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Synthesis of polyfuncţional drimanic sesquiterpenoids from labdane diterpenoids larixol and sclareol


Author: Alexandru Ciocârlan
Degree:doctor of chemistry
Speciality: 02.00.10 - Bioorganic chemistry; chemistry of natural and physiological active compounds
Year:2007
Scientific adviser: Pavel Vlad
doctor habilitat, professor, Institute of Chemistry of the ASM
Institution:
Scientific council:

Status

The thesis was presented on the 8 November, 2007
Approved by NCAA on the 20 December, 2007

Abstract

Adobe PDF document – 0.38 Mb / in romanian

Thesis

CZU 544.5+547.544.16+547.7/8+547.91+577.1

Adobe PDF document 1.02 Mb / in romanian
135 pages

Keywords

Labdane diterpenoids, norlabdane compouds, drimane sesquiterpenoids, Norrish II type photolytic degradation, Norrish I sensibilysed photooxidation, photooxidative dehydrogenation, X-rays diffraction

Summary

The dissertation is devoted to the elaboration of new and efficient methods for directed and stereoselective synthesis of biologic active polyfuncţional drimanic sesquiterpenoids. Starting from accesibile labdane diterpenoids larixol, sclareol and their norlabdane derivatives, using as key step photolytic degradation by Norrish II reaction were obtained drimanic dienes: 6a-acetoxy-drim-8(12),9(11)-diene, drim-8(12),9(11)-dien-6-one, drim-7,9(11)-dien-6-one and drim-7,9(11)-diene, convenient syntones for synthesis of polyfunctional drimanic derivatives and highly terpenoids.

From photolytic reaction products were izolated and identified, by X-ray diffraction including, the secondary norlabdanic compounds with unusual bi- and tricyclic structure: 6a-acetoxy-9,13b-epoxy-13b-methylpodocarpane, (1S,3S,6R,7R,9S,10R)-3,6,7,11,11-pentametyl-2-oxa-tetracyclo-[8.4.0.01,6.03,7]-tetradec-9-yl аcetate, 6a-acetoxy-8b,13β;13α,17-diepoxy-14,15-bisnor-labdane, ciclobuto-(18→6)-14,15-bisnorlabd-8(17)-en-6-ol-13-one and 2,4-dinitrofenyl-hidrazones obtained from the last compound.

Were realized new, short and efficient synthesis of natural and biologic active compounds: (+)-drim-9(11)-еn-8a-ol, (-)-albrassitriol, (-)-epi-albrassitriol, fragrolide, 6a-acetoxyeurifurane, 6a-hydroxyeurifurane, 6-cetoeurifurane and prouved the utility of photooxidative dehydrogenation reaction of drimanic and homodrimanic compounds with „8-en-7-on” structural unite for preparation of a,a¢-dienones: methyl ester of 11-homodrim-5,8-dien-7-on-12-oic acid and 11,12-diacetoxydrim-5,8-dien-7-one.

In base of drim-7,9(11)-diene were selectively synthesised polyhidroxylated compounds: drim-7-en-9α,11-diol, drim-9(11)-en-7α,8α-diol, drim-7α,8α,9α,11-tetraol şi drim-7β,8β,9α,11-tetraol, which can serve as intermediates for synthesis of biologic active labdane diterpenoids.