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Two new scalaranes (1 and 2) have been isolated from the dorid nudibranch Glossodoris atromarginataand its prey. The structures were deteremined by spectral techniques and confirmed by chemical methods. Compounds 1 and 3 showed selective cytotoxic activity against human thyroid carcinoma.
Herein we report a feasible study concerning the design, synthesis, and in vitro antimicrobial activity of some novel homodrimane sesquiterpenoids with diazine skeleton. The reaction pathway is efficient and straight, involving the direct N-acylation of diazine with homodrimane sesquiterpenoids bearing acyl chlorides or organic acids functionality. A(More)
The paper reviews the known examples of cyclic terpenoids produced from open chain polyenic precursors by an "unusual" biosynthetic pathway, involving selective electrophilic attack on an internal double bond followed by cyclization. The resulting compounds possess cyclic backbones with pendant terminal prenyl groups. Synthetic approaches applied for the(More)
A new diacylguanidine, actinofide (1), has been isolated from the marine mollusk Actinocyclus papillatus. The structure, exhibiting a guanidine moiety acylated by two terpenoid acid units, has been established by spectroscopic methods and secured by synthesis. Following this, a series of structural analogues have been synthesized using the same procedure.(More)
The synthesis of isoagatholactone has been effected by the successive oxidation of (14R)-isoagath-12-en-15-ol with selenium dioxide and manganese dioxide. Methyl spongia-13(16),14-dien-19-oate has been obtained by the cyclization of methyl lambertianate with 100% sulfuric or fluorosulfonic acid.
Δ12- and Δ13(14)-Iso-20-deoxyluteones have been synthesized from 13E- and 13Z-bicyclogeranylgeranylacetones. The latter were reduced to the corresponding alcohols, which were acetylated, and the acetates obtained were cyclized with fluorosulfonic acid in nitropropane. The reaction product was saponified to a mixture of tricyclic alcohols which were oxidized(More)
We have shown previously for the case of sesquiand diterpenes that fluorosulfonic acid is an effective cyclizing agent, ensuring the structurally selective stereospecific occurrence of the reaction [i, 2]. It appeared of interest to investigate the interaction of fluorosulfonic acid with E,E,E,E-geranylfarnesol (I) and its acetate (II), since, in the first(More)
A series of dihomodrimane sesquiterpenoids containing an NH2 group were synthesized. 11-Dihomodriman-8α-ol-12-one and its dehydration products, ketones with double bonds in the C7-C8 and C8-C9 positions, were prepared from commercially available norambreinolide. The oximes of the ketones were reduced by LiAlH4 to the corresponding amines.
It has been shown that the opening of the cyclopropane ring in (1R, 2S, 7S, 10S, 11R, 12S, 13S)-2,6,6,10,12-pentamethylpentacyclo[10.2.1.01,10.02,7.011,13]pentadecane takes place under the action of fluorosulfonic acid at all three carbon-carbon bonds, but at low temperatures the main isomerization product is (1R, 2S, 7S, 10S, 12S,(More)
From the product of the cyclization of a mixture of isomeric ent-copalols (i) [i] with a mixture of formic and concentrated acids, we have isolated an oxygen-containing fraction (yield 47%) consisting of a mixture of five alcohols and their formates. Three of the alcohols proved to be known: isoagath-12-en-15-ols epimeric at Cz4 [2] and 14~-hibanol [3]. For(More)