Synthesis of (±)-Bimatoprost

A general synthetic approach has been developed for the synthesis of a key intermediate (6) that can be elaborated into several ophthalmic prostaglandins and their derivatives. Using these strategy, we have obtained (±)-bimatoprost (1) and its analog, (±)-homobimatoprost (5).     

Synthesis of (±) Combretastatin

Combretastatin (1) is a new plant product isolated recently by Pettit et al ¹. from the South African tree, Combretum caffrum that possesses central nervous system antineoplastic activity and is being evaluated against several of National Cancer Institute's key evaluation systems. The structure of 1 was established on the basis of its spectral properties and confirmed by X-ray analysis. However, the absolute configuration and the synthesis of 1 have not been reported so far. As combretastatin is present in the plant in only 0.0008% and the isolation technique is much tedious, there is an urgent need for the synthesis of 1 for further evaluation of its activity. This prompted us t o report the first synthesis of (±)1.     

Synthesis of (±)-zearalenone

The aliphatic portion of (±)-zearalenone has been synthesised by a new simple route starting from 2,3-dihydropyran and 2-acetyl-γ-butyrolactone by employing dithiane for C-C bond formation. The final condensation of this segment with the aromatic part and subseqnet transformations led to (±)-zearalenone.     

Total Synthesis of (±) Thaicanine

A convenient total synthesis of (±) thaicanine (5) is described from 2-benzyloxy-3,4-dimethoxyphenylethylamine (1).     

Total Synthesis of (±)Chrysotricine

Chrysotricine1wasisolatedfromtheChineseherbmedicineHedyotiSChrysotricha'anditssthectUrehasbeenestablishedasanew0-carbolinealkaloidwitha2,5-trans-substitutedtetrahydrofuranylgrouPatitsl-positionbyX-raydiffractionandspectralanalysis.PharmaceuticalstUdiesshowedpotentialantitUmoractivity.Theinterestingbiologicalactivityandthechemistryof6-carb0linesmict[JIehaveattiactedconsiderableattentioninrecentyears.InordertostUdythisstrUctUre-activityrelationshiPfurther,wewereillterestedinthedevelopmento…     

New Synthesis of (±)Shikalkin

The naturally occurring enantiomers mixture of shikonin (R-1) and alkannin (S-1) has been named shikalkin by H.Brockmann1. Shikonin was first isolated as its acetate from the roots of Lithospermum erythrorhizon (LE) which has been used for dyeing in China, Japan, and Korea from ancient times2. Alkannin was found in Alkanna tincloria(AT) and many other type of Boraginaceous roots1. Shikalkin 1 and their ester derivatives showed antitumor3, antiinflammatory4, antibacerical5, immunostimu…     

Total Synthesis of (±) Flavipucine

In 1972 we proposed¹ structure 3 for flavipucine, an antibiotic from an Aspergillus flavipes strain. Later we reported² a novel reaction of 6-methyl-4-hydroxy-2-pyridone with α keto aldehydes which provided 1a from isobutylglyoxal and it was stated that we believed 1a would serve as a key intermediate in the total synthesis of flavipucine 3.     

Total Synthesis of (±)-Glabridin

An efficient formal synthesis of (±)-glabridin was accomplished in 10 steps from resorcinol using Raney Ni to reduce carbon–carbon double bonds in α,β-unsaturated carbonyl compound as the key step.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis of (±)-heliannuol C

A synthesis of (±)-heliannuol C is described involving Bargellini condensation, Dieckmann cyclization and ortho-ester Claisen rearrangement followed by a regioselective epoxide reduction. A new CuI-catalyzed [2+2] cycloaddition reaction is also described.     

Total Synthesis of (±)-Boschnialactone and (±)-Tetrahydroanhydrodesoxyaucubigenin

A total synthesis of (±)-boschnialactone ( 1 ) and (±)-tertahydroanhydrodesoxyaucubigenin ( 2 ) is described and trisubstitued cyclopentenoid 3 is a key intermediate.     

Total Synthesis of (±)-Waihoensene

The first total synthesis of waihoensene, a tetracyclic diterpene containing an angular triquinane and a six-membered ring, with four contiguous quaternary carbon atoms, was achieved through the tandem cycloaddition reaction of an allenyl diazo substrate containing a six-membered ring via trimethylenemethane (TMM) diyl intermediate.     

Stereoselective Synthesis of (±) Neocnidilide

The lactone neocnidilide 8 occur in the roots of Cnidilide officinale1 which is shown to inhibit the growth and toxin production of mycotoxin-producing fungi2. Although The synthesis of lactones 7, which is stereoisomer of cnidilide, and 8 had been reported by others3, 4, we would like to report the highly stereoselective synthesis of its racemic isomer 8 as shown in Scheme 1. Scheme 1 COOHHOOCbcOOHH1234d5eOHOHHH 6fOOHHH 7g8COOHOHa12345673a7aOHHOH1235673 a7a1234561'1'2'…     

Synthesis of (±)-phthalascidin 622

A synthesis of functionalized phenolic α-amino-alcohols (±)-8 and (±)-16 as synthetic precursors of the catechol tetrahydroisoquinoline structure of phthalascidin 650 was disclosed. (±)-8 was prepared in 5 steps from the commercially available sesamol. Starting from 3-methyl catechol 5, 8 steps gave rise to the synthesis of phenolic α-amino-alcohol (±)-16 in 27% overall yield. This synthetic strategy involved the elaboration of fully functionalized aromatic aldehyde 13 and its transformation into a phenolic α-amino-alcohol (±)-16, through a Knoevenagel condensation, simultaneous reduction of nitroketene and ester functions, and hydrogenolysis of the benzyl protecting group. The pentacycle (±)-4 was obtained after 4 additional steps. The Pictet-Spengler cyclisation between the phenolic α-amino-alcohol (±)-16 and the N-protected α-amino-aldehyde 4 allowed to obtain (1,3′)-bis-tetrahydroisoquinoline 17 with N-methylated and N-Fmoc removed. The last step was a Swern oxidation allowing the expected intramolecular condensation.     

Total Synthesis of (±)Hinesol

Hinesollanditsrelatedspiro[4.5]decenesesquiterpeneagarospir0l2wereisolatedfromavarietyofplants.Althoughmanmethodshavebeendevelopedfortheirsynthesis,fewofthemgivesatisfactoryresults,especiallywithcontrolofstereochendstryatthespirocenteraswellinC2andC1O.Inl985,YangreportedthattWonewspiro[4.5]decenesesquiterpenes,whichhaveunusualbiologicalactivity,wereis0latedfromAquilariasinensiS(Lour.)Gilgandnamedbadrixinicacid3andbairnuxinal4l.InordertostUdytheirsmictUre-activityrelati0nshiPfurther,wehave…     

Total Synthesis of (±)-Corymine

The first total synthesis of the hexacyclic indole alkaloid (±)-corymine is described. Starting from the readily available N-protected tryptamine, the title compound was achieved in 21 steps in 3.4 % overall yield. Key steps of the synthesis include: a) the addition of a malonate to a 3-bromooxindole to afford 3,3-disubstituted oxindole, b) the formation of a 12-membered cyclic enol ether by intramolecular O-propargylation, immediately followed by propargyl Claisen rearrangement to provide the α-allenyl ketone stereospecifically, c) DMDO oxidation to install a hydroxy group in a highly stereoselective manner, and d) the SmI₂-mediated reductive C−O bond cleavage to remove the α-keto carboxyl group.     

Concise Synthesis of(±)-epi-Chrysotricine

Chrysotricine 1 was isolated from the Chinese herb medicine Hedyotis Chrysotricha and was shown to possess antitumor activity1. Its structure has been elucidated as a novel zwitterionic (-carboline alkaloid containing a 2,2,5-trisubstituted tetrahydrofuranyl group. The (-carboline compounds have attracted considerable attraction in recent years because of their promising and intriguing biological activities2. Recently, we have established the absolute configuration of chrysotricine by the fir…     

The Total Synthesis of (±)-Hinesol and (±)-Agarospirol

Eversinceβ-vetivoneanditscongenerswererecognizedtohavespiro[4,5]decaneratherthanthehydroazuleneskeleton,[1]themembersofthisclasshavebecomeafavoritetargetforsynthesis.Herein.weshowafacileconversionofthemajorphotoproductformedinthereactionofmethyl2,4-dioxopentancate(1)with1,5-dimethyl-6-methylenecyclochexene(2)[2]intovetispiranederivatives,hinesol(3),ametaboliteofAtractylodeslancea[3,4],andagarospirol(4)foundinAquilariaagollocha,[5]inracemicforms,respectively.WhenanEtoAsolutionof1and2wasintema…