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1.
A New Synthesis of (±)-Dihydrorecifeiolide Ethyl 1-(2′-formylethyl)-2-oxocyclooctane-1-carboxylate ( 2 ) prepared by Michael reaction of ethyl 2-oxocyclooctane-1-carboxylate ( 1 ) was regioselectively methylated at the aldehyde group with (CH3)2Ti[OCH(CH3)2]2 to give 3 (Scheme 1). The alcohol 3 was treated with Bu4NF to give the deethoxycarbonylated product 4 which by distillation gave the bicyclic enol ether 5 . Oxidation (m-chloroperbenzoic acid) of 5 and reduction of the resulting oxolacton 6 yielded the title compound (±)-dihydrorecifeiolide ( 7 ) in an overall yield of nearly 50 %. Methylation of the aldehyde 2 with MeLi gave the ring-enlarged lacton 9 in poor yield (13 %). The deethoxycarbonylation reaction 3 → 4 was studied in more detail (Scheme 3). 相似文献
2.
Peichun Li Amar Zerroukhi Jianding Chen Yvan Chalamet Thomas Jeanmaire Zhean Xia 《Journal of polymer science. Part A, Polymer chemistry》2008,46(23):7773-7784
Ti[O(CH2)4OCH?CH2]4, used for the ring‐opening polymerization (ROP) of ε‐caprolactone, was synthesized through the ester‐exchange reaction of titanium n‐propoxide and 1,4‐butanediol vinyl ether, and its chemical structure was confirmed by nuclear magnetic resonance (1H NMR) and thermogravimetric analysis (TGA). The mechanism and kinetics of Ti[O(CH2)4OCH?CH2]4‐initiated bulk polymerization of ε‐caprolactone were investigated. The results demonstrate that Ti[O (CH2)4OCH?CH2]4‐initiated polymerization of ε‐caprolactone proceeds through the coordination‐insertion mechanism, and all the four alkoxide arms in Ti[O (CH2)4OCH?CH2]4 share a similar activity in initiating ROP of ε‐caprolactone. The polymerization process can be well predicted by the obtained kinetic parameters, and the activation energy is 106 KJ/mol. Then, the rheological method was employed to investigate the feasibility of producing the crosslinked poly(ε‐caprolactone)‐poly (n‐butyl acrylate) network by using Ti[O(CH2)4OCH?CH2]4 as the ROP initiator. The tensile test demonstrates that the in situ generated crosslinked PCL‐PBA network in PMMA matrix provides the possibility of ameliorating the tensile properties of PMMA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7773–7784, 2008 相似文献
3.
Synthesis of 12-Cyano-15-hexadecanolide by Ring Enlargement of 1-(3′-Hydroxybutyl)-2-oxocyclododecane-1-carbonitrile In the presence of Bu4NF, 2-oxocyclododecane-1-carbonitrile ( 1 ) reacted with acrylaldehyde to form the corresponding aldehyde 2 which was methylated, e.g. with CH3 Ti[OCH(CH3)2]3. The resulting 1-(3′-hydroxybutyl)-2-oxocyclododecane-1-carbonitrile ( 5 ) was converted to 12-cyano-15-hexadecanolide ( 6 ) in nearly quantitative yield under the influence of Bu4NF. 相似文献
4.
Short Total Syntheses of (±)-Sativene and (±)-cis-Sativenediol Our approach to (±)-sativene (7) and (±)-cis-sdtivenediol (9) involves: (a) reaction of 3-methylbutanoyl chloride with Et3N/cyclopentadiene to give the endo-isopropyl-ketone 1 (here improved to 71%), (b) NBS bromination of 1 to a 5:1 mixture (87%) of the bromo-ketones 2 and 3 , (c) NFD-reaction sequence initiated by the attack of 1,2-butadienyl titanate (complex of 15 , obtained from 2-butine) on 2/3 to afford 52% of the brexenone derivative 4 (along with 8% of its epimer 16 ), (d) addition of dibromomethane to 4 forming 63% of the diene-alcohol 5 (along with 13% of the diene-carbaldehyde 38 ), and (e) carbenoid ring-expansion with MeLi applied to 5 resulting in 41% the diene-ketone 6 (along with 15% of a 1:3 mixture of the diene-ketones 32 and 33 ). Wolff-Kishner reduction of 6 led to 81% of (±)-sativene (7), when enough O2 was present, but to 97% of the diene 8 in the strict absence of O2. (±)-cis-Sativenediol (9) was obrained (86%) by OsO4 hydroxylation of 8 . The brexenone derivatives 4 and 16 (6:1, 50%) were also produced when the NFD-reaction sequence was applied to the isomeric bromo-ketone mixture 13/13 (1:3). The latter was obtained by NBS bromination of 10 , which in turn was available by base epimerization of 1 , followed by destructive removal of unreacted 1 by repeated gas-flow thermolysis. An analogous (less convenient) route to (±)-sativene (7) passed through a series of dihydro compounds (the ene series) it started with the methylidene-ketone 36 , which was the product (97%) of a partial hydrogenation of 4 . Addition of dibromomethane to 36 led t 62% of the methylidene-alcohol 39 (along with a little tetracyclic ether 40 ). Carbenoid ring expansion of 39 with MeLi afforded ca. 42% of the methylidene-ketone 41 (along with 7% of the methylidene-ketone 43 or, under slightly different condition, along with 9% of the methylidene-ketone 42 and 10% of the methylidene-carabaldehyde 44 ). The methylidene-alcohol 39 and the methylidene-ketone 43 were also obtained by partial hydrogenation of 5 and 33 , respectively. Wolff-Kisher reduction converted 41 into (±)-sativene ( 7 99%); the same conditons applied to 42 afforded only ca. 8% 7 (along with three other hydrocarbons, one of them (ca. 21%) probably being (±)-copacamphene (45)). In the diene series, the two succeeding reactions ( 4→5 and 5→6 ) competed with the same side reaction, a rearrangement leading to the brendene-aldehyde 38. In the ene series, the corresponding dihydro-by-product 44 was found in the reacton 39→41 , but not during 36→39. These side reactons could largely be suppressed by keeping the reaction temperature low. An explanation is proposed. 相似文献
5.
A new Synthesis of (±)-Pyrenophorin The synthesis of pyrenophorin (I), a 16-membered dilactone metabolite of plant pathogenic fungi is described. Reaction of the Grignard reagent II with the activated succinic acid ester III gave the methyl (t-butyl)dimethylsilyloxy-oxo-octanoate IV which was converted into the corresponding ethylene acetal. Dehydrogenation via the benzeneselenenyl derivative lead to pyrenophorinic acid V with protected functional groups. Selective removal of silyl group followed by saponification of the ester group provided the ethylene acetal-hydroxy acid VI suitable for the cyclodimerisation reaction. This was effected with azodicarbonic acid ester and triphenylphosphine at ?40° in a dilute toluene solution. The 16-membered dilactones VII with protected carbonyl groups were isolated in 24% yield. Silver-ion induced cyclodimerisation of the S-2-pyridyl carbothioate of VI gave much lower yields. Removal of the acetal groups lead to (±)-pyrenophorin (I) and meso-pyrenophorin in about equal amounts. 相似文献
6.
A total synthesis of racemic 3-deoxy-7,8-dihydromorphine ((±)- 2 ) and 4-me-thoxy-ALmethylmorphinan-6-one ((±)- 3 ) is described. The key intermediate was 2,4-dihydroxy-N-formylmorphinan-6-one (11) , obtained from 3,5-dibenzyloxy-phenylacetic acid (4) in 41.8% overall yield. Bromination of 11 , and treatment with aqueous NaOH-solution afforded, after N-deblocking and reductive N-methylation with concomitant removal of the aromatic bounded Br-atom, the morphinanone 14. Elimination of the HO–C(2) group in 14 was accomplished by hydrogenolysis of its N-phenyltetrazolyl ether 15 , to give 3-deoxy-6,0-didehydro-7,8-dihydromorphine (16). Reduction of 16 with L-Selectride at low temperature provided (±)- 2 in high yield. The ether 15 directly afforded, under more vigorous reduction conditions, 4-hydroxy-N-methylmorphinan-6-one (17). and after O-methylation of 17 , the methyl ether (±)- 3 was obtained. A (1:l)-mixture of 4-hydroxy-2-methoxy-N-methylmor-phinan-6-one (28) and its 2-hydroxy-4-methoxy isomer 30 svere obtained by Grewe-cyclization of a mono-methoxylated aromatic precursor similar to that which afforded 11. The 2,4-dioxygenated N-methylmorphinan-6-ones 29 , 31 and 38 were also prepared and characterized. 相似文献
7.
Synthesis of Two Naturally Occurring 10-Membered Ring Lactones: (±)-Phoracantholide J and I Two 10-membered ring lactones 7 and 11 from the metasternal secretion of the eucalypt longicorn Phoracantha synonyma have been synthesized by the following method. Reaction of the dilithium derivative of 4-pentynoic acid ( 3 ) with 4-tetrahydropyranyloxy-1-pentylbromide ( 2 ), followed by removal of the protecting group and by esterification with diazomethane, gave methyl 9-hydroxy-4-decynoate ( 4 ; s. Scheme 1). Partial hydrogenation of the triple bond in 4 with Lindlar palladium catalyst, followed by saponification lead to cis-9-hydroxy-4-decenoic acid ( 6 ). The 9-hydroxydecanoic acid ( 9 ) was synthesized by addition of methyl magnesium iodide to methyl 8-formyloctanoate ( 8 ) followed by saponification (s. Scheme 2). The hydroxy acids 6 and 9 were converted into the S-(2-pyridyl) thioesters and cyclized in dilute benzene solution under the influence of silver ions to yield (±)-phoracantholide J ( 7 ) and I ( 11 ) in 74 and 71% yield, respectively. 相似文献
8.
Karl H. Schulte-Elte Herv Pamingle Arnold P. Uijttewaal Roger L. Snowden 《Helvetica chimica acta》1992,75(3):759-765
Acid-mediated cyclisation of trienone 8 , readily available from 2,3-dimethylbutanal ( 1 ; five steps: 47% yield), using fluorosulfonic acid (6.8 mol-equiv.) in 2-nitropropane at ?70°, afforded a 14:9:1 mixture (70% yield) of (±)-cis-α-irone ( 9 ), (±)-trans-α-irone ( 10 ), and (±)-β-irone ( 11 ). Other acidic conditions examined, using 95% aq. H2SO4 solution, 85% aq. H3PO4 solution, or SnCl4, gave inferior results. 相似文献
9.
Stefan Bienz Armin Guggisberg Rudolf Wlchli Manfred Hesse 《Helvetica chimica acta》1988,71(7):1708-1718
Syntheses of the Spermidine Alkaloids (±)-Inandenin-10-ol, Inandenin-10-one, and (±)-Oncinotine New syntheses of the title compounds using two-ring-enlargement reactions are described. Starting from the aldehyde 1 , the corresponding 4′-aza derivative 15 could be obtained by reductive amination with the appropriate and protected spermidine derivative 14 (Scheme 4). Enlargement of the carbocyclic ring in 15 by five members gave, after further transformations, the hydroxylactam 18 . Transamidation of 18 , the second ring-enlargement step, led to (±)-inandenin-10-ol (7;22.9% overall yield) and, after oxidation, to inandenin-10-one ( 8 ; 22.5%, overall yield). (±)-Oncinotine 6 was synthesized by two pathways (Scheme 6): protection of the terminal NH2 group by treatment with the Nefkens reagent and replacement of the OH group by Cl gave 24 , which by thermal transamidation followed by direct ring closure led to the oncinotine derivative 26 . The same intermediate could be obtained in higher yield via 28 by oxidation and protection of 18 followed by transamidation and reductive ring closure. Treatment of 26 with hydrazine finally gave (±)-oncinotine 6 in 15.9% overall yield. 相似文献
10.
Biomimetic syntheses of racemic aristomakinine ((±)- 3 ) and aristomakine ((±)- 4 ), an unusual indole alkaloid bearing an N-isopropyl group, are described. The key step is a Grob-type fragmentation of anti-15-aristotelinyl methanesulfonate ((±)- 2 ) to the intermediate iminium ion I which, upon subsequent hydrolysis, furnished aristomakinine ((±)- 3 ). On the other hand, the same intermediate could be reduced in situ to aristomakine ((±)- 4 ). The controversial relative configurations of the two alkaloids have been firmly established by means of NOE difference experiments. 相似文献
11.
The abstraction of the halogenide ligands in [Re(CH3CN)2Cl4]? should result in a solvent‐only stabilized ReIII complex. The reactions of salts of [Re(CH3CN)2Cl4]? with silver(I) and thallium(I) salts were investigated and the solid‐state structures of cis‐[Re(CH3CN)2Cl4]·CH3CN and cis‐[Re(NHC(OCH3)CH3)2Cl4] are described. 相似文献
12.
Nandu Bala Sharma Jayshree Shahai Rajendra Singh Ghadwal Erwann Jeanneau 《Journal of Coordination Chemistry》2016,69(1):135-148
Reaction of Ti(OPri)4 with 2-methyl-2,4-pentanediol [HOGOH, where G = CMe2CH2CH(Me)] in 1?:?3 M ratio under reflux afforded the monomeric [Ti(OGO)(OGOH)2] (1), which on further reactions with [Al(OPri)3] or [Nb(OPri)5] in 1?:?1 and 1?:?2 M ratios afforded heterometallic derivatives, [Ti(OGO)3{M(OPri)n?2}] and [Ti(OGO)3{M(OPri)n?1}2] [where M = Al (n = 3), Nb (n = 5)], respectively. Similar reactions of Zr(OPri)4?PriOH with a number of glycols [HOGOH, where G = CH(Me)CH(Me), CMe2CMe2, CMe2CH2CH(Me)] yielded dimeric [Zr2(OGO)2(OGOH)4]. [Zr2(OGO)6{M(OPri)n?2}2] and [Zr2(OGO)4(OGOH)2M(OPri)n?2] [M = Al (n = 3), Ti (n = 4), Nb (n = 5)] were prepared by 1?:?2 and 1?:?1 reactions, respectively, of [Zr2(OGO)2(OGOH)4] with Al(OPri)3, Ti(OPri)4, or Nb(OPri)5. Surprisingly, a 1?:?2 reaction of [VO(OPri)3] with 2,2-diethyl-1,3-propanediol in benzene followed a different reaction and produced a neutral tetranuclear derivative [V4(O)4(μ-OCH2CEt2CH2O)2(OCH2CEt2CH2O)4] (18). All of these derivatives were characterized by elemental analysis, molecular weight measurements, FT-IR, and 1H NMR (and wherever possible, by 27Al or 51V NMR) spectroscopic studies. The derivatives [Zr2(OCMe2CH2CH(Me)O)2(OCMe2CH2CH(Me)OH)4] (9 and 18) were additionally characterized by single-crystal X-ray structure analysis. 相似文献
13.
Song Won Ko Devin A. Mourey Trevor Clark Susan Trolier-McKinstry 《Journal of Sol-Gel Science and Technology》2010,54(3):269-275
A chemical solution was employed for deposition of gadolinium molybdate [β-Gd2(MoO4)3] thin films. Gadolinium acetylacetonate hydrate {[CH3COCH = C(O–)CH3]3Gd·xH2O}, molybdenum isopropoxide {Mo[OCH(CH3)2]5}, and acetylacetone were used in synthesis of this molybdate. Thermal gravimetry and differential scanning calorimetry suggested
that crystallization of β-Gd2(MoO4)3 occurs at around 480 °C. Phase-pure, orthorhombic β-Gd2(MoO4)3 films were deposited on Pt/Ti/SiO2/Si(100) substrates. β-Gd2(MoO4)3 films crystallized at 750 °C showed a strong (00l) preferred orientation. The film dielectric constant measured was 10~14 and the dielectric loss was less than 3%. There was
no marked signature in the permittivity at the bulk Curie temperature, approximately 159 °C. 相似文献
14.
Olga Crespo M. Concepcin Gimeno Peter G. Jones Antonio Laguna 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):46-47
The title compound, 7‐[(Ph2P)Au(PPh3)]‐8‐(CH3)‐7,8‐nido‐C2B9H10]·0.5CH2Cl2 or [Au(C15H23B9P)(C18H15P)]·0.5CH2Cl2, is the first reported gold derivative of the ligand [7‐(Ph2P)‐8‐(CH3)‐7,8‐nido‐C2B9H10]?. It has a mononuclear structure with the gold centre in an essentially linear coordination [P—Au—P 174.041 (15)°]. The open C2B3 face contains one H atom that is strongly bonded to the central B atom and semi‐bridging to a neighbouring B atom [B—H distances 1.070 (16) and 1.45 (3) Å]. 相似文献
15.
D. V. Griffiths S. J. Parrott M. Togrou J. R. Dilworth Yifan Zheng S. Ritter U. Abram 《无机化学与普通化学杂志》1998,624(9):1409-1414
Novel tetrameric rhenium(V) complexes have been prepared from [ReNCl2(PPh3)2] and [ReN(PMe2Ph)(S2CNEt)2], respectively. [ReNCl2(PPh3)2] reacts with 1.5 equivalents of KS2CNEt2 in methanol to yield the unusual dark red species [{cyclo-ReN}4(S2CNEt2)6(MeOH)2(PPh3)2][BPh4]2 · CH2Cl2 · 2 H2O ( 1 ). The crystal structure of the tetramer (triclinic, space group P1, a = 13.842(2), b = 15.213(2), c = 16.796(3) Å, α = 67.88(1), β = 70.90(1), γ = 88.05(1)°, U = 3080.2(8) Å3, Z = 1) shows four rhenium atoms in a square configuration which are bridged via linear asymmetric Re≡N–Re groups with bond lengths of about 169 and 203 pm. The molecule contains a centre of symmetry with two distinct octahedral rhenium environments. The first rhenium environment contains two bidentate dithiocarbamate ligands which complete the octahedral geometry and the second contains a bidentate dithiocarbamate ligand, coordinated methanol and has retained a single phosphine coligand. A symmetric compound containing the {cyclo-ReN}4 core is obtained from the reaction of [ReN(PMe2Ph)(S2CNEt2)2] with Al2Cl6 in acetone. [{cyclo-ReN}4(S2CNEt2)4Cl4(PMe2Ph)4] · 2 acetone ( 2 ) forms red crystals (monoclinic, space group C2/c, a = 21.432(6), b = 13.700(3), c = 28.060(9) Å, β = 102.37(1)°, U = 8048(4) Å3, Z = 4) with each rhenium atom coordinated by a bidentate dithiocarbamato, a phosphine and a chloro ligand. The non-planar 8-membered {ReN}4 ring contains asymmetric Re≡N–Re bridges (mean values: 1.69 Å and 2.029 Å, respectively). In contrast, reaction of [ReNCl(S2CNEt2)(PMe2Ph)2] with one equivalent of K[S2CN(Me)CH2CH2NMe3]I gave the mixed dithiocarbamato-cation [ReN(S2CNEt2)(S2CN(Me)CH2CH2NMe3)(PMe2Ph)]+ ( 3 ) which was isolated as a tetraphenylborate salt. 相似文献
16.
Manat Pohmakotr Wacharee Harnying Patoomratana Tuchinda Vichai Reutrakul 《Helvetica chimica acta》2002,85(11):3792-3813
The vicinal dianion 2 derived from triethyl ethanetricarboxylate reacted regioselectively with aldehydes and ketones at C(β) to provide paraconic acid derivatives 5a – f in moderate to high yields as mixtures of diastereoisomers. The paraconic acid derivatives 5e and 5f were utilized as the starting materials for the syntheses of (±)‐lichesterinic acid ( 12 ), (±)‐phaseolinic acid ( 13 ), (±)‐nephromopsinic acid ( 14 ), (±)‐rocellaric acid ( 15 ), and (±)‐dihydroprotolichesterinic acid ( 16 ). 相似文献
17.
Rate coefficients have been measured at 298 ± 4 K and 1000 mbar total pressure for the reactions of OH with a series of symmetrical acetals (R O CH2 O R, R = C1 to C4) using a relative kinetic technique. The investigations have been performed in a laboratory photoreactor and also in the large outdoor EUPHORE simulation chamber facility in Valencia, Spain. The following rate coefficients (in units of 10−11 cm3 molecule−1 s−1) have been obtained: dimethoxy methane (R = CH3), 0.49 ± 0.02; diethoxy methane (R = CH3CH2), 1.84 ± 0.18; di‐n‐propoxy methane (R = CH3CH2CH2), 2.63 ± 0.49; di‐iso‐propoxy methane (R = (CH3)2CH), 3.93 ± 0.48; di‐n‐butoxy methane (R = CH3CH2CH2CH2), 3.47 ± 0.42; di‐iso‐butoxy methane (R = (CH3)2CHCH2), 3.68 ± 0.57; di‐sec‐butoxy methane (R = CH3CH2C(CH3)H), 4.68 ± 0.05. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 797–803, 1999 相似文献
18.
Synthesis and Crystal Structures of [P(C6H5)4][1-(NH3)B10H9] and Cs[(NH3)B12H11] · 2CH3OH The reduction of [1-(NO2)B10H9]2? with aluminum in alkaline solution yields [1-(NH3)B10H9]? and by treatment of [B12H12]2? with hydroxylamine-O-sulfonic acid [(NH3)B12H11]? is formed. The crystal structures of [P(C6H5)4][1-(NH3)B10H9] (triclinic, space group P1 , a = 7.491(2), b = 13.341(2), c = 14.235(1) Å, α = 68.127(9), β = 81.85(2), γ = 86.860(3)°, Z = 2) and Cs[(NH3)B12H11] · 2CH3OH (monoclinic, space group P21/n, a = 14.570(2), b = 7.796(1), c = 15.076(2) Å, β = 111.801(8)°, Z = 4) reveal for both compounds the bonding of an ammine substituent to the cluster anion. 相似文献
19.
Mixed-ligand Complexes of Rhenium. V. The Formation of Nitrene Complexes by Condensation of Acetone at Coordinated Nitrido Ligands. Syntheses and Structures of fac-[Re{NC(CH3)2CH2C(O)CH3}X3(Me2PhP)2] Complexes (X = Cl, Br) The reaction of rhenium(V)-mixed-ligand complexes of the general formula [ReN(Cl)(Me2PhP)2(R2tcb)] (HR2tcb = N? (N,N-dialkylthiocarbamoyl)benzamidine) with HCl or HBr in acetone initializes a condensation of the solvent and results in nitrene-like compounds as a consequence of a nucleophilic attack of the coordinated nitrido ligand on the condensed acetone. The chelate ligands are removed during this reaction and complexes of the type fac-[Re{NC(CH3)2CH2C(O)CH3}X3(Me2PhP)2] (X = Cl, Br) are formed. fac-[Re{NC(CH3)2CH2C(O)CH3}Cl3(Me2PhP)2] crystallizes triclinic in the space group P1, a = 8.575(4); b = 9.088(3); c = 18.389(9) Å; α = 75.67(3)°, β = 85.30(3)°, γ = 70.58(4)°; Z = 2. A final R value of 0.031 was obtained on the basis of 6011 independent reflections with I ≥ 2σ(I). Rhenium is coordinated in a distorted octahedral environment with the three chloro ligands in facial positions. The rhenium-nitrogen bond (1,68(1) Å) is only slightly longer than typical Re? N bonding distances in nitrido complexes. fac-[Re{NC(CH3)2CH2C(O)CH3}Br3(Me2PhP)2] is isomorphous with the chloro complex. Triclinic cell with a = 8.625(4); b = 9.198(3); c = 18.581(5) Å; α = 75.62(3)°, β = 85.40(3)°, γ = 70.91(3)°; Z = 2. The R value converged at 0.049 on the basis of 3644 independent reflections with I ≥ 2σ(I). fac-[Re{NC(CH3)2CH2C(O)CH3}Cl3(Me2PhP)2] as well as fac-[Re{NC(CH3)2CH2C(O)CH3}Br3(Me2PhP)2] crystallizes in the noncentrosymmetric space group P1. 相似文献
20.
The crystal network of [Cp′2Ti(N?CH3? Gly)2]2+[Cl?]2 (Cp′ = (CH3)C5H4) complex, which crystallizes as a solvate with CH3OH, is built up with discrete cationic units connected through intermolecular H· · ·Cl bonds. The α‐amino acid ligands are attached through an intramolecular H· · ·O bond within one cationic unit. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献