3-ethyl-3-phenylazetidinone-2—I. Synthesis of (R)-, (S)- and (RS)-monomer,polymerization and properties of polymers

Synthesis and optical resolution of 3-ethyl-3-phenylazetidinone-2 were improved to obtain (RS)-, (R)- and (S)-monomers having optical purities up to 98%, which could successfully be determined by ¹H-NMR 250 MHz using tris[3-(2,2,2-trifluoro-l-hydroxymethylidene)d-camphorato]europium III as a shift reagent. These monomers were polymerized anionically in HMPT using potassium salt as a catalyst and by the addition of 1-acetyl-4,4-dimethylazetidinone-2 as a chain initiator. Optical purity of the starting monomer seemed to be maintained in the resulting polymers, the thermal properties of which were found to depend on the mean length of the stereoblocks contained in the chain. While the reactivity, in particular the case of polymerization, of monomer increased with the optical purity, no evidence could be obtained for stereoregulation by a preferential incorporation of a monomer enantiomer according to the configuration of the growing chain end unit.     

Asymmetric Synthesis of (-)-(2R,3R,6S)-Irnigaine

Introduction　　Asarelativelynewmemberofnaturalalkaloidswith2 ,6 disubstituted 3 piperidinolskeleton ,irnigaine 1wasisolatedfromthetubersofArisarumVulgare (Araceae)in1995byMelhaouiandBode .1Itsstructureandrelativeconfigurationswereelucidatedby1HNMRstudiesandtheabsoluteconfigurationwasproposedonthebasisofitsopti calrotation .1Soonafterthen ,Meyerandhisco workersreportedthefirstsynthesisof (- ) (2R ,3R ,6S) irni gaineandtheconfigurationconfirmation .Althoughtheirsynthesisroutewasshortan…     

Non-thiazolidinedione antihyperglycaemic agents. Part 4: Synthesis of (±)-, (R)-(+)- and (S)-(−)-enantiomers of 2-oxy-3-arylpropanoic acids

The synthesis of a new series of potent 2-oxy-3-arylpropanoic acid antihyperglycaemic agents in both racemic and non-racemic form is described. Resolution of racemic acids 1 is accomplished via amide formation with either (S)-2-phenylglycinol or (S)-4-benzyloxazolidin-2-one as complementary resolving agents.     

Synthesis and cytotoxicity of dinuclear platinum(Ⅱ) complexes of (1S, 3S)-1, 2, 3, 4-tetrahydroisoquinolines

A series of novel dinuclear platinum(Ⅱ) complexes with (1S, 3S)-1,2,3,4-tetrahydroisoquinolines as the ligands were synthesized as potential anticancer agents in several steps starting from commercially available L-DOPA. The cytotoxicities of the series of dinuclear platinum(Ⅱ) complexes of tetrahydroisoquinoline were tested against HCT-8, BEL-7402, A2780, MCF-7, Hela, A549 and BGC-823 cell lines by the MTT test. These complexes showed selective inhibition activity against cisplatin-insensitive cell line Skov3.     

2-Polyfluoroalkylchromones. 11. Synthesis and structures of 5-hydroxy-3-(2-hydroxyaryl)-5-polyfluoroalkyl-Δ2-pyrazolines and 3(5)-(2-hydroxyaryl)-5(3)-polyfluoroalkylpyrazoles

The reaction of 2-hydroxy-2-polyfluoroalkylchroman-4-ones with hydrazine affords 5-hydroxy-3-(2-hydroxyaryl)-5-polyfluoroalkyl-²-pyrazolines, whereas 2-polyfluoroalkylchromones under similar conditions produce 3(5)-(2-hydroxyaryl)-5(3)-polyfluoroalkylpyrazoles. 5-(2-Hydroxyaryl)-1-methyl-3-polyfluoroalkylpyrazoles were synthesized in the reaction with methylhydrazine, and the reaction with phenylhydrazine afforded regioisomeric 3(5)-(2-hydroxyphenyl)-1-phenyl-5(3)-polyfluoroalkylpyrazoles.     

Asymmetric synthesis of heteroorganic analogs of natural products 5. Synthesis of pure diastereomers and enantiomers of fluoro-substituted (2S,3R)- and (2R,3R)-β-phenylserines

A convenient method is proposed for the preparative synthesis of pure diastereomers and enantiomers of fluoro-substituted (2S,3R)- and (2R,3R)--phenylserines by the hydroxyalkylation of the Ni(II) — complex of the Schiff base of glycine with (S)-2-N-(N¹-benzylpropyl)aminobenzophenone using the corresponding fluoro-substituted benzaldehydes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya. No. 8, pp. 1906–1913, August, 1991.     

Total Synthesis of 3 (R)-Panaxynol

Panaxynol1,asacommonconstituentofmanyplantparts',wasfirstdescribedbyTakahashietal.2in1964asaconstituentofPanaxyginseng.C.A.MeyershowedinhisBioassayshowedthatpanaxynolhadselectiveinvitrocytotoxicityagainstL-1210',MKI,B-16,andL-929cancercelllinescomparedtonormalcellcultures4.TheabsoluteconfigurationhadbeenestablishedbyLarsenetal.5tobe3R.Hereinwereportthefirsttotalstereoselectivesynthesisofpanaxynol(l).C'-CIafragmentofpanaxynol1wasobtainedaccordingtothefollowingsequencefReagentsandconditio…     

Total Synthesis of (-)-α-Pinguisene

In previous work from our laboratory, we demonstrated that α-carbonyl radical cyclization reactions can serve efficiently as key steps in total synthesis of natural products.1 In this presentation,we report the total synthesis of (-)-α-pinguisene from enone 1 via α-carbonyl radical cyclization.     

Synthesis and reactivity of 3-(trichlorogermyl)propanoic acid and 3-(triphenylgermyl) propanoic acid

3-(Trichlorogermyl)propanoic acid (la) reacts with phenylmagnesium bromide in malar ratio 1:4 to give 3-(triphenylgermyl)propanoic acid (2a).In the compounds la and 2a theβ-carboxylic functional group shows some unusual properties when they react with excess of phenylmagnesium bromide.The compound la reacts with phenylmagnesium bromide in molar ratio 1:5 to give phenyl 2-(triphenylgermyl)ethylketone (3a) and in molar ratio 1:6 to give l,l-diphenyl-3-(triphenylgermyl)propanol (4a).The compound 2a reacts with phenylmagnesium bromide in molar ratio 1:2 to give 3a and in molar ratio 1:3 to give 4a also.Dehydration of the compound 4a with dilute hydrochloric acid seems especially easy.Moreover,the compound la reacted with phenylmagnsium bromide in molar ratio 1:6,then the mixture was treated with dilute hydrochloric acid to give 1,1-diphenyl-3-(triphenylgermyl)-1-propene (5a) in one pot reaction.Alkyl Ge-C bond in the compound 5a can be cleaved selectively by lithium aluminium hydride ( LiAlH4) in good yiel     

Synthesis, Structure and Dielectric Property of Ba_(1- x)Sr_xZr_yTi_(1- y)O_3

ＩｎｔｒｏｄｕｃｔｉｏｎＢａＴｉＯ３ｉｓａｓｔｒｏｎｇｄｉｅｌｅｃｔｒｉｃｍａｔｅｒｉａｌ，ｗｈｉｃｈｉｓｗｉｄｅｌｙｕｓｅｄｉｎｔｈｅｐｒｏｄｕｃｔｉｏｎｏｆｅｌｅｃｔｒｉｃｃｏｍｐｏｎｅｎｔｓｓｕｃｈａｓｃｅｒａｍｉｃｃａｐａｃｉｔｏｒ，ＰＴＣ，ｍｅｄｉｕｍａｍｐｌｉｆｅｒ［１］．Ｉｔｈａｓｔｈｅｈｉｇｈｅｓｔｄｉｅｌｅｃｔｒｉｃｃｏｎｓｔａｎｔａｔ１２０℃（ｃａ．１０４），ｗｈｉｌｅｉｔｓｄｉｅｌｅｃｔｒｉｃｃｏｎｓｔａｎｔａｔｒｏｏｍｔｅｍｐｅｒａｔｕｒｅｉｓｏｎｌｙ１／６ｏｆｔｈｅＣｕ…     

Total Synthesis of (-)-Baimuxifuranic Acid

ThenatieChenmanginclha,oneofthemoStbeandexpensivCherbaldrugSin~tionalChjnsemdednesisthewoodypartofAquIIarasinensisW.)Gilg.,whoseVofatileoilseforitaIUUnberofinterestinbiologicalandphannacologicalactivities,suchasanestheha,muscularrelaxationandanalgesta'.ReCentiyYanetaI2isolated(-)taim~cacid(1)frOmtheVOboleoilofChenAlang,anddeennineditSStIUCtUrbySpeCtrscoPicmethodandred~1toaknowncornPOunisobaimndnolCoInPOun1isthefirStcarboxylicacidwithdihydragarohanskeletonisolatedfromnisources.He…     

Synthesis of (±)-7-hydroxylycopodine

A six step synthesis of (±)-7-hydroxylycopodine has been achieved in 5% overall yield. In the key step, a Prins cyclization of a bicyclic keto alkyne in 60% H(2)SO(4) forms a tricyclic dihydroxy amino ketone.     

A Total Synthesis of (±)-α-Chamigrene-3-one

Thephotocycloadditionofmethyl2,4-dioxopentanoate1toalkenesorconjugatedolefins2regioselectivelygavethecycloadduct3(Schemel).ThisreactioncouldconvenientlybeusedtoconstructthebasicframeworkofvariousnatUraIlyoccutringchamigran-tyPespirosesquiterPenes,suchasa-chamigrene",6-chamigrene:=,andaseriesofrelatedhaIogenatedderivativesd.The(i)-Q-Chamigrene-3-onewasanewmemberofthisfamilyandwasrecentlyisolatedfromMarchantiapolymorPha".whichpossessedthestrUctUreofasyntheticintermediate,1-methoxycarbonyl-5,…     

Europium,terbium, and ytterbium 3-(3′-triethoxysilylpropyl)pentane-2,4-dionates. Synthesis and the formation of luminescent sol-gel films

3-(3′-Triethoxysilylpropyl)pentane-2,4-dione, (EtO)₃SiCH₂CH₂CH₂C[-C(O)CH₃]₂ (I), was synthesized from 3-allylpentane-2,4-dione, CH₂ = CH-CH₂-C[-C(O)CH₃]₂, and triethoxysilane, (EtO)₃SiH, in the presence of Speier’s catalyst. The silylation occurred mainly at the terminal C atom of the allyl group. The corresponding europium(III), terbium(III), and ytterbium(III) β-diketonates were synthesized from compound I and appropriate metal isopropoxides and used to obtain transparent sol-gel films containing Eu³⁺, Tb³⁺, and Yb³⁺ cations. The film formation was studied by IR spectroscopy. It was found that moisture causes not only the hydrolysis and condensation of triethoxysilyl groups but also the hydration of the cation of the rare-earth metal. When the terbium complex was excited at the wavelength of one of the two peaks (230 and 308 nm) in the excitation spectrum, the cation fluoresced intensely at 491, 547, 585, and 623 nm due to the transitions ⁵ D ₄ → ⁷ F ₆, ⁵ D ₄ → ⁷ F ₅, ⁵ D ₄ → ⁷ F ₄, and ⁵ D ₄ → ⁷ F ₃, respectively. All these bands were narrow, the band at 547 nm being most intense. No emission from the organosilicon matrix at 440 nm was observed. The emission spectra of Eu³⁺-containing films showed, along with the bands at 593, 618, 667, and 700 nm due to the emission from the cation (⁵ D ₀ → ⁷ F ₁, ⁵ D ₀ → ⁷ F ₂, ⁵ D ₀ → ⁷ F ₃, and ⁵ D ₀ → ⁷ F ₄ transitions, respectively), an intense band at 491 nm due to the emission from the matrix.     

Synthesis of (±)-7-hydroxylycopodine

A seven-step synthesis of (±)-7-hydroxylycopodine that proceeds in 5% overall yield has been achieved. The key step is a Prins reaction in 60% sulfuric acid that gave the key tricyclic intermediate with complete control of the ring fusion stereochemistry. A one-pot procedure orthogonally protected the primary alcohol as an acetate and the tertiary alcohol as a methylthiomethyl ether. The resulting product was converted to 7-hydroxydehydrolycopodine by heating with KO-t-Bu and benzophenone in benzene followed by acidic workup. During unsuccessful attempts to make optically pure starting material, we observed the selective Pt-catalyzed hydrogenation of the 5-phenyl group of a 4,5-diphenyloxazolidine under acidic conditions and the Pt-catalyzed isomerization of the oxazolidine to an amide under neutral conditions. In attempts to hydroxylate the starting material so that we could adapt this synthesis to the preparation of (±)-7,8-dihydroxylycopodine (sauroine) we observed the novel oxidation of a bicyclic vinylogous amide to a keto pyridine with Mn(OAc)(3) and to an amino phenol with KHMDS and oxygen.     

Synthesis,characterization and reactivity of bromo(syn-η3-2,4-pentadienyl)tricarbonyliron

The reaction between trans-1-bromopenta-2,4-diene and nonacarbonyldiiron in pentane yields (syn-η³-C₅H₇)Fe(CO)₃Br. The spectroscopic data and chemical reactivities of this compound are reported and discussed.     

Oxiranyl β-Aminovinyl Ketones. 7. Synthesis of 5-Hydroxy-3-(1-oxo-2,3-epoxyalkyl)benzofurans

5-Hydroxy-3-(1-oxo-2,3-epoxyalkyl)benzofurans were obtained with yields of up to 81% by the reaction of p-benzoquinone with oxiranyl -dimethylaminovinyl ketones in acetic acid.     

Synthesis of α-(perfluoroalkyl)-ω-(trialkylsilyl)alkanols

The synthesis of alkanols of the general formula R₃Si(CH₂)_nCH(OH)R_F (n = 1–3) is elaborated and their behavior under GC-MS is studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1516-1519, June, 1996.