Search

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.

The infrared and ultraviolet spectra of 15 alkyl nitrites were studied in the gaseous state. In the infrared, the O–N=O group is characterized by very strong absorption in the three regions 600, 800, and 1650 cm−1, corresponding to O–N=O bending, N–O stretching, and N=O stretching frequencies, respectively. The doubling of the characteristic frequencies and the temperature dependence of the bands of methyl nitrite are explained by rotational isomerism, which appears to be a general property of alkyl nitrites. The influence of the length, shape, and kind of the carbon chain on the frequencies and intensities of the characteristic bands has been studied. The intensity variation of the νN=O bands strongly suggests that the relative abundances of the two isomers vary widely from primary to secondary and tertiary nitrites, but depend only to a small extent upon the length and shape of the carbon chain. Application of this property to the diagnosis of primary, secondary, or tertiary alcohols is suggested.The uv...

Summary A titrimetric method for the determination of primary aromatic amines and compounds containing a reactive methylene group by diazotisation and C-nitrosation respectively is described. The endpoint is detected potentiometrically with a platinum indicator electrode. The advantages of standard alkyl nitrite solutions over alkali metal nitrites is discussed.

It has already been shown that the first three straight chain members of the nitrite homologous series, i. e ., methyl, ethyl, and n -propyl nitrites, have exhibited in their thermal decomposition the characteristics pertaining to homogeneous unimolecular reactions. This paper deals with the investigation carried out on iso -propyl nitrite decomposition. This member of the series is particularly interesting as it allows comparison to be made between a straight-chain and a branched-chain isomer. The effect of these chemical configurations on the activation energy and the decomposition rates can be very effectively studies as no complications enter into the reactions to confuse measurements. Experimental Reaction velocities were measured as before by observing the rate of pressure change in a system at constant volume. The reaction vessels were Pyrex glass bulbs with a capacity of about 125 cc. The apparatus was similar to that used in previous experiments. The connecting tubing was heated to 105° C to prevent any of the products of the reaction condensing out. Control and measurement of the temperature was carried out as before. The temperature could be maintained constant to within 0·25° C.

A technique for studying rapid chemical exchange and reorientation reactions by nuclear magnetic resonance techniques is discussed. A treatment for the general case relating the changes in the proton line width with changes in the frequency of rotation about the O–N bond in the alkyl nitrites is developed. Such a treatent gave fairly accurate potential energy barriers to rotation for methyl, ethyl, n‐propyl, and isopropyl nitrite. A temperature controlling device for low temperatures applicable to proton resonance techniques is discussed.

A series of alkyl nitrites and nitrosamines has been investigated by means of NMR. As a result of the solvent effects and steric hindrance effects, it was found necessary to reverse the assignments of the cis and trans isomers made by previous workers. Also, there is some question that the kinetic phenomenon in these compounds is indeed internal rotation.

The proton magnetic resonance spectra of several alkyl nitrites were investigated over the temperature range −100° to 20°. At temperatures less than −55°C the rate of rotation about the ON bond is reduced to less than about 160 sec−1 and the separate resonances for the CH2ONO protons of the cis- and trans-forms have been observed. Cis/trans isomer ratios are presented for −100° and 20°, the cis-isomer slightly predominating over the trans for this temperature range. ΔH for the trans → cis conversion is shown to be −130 cal, and the free energy of activation for reorientations about the ON bond is estimated to be 10 kcal. Ratios of infrared absorption coefficients for the cis- and trans-isomers were determined by combining infrared optical density ratios and nmr isomer ratios.

Acryl radicals combine with nitroso compounds to give acyl-alkyl-nitroxides, which are identified by their ESR spectra. The acyl radicals are generated by oxidation of aldehydes with suitable hydrogen-acceptors such as t-butoxy radicals or by intermediates obtained int he photochemical and thermal decomposition of nitroso compounds. During photolysis of alkyl nitrites in hydrocarbon solvents the acyl-alkyl-nitroxides appear also and this is explained on the basis of known reactions of alkyl nitrites and their decomposition products.

The decomposition of n‐butyl nitrite has been investigated from 5 to 40 cm pressure in the temperature range 170 to 212°C. The reaction is homogeneous and first order. The mechanism is, in the main, the same as with the lower members of the series. The reaction is, however, complicated by the formation of condensation products and the results are therefore less accurate than those obtained with the lower members of the series. The activation energy is approximately the same as those of the other nitrites. The velocity constant at 189.9°C is 8.88×10—4 sec.—1, as compared with 0.97 for methyl, 1.89 for ethyl, and 3.95 for n‐propyl nitrite.

Die N.N′-disubstituierten 1.5-Benzodiazepin-dione 1 reagieren nicht mit HNO2 oder Alkylnitriten. Ihre Na-Salze 6 lassen sich hingegen mit Brom, Chloramin und Tosylazid leicht umsetzen. Aus den mit Tosylazid aus 6 oder durch Diazotierung der 3-Amino-1.5-benzodiazepindione 3 dargestellten 3-Diazo-Verbindungen 12 erhalt man 3-Halogen-, 3-Hydroxy-, 3-Alkoxy-und 3-Acetoxy-1.5-benzodiazepin-2.4-dione. Die Salze 6 ergeben bei der Acylierung mit Benzoylchlorid die Benzoyloxybenzyliden-1.5-benzodiazepin-dione vom Typ 14. Benzodiazepines with Psychotropic Activity, VI1). – Reactions of N,N′-Disubstituted 1,5-Benzodiazepine-2.4-diones in Position 3 Whereas N,N′-disubstituted 1,5-benzodiazepinediones 1 do not react with HNO2 or alkyl nitrites, their sodium salts 6 easily react with bromine, chloroamine and tosyl azide. The 3-diazo compounds 12 obtained from 6 with tosyl azide or by diazotization of 3-amino-1,5-benzodiazepinediones 3 yield 3-halo-, 3-hydroxy-, 3-alkoxy- and 3-acetoxy-1,5-benzodiazepinediones. With benzoyl chloride 6 yields benzoyloxybenzylidene-1,5-benzodiazepinediones of type 14.

Studies of the photo‐ionization of the methyl, ethyl, propyl, and isopropyl radicals are reported. The radicals were prepared by pyrolysis of the appropriate alkyl nitrites, tetra‐alkyllead compounds, and the dialkylmercury compounds. Secondary processes occurring in the energy range covered (7.2–11.7 ev) are discussed.The appearance potentials for the methyl, ethyl, propyl, and isopropyl radicals, as measured by photo‐ionization—mass spectrometric techniques are 9.82±0.04, ≤8.4, ≤8.1, and ≤7.5 ev, respectively. The adiabatic transition is accessible for the methyl radical only. Hence, the ionization potential of the ethyl, propyl, and isopropyl radicals cannot be determined by ordinary photon or electron impact experiments.

A general discussion is given of the rate of unimolecular decomposition of an homologous series of compounds from the point of view of the Kassel theory. The experimental evidence is discussed with special reference to the decomposition of the alkyl nitrites. It is concluded that existing theories are unable to account for the progressive increase in rate as one ascends the homologous series.

The kinetics of the decomposition of ethyl and n‐propyl nitrites have been investigated at low pressures. The results, together with those for the other members of the nitrite series, are discussed from the point of view of the Kassel theory. Attention is focused particularly on the effect of increasing molecular complexity as one ascends an homologous series, since the nitrites furnish an ideal series for such a discussion. It is concluded that the Kassel theory furnishes a complete explanation of the facts insofar as the effect of pressure on the rate is concerned. On the other hand, there is no satisfactory quantitative explanation of the increase in the high pressure rate with increasing molecular complexity. The factors which might contribute to such an increase are discussed, and it is concluded that the main factor is probably a progressive change in binding energy as one ascends an homologous series.

The dipole moment measurement was made at various temperatures on ethyl, i-propyl and t-butyl nitrites. Observed moments are 2.41D for ethyl, 2.57D for i-propyl, 2.70D for t-butyl nitrite at room temperature. The moment of the latter two compounds decrease slightly with temperature while ethyl compound remains constant. These esters are considered to consist of two isomers: the trans and the cis separated by a barrier of several kcal. due to a resonance effect. The energy difference ΔE between the two isomers is found to be zero in ethyl

The dielectric constants of liquid methyl, n‐propyl and isopropyl nitrite have been measured over an extensive range of temperature and the results used to estimate the relative abundances of the trans and cis isomers. It is concluded that the trans form predominates in all three liquids, in contradiction, in the case of the propyl nitrites, to the conclusions from recent NMR studies. It is suggested that the assignments to the appropriate NMR peaks should be reversed for the higher alkyl nitrites. Dielectric relaxation in n‐propyl nitrite was found to be of the asymmetrical Cole‐Davidson type.

New microwave results confirm Brown and Hollis' trans-cis assignment for alkyl nitrites. In the present paper, the experimental material is widened by investigating compounds of the type XCH2CH2ONO where X = F, Cl, Br, I, CN. The barrier to trans-cis conversion is fixed to ca. 10 kcalmole−1 in all cases. Likewise, Ecis - Etrans is close to 1 kcalmole−1, and Scis - Strans ∼ 2 gcalmole−1 deg−1. Rotation about the C,C bond generates 3 isomers, 2 in which X is gauche, and 1 in which X is trans to the ONO group. By measuring proton chemical shifts and proton spin-spin couplings at room temperature where effective averaging over rotations about the C, O single bond and the ON single bond takes place, it is shown that the gauche forms are more abundant than statistics would indicate ( 2 3 ). Since the same gauche:trans ratio is observed in the case X = F for the pure trans (O,N) form at −70°C, we conclude that gauche preference also applies to the cis isomer. This rules out the idea of some intramolecular bond between non-neighbouring atoms, stabilizing the cis isomer. The new compounds X = F, Br, I, CN are characterized by their infrared spectra.

A time‐of‐flight mass spectrometer with a source of effectively monoenergetic electrons has been utilized to determine the ionization potentials and ionization‐efficiency curves of the stable compounds benzene, toluene, triethylamine and of the free radicals, methyl, ethyl, n‐propyl, and isopropyl. The appearance potentials in electron volts observed for the stable compounds were C6H6: 9.20, 9.40, 9.65; C6H5CH3: 8.80, 9.20, 9.50; (C2H5)3N: 7.68, 8.18, 8.55, 8.95, 9.40. Published values for the appearance potentials by electron impact of these compounds tend to converge upon one of the higher values observed in this work.The radicals were produced by thermal—catalytic decomposition of appropriate alkyl nitrites, isopropyl ether, and isobutane. Appearance potentials (electron volts) determined for the free radicals were as follows: methyl—9.80, 10.3, 10.7, 11.4; ethyl—8.25, 8.7, 9.3; n‐propyl—8.15, 8.6, 8.8, 9.2, 9.6; isopropyl—7.52, 8.1, 8.6. The measured ionization potentials of methyl, ethyl, and propyl ...

It is of considerable interest to investigate the homogeneous unimolecular decomposition of a series of related chemical compounds. The only series so far investigated is that of the aliphatic ethers. On account of their simplicity, low boiling points, and lack of stability, the alkyl nitrites appeared to be worth investigation. The present paper deals with the first member of the series, viz., methyl nitrite. As will be shown, the decomposition of this compound is, in fact, homogeneous and unimolecular. Experimental Procedure Reaction velocities were measured in the usual way by observing the rate of pressure change in a system at constant volume. The reaction vessels were pyrex bulbs having a capacity of about 125 cc. The apparatus was similar to those used in a number of previous investigation. The required temperatures were obtained by the use of a well-stirred oil bath, heated electrically. Temperatures were measured with standard mercury thermometers. The temperature could be maintained constant to within 0·25° C.

Steacie and Shaw have made a study of the thermal decomposition of a series of alkyl nitrites at temperatures between 170° and 240°. Their results are contained in the series of papers to which reference is made; but of these only the first is at present significant, for in it they consider the decomposition of methyl nitrite, and give their reasons for the conclusions which they arrive at regarding the nature of the decomposition process, which they assume to be common to the whole series. Their results led them to the conclusion that the decomposition process proceeds in accordance with the equation, 2CH 3 NO 2 = CH 2 O + CH 4 O + 2NO, (1) the process being of the first order. Assuming that this was so, the critical increment calculated from the temperature coefficient was found to be 36⋅4 kcals. If the decomposition process really does take place in accordance with the equation written above, the conclusion that the process is uni-molecular is confusing rather than helpful. It appeared possible that a study of the problem by methods more detailed than that applied by Steacie and Shaw might throw further light upon it, and with that object in view the present work was undertaken.

Photolysis of 1-pentyl and menthyl nitrites in the presence of oxygen were shown to give mainly the oxidized rearrangement products 4-nitratopentyl and 10-nitratomenthyl derivatives in disagreement with the published report (2). Under the photo-oxidation conditions, menthyl nitrite also gave 10-nitrosomenthyl derivatives which were also shown to be photo-oxidized to 10-nitratomenthyl derivatives. The photo-oxidation products were conveniently reduced to the corresponding diols and were, in turn, identified as bisbenzoate.

Irradiation of 3-substituted 2-nitrosoimino-2,3-dihydrobenzothiazoles (I) with a medium pressure mercury lamp gave bis[o-(N-substituted cyanamino)phenyl] disulfides (III) in high yields. Irradiation of 4,5-diphenyl-2-nitrosoimino-2,3-dihydrothiazole (VI) gave bis[(2-phenyl-2-N-phenylcyanamino)vinyl] disulfide (VIII). The photolysis was shown to be due to the π-π* excitation from the results of specific irradiation to π-π* and π-π* bands. The relative rates of photolysis of 2-nitrosoimino-3-phenyl-2,3-dihydrobenzothiazole (Ia) were measured in several solvents. The mechanism has been discussed in connection with that in alkyl nitrites and nitrosamines.

Cysteine reacts quite rapidly with isopentyl, isopropyl, and t-butyl nitrite in water at 25 °C in the pH range 6–13 to give the somewhat unstable S-nitrosocysteine. Rate measurements show clearly that reaction occurs exclusively via the RS– species. Plots of the measured second-order rate constants against pH are in excellent agreement with the calculated curves, for all three alkyl nitrites, and the order of reactivity is (CH3)2CHCH2CH2ONO: (CH3)2CHONO:(CH3)3CONO 16:6.7:1. The methyl ester of cysteine behaves similarly whereas S-methylcysteine does not form the thionitrite. The results suggest that the reaction involves a direct electrophilic nitrosation by the alkyl nitrite itself at the sulphur site in RS–. The conclusions are discussed in terms of steric effects and of the other known reactions of alkyl nitrites.

Mass spectra of seven N-nitrosamines and five alkyl nitrites, the O-nitroso compounds, have been obtained by low pressure negative chemical ionization with CO2 as reagent gas. Intense anions were observed at m/z M−32 for N-nitrosamines and at m/z M−30 for alkyl nitrites. Addition products were found at m/z M+12 and M+43 for N-nitrosamines and at m/z M+14 for alkyl nitrites. By using isotopically labeled CO2, it could be shown that the anions at m/z M+12, M+14 and M+43 correspond to [M - H2NO + CO2 −, [M − NO + CO2]−, and [M − H + CO2]−, respectively.

The effect of the aliphatic alcohols methanol, ethanol, propanol, isopropanol, 2-butanol, isobutanol, and tert-butanol on the rate of nitrosation of morpholine at pH 3 and 25 °C has been studied. The inhibition observed is attributed to the formation of alkyl nitrites, which are poor nitrosating agents in acid media. The equilibrium constants for the formation of alkyl nitrites from nitrous acid and alcohols have been calculated both spectrophotometrically and from kinetic data for the inhibitory effect, and there is agreement between the two sets of results. The molar absorptivities at 265 nm of the alkyl nitrites have also been determined. When the concentration of alkyl nitrite is very low, a slight catalytic effect considered to be an effect of the medium has been observed.

1. 2,4,6-Trisubstituted phenols react with alkyl nitrites by a radical mechanism. 2. The direction of the reaction depends on the stability of the phenoxyl radicals which are formed as intermediates.

Tributyl phosphate extracts nitrous acid almost quantitatively from aqueous solutions./The spectrum, from 320 to 400 m mu , shows the enhanced fine structure characteristic of molecular nitrous acid and of alkyl nitrites. Distribution data indicate a 1: 1 complex, STABu/sub 3/PO/sub 4/,HO NO!, and infrared spectra that the hydrogen-bonding to the phosphoryl-oxygen atom modifies the bonding in nitrous acid toward an ionic structure. (auth)

Conclusions1. The pharmacology of the higher alkyl nitrites has been investigated. 2. The relationship between molecular weight, vapor pressure and depressor response is demonstrated. 3. Certain theoretical considerations of the desiderata in physical properties necessary for depressor response are discussed.