Transformations of sclareol oxide by bromination. Synthesis of driman-8α, l l-diol from sclareol oxide

Depending on reaction conditions, the reaction of sclareol oxide with N-bromosuccinimide affords either 12-bromo- or 12,16-dibromosclareol oxide, whereas the reaction of sclareol oxide with bromine in methanol gives l2-monobromide or (13S)-1 1,12-dibromo-8,13-epoxy-13-methoxy-14,15-bisnorlabdane. Dehydrobromination of the latter with potassium hydroxide in toluene in the presence of polyethylene glycol gives (13S)-12-bromo-8, 13-epoxy-l3-methoxy-14,15-bisnorlabd-11-ene, ozonolysis of which followed by reduction of the ozonide with LiAlH₄ affords drimane-8, 11 I-diol.Translated fromIzvestiya Akademi Nauk. Seriya Khimicheskaya, No. 11, pp.2780–2784, November,1996     

Synthesis of bicyclohomofarnesane derivatives from bis(8α,13-epoxy-14,15-bisnorlabd-12-en-12-yl)methane — A product of the ozonolysis of sclareol

A seven-stage method of obtaining a new odoriferous product with a strong amber odor analogous to ambroxide from sclareol has been developed. It includes odoriferous oxide compounds of the tetrahydrofuran series: (VIII), (IX), (XIII), and (XIV). The key stages in the synthesis of this product are the ozonolytic cleavage of sclareol with the formation of bis(8,13-epoxy-14,15-bisnorlabd-12-en-12-yl)methane (II), its ozonolysis to bis(8-acetyl-12-oxo-13,14,15,16-tetranorlabdan-12-yl)methane (III), and the alkaline cleavage of the latter.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kishenev. Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 343–349, May–June, 1991.     

Synthesis of (+)-drim-9(11)-en-8α-ol from sclareol

A drimane-type sesquiterpenoid, (+)-drim-9(11)-en-8-ol, was synthesized from sclareol in four steps. The ozonolysis product of sclareol diacetate reacts with Cu(OAc)₂·H₂O to give 8-acetoxy-14,15-bisnorlabdan-13-one. Photolysis of this compound followed by alkaline hydrolysis results in the target compound belonging to the normal steric series. (+)-Drim-9(11)-en-8-ol acetate is highly unstable and decomposes during chromatography on SiO₂.     

First Total Synthesis of 12-Hydroxy-13-methylpodocarpa-9, 11, 13-trien-3-one

12-Hydroxy-13-methylpodocarpa-9, 11, 13-trien-3-one 9 was isolated from the twigs ofCroton salutaris1. Many diterpenes exhibit significant bioactivities, such as antibac-terial and antitumour and 9 has a rare structure. In order to study the relationshipb…     

A Facile Synthesis of 3-Oxo-7αH-eudesma-4-ene-9β, 12-diol

3-Oxo-7αH-eudesma-4-en-9β,12-diol1awasfirstisolatedfromCassinauncatabyKingetal.,anditsstructurewasdeterminedbyhighfieldNMRtechniques;however,theabsoluteconfigurationofC-llremainedunsolved.RecentlyPedroetalreportedthefirsttotalsynthesisof(llS)-3-oxo-7aH-eudesma-4-en-95,l21bfromartemisin2inl3steps'.Herein,wereportafacileprocedureforsynthesisofC-llisomericdiolsandthestereochemistryofnaturaldiol.Oursyntheticrouteisshownasbelow:a)ref5,36%;b)Vilsmeierreagent.30%H202,CH2Cl2.-20"C,lh.62%,c)i.…     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-containing drimane sesquiterpenoids from 11-dihomodriman-8α-ol-12-one

Beckmann reaction products of 11-dihomodriman-8α-ol-12-one oxime with Ac₂O in pyridine, 86% H₃PO₄, p-TsCl in pyridine, and PCl₅ in ether were investigated. It has been found that the major product from treatment of the oxime with Ac₂O is the oxime acetate. Reaction of the oxime with 86% H₃PO₄ gave (1S,2S,4aS,8aS)-2,5,5,8a-tetramethyldecahydro-1H-naphtho[1, 2][5, 6]-3-methyl-4,5-dihydro[1, 2, 6]oxazine; with p-TsCl, (1S,2S,4aS,8aS)-2,5,5,8a-tetramethyldecahydro-1H-naphtho[1, 2][5, 6]-2-methyl-4,5dihydro[1, 3, 6]oxazine; with PCl₅, a mixture of products containing 11-acetylamino- and 11-methylaminooxodrimenes that were isomeric at the double bond, norambreinolide, and a 1,3,6-oxazine.     

Synthesis of 3β,6α-dihydroxy-5α-cholan-23-one

Evidence for the presence of 3β,6α-dihydroxy-5α-chol-9(11)-en-23-one in the aglycone mixture from the starfish Marthasterias glacialis is provided by the synthesis of 3β,6α-dihydroxy-5α-cholan-23-one (19) and its identification in the hydrogenated aglycone mixture. The side-chain is constructed from the 23,24-dinorcholanol (13) by reaction of the 22-tosylate (16) with the acetylide anion, followed by hydration of the resulting 23-yne (17).     

Synthesis of diglycosides of 3β,20S-dihydroxydammar-24-en-12-one

The 3-O-β-D-galactopyranosyl-20-O-β-D-glucopyranoside and 3-O-β-D-glucopyranosyl-20-O-β-Dgalactopyranoside of 3β,20S-dihydroxydammar-24-en-12-one, which are structural analogs of chikusetsusaponin-LT₈ (1), a minor glycoside from Panax japonicus, were synthesized for the first time.     

The First Total Synthesis of 3-Oxo-11, 12, 13-trihydroxyeudesm-4-ene

The first total synthesis of 3-oxo-11, 12, 13-trihydroxyeudesm-4-ene, a highly oxygenated natural eudesmane, was described.     

Asymmetric dihydroxylation of drim-7-en-11-ol: synthesis of diastereomerically pure driman-7α,8α,11-triol and its elaboration into novel chlorinated norlabdanic compounds

The asymmetric dihydroxylation of drim-7-en-11-ol was studied in detail and diastereomerically pure driman-7α,8α,11- and driman-7β,8β,11-triols were prepared. Further elaboration of driman-7α,8α,11-triol afforded 14,15-bisnorlabd-7α,8α-isopropylidenedioxy-11,13-dione from which a novel chlorinated bisnorlabdanic compound (14,15-bisnorlabd-12-ene-12-chloro-8α,13-epoxy-7α-ol-11-one) and an unusual dichloro-derivative, 13,14,15,16-tetranorlabd-12-dichloro-7α-acetoxy-8α-ol-11-one, were obtained.     

Synthesis of New Dioxacyclophanes Derived from 1,1′-Binaphthyl-2, 2′-diol

Abstract

The Williamson reaction between (R,S)-[1,1′-binaphthyl]-2, 2′-diol 1 and (R,S)-2,2′-bis (bromomethyl)-1,1′ binaphthyl 2 in acetone, gave the diastereoisomeric dioxacyclophanes (R?, S?)-3a and (R?, R?)-3b in high yield.     

Pd-catalyzed synthesis of 2-alkynyl derivatives of 19β,28-epoxy-18α-olean-1-en-3-one

Basing on Sonogashira reaction of 2-iodo-19β,28-epoxy-18α-olean-1-en-3-one with alkynes an effective approach was developed to the synthesis of 2-alkynyl derivatives of 19β,28-epoxy-18α-olean-1-en-3-one. Initial 2-iodo-19β,28-epoxy-18α-olean-1-en-3-one was obtained by isomerization of the accessible betulin into allobetulin in the presence of Amberlyst 15, oxidation of allobetulin to 19β,28-epoxy-18α-olean-1-en-3-one under the action of 2-iodoxybenzoic acid, and iodination of the obtained enone in the presence of DMAP.     

Synthesis and Crystal Structure of 3a-Hydroxy-3-phenyl-1,2,3,3a,8a-pentahydrocyclopenta[α]inden-8-one

The title compound 3a-hydroxy-3-phenyl-1,2,3,3a,8a-pentahydrocyclopenta[α]inden-8-one 2 (C18H16O2, Mr = 264.31) has been obtained by the treatment of 2-(3-iodopropyl)-2phenylindan-1,3-dione 1 with tributyltin hydride in refluxing benzene, and its crystal structure was determined by single-crystal X-ray diffraction. The analysis was carried out by direct and Fourier methods and the structure was refined by full-matrix least-squares computations. The title compound crystallizes in monoclinic, space group P21/n with a = 9.947(3), b = 10.336(3), c = 13.239(4) (A), β = 95.565(6)o, V = 1354.7(7) (A)3, Z = 4, Dc = 1.296 g/cm3, μ(MoKα) = 0.083 mm-1, F(000) = 560, the final R = 0.0749 and wR = 0.1191. X-ray analysis revealed that the bond length of O(2)C(12) is 1.219(2) (A), slightly longer than that of the normal C=O bond (1.119 (A)). The dihedral angle between planes II and III is almost 180°, while plane II is almost vertical to plane I consisting of C(1), C(3), C(4) and C(5) with the deviation of C(2) being 0.6269 (A). In addition, there exist intermolecular hydrogen bonds between O(2) and H(1)-O(1) in the crystal structure.     

Synthesis and Crystal Structure of 3a-Hydroxy-3-phenyl-1,2,3,3a,8a-pentahydrocyclopenta [α]inden-8-one

1 INTRODUCTION Many organic substances of interest contain vari-ous types of rings and it becomes important to ex-plore and develop new approaches to appropriatelyfunctionalize medium and large rings. Free radicalcyclization reaction is a new strategy to constructdifferent types of cyclic compounds including biolo-gically active natural products and pharmaceuti-cals[1～4], and nowadays it is one of the importantresearch fields of organic chemistry. Up to date, noreport on the radical cycl…     

Simple Synthesis of 17α,20β-Dihydroxypregn-4-en-3-one

Reduction of 17-hydroxyprogesterone (1) with NaBH ₄ produces 17,20-dihydroxypregn-4-en-3-one (2) and pregn-4-en-3,17,20-triol (3)     

Synthesis of β-Amino-α,α-dichloro Sulfones from Vinyl Sulfones

β-amino-α,α-dichloro sulfones 3 are prepared by the reaction of vinyl sulfone 1 with primary or secondary amines 2in the presence of CCI₄ and NaH.     

Ozonolysis of Alkenes and Study of Reactions of Polyfunctional Compounds: LXIV. Synthesis of Ambreinolide and 8α,13-Epoxy-14,15,16-trisnorlabd-12-ene Proceeding from Isoabienol Ozonolysis

The ozonolysis of isoabienol in MeOH followed by hydrogenation of the peroxide ozonolysis products on Lindlar catalyst afforded ambreinolide that under treatment with diisobutylaluminum hydride furnished 8,13-epoxy-14,15,16-trisnorlabd-12-ene.     

Synthesis of novel chiral phosphines from α,α-trehalose

New disaccharide chiral phosphines, such as 4,6-O-benzylidene-2-(diphenylphosphino)-2-deoxy-α-d-altropyranosyl-(1,1)-4,6-O-benzylidene-2-(diphenylphosphino)-2-deoxy-α-d-altropyranoside 1 and 2-(diphenylphosphino)-2-deoxy-4,6-O-isopropylidene-α-d-altropyranosyl-(1,1)-2-(diphenylphosphino)-2-deoxy-4,6-O-isopropylidene-α-d-altropyranoside 9, were prepared from α,α-trehalose. We also succeeded in the synthesis of polyhydroxy chiral diphosphine 2-(diphenylphosphino)-2-deoxy-α-d-altropyranosyl-(1,1)-2-(diphenylphosphino)-2-deoxy-α-d-altropyranoside 5 by deprotection of isopropylidene groups.