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The reactions of ethyl 1,2-diaminoazulene-3-carboxylate with formic acid, nitrous acid, glyoxal sodium bisulfite, diacetyl, and benzil afforded the corresponding azulene derivatives condensed at the 1,2-position with nitrogen-containing heterocycles, namely, imidazole, triazole, and pyrazine rings. 2-Amino-1-formylazulene reacted with guanidine or thiourea to give 2-aminoazuleno[2,1-d]pyrimidine. The ultraviolet and visible absorption spectra of these azulenes are presented.

The base-catalyzed proton migration (from the 7- to 2-position) and proton exchange (at the 7-position) of cycloheptatrienes carrying an electron-withdrawing group were studied in a medium of aqueous sodium hydroxide or alcoholic potassium hydroxide. The order of the effect of the various substituents upon the relative rates is approximately: CN>CONH2>COO−, Ph. The base-catalyzed prototropic isomerization proceeds through: i) the abstraction of a proton of the 7-position by the base, ii) the migration of the resulting carbanion to the allylic position (the rate-determining step), and iii) the recovery of a proton from the solvent. The kinetic study of the isomerization of 7-carboxycycloheptatriene (Ia) discloses the rate of the isomerization (k[the cycloheptatriene][base]) and the parameters (Ea=22.6 kcal/mol, ΔH\eweq=22.0 kcal/mol, ΔS\eweq=−15.4 e.u. at 60°). The structure of the cycloheptatrienyl anions formed as intermediates is discussed.

The general observation is made that on electron impact the molecular ions of tropone derivatives eliminate carbon monoxide as a neutral molecule and the resultant ions behave as benzene derivatives. Exceptions from this rule can be explained in terms of the presence of specific structural features.

1-Phenylazulene (I) and 2-phenylazulene (II) were synthesized from the troponoid compound. 3-Phenyl-(III) and 3-benzoyl-2H-cyclohepta[b]furan-2-ones (IV) were prepared by the reaction of 2-chlorotropone with ethyl phenylacetate and with ethyl benzoylacetate respectively. The reactions of III with malononitrile or ethyl cyanoacetate gave 1-phenylazulene derivatives, from which I was derived. On the other hand, the reactions of IV with ethyl cyanoacetate or diethyl malonate gave 2-phenylazulene derivatives, from which II was derived.

The acid hydrolysis of some polyhalotropones and some reactions of the products were investigated. The treatment of 2,5-dichlorotropone with hydrochloric or sulfuric acid afforded 2-chloro-5-hydroxytropone (I) and a small amount of 5-chlorotropolone. The compound I gives only one kind of the methyl ether and one kind of the acetyl or benzoyl derivative. From the methyl ether, 5-amino- and 5-methylamino-2-chlorotropone were derived. The methoxyl and the amino groups of these compounds are reactive to alkaline hydrolysis, giving I without any of the skeletal rearrangement usually observed in the alkaline treatment of similar 2-halotropones. The hydrolysis of 2,4,7-tribromotropone with hydrochloric acid gave 3,6-dichlorotropolone and 7-chloro-4-hydroxytropolone.

The dipole moments of tropone, 2-phenyltropone, tropolone methyl ether and their derivatives were measured in benzene solution at 25°. The increase of moment of tropone over that of cycloheptanone was adequately explained by mesomeric effect and an additional effect due to the formation of cycloheptatriene ring. The latter effect was supported by the theoretical moment for heptafulvene. The moments of various derivatives were compared with the theoretical data. The agreement between them confirmed the correctness of the position of substituents in these compounds already determined or inferred from the standpoint of organic syntheses. The apparent moment of tropolone methyl ether hydrate indicates that in benzene the hydrate dissociates into three separate molecules.

The oxidation of benzo-1, 4-thiazino[3,2-b]tropone and its 8-isopropyl derivative with hydrogen peroxide afforded the corresponding 5-oxides or 5, 5-dioxides. The stability of these oxides to heating, acid and alkali was examined. The bromination or nitration of these oxides gave mainly 9-bromo or 9-nitro derivatives. 7- or 9-Aminobenzo-1, 4-thiazino[3,2-b]tropones were obtained by the reduction of the corresponding nitro compounds.

The diazo coupling reaction of 2-amino- (I), 2-acetamido-, and 2-amino-1-ethoxycarbonyl-azulene with p-toluene diazonium salt gave the corresponding l-(p-tolylazo)azulene derivatives, II, V, and VIII respectively, in good yield; 2-amino-1,3-di(p-tolylazo)azulene (III) was also obtained by the reaction of I and two molar equivalents of p-toluene diazonium salt. The catalytic reduction of V and VIII afforded 2-acetamido-1-aminoazulene and ethyl 1,2-diaminoazulene-3-carboxylate as hydrochloride. The similar reduction of II and III yielded only a resinous product, and 1,2-diamino- or 1,2,3-triaminoazulene could not be isolated, not even as their salts. However, the reductive acetylation of II and III afforded the corresponding polyacetamidoazulenes. The ultraviolet and visible absorption spectra of these azulenes are indicated.

The current-voltage curves of tropolone were recorded at the dropping mercury electrode in buffer solutions of various pH’s containing no borate. One reduction wave was observed in the pH region of 2.2 to 4.0, two waves with nearly equal heights, in the pH region of 5 to 6 and one wave, in the solution of pH higher than 8. All waves except the second in the intermediate pH region were found to shift to negative potentials with the increase of pH of the solution by approximately 70 mV./pH. The number of electrons involved in the reduction was determined by the controlled potential coulometric method. One-electron reduction was confirmed for the first wave at lower pH’s, two-electron reduction for the two-step waves at the intermediate pH region and two-electron reduction for the wave at higher pH’s. The current-voltage curves which were recorded with the solution preliminarily subjected to the controlled potential electrolysis gave two new waves; one is anodic and the other, cathodic. The former decreased ...

トロピリデン(シクロヘプタトリエン)(I)を酢酸中で無水クロム酸で酸化すると,ベンズアルデヒドや安息香酸の得られることが知られているが,クロム酸ピリジン錯体でIを酸化すると,約30%の収率でトロポン(II)が得られることが見いだされた。なお同様な酸化法によってトロピリウムイオン(V)もトロポン(II)を40%の収率で与える。この方法を7-フェニルトロピリデン(IX)に適用したところ,4-フェニルトロポン(X)を低収率で与えた。IXは水酸化カリウム-エタノール溶液で加熱すると異性化を起し,2-または3-フェニルトロピリデン(XII)となる。XIIを同様な方法で酸化しても,4-フェニルトロポン(X)を低収率で与えるにすぎない。

The electrophilic substitution reactions of 2-aminotropone (I), 2-methylaminotropone (II), and 2-dimethylaminotropone (III) were investigated. The structure of the products was proved by hydrolysis to lead to known tropolone derivatives. By the nitrosation of II, N-nitroso-2-methylaminotropone was obtained in a good yield; this compound is a new type of active troponoid compound. The substitution reactions of III gave tropolone derivatives, accompanied by the hydrolysis of the dimethylamino group. The mechanism of the hydrolysis is then discussed.