Masaru Ogata

Organic photochemical reactions—V: Photorearrangement of anthranils into azepines

Abstract The photolysis of anthranils (III) led to ring enlargement with the formation of 3-acyl-2-methoxy-3H-azepines (IV). The reaction in ether containing water or amines yielded the corresponding 2-oxo- or 2-amino-3H-azepines (V or VII). On the other hand, photolysis of some 7-substituted 3-phenylanthranils (IX and XIII) gave the corresponding 9-acridanone derivatives (X and XIV). A hypothetical scheme (anthranil → nitrene → azirene → azepine) similar to that proposed by Huisgen and Appl for the analogous ring enlargement of phenylazide is applicable to the anthranil rearrangement. By UV and IR spectroscopic methods, the last step was proved to involve a dark reaction of an intermediate (probably azirene species) with protic solvents.

The fluoride-induced reaction of phenylthio-, methylthio- and methoxy-substituted silylmethylazoles with carbonyl compounds

Abstract Phenylthio-, methylthio- and methoxy-substituted silylmethylazoles, which act as substituted (N-azolyl)methylanion equivalents, were prepared and made to react with carbonyl compounds in the presence of fluoride anion to obtain 2-phenylthio-, 2-methylthio- and 2-methoxy-substituted 2-azolylethanols. Also examined in this study was the lithiation of 1-methylthiomethyl-1,2,4-triazole and 1-bis(methylthio)methyl-1,2,4-triazole.

Reaction of N,N′-carbonyldiimidazole and N,N′-thionyldiimidazole with carbonyl compounds: a new imidazole transfer reaction

Abstract Ketones and aldehydes undergo facile addition reaction with N,N′-thionyldiimidazole to give the monoimidazole and the diimidazole.

Synthesis and oral anti-fungal activity of novel 1,3-bis-(azolyl)-2-arylpropan-2-ols

Synthesis of 1-alkoxy- or 1-alkylthio-1,3-bis(azolyl)-2-anylpropan-2-ols is described. The title compounds were examined for their anti-fungal activities in vitro by evaluation of broth dilution MIC values against 3 species of fungi and the inhibitory effect on the pseudomycelium formation by Candida albicans and oral efficacy in vivo against systemic candidiasis in mice. (1R∗, 2R∗)-2-(4-Chlorophenyl)-1-methoxy-1,3-bis(1,2,4-triazol-1-yl)-2-propanol exhibited strong oral anti-fungal activity. Structure—activity relationships of the compounds examined are described.

A Convenient Synthesis of 1H-1,2,4-Triazol-1-Yl-Propan-3-One Derivatives by Modified Mannich Reaction

Abstract 1H-1,2,4-Triazol-1-yl-propan-3-ones were synthesized regioselectively using a modified Mannich reaction. Reactions of enones and Mannich bases with imidazole are also described.

N-(Chlorosulfinyl)-Imidazole as a New Imidazole Transfer Reagent1

Abstract The usefulness of diimidazoles2 such as N, N′-carbonyldi-imidazole (1), and N, N′-thionyldiimidazole (2) in organic synthesis has been accumulated recently. In connection with the continuing our studies on the reaction using 1 or 2 3 (carbonyl, thionyl, and imidazole transfer reactions), our particular interest was focused on the synthesis of N-(chlorosulfinyl)-imidazole (3) in which one imidazole group in 2 was replaced by the other leaving group (Cl). Also, 3 was interesting for preparative purposes as a chlorine atom could be introduced via the addition reaction of 3 to carbonyl compounds as known in the reaction of 1 or 2 with ketones.

Organic photochemical reactions—VI: Photochemical and thermal ring contractions of 2-methoxy- and 2-amino-3-acyl-3H-azepines

Abstract Photolysis of 3-benzoyl-2-methoxy-3 H -azepine (IIa) in methanol led to 7-benzoyl-2-methoxy-3-azabicyclo[2.1.0]hepta-2,4-diene (IVa), 2-methoxy-3-phenacylpyridine (Va) and 2-phenylfuro[2.3- b ]-pyridine (VIa). This reaction was extended to 3-benzoyl-5-chloro- and -6-chloro-2-methoxy-3H-azepines (IIb, c) and 3-acetonyl-2-methoxy-3 H -azepine (IId) which underwent analogous conversion into the corresponding pyridine derivatives (Vb–d and VIb), respectively. Pyrolysis of IIa–c gave similar pyridine derivatives. Thermal rearrangement of 2-amino-3-acyl-3 H -azepines (IIIa–c) gave pyrrolo[2.3- b ]pyridine derivatives (XIa–c) or 2-diethylamino-3-phenacylpyridines (XIIa, b). A tentative mechanism of these ring contractions is presented.

Alkoxide-Induced Reaction of 1-[(Trimethylsilyl)-Methyl]Azoles with Imines and Carbonyl Compounds

Abstract t-BuOK-induced reaction of 1-[(trimethylsilyl)methyl]-1,2,4-triazole with imines to yield (triazol-1- yl)ethylamines and (triazol-5-yl)methylamines was explored. Also, alkoxide-induced desilylation of 1-[(trimethylsilyl)methyl]azoles in the presence of carbonyl compounds was demonstrated, and (-BuOK and potassium trimethylsilanolate were found to be effective in this reaction.

Photochemical synthesis of 2-benzimidoyl-3-hydroxy-1,4-naphthoquinone and its analogues. A new type of plant growth regulator

The photochemical synthesis of 2-benzimidoyl-3-hydroxy-1,4-naphthoquinone and related compounds having plant growth regulating activity is described.