Keiiti Sisido

Preparation and reaction of cyclopropyltriphenylphosphonium salt

Abstract Cyclopropyltriphenylphosphonium bromide ( 2a ) was conveniently prepared from 3-bromopropyltriphenylphosphonium bromide ( 1a ). The Wittig reaction of cyclopropyltriphenylphosphonium bromide ( 2a ) with carbonyl compounds gave alkylidenecyclopropanes ( 4 , 6 and 7 ). Successive treatment of 1a with two equivalents of base and carbonyl compounds gave alkylidenecyclopropanes ( 4 and 5 ) without isolation of intermediary 2a . 2-Methylcyclopropyltriphenylphosphonium bromide ( 2b ) was prepared and allowed to react with carbonyl compounds.

Formation of organotin-nitrogen bonds IV. N-trialkyltin derivatives of 4-mono- or 4,5-disubstituted 1,2,3-triazoles, 3-phenyl-1,2,4-triazole, 3-phenylpyrazole and 4-phenylimidazole☆

Abstract N -(Trialkylstannyl)-4-mono- or 4,5-disubtituted 1,2,3-triazoles have been prepared by the 1,3-cycloaddition of tri-n-butyltin azide to alkynes and by the condensation of 1,2,3-triazoles with bis(tri-n-butyltin) oxide or trimethyltin hydroxide. The trialkyltin group has been shown to be attached to the 2-nitrogen of the 1,2,3-triazole ring. N -Tri-n-butyltin derivatives of 3-phenylpyrazole, 4-phenylimidazole and 3-phenyl-1,2,4-triazole have been prepared by the condensation of bis(tri-n-butyltin)oxide with the corresponding azoles, the tri-n-butyltin group becoming attached to the 1-nitrogen atom of the latter.

Reaction of phenylcarbene formed from benzaldehyde tosylhydrazone in certain solvents

Abstract Treatment of benzaldehyde tosylhydrazone (I) with sodium methoxide in various solvents under irradiation and/or heating yields products arising from phenylcarbene (IV) which is produced by photolytic or pyrolytic decomposition of initially formed phenyldiazomethane (III). Reaction products originating solely from the tosylhydrazone (I) are (VI ∼ XI) while those produced by the interaction with solvents are formulated as addition products of (VI) to olefinic and aromatic CC bonds and insertion products of (IV) to aliphatic and to aromatic CH bonds. The reaction with aniline yields an insertion product of (IV) to the NH bond, or N-benzylaniline, in 26% yield, besides ring-benzylated compounds. o -Toluadehyde and 2,4,6-trimethylbenzaldehyde tosylhydrazones react similarly.

The reaction of optically active (1-methyl-2,2-diphenylcyclopropyl)trimethyltin with bromine or iodine

Abstract Reaction of an optically active (1-methyl-2,2-diphenylcyclopropyl)trimethyltin (I) with bromine (or iodine) afforded 1-bromo-(or iodo)-1-methyl-2,2-diphenylcyclopropane (II) with a small degree of retention of configuration. This is best interpreted in terms of radical mechanism for the cleavage of the cyclopropyl carbontin bond in (I) by bromine or iodine.

Direct Synthesis of Organotin Compounds V. Di- and trialkyltin chlorides and bromides

Abstract Di- and trialkyltin chlorides were prepared in good yields by the direct reaction of alkyl chloride with metallic tin when organic ammonium halides or a mixture of organic base and iodine-compound was used as the catalysts. Distribution of di- and trialkyltin chlorides varied with the kind and the amount of organic base, and reaction conditions. In the presence of a large amount of organic base, pure trialkyltin chloride was obtained. For the direct synthesis of alkyltin bromides, iodine source was not necessary.

Hydroboration of alkylidenecyclopropanes

Abstract Hydroboration of diphenylmethylenecyclopropane (1) and α-methylbenzylidenecyclopropane (2) gives 1-diphenylmethyl-cyclopropanol (5) and 1-(α-methylbenzyl)cyclopropanol (7), respectively, by the attack of boron on cyclopropylidene carbon. With benzylidenecyclopropane (3), 1-phenyl-2-butanone (16), phenylcyclopropylcarbinol (14) and 1-phenyl-1,4-butanediol (17) is obtained. The diol is considered to be produced from intermediary cyclopropylborane (11) via homoallylic rearrangement and intramolecular hydroboration.

Direct synthesis of organotin compounds IV. Reaction of benzyl chloride with metallic tin

Abstract By the investigation of the solvent effects in the reaction of benzyl chloride and tin powder, it was elucidated that dibenzyltin dichloride was formed at first, and the conversion into tribenzyltin chloride occurred in polar solvents. In water, bis(dibenzylchlorotin) oxide was an intermediate in the conversion. Catalytic effects in the reaction was also studied.

Preparation and Thermal Decomposition of 1,4,5- and 1,3,5-Trimethyltetrazolium Iodides

1,4,5- and 1,3,5-Trimethyltetrazolium iodides were prepared by the reaction of methyl iodide with 1,5- and 2,5-dimethyltetrazoles, and the reaction of methyl iodide with 5-methyltetrazole. The latter method is more facile for the preparation of these iodides. Upon thermal decomposition of the 1,3,5-trimethyl salt at 130°C, the 1-methyl group was eliminated predominantly to yield 2,5-dimethyltetrazole. When the 1,4,5-trimethyl salt was decomposed at 270°C, a mixture of 1,5- and 2,5-dimethyltetrazole was obtained in 74% and 21% yields, respectively. For the formation of 2,5-dimethyltetrazole from the 1,4,5-trimethyl salt, there has been shown an intermolecular methylation scheme that the 1,4,5-trimethyl salt methylated 1,5-dimethyltetrazole being formed in situ to give the 1,3,5-trimethyl salt.

Partial asymmetric synthesis of trans-2-phenylcyclopropanecarboxylic acid

Abstract Optically active trans-2-phenylcyclopropanecarboxylic acid (I) was obtained by hydrolysing the reaction products of (1) cycloalkylation of (−)-menthyl or (+)-bornyl (±)-γ-chloro-γ-phenyl-butyrate (IV) and of (2) condensation of styrene oxide and (−)-menthyl or (+)-bornyl phosphonoacetate (VI). The effects of reaction conditions on the optical rotation of I were examined.

Reaction of alkyl halides with dialkyltins

Abstract Treatment of a dialkyltin, (R2Sn)m, with an alkyl halide, R′X, gives the halides R2R′SnX and R3SnX. Alkyl iodides give only R2R′SnI compounds, alkyl bromides give both R2R′SnBr and R3SnBr compounds, while alkyl chlorides give only R3SnCl compounds. In the presence of amine or quaternary ammonium halide, however, alkyl chlorides give a mixture of R2R′SnCl and R3SnCl compounds. The routes by which R3SnX products are formed have been established.