N. Danieli

A new quinolone type alkaloid from haplophylum tuberculatum (rutaceae)

Abstract A new alkaloid, 3-dimethylallyl-4-dimethylallyloxy-2-quinolone, has been isolated from Haplophylum tuberculatum (Rutaceae) and characterized by NMR and mass spectrometry as well as by conversion into dihydroflindersine. The known alkaloid flindersine has been also isolated from this plant.

The synthesis of digitoxigenin

Abstract Digitoxigenin (VIIIb), a typical member of the cardenolide family, has been synthesized from methyl 3β-acetoxy-14β-hydroxy-5β-etianate (II) by a seven-step sequence.

Syntheses in the terpene field—XIII : A new route to a key intermediate in the total synthesis of α-onocerin☆

Abstract 6β-Hydroxy-2-keto-5,5,9-trimethyl-tans-decal-1β-ylacetic acid (XIIa) is an important intermediate in the synthesis of α-onocerin (I) by Stork . A new and convenient synthesis of XIIa is described proceeding in 8 steps from 1β-hydroxy-5,5,9-trimethyl-Δ4-octal-6-one benzoate (IVa). The key reactions are the selenium dioxide oxidation of the αβ-unsaturated ester Xb to the αβ-unsaturated γ-lactone XI, and the direct conversion of XI to XIIa with sodium hydroxide.

The 17α-hydroxylation of cardenolides. Conversion of the cardenolideto the cortisone side-chain

Abstract Oxidation of digitoxigenin acetate (III) with selenium dioxide in dioxan gives rise to the corresponding 17α-hydroxy derivative II. The same substance is obtained under these conditions from the previously described ester I. Ozonolysis of II, and subsequent saponification, leads to 3β, 14β, 17α,21-tetrahydroxy-5β-pregnan-20-one 3-monoacetate (VIIa), a substance containing the cortisone side-chain; in addition, the 17-ketone IV and the cyclic hemi-acetal VIIIa are obtained. The analogous selenium dioxide oxidation of gitoxigenin diacetate (X) produces the corresponding 17α-hydroxy derivative XI.

Applications of 2-methyl-2-carboxymethyl-3-oxocyclopentanecarboxylic acid derivatives in steroid syntheses

Abstract A Friedel-Crafts condensation of 1,7-dimethoxynaphthalene with the anhydride IV gave a mixture of products from which, after esterification, the ketoesters IX and X could be isolated in 16 and 4·25% yield, respectively. These were hydrogenolysed with PdC to the desoxyesters XI and XII. Cyclodehydration of the latter with an acetic-hydrochloric acid mixture furnished the desired estrahexaene III. Reaction of the lithio derivative of 2-methoxynaphthalene with the dimethyl ester Vc yielded the hydroxyester XVb which was dehydrated to the unsaturated compound XVIII. Assignment of structures to the isomers IX and X by means of mass spectrometry is discussed.

Desulphurization of the thioketal of testosterone acetate with deactivated Raney nickel.

Abstract Desulphurization of the thioketal of testosterone acetate 2, with deactivated Raney Ni leads to the following olefins: 5β-ene 5, 4-ene 6, 5α-2-ene 7, 3,5-ene 3, and the two dimeric trienes 4. The formation of all these products may be rationalized by postulating the intermediacy of the allylic radical I. The deactivated Raney Ni may donate H atoms to this radical or to products subsequently formed. It may also abstract hydrogens at the allylic positions. It was found that deactivated Raney Ni converts cyclohexene to benzene.