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The crystal structures of two endo-endo-dienes, 5,6,7,8,9,9-hexachloro-1,4,4a,5,8,8a-hexahydro-endo-endo-1,4-ethano (and propano)-5,8-dimethanonaphthalene, 1band 1chave been determined. These, together with the methano-homolog 1a(of known structure), are shown to exhibit decreasing across-space double-bond/double-bond repulsion which correlates with the observed decrease in the ease of cyclization in solution.

The changes in the ultraviolet absorption spectra of aliphatic ketones in aqueous sulphuric acid have been followed as the acid strength is increased from 0 to 98%. With increase in strength up to 65% the weak peak at about 270 mμ is shifted to shorter wavelengths by a medium effect. However, with further increase in acid strength the peak disappears altogether because of protonation of the carbonyl group. The pKBH+values of several ketones have been calculated from the spectrophotometric results to be about −7. The pKBH+values of cyclic ketones vary systematically with ring size. The significance of the present work to recent studies on the rate of enolization of acetone is discussed.

The basicities of benzamide and of 11 meta- and para-substituted benzamides in sulphuric acid media have been determined by a spectrophotometric method. The values of the protonated benzamides were found to be proportional to the Hammett σ constants for the substituents, unlike the values of the protonated benzaldehydes, acetophenones, and benzoic acids, which are approximately proportional to σ+constants. The lack of conjugation between the protonated amide group and the ring, which is indicated by these results, is most easily interpreted in terms of N-protonation although O-protonation cannot be completely excluded. Various other aspects of the problem of N- versus O-protonation are also discussed.

The Beckmann rearrangement of the oxime of A-nor-5β-cholestan-3-one gave 4-aza-5β-cholestan-3-one; the isomeric lactam obtained by the reduction of the oxime of 5-oxo-3,5-seco-A-norcholestan-3-oic acid with sodium in alcohol must consequently be 4-aza-5α-cholestan-3-one. Other methods of reducing the oximino acid afforded hydroxamic acids. 4-Aza-5α- and 4-aza-5β-cholestane were obtained by reduction of the appropriate lactam or hydroxamic acid.

The oxidation of A-nor-5β-cholestan-3-one with peracids gave 4-oxa-5β-cholestan-3-one. This was identical with one of the two lactones produced by the reduction of Windaus' keto acid; the other lactone must be 4-oxa-5α-cholestan-3-one. The two lactones were reduced by lithium aluminum hydride to diols, which were cyclized to 4-oxa-5α- and -5β-cholestane.

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The ionization in aqueous sulphuric acid of thiolactams consisting of five-, six-, and seven-membered rings has been studied. With increasing concentration of acid the ionization ratio increases more rapidly than h0. A possible explanation involving the hydration of the thio-lactam is given. Changes in the basicity of thiolactams with ring size parallel changes previously found for lactams.

9-Methylhydrindan-1-one was obtained as a mixture (80% trans, 20% cis) in four steps from 10-methyl-Δ1,9-octal-2-one. In the presence of alkali it epimerized to cis-9-methylhydrindan-1-one containing less than 1% of the transisomer. Oxidation of this cisketone with peroxytrifluoroacetic acid gave cis-1-oxa-10-methyldecal-2-one.

The influence of the acidity of the solvent on the proportions of axial and equatorial alcohols obtained by hydrogenation of some steroidal ketones was investigated.

The configurations at the 3 positions of 3β-hydroxy-4-oxa-5α-estrane and of 3α, 17β-dihydroxy-4-oxa-5α-estrane were assigned from a study of the anomerizations of these compounds in aqueous tetrahydrofuran. 3α-Chloro-4-oxa-5α-estrane solvolyzed in alkaline methanol to give a mixture of 3α- and 3β-methoxy-4-oxa-5α-estrane, the former predominating. The difference in the solvolytic behavior of 3α-chloro-4-oxa-5α-steroids and of α-glycosyl halides is discussed.

The chemical shift of the methyl protons relative to the methylenic protons of an ethyl group attached to a basic center increases with the acidity of the medium. This increase may be attributed to two effects: over a relatively narrow range of acidity function (H0) values, to protonation of the basic center; over the complete H0range investigated, to a general solvent effect, which may be due to changing strengths of hydrogen bonds between the basic center or its conjugate acid and solvent water molecules. Protonation constants of −1.1 for propionamide and −6.9 for propionic acid have been calculated, in good agreement with values obtained by the ultraviolet spectrophotometric method; the constants calculated for diethyl ether (−6.2) and ethanol (−4.8) are much less certain, because of the greater magnitude of the solvent effect with these compounds.

Protonation constants (pKBH+) of −6.8 and −0.9 have been determined for propionic acid and propionamide, respectively, from measurements of their ultraviolet absorption in various concentrations of sulphuric acid. The ionization ratio of propionamide and of other amides increases more slowly than the Hammett acidity function, h0, with increase in acid concentration. This may be explained by assuming that in a given concentration of sulphuric acid the protonated amide is more heavily hydrated than the protonated Hammett indicator used to establish the h0scale for this region of acid concentrations.

In inert solvents in the presence of aluminum chloride, aroyl peroxides decompose to esters and carbon dioxide. In highly nucleophilic solvents such as anisole or mesitylene, p,p′-dinitrobenzoyl peroxide effects a Friedel–Crafts type of substitution of the solvent molecule. Both decomposition and substitution reactions probably depend on a heterolytic fission of the peroxide linkage catalyzed by aluminum chloride.

The α- and β-anomers of 3-methoxy-, 3-isopropoxy-, 3-cyclohexyloxy-, and 3-phenoxy-4-oxa-5α-cholestane were separated by chromatography on alumina. The configurations of the anomers were assigned from a consideration of their optical rotations. Acid-catalyzed equilibration of the 3-alkoxy anomers favored formation of the axial isomer, the proportions of α- to β-forms being about 7:3. 2α-Phenoxy-4-oxa-5α-cholestane in acid solution was in equilibrium with phenol and 4-oxa-5α-cholest-2-ene.

Optimum conditions for obtaining arylalkyl ethers from the reactions of aryl-lithium or -magnesium compounds with dialkyl peroxides have been investigated. The reactions are considered to take place by ionic or four-center mechanisms.

The ionization ratio of thioacetamide in aqueous sodium hydroxide, determined spectrophotometrically, is proportional to the concentration of hydroxide ion up to a concentration of about 1 M, and indicates a pKHAof 13.4. For more concentrated solutions the ionizing power increases more rapidly than the hydroxide ion concentration; from the experimentally determined ionization ratios the values of the h−acidity function for 1–6 Msodium hydroxide have been calculated. The relation of h−values to the salting-out parameters and water activities of concentrated sodium hydroxide solutions is discussed.

Catalposide extracted from the unripe fruit of Catalpaovataaffords bisdesoxyaucubin on reduction with lithium in liquid ammonia. The reduction is accompanied by the shift of a double bond. From this and other evidence, two possible structures are proposed for the compound.

4-Oxa-5α-cholestan-3α-ol was prepared by reduction of 4-oxa-5α-cholestan-3-one with lithium aluminum hydride. It showed several typical carbohydrate reactions, such as mutarotation in aqueous tetrahydrofuran and condensation with alcohols in the presence of hydrogen chloride to give 3-alkoxy-4-oxa-5α-cholestanes. These compounds were also prepared by the reaction of alcohols with 3α-chloro-4-oxa-5α-cholestane in the presence of base. Factors governing the proportions of 3α and 3β isomers formed in these reactions are discussed.

Studies of the ultraviolet absorption of dilute aqueous solutions of lithium, sodium, potassium, and ammonium sulfates show that the concentration of sulfate ion in the presence of univalent cations can be determined from the optical density of the solution at 190 mμ. The concentrations of sulfate ion thus determined in dilute solutions of sulfuric acid are in agreement with values reported previously from Raman spectral, conductivity, and other studies, which indicate a dissociation constant K2 = 0.01 for the second stage in the ionization of sulfuric acid.

Strychnine N-oxide (8; X = H) reacts with sulfur dioxide in benzene to form the sulfitoamine 9(X = H), which rearranges in boiling water to the substituted sulfamic acid 10(X = H) by a free-radical mechanism. The sulfamic acid 10(X = H) is also formed by reaction of strychnine N-oxide with cold aqueous sulfur dioxide, and may be an intermediate in the reduction of the amine oxide by sulfur dioxide in hot water. With aqueous sulfur dioxide at 0°, N,N-dimethylbenzylamine N-oxide gives tertiary amine by reduction and secondary amine and aldehyde by a Polonovski-type reaction; however, N,N-dimethylaniline N-oxide gives tertiary amine, o- and p-dimethylaminobenzene sulfonic acids, but no appreciable amount of secondary amine. The sulfonic acids are probably formed by a free-radical mechanism, since their formation is largely suppressed by the addition of hydroquinone. The reactions of hydroxylamine and of β-phenylhydroxylamine with sulfur dioxide in water have also been studied.

The kinetics of the transformation of benzonitrile oxide in dilute sulfuric acid into benzohydroxamic acid have been followed by u.v. spectrophotometry at a temperature near room temperature. A mechanism is proposed on the basis of the effects of substituents and sulfuric acid concentration.The rate profile for the hydrolysis of benzohydroxamic acid in hot dilute sulfuric acid has been obtained.The results of these studies are applied to the detailed mechanism of the Meyer rearrangement – hydrolysis of phenylnitromethane in acid.

The rate-acidity profiles for the Meyer rearrangement–hydrolysis of phenylnitromethane in sulfuric, perchloric, and hydrochloric acid show a maximum near 3 Macid. Ring-substituted phenylnitromethanes also show a maximum in their rate profiles, at slightly different acid concentrations. These maxima arise because the slow formation of the aci-form is followed by two competing reactions: fast tautomerization back to the nitro-form, and fast rearrangement–hydrolysis to the Meyer products. The rearrangement is rate-limiting in dilute acid and is acid-catalyzed, causing the rate increase. In more concentrated acid, the rate-limiting step is the nitro to acitautomerization, which is not acid-catalyzed, and which goes more slowly as the activity of water decreases.The tautomerization was studied by means of primary and solvent deuterium isotope effects, and was found to occur through proton abstraction by water, through a transition state closely resembling the products.

Phenyl-aci-nitromethane reacts in aqueous sulfuric acid at room temperature to form phenylnitromethane and benzohydroxamic acid. The relative amounts of these two products depend on the concentration of the acid. Benzohydroxamic acid is formed by reaction of the intermediate, benzonitrile oxide, with water.Solvent effects, substituent effects, and isotope effects have been studied to determine mechanisms for these reactions of phenyl-aci-nitromethane.

Amine oxides, azoxybenzenes, and nitrones are deoxygenated in good yields by iron pentacarbonyl in hot butyl ether. Substituted nitro- and nitrosobenzenes are reduced under these conditions to azo and/or amino compounds, depending on the nature and location of the substituents; some evidence for nitrene or nitrene-like intermediates in these reactions is presented.

The supposed 5-phenyl-2,4-dithiohydantoin (3) actually exists as its tautomer 5-mercapto-4-phenyl-4-imidazolin-2-thione (12). The reactions of the compound have been clarified by spectral studies of the products; in particular, mono- and dibenzylation have been shown to take place on sulfur and not (as reported) on nitrogen.

The acid and base dissociation constants of 5,5-pentamethylene-4-thiohydantoin, 5,5-pentamethylene-2,4-dithiohydantoin, and their 1-methyl derivatives, have been determined by ultraviolet studies in basic and acid media. In aqueous sulfuric acid the 4-thiohydantoins are protonated on oxygen at the 2-position, so that the extent of protonation varies with the HAfunction of the acid solution, while the 2,4-dithiohydantoins are protonated on sulfur at the 2-position, so that the extent of their protonation varies with H0′′′. The importance of using acidity functions appropriate to the different types of compounds when comparing their basicities is emphasized.

Acylation of 5,5-diphenylimidazolid-4-one gives 1,3-diacyl-5,5-diphenylimidazolid-4-ones, and not 2-acyl-4,4-diphenyl-2,5-diaza-7-oxabicyclo[3.2.0]heptan-3-ones as claimed by Biltz and his co-workers. The reason for the unusual stability of the N1-acyl groups to acid and alkaline hydrolysis is discussed. The revised formulation allows the oxidation products of 1-acetyl-5,5-diphenylimidazolid-4-one to be rationalized in a simple fashion.

Photolysis of ethyl diazoacetate and of ethyl diazomalonate in acetonitrile gave oxazoles. Photolysis of ethyl diazoacetate in the presence of benzophenone gave an oxazoline incorporating the elements of carbethoxymethylene. benzophenone, and acetonitrile. Photolysis of ethyl diazomalonanilate gave 5-ethoxy-2-methyl-4-phenylcarbamoyloxazole, 5-ethoxy-3-methyl-4-phenylcarbamoylisoxazole, and ethyl α-hydroxymalonanilate. With 2537 Å wavelength radiation the oxazole was formed predominantly; on the other hand, with benzophenone-sensitization, the isoxazole was formed (among other products) but no oxazole. The oxazole was isomerized to the isoxazole when irradiated in the presence of a sensitizer, while the isoxazole was isomerized to the oxazole when irradiated with radiation of 2537 Å wavelength. A tentative mechanism is advanced to explain formation of the different products.

Ethyl diazomalonanilate was photolyzed in three alcohols (methanol, ethanol, and isopropanol) to produce the corresponding ethyl α-alkoxymalonanilates, ethyl alkyl α-N-phenylaminomalonates, and ethyl malonanilate. Thermolysis of the diazoanilide in ethanol and isopropanol yielded the same products as photolysis, but in lower yields. The yield of ethyl malonanilate increased with benzophenone sensitization.Photolysis and thermolysis of 5-hydroxyl-1,4-diphenyl-1,2,3-triazole in isopropanol produced α-isopropoxy-α-phenylacetanilide, isopropyl α-N-phenylamino-α-phenylacetate, and 2,5-diketo-1,3,4,6-tetraphenylpiperazine.Possible mechanisms for the decomposition of both compounds are discussed; an α-lactam may be an intermediate in the formation of the α-N-phenylamino esters.

The methylation product of 5,5-pentamethylene-2-thiohydantoin has been shown by u.v. and i.r. spectral studies to exist predominantly as 2-methylthio-4,4-pentamethylene-2-imidazolin-5-one in chloroform or cyclohexane, and as 2-methylthio-5,5-pentamethylene-2-imidazolin-4-one in water. The tautomerism of the methylation product of 5,5-pentamethylene-2,4-dithiohydantoin exhibits a similar sensitivity to solvent.

Epimerization of 4-oxa-3-oxo-5α-cholestane by Brewster and Kucera's method gave only a 23% yield of the 5β-lactone; several other compounds were formed, apparently via skeletal rearrangement during hydrolysis of the tosylate. The attempted epimerization of 4-oxa-3-oxo-5β-cholestane gave mainly unsaturated acids, but no 5α-lactone (a small amount of skeletal rearrangement also occurred). Both epimers undergo rearrangement to γ-lactones when treated with trifluoroacetic acid.Mass spectra, used in conjunction with infrared and nuclear magnetic resonance spectra and other data to make structural assignments, were found to be highly sensitive to certain structural features. In particular, they can usually distinguish sharply between molecules that contain a pendant ring structure and those that do not.

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A study of the u.v., i.r., and n.m.r. spectra of 5-hydroxy-2-pentanone and of 6-hydroxy-2-hexanone has shown that in most organic solvents there is a slight preference for the open-chain form of the hydroxyketone over the cyclic hemiketal. Increase in temperature and in polarity of solvent further favors the open-chain tautomer; in water there was no evidence of any cyclic form.

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The difference between the chemical shifts of the α and β hydrogens of the mono-, di-, tri-, and tetra-ethylammonium ions changes as the concentration of the solvent sulfuric acid is increased from 0 to 94%. A tentative explanation based on hydration of the ions is presented.

Two reports in which it was claimed that the 1-acyl group of a 1-acyl-2-thiohydantoin was not rapidly removed by dilute acid or alkali were investigated and found erroneous.

The direction of the optical rotation of the steroid 3can be reconciled with Brewster's rules, if account is taken of "bond fixation", but the direction of the optical rotation of 2cannot be.

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Iron pentacarbonyl catalyzes the cleavage of alkyl ethers by acid chlorides to form alkyl chlorides and alkyl esters.

Fourteen acylhydrazides such as (II) are condensed with pyridoxal (I), salicylaldehyde (IV), and hydroxynaphthaldehyde (VI) to give 42 acylhydrazones of type (III), (V) and (VII), respectively, of which 38 are new.