Kazuo Kigasawa

Studies on steroids

Several kinds of omega-haloalkoxyamines have been prepared as new derivative-forming agents applicable for the gas chromatography-mass spectrometry of carbonyl compounds. Of these reagents, 2-chloroethoxyamine hydrochloride [O-(2-chloroethyl)hydroxylamine] was the most suitable for use with oxosteroids because of its higher reactivity and the appropriate retention value and satisfactory chromatographic properties of the resulting oximes. The contribution to the retention value due to formation of the 2-chloroethyloxime was determined for 5alpha-androstanones having the oxo-group at various positions in the steroid nucleus. As expected, 17-oxosteroid O-2-haloethyloximes exhibit readily distinguishable isotope peaks as a cluster in the mas spectrum.

Studies on steroids : CIII. A new type of derivatives for electron capture-gas chromatography of ketosteroids

Pentafluorobenzyloxyamine is presented as a new derivatizing agent for gas chromatography of ketones using electron capture detection. The typical 17-ketosteroid was readily transformed into the O-pentafluorobenzyloxime which on usual trimethylsilylation led to a 3-trimethylsilyl ether derivative exhibiting good gas chromatographic properties. The derivatization procedure was applied to the determination of dehydroepiandrosterone in human plasma by electron capture-gas chromatography employing an internal standard method and in consequence satisfactory results were obtained.

Studies on the syntheses of heterocyclic compounds. Part DLXXVII. Synthesis of 2,3,4,5-tetrahydro-1H-benzazepine derivatives by phenolic cyclisation

Die aus 3-Benzyloxy-benzaldehyd und Cyanessigsaure in Benzol/NH4-acetat zugangliche Saure (I) wird zu dem Nitril (II) decarboxyliert, dessen Hydrierung am Raney-Ni unter Hochdruck das Amin (III) gibt.

Studies on the syntheses of heterocyclic compounds. Part DII. Synthesis of 1-substituted 1,2,3,4-tetrahydrophthalazines by a pictet–spengler-type reaction of 3-hydroxybenzylhydrazine with carbonyl compounds

Condensations of 3-hydroxybenzylhydrazine with acetone, ethyl methyl ketone, diethyl ketone, cyclohexanone, and 1-methyl-4-piperidone in the presence of acid gave the 1,1-disubstituted 1,2,3,4-tetrahydrophthalazines (2)–(6). On the other hand, the reactions of 3-hydroxybenzoylhydrazine (7) with acetone, cyclohexanone, and benzalde-hyde gave the Schiffs bases (8)–(10).

The Color Reaction in Non-Aqueous Solvents. VI. The Comparison of Tetrabromobenzaurine with Bromophenol Blue in Non-Aqueous Solvents

We studied in this work the comparison of the reactivity of tetrabromobenzaurine (II) with that of bromophenol blue (I) in methanol-benzene and benzene.We discussed how the bulky aminated sulfone group in the ortho position of I influenced the arrangement of the three phenyls, the approach of anion to a center carbon atom, and the behavior of amines bonded to the phenolic hydroxy group, based on a shift to the longer wave length of II, the fading of II in methanol-benzene, and the comparison of the enthalpies and entropies of the reaction of II with those of I.It was found that the use of. II in the reaction with amines was undoubtedly advantageous over I since an absence of the sulfone group in II resulted in an increase in reactivity of the phenolic hydroxy group with amines and simplification of the reaction.