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1.
Chen Y. -M. Chen D. -M. Wu Q. -M. Ye W. -J. Zhao C. -S. Liao W. -K. Zhou Z. -X. 《Journal of Structural Chemistry》2021,62(10):1501-1510
Journal of Structural Chemistry - (2S,2′S,6R,6′R)-4,4′-(6-Bromopyrido[2,3-d]pyrimidine-2,4-diyl)bis(2,6-dimethylmorpholine) is a novel organic intermediate having... 相似文献
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环己胺与手性元5-(R)-(1′R,2′S,5′R)-孟氧基-3-溴-2(5H)-呋喃酮的不对称M ichael加成/分子内亲核取代反应,得到含有两个新手性中心的氮杂环丙烷/稠合丁内酯标题化合物。对其进行了谱学表征和X-射线单晶衍射测定。标题化合物分子式为C20H33NO3,M r=335.47,三斜晶系,P1空间群,晶胞参数:a=5.438(11)。A,b=8.117(2)。A,c=11.572(2)。A,α=96.84(3)°,β=94.48(3)°,γ=101.86(3),°V=493.5(2)。A3,Z=1,D c=1.129g/cm3,R=0.0867,wR=0.2344。 相似文献
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The total synthesis of (+)-(6R,2′S)-cryptocaryalactone and (?)-(6S,2′S)-epi cryptocaryalactone is reported based on asymmetric acetate aldol reaction. Still–Gennari reaction, Evans acetal intramolecular oxa-Michael reaction and lactonisation are the key steps in the target synthesis. 相似文献
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Introduction Asarelativelynewmemberofnaturalalkaloidswith2 ,6 disubstituted 3 piperidinolskeleton ,irnigaine 1wasisolatedfromthetubersofArisarumVulgare (Araceae)in1995byMelhaouiandBode .1Itsstructureandrelativeconfigurationswereelucidatedby1HNMRstudiesandtheabsoluteconfigurationwasproposedonthebasisofitsopti calrotation .1Soonafterthen ,Meyerandhisco workersreportedthefirstsynthesisof (- ) (2R ,3R ,6S) irni gaineandtheconfigurationconfirmation .Althoughtheirsynthesisroutewasshortan… 相似文献
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YU An-Guang WANG Nai-Xing ZHANG Jun-Ping YANG Yun-Xu WANG Wu-Wei SHENG Rui-Long 《有机化学》2004,24(Z1):31-32
Benzopyran compounds possess diverse pharmacological properties such as β-blockade, anticonvulsant and antimicrobial.[1,2] Our interest has been focused on the synthesis of 1-[6-Fluoro-2S]-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2-ethanediol (6) and 1-[6-fluoro-(2R)-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2-ethanediol (7) which are particularly convenient precursor to (S,R,R,R)-NE (8). 8 containing four asymmetrical carbon atoms was reported to be the most active isomer.[3] Chandrasekhar[4] has reported on the synthesis of 8. The key step to synthesize this compound is to obtain the chiral chromanone 6 and 7. 6 was accomplished in 8 steps by the Clasien rearrangement and a one-pot Sharpless asymmetric epoxidation, but the compound 7 was accomplished in 10 steps. Johannes[5] used Zr-catalytic kinetic resolution of allylic ethers and Mo-catalyzed chromene formation to synthesize 8 in 14 steps. However both of the methods request many synthetic steps and expensive reagents. 相似文献
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I. B. Davydova V. M. Senyavin O. N. Zefirova G. M. Kuramshina Yu. A. Pentin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(4):671-680
IR absorption and Raman spectra of N-methylacetamide and (1S,5S,6R)-6-acetylamino-(5′-methoxyindolo[2,3-b])bicyclo[3.2.1]oct-2-ene are investigated. Optimized structures and harmonic force fields of stable conformers of both compounds are obtained by means of MP2 and DFT (B3LYP) methods using the 6-31+G** basis set. Based on quantum mechanical calculations, a detailed interpretation of spectra is proposed and vibrational frequencies of the most stable conformations are assigned. Correlations between structures and the spectra of N-methylacetamide and (1S,5S,6R)-6-acetylamino-(5′-methoxyindolo[2,3-b])bicyclo[3.2.1]oct-2-ene were considered and analytical spectral regions were proposed. 相似文献
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An unsaturated 2-methoxy-substituted 1-O-alkylglycerol, (Z)-(2′R)-1-O-(2′-methoxynonadec-10′-enyl)-sn-glycerol, a new analog of bioactive ether lipids, was synthesized from oleic acid and 2,3-isopropylidene-sn-glycerol. The two key steps of this synthesis were the conversion of oleyl aldehyde to a monounsaturated epoxide using Matteson’s method followed by hydrolytic kinetic resolution and a nucleophilic epoxide opening by 2,3-isopropylidene-sn-glycerol in the presence of potassium tert-butoxide in anhydrous DMF, which appeared to be a good reagent for this purpose. Furthermore, the diol by-product of the HKR process was also easily converted back to the starting epoxide thus almost doubling the amount of target molecule. 相似文献
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《Tetrahedron: Asymmetry》1999,10(18):3479-3482
A new approach towards the enantioselective synthesis of (2S,2′R)-erythro-methylphenidate (1) is described. The key step in the synthesis utilizes Evans' 4-substituted-2-oxazolidinone chiral auxiliary to control the diastereofacial selectivity in the hydrogenation of enamine intermediate 6, yielding the hydrogenated product 7 with excellent diastereoselectivity. Methanolysis of 7 afforded 1 with excellent enantiopurity. 相似文献
11.
Anca Beleaga Monika Kulcsar Calin Deleanu Alina Nicolescu Cristian Silvestru Anca Silvestru 《Journal of organometallic chemistry》2009,694(9-10):1308-1316
Arylselenium(II) derivatives of dithiophosphorus ligands of type ArSeSP(S)R2 [Ar = Ph, R = Ph (1), OPri (2); 2-[MeN(CH2CH2)2NCH2]C6H4, R = Ph (3), OPri (4); 2-[O(CH2CH2)2NCH2]C6H4, R = OPri (6)] were prepared by redistribution reactions between Ar2Se2 and [R2P(S)S]2. The derivative [2-{O(CH2CH2)2NCH2}C6H4]SeSP(S)Ph2 (5) was obtained by the salt metathesis reaction between [2-{O(CH2CH2)2NCH2}C6H4]SeCl and NH4S2PPh2. The compounds were investigated by multinuclear (1H, 13C, 31P, 77Se) NMR and infrared spectroscopy. The crystal and molecular structures of 1, 3, 4 and 6 were determined by single-crystal X-ray diffraction. In compounds 3, 4 and 6 the N(1) atom is intramolecularly coordinated to the selenium center, resulting in a T-shaped geometry (hypervalent 10-Se-3 species). The dithiophosphorus ligands act as anisobidentate in 1 and monodentate in 3, 4 and 6. Supramolecular architectures based on intermolecular S?H and N?H contacts between molecular units are formed in the hypervalent derivatives 3 and 4, while in the compounds 1 and 6 the molecules are associated into polymeric chains through either Se?S or O?H contacts, with no further inter-chain interactions. 相似文献
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Introduction1,4 Diazabicyclo[2 .2 .2 ]octane (DABCO)wasre portedtocatalyzeorganicreactionsduetoitsstrongbasici ty .1,2 Severalchiraltrans 2 ,3 disubstitutedDABCOshavebeensynthesizedandappliedtotheasymmetricBaylis Hillmanreaction3andvicinalhydroxylation .4ThefirstsynthesisofthetitlecompoundwasreportedbySoai5from (2S ,5S) bis(phenylmethyl)piperazine (1) ,asshowninScheme 1.Butthisprocedureislengthy ,andtheoverallyieldisnotsosatisfactory .Besides ,thereport edmethodforthepreparationof 1is… 相似文献
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为了检验Davidson和Clark的局部自旋原理对铁硫蛋白簇合物的可行性,[Fe2S2(SR)4]2-(R=-H,-CH3)模型被选为研究对象.该目的可通过计算这些体系的局部自旋期望值〈SA.SB〉,〈S2A〉和mA,并讨论它们与Heisenberg自旋模型(HSM)和Noodleman对称破缺理论之间的联系来实现.在具体的计算中采用了自旋非限制Hartree-Fock(UHF)和自旋极化密度泛函(Spin-polarized DFT)方法,同时比较它们的计算质量.此外,采用多种方案计算了它们的交换耦合常数,并同前人的结果作了比较. 相似文献
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Heating 5,13-dihydro-11H-isoquino[3,2-b]quinazolin-11-one with isonicotinoyl chloride in pyridine gives 6-isonicotinoyl-5,13-dihydro-11H-isoquino[3,2-b]quinazolin-11-one. The 1-alkyl-4[(11-oxo-5,13-dihydro-11H-isoquino[3,2-b]quinazolin-6-yl)carbonyl]pyridinium iodides obtained by alkylation of 6-isonicotinoyl-5,13-dihydro-11H-isoquino[3,2-b]quinazolin-11-one using alkyl iodides in the presence of NaH are converted to 1′-R-spiro[7H,8H-2a,7a-diazacyclopenta[fg]naphthacene-2,4′(1′H)-pyridine]-1,8(2H)-diones. The chemical and spectroscopic properties of the spiro compounds obtained
were studied.
For Communication 32 see [1].
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 52–58, January, 2009. 相似文献
15.
2-[2-(6-methyl-benzothiazolyl)azo]-5-dimethylaminobenzoic acid (MBTAMB) has been synthesized and employed as a new reagent for the spectrophotometric determination of copper(II). A blue complex is formed from MBTAMB and Cu(II) in the range of pH 2.0–5.0 in aqueous ethanol. The composition of the complex is Cu(II) MBTAMB=1 1. The maximum absorption of the complex is at 660 nm, its apparent molar absorptivity is 7.0 × 104 1· mole–1 · cm–1. Beer's law is obeyed for copper in the range of 0–0.72 g/ml. The method has been used for the determination of micro amounts of copper in aluminium alloy. The proposed method is simple, rapid and accurate. 相似文献
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1 INTRODUCTION In recent years, phosphorus compounds havebeen playing an important role in the new “high-tech” areas including life science and industrial te-chnology[1, .At the same time, the asymmetric syn- 2]thesis of various natural compounds containing cyc-lopropane components and organophosphorus grouphas attracted much attention due to their special bio-logical functions and antibiological activities[3~5].Despite the great advances in these areas, no novelapproach to the efficien… 相似文献
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《中国化学快报》1997,(5)
(R)-(-y5-[(IR,2S,5R)-menthyloxy](1)isausefulchiralsynthonreadilypreparedonatWo-stepprocedure-l']FindingsoffuranoneringsexistingascomponentSofsomenaturalproductSI'laswellastheiractivereactivityl']havestimu1atedeXtensiveresearchofitSasymmetricreactionswhichincludeDiels-Alderreactions,l']l,3-dipo1arcycloadditions,['1Michaelauditionsl5]andconjugateedditionsofaminesl']andmercaPtans.g4:,::7f:7':theseadductsledtovariousmultifunctionalhomochiralbuildingblockssuchas2-alkyl-l,4-butanediols,I'l2-aI… 相似文献
20.
《Tetrahedron: Asymmetry》2006,17(5):822-828
Compared to the analogous bornane-10,2-sultam derived dienophile (−)-1b, the reversed topology observed during the [4+2] cycloaddition of cyclopentadiene or cyclohexadiene to the (−)-1a–TiCl4 chelate can be rationalised on the basis of IR studies of their complexes with different Lewis acids. According to X-ray analyses, the origin of this differentiation resides in the loss of masked C2 symmetry, due to the pseudoequatorial ‘down’ orientation of the SO(1) bond in (−)-1a,c as compared to the pseudoequatorial ‘up’ direction adopted by the SO(2) bond in (−)-1b,d, associated with the steric influence of the apical Ti–Cl atoms. Dependent on the strength of the Lewis acid, the much higher constraint of the SO2/CO syn-s-cis conformer diminishes the chelating properties of this type of fenchane-8,2-sultam derived dienophiles (−)-1a and 1c. 相似文献