropyl and of ethyl nitrite at 254 nm, in the gas phase, each yields nitrosomethane and an aldehyde or ketone. The overall reaction, in presence of nitric oxide, corresponds to: where R′ and R″ are either H or CH 3 . The dependence of the quantum yield of nitrosomethane and of other products on the pressure of alkyl nitrite, of nitric oxide and of other added gases was investigated to seek confirmation of the excited alkoxy mechanism, to determine primary yield and to obtain information about the deactivation of excited radicals. The results for t-butyl nitrite fully confirm the excited alkoxy mechanism. A value of 0.87 is derived for the quantum yield of t-butoxy radicals sufficiently excited to undergo decomposition, in excellent agreement with a previous estimate. The results for ethyl nitrite also support the excited alkoxy mechanism, with the quantum yield of excited ethoxy radicals estimated to be 0.45. The results for isopropyl nitrite differ in several respects from those for the other two systems. A contribution from a primary process involving an intramolecular rearrangement to nitrosomethane and acetaldehyde cannot be excluded, although an alternative explanation in terms of an excited alkoxy mechanism is suggested.

A detailed comparison between the dynamics of photodissociation of (CH3)3CONO from its first two excited singlet states is presented. The fragmentation processes are studied by exciting the molecule at 365.8 and 351.8 nm [S1(nπ*)←S0 transition] and at 250 nm [S2(ππ*)←S0 transition] and probing the NO fragment by single photon laser induced fluorescence combined with polarization and sub‐Doppler spectroscopy. The μ, v, and J vector correlations, Λ‐doublet and spin–orbit populations, and the vibrational, rotational, and translational energy content of the NO fragment are determined. The scalar and vectorial properties point on different mechanisms of fragmentation from the S1 and S2 states, but both are highly selective. The findings of this study, especially those concerning the less studied S2 state, can be utilized to predict the behavior of other alkyl nitrites and demonstrate the power of the techniques mentioned above in characterizing the dynamics of photodissociation, even for large molecules.

The decomposition of methyl nitrite has been investigated from 0.005 to 5.0 cm in the temperature range 210–240°C. In this region the rate falls off steadily with diminishing pressure. The reaction is appreciably heterogeneous at the lower pressures. The results are in satisfactory agreement with the previous observations of Steacie and Shaw at higher pressures. The fallingoff in rate with decreasing pressure is satisfactorily accounted for by the Rice‐Ramsperger theory, assuming 13 degrees of freedom and a molecular diameter of 5.0×10—8 cm.

Aqueous potassium pentacyanocobalt(II), K3Co(CN)5, reacts immediately under nitrogen with α-substituted nitrosoparaffins and more slowly with nitro-olefins and α-halogenated nitroparaffins to give alkyl pentacyanocobalt(III) nitroxide radical-anions, {(NC)5Co–NR–O·}3–, detectable by their e.s.r. spectra which are listed and discussed. These radical-anions are unstable; under nitrogen they disappear within a very few hours and rapidly on exposure to air. Simpler nitroparaffins give similar but transient spectra on treatment with K3Co(CN)5 plus NaBH4. Aqueous K3Co(CN)5 reacts rapidly with alkyl nitrites and nitric oxide, and slowly with sodium nitrite, to give red, diamagnetic {(NC)5Co–NO}3–which by reduction gives a radical-anion thought to be {(NC)5Co–N–Ō}4–. If cyanide ions are present in excess, or are added initially, alkyl nitrites and some C-nitroso-compounds yield a radical-anion thought, from its e.s.r. spectrum, to be {(NC)5Co–N(CN)–O·}3–, nitrosyl cyanide being the probable precursor. With excess of K3Co(CN)5 the α-halogenated α-nitroso- or nitro-paraffins slowly give secondary radical-anions which have larger aco hyperfine splittings than those first formed: these are stable in air. Two series of e.s.r. spectra have been obtained from nitrolic acids (α-nitro-oximes); both show splittings due to one 59Co and two 14N atoms. These radical-anions are stable in air. No e.s.r. spectra have been obtained from N-nitrosamines. E.s.r. spectra of the stable nitroxides, R2NO·, from the nitroso-compounds examined are listed.