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The N–X bond of positive halogen compounds (I) can be readily methylenated at 15° with diazomethane to give the N-halogenomethyl derivatives (III), not isolated as such but directly condensed with nucleophiles [sodium p-nitrophenoxide, diethyl phthalimido(sodio)malonate, and morpholine]; the parent N–H compounds (VII) are formed as secondary products. This new reaction has been applied to N-halogeno-N-substituted carboxamides, sulphonamides, phosphoramides, and urethanes. The mechanism of the methylene insertion into the N–X linkage is discussed.

The behaviour of the hydantoin ring in the aminomethylation reaction was studied in order to determine the orientation of this substitution. It was found that position 3 is the most reactive one and this result is rationalized in terms of influence of structural factors. Mono-aminomethyl derivatives of hydantoins (I to XV) are described.

In this paper an estimate of the effective neutron crosssections for a number of nuclei involved in thes-process in stars is given. The effective cross-sections were obtained as weighted averages of neutron radiative-capture cross-sections over Maxwellian energy distributions at various temperatures. The semi-empirical method adopted for the calculation of the energy-dependent cross-sections is shortly outlined. The effective cross-sections are given in tabular form forKT ranging from 0.01 to 0.1 MeV.

New tertiary alkaloids with a 4-quinolone skeleton, (±)-ribalinine ( 3b ), (−)-ribalinidine ( 3c ), (±) and (+)-ribaline ( 2b ), have been obtained from Balfourodendron riedelianum . During isolation, 3c and 3b were found together with the quaternary alkaloidal fraction. The structure elucidations were in part based on spectrometric data. Furthermore, 2b and 3c were chemically correlated with the known ribalinium whilst the structure of 3b was confirmed by total synthesis. The configuration of 3c is S as determined by the Korean's method.

Taking into account the chemical shifts of protons at positions 1, 3 and 5, the characteristic changes of the N1H and N3H signals on addition of bases and the absorption area of the C5H region, all the unsubstituted sites of the ring in hydantoin compounds can be easily determined; comparison of the behavior towards bases in deuteriochloroform and dimethyl sulfoxide is helpful (Table 1). The localization of methyl substituents at ring positions 1, 3 and 5 is ascertained by considering the chemical shifts (Table 2).

The action of 2 methyl-4-mercapto-6 methoxy-quinoline on « in vitro » cultures of chick embrio fibroblasts is briefly described. The substance, at concentrations higher than 5 γ ml causes within 24 hours metaphase block; at the highest concentrations, widespread cell damage and fall in growth indexes are the prevalent effects.

Extraction of the trunk bark of Aspidospermaspegazzinii Molf. ex Meyer yielded ajmaline and two quaternary alkaloids. One of the latter, characterized as the tetraphenylboride salt, was found to be identical with the Nb-metho derivative of akuammidine. Methylation of the phenolic group of the second quaternary alkaloid (named spegatrine) followed by thermal degradation led to the corresponding nor-base, which was identified as lochnerine; therefore, the structure and absolute stereochemistry of spegatrine are given by formula I. A confirmation was provided by Nb-methylation of sarpagine to spegatrine.

Six mercapto-quinoline derivatives have been tested on « in vitro » cultures of KB cells at concentrations ranging from 0.1 γ/ml to 50 γ/ml. Three of them, i. e. No. 1 (4-mercapto-2-methyl-quinoline), No. 2 (6-methoxy-4-mercapto-2-methyl-quinoline) and No. 4 (8-methoxy-4-mercapto-2-methyl-quinoline) showed interesting anticellular activities consisting in: 1) antimitotic action: compounds No. 1 and No. 2 cause principally a methaphase block with colchicine-like effect; compound No. 4 shows a clear inhibiting action of preprophasic type. 2) aspecific and late cytotoxic action: more or less common to the three derivatives, it causes severe cell damage. The most active of these three compounds was found to be No. 2. On the other hand three other compounds: 7-methoxy-4. thio-2. methylcholine; acid (6-methoxy-2-methyl-quinoline-4) thioglycolic; 6. ethoxy-4. thio-2. methylcholine, proved inactive. It is concluded that these mercapto-quinoline compounds, require, to be active, the presence of a free sulfhydryl group in their molecule.

The action of a new quinoline compound, the 2-Methyl-4-Mercapto-6-Methoxy-Quinoline, on « in vitro » cultures of human cancer cells (strain KB) is described. The substance tested at concentration ranging from 0.1 γ/ml to 100 γ/ml, showed a powerful and specific citotoxic action at concentrations higher than 1 γ/ml.

Departing from structurally related quaternary compounds, the phenolic ribalinium ion(Ia) does not suffer opening of the dihydrofuranic ring under mild basic condition due to conversion to a resonance stabilized anhydronium system (II). The stereochemical results in the ring-opening of O6-methylribalinium (Id) in buffer pH 10·6 and of Ia in stronger basic medium, suggest a dual reaction mechanism. The epoxide IV, an intermediate in a proposed route, has been isolated when working under conditions that prevent its hydrolysis.

From the trunk bark of Balfourodendron riedelianum (Engler) Engler (Rutaceae) the chloride and the perchlorate of the new quaternary alkaloid ribalinium (I) have been isolated. According to functional groups analyses and UV absorption, I contains a 2,4-dialkoxy-1-methyl-quinolinium moiety (A), and the presence of a linerly fused oxygenated ring is indicated by the 4-quinolone nature of the nor-base (V) obtained by dequaternization of O-methylribalinium (IV). Coupled mass and NMR spectrometry established the oxygenated ring as 20-substituted-dihydro-furane; the side chain, an α-hydroxylated isopropyl fragment was proved by combined chemical, IR and NMR data. Finally, location of the phenolic function at position-6 by NMR measurements of I and V have led to the complete structure of the ribalinium cation.

Auf Grund von Protonresonanz und massenspektrometrischen Messungen werden die Strukturen III und VII fur die Aspidosperma-Alkaloide Spegazzinidin und Spegazzinin vorgeschlagen.

The crude mixture of alkaloids obtained from the alcoholic extract of the bark of Pterogyne nitens Tul. (Leguminosae) was subjected to column chromatography on alumina followed by purification through the picrate., Facultad de Ciencias Exactas