György Dombi

Steroids, LIII: New routes to aminosteroids

SummarySteroid ketoximes were reduced with sodium tetrahydroborate in the presence of nickel chloride or molybdenum trioxide. These processes yielded 17α- and 20α-aminosteroids (1c–5c) in higher yields than common reduction methods.ZusammenfassungOxime von Ketosteroiden wurden mit NaBH4 in Gegenwart von NiCl2 und MoO3 reduziert. Dieses Verfahren lieferte 17α- und 20α-Aminosteroide(1c–5c) in größeren Ausbeuten als übliche Methoden.

STRUCTURAL CHARACTERIZATION AND DYNAMIC NMR STUDIES OF A NEW PERACYLATED MACROCYCLIC DITERPENE

A heptaester of a new diterpene alcohol was isolated from the dichloromethane extract of the whole plant of Euphorbia esula L. A detailed NMR and mass spectral analysis revealed that its structure is (E)‐(2R*, 3R*, 4S*, 5R*, 7S*, 8R*, 9S*, 13R*, 15R*)‐2,3,5,8,9‐pentaacetoxy‐7‐isobutanoyloxy‐14‐oxojatropha‐6(17),11‐diene. Its conformation was studied in three different solutions. The temperature dependence of the spectral parameters revealed conformational changes through internal rotation of the macrocycle part of the molecule. Copyright

Jatrophane diterpenoids from Euphorbia esula

Two new jatrophane diterpenoids, esulatin D and E, have been isolated from the dichloromethane extract of the whole, undried plant of Euphorbia esula. The structures have been assigned on the basis of spectral analysis, including 2D NMR experiments.

Stereochemical studies, 145. Saturated heterocycles, 152. Preparation and conformational analysis of stereoisomeric 1,6,7,11b- tetrahydro-2 H [1,3]oxazino [4,3-a]isoquinolin-4-one derivatives

Abstract Starting from 1- [bis(hydroxymethyl)-methyl]-6,7-dimethoxy-1, 2, 3, 4-tetrahydroisoquinoline 3a, trifunctional 1,2,3,4-tetrahydroisoquinolines were synthetized. From the N -ethoxycarbonyl derivative of 3a, ( r -11b,c-1)-1-hydroxymethyl- (8) and ( r -11b, t -1)-1-chloromethy1-9,10-dimethoxy-1,6,7,llb--tetrahydro-2 H 1,3]oxazino[4,3- a ] isoquinolin-4-one (9) were formed in unexpected reactions. High-resolution NMR revealed that the tetrahydroisoquino-line-fused C-1 epimer oxazinone derivatives 8 and 9 have different conformations in solution. The first X-ray diffraction evidence of the presence of two different conformations of oxazinoisoquinolines 8 and 9 in the solid state is provided.

2-Substituted hexahydroacylanthranils: Synthesis and selective reactions with amines

SummaryIn contrast to their aromatic analogues, the corresponding saturated diamides5–9 are formed exclusively when hexahydro-3,1,4-benzoxazinones (3,4) are reacted with amines. The cyclodehydration reaction of the diamides5–9 cannot be carried out at arbitrarily high temperatures.ZusammenfassungIm Gegensatz zu den aromatischen Analoga bilden sich bei der Reaktion von Hexahydro-3,1,4-benzoxazinonen (3,4) mit Amien ausschließlich die entsprechenden gesättigten Diamide5–9. Die Cyclodehydrierungsreaktion der Diamide5–9 kann nicht bei beliebig hoher Temperatur durchgeführt werden.

The preparation of 2,4-dibromoestra- 1,3,5(10),6-tetraene-3,17 β-diol diacetate

Abstract [ 2,4,6,7 - 3 H 4 ]Estradiol is used for the quantitative determination of estradiol receptors. The synthesis of 2,4-dibromoestra-1,3,5(10),6-tetraene-3,17β-diol 3,17-diacetate, the convenient precursor of [2,4,6,7- 3 H 4 ]estradiol, is described. 6-Alkoxy compounds were also prepared and investigated.

Basicity, quaternization and hydrolysis of 2H- and 4H-1,3-benzothiazine isomers

SummaryThe basicities of 2H- and 4H-1,3-benzothiazines (1,2) were measured spectrophotometrically in buffer solutions. The rates of quaternization with methyl iodide were monitored in sealed ampoules by an oscillometric method. The stabilities were determined by measurement of the rate of acidic hydrolysis via changes in the uv/vis spectra. As a cyclic Schiff base, 4-aryl-2H-1,3-benzothiazine (2) is the stronger base, and reacts about ten times faster with methyl iodide; its stability is greater than that of 2-aryl-4H-1,3-benzothiazine (1). On the basis of these results and by means of the different water-solubilities of the hydrochlorides the isomers formed during the synthesis can be separated and purified.ZusammenfassungDie Basizität und die Geschwindigkeit der Hydrolyse von 2H- und 4-H-Benzothiazinen (1,2) in saurer Lösung wurde UV/VIS spektroskopisch gemessen. Die Reaktionsgeschwindigkeit der Quarternisierung mit Methyljodid wurde oszillometrisch in geschlossenen Ampullen bestimmt. 4-Aryl-2H-1,3-benzothiazin (2) ist als zyklische Schiffsche Base die stärkere Base, deren Reaktionsgeschwindigkeit mit Methyljodid ungefähr zehnmal größer ist als die des 2-Aryl-4H-1,3-benzothiazin (1);2 ist auch stabiler. Aufgrund dieser Ergebnisse und der unterschiedlichen Wasserlöslichkeit ihrer Hydrochloride konnten die während der Synthese nebeneinander entstehenden Isomeren getrennt werden.