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1.
A convenient approach for the preparation of (2S,3R,4R,5S,6R)-2-(3-(4-ethylbenzyl)-4-chlorophenyl)-6-(hydroxymethyl)- tetrahydro-2H-pyran-3,4,5-triol I is developed. The target compound via four steps is synthesized from 4-bromo-2-(bromomethyl)- 1-chlorobenzene and the isomers of undesired ortho-products were avoided during the preparation. 相似文献
2.
Wen Xin GU Xiao Bi JING Xiao Chuan CHEN Xin Fu PAN* Department of Chemistry National Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 《中国化学快报》2001,(3)
Numerous lignans containing 1,4-benzodioxane nucleus represent a class of natural products with cytotoxic and hepatoprotective activities1,2. Recently we have reported the racemic total synthesis of sinaiticin, a flavonolignan of the 1,4-benzodioxane type which was isolated from sinaiticum leaves found in sinai region of Egypt, using 2-(4-hydroxyphenyl)-3-hydroxymethyl-1,4-benzodioxan-6-carbaldehyde as the key interme-diate3,4. This species exhibits significant inhibitory activity against the … 相似文献
3.
1,4-苯并二氧六环木脂素类天然产物多数具有增加胆碱乙酰化酶和抗肝毒等活性 ,其活性主要源于 1 ,4-苯并二氧六环官能团 [1] . 1 ,4-苯并二氧六环木脂素的消旋全合成已有报道 [2 ] ,但其不对称合成还是空白[3] .我们发展了一条对映选择性合成 1 ,4-苯并二氧六环木脂素的简捷有效的路线 .基于前面的工作 [4 ] ,我们发现 1 ,4-苯并二氧六环醛类衍生物是合成此类天然产物的关键中间体 ,选择 2 - (4-羟基- 3-甲氧基 ) - 3-羟甲基 - 1 ,4-苯并二氧六环 - 6-醛 (1 )作为目标分子 ,其合成路线如下 :Reagents and conditions:( ) Me OH,H2 SO4,9… 相似文献
4.
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
5.
The title compound, spiro[1-bromo(S)-4-(R)-hydroxy-5-oxa-6-oxo-bicyclo[3.1.0]-hxane-2,2'-(3'-diethyl-α-(S)-4'-Cl-benzyloxyphosphonyl-4'-(1R,2S,5R)-menthyloxybutyrolactone)] has been synthesized via the tandem asymmetric reaction and it crystallizes in a monoclinic system, space group P21 with a = 11.067(3), b = 12.484(2), c = 12.356(2)(A), β = 101.95°,C29H39BrC1O10P, Mr = 693.93, V= 1670.2(6) (A)3, Z= 2, Dc= 1.380 g/cm3, λ(MoKα) = 0.071073nm, μ = 1.410 mm-1, F(000) = 720, the final R = 0.0570 and wR = 0.0758 for 6190 observed reflections with I > 2σ(I). The structure is characterized by the special combination of biologic phosphonyl group and one cyclopropane as well as two butyrolactones. The intermolecular hydrogen bond between O(3)-H(3A)…O(10) in the crystal lattice has been observed. 相似文献
6.
Indenestrol A (IA) is a metabolite of diethylstilbestrol (DES), and indenestrol B (IB) is an analog of IA. IA was simply obtained from E,E-dienestrol in the presence of dilute sulfuric acid, and a mixture of IA and IB was formed by thermal cyclization of E,E-dienestrol. In order to elucidate the effects of optically active IA and IB on microtubule assembly, the IA and IB enantiomers were separated to greater than 99% purity by high-pressure liquid chromatography using a chiral column. The di(4-bromobenzoate) of (-)-IB was analyzed by X-ray crystallography and its absolute structure was determined as C(3)-S. The (+)-, (-)-, and (+/-)-indenestrols A and B were shown to be inhibitors of microtubule assembly in vitro using microtubule proteins from porcine brain. (+/-)-IB is more active than (+/-)-IA, and the order of inhibitory activity of the enantiomers on microtubule assembly was (+)-IB greater than (+)-IA greater than (-)-IA greater than (-)-IB. 相似文献
7.
The title compound(E)-2-(4-tert-butyl-5-(4-methoxybenzyl)thiazol-2-ylimino)me-thylphenol was synthesized by the reaction of 5-(4-methoxybenzyl)-4-tert-butylthiazol-2-amine with salicylaldehyde=and its crystal structure was determined by single-crystal X-ray diffraction.The crystal belongs to the monoclinic system=space group P21/c with a=5.9362(8)=b=11.5070(15)=c=29.460(4)=β=97.326(3)°=V=1995.9(5)3=Z=4=F(000)=808=C22H24N2O2S=Mr=380.49=Dc=1.266 g/cm3=S=1.031=μ=0.181 mm--1=the final R=0.0474 and wR=0.1441 for 4327 observed reflections(I > 2σ(I)).Intramolecular O-H…N hydrogen bond is observed in the crystal.The preliminary bioassay showed that the title compound exhibits 95% inhibition rate against Rhizoctonia solani at the test concentration of 500 mg/L. 相似文献
8.
Bunnage ME Chippindale AM Davies SG Parkin RM Smith AD Withey JM 《Organic & biomolecular chemistry》2003,1(21):3698-3707
Conjugate addition of lithium dibenzylamide to tert-butyl (+/-)-3-methylcyclopentene-1-carboxylate occurs with high levels of stereocontrol, with preferential addition of lithium dibenzylamide to the face of the cyclic alpha,beta-unsaturated acceptor anti- to the 3-methyl substituent. High levels of enantiorecognition are observed between tert-butyl (+/-)-3-methylcyclopentene-1-carboxylate and an excess of lithium (+/-)-N-benzyl-N-alpha-methylbenzylamide (10 eq.) (E > 140) in their mutual kinetic resolution, while the kinetic resolution of tert-butyl (+/-)-3-methylcyclopentene-1-carboxylate with lithium (S)-N-benzyl-N-alpha-methylbenzylamide proceeds to give, at 51% conversion, tert-butyl (1R,2S,3R,alphaS)-3-methyl-2-N-benzyl-N-alpha-methylbenzylaminocyclopentane-1-carboxylate consistent with E > 130, and in 39% yield and 99 +/- 0.5% de after purification. Subsequent deprotection by hydrogenolysis and ester hydrolysis gives (1R,2S,3R)-3-methylcispentacin in > 98% de and 98 +/- 1% ee. Selective epimerisation of tert-butyl (1R,2S,3R,alphaS)-3-methyl-2-N-benzyl-N-alpha-methylbenzylaminocyclopentane-1-carboxylate by treatment with KO'Bu in 'BuOH gives tert-butyl (1S,2S,3R,alphaS)-3-methyl-2-N-benzyl-N-alpha-methylbenzylaminocyclopentane-1-carboxylate in quantitative yield and in > 98% de, with subsequent deprotection by hydrogenolysis and ester hydrolysis giving (1S,2S,3R)-3-methyltranspentacin hydrochloride in > 98% de and 97 +/- 1% ee. 相似文献
9.
(2S,3S)-[3-(2)H1]-4-Methyleneglutamic acid 1a and (2S,3R)-[2,3-(2)H2]-4-methyleneglutamic acid 1b have been synthesised for use in biosynthetic and metabolic studies. 相似文献
10.
M. Madesclaire P. Coudert V. Goumet V. P. Zaitsev J. V. Zaitseva 《Chemistry of Heterocyclic Compounds》2006,42(6):813-817
The configuration of the asymmetric atoms in the molecule of (1R,2R,4S,5S,8S)-2,8-bis(4-chlorophenyl)-4-(4-nitrophenyl)-1-aza-3,7-dioxabicyclo[3,3,0]octane
has been determined using X-ray analysis.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 930-934, June, 2006. 相似文献
11.
A reaction of methyl (4R,5R)-4,5-epoxy-2(E)-hexenoate 1 with N-benzylmethylamine gave a diastereomerically pure methyl (4R,5R)-4,5-epoxy-(3S)-N-benzylmethylamino hexanoate 6 and methyl (4S,5R)-4-N-benzyl-methylamino-5-hydroxy-2(E)-hexenoate 7. The former was chemoenzymatically converted to (-)-osmundalactone 11, which is an aglycone of osmundalin. On the other hand, the directly conjugated addition of dimethylamine to methyl (4S,5S)-4,5-epoxy-2(E)-hexenoate 1 followed by treatment with MeOH at 40 degrees C exclusively provided methyl (4R,5S)-4-dimethylamino-5-hydroxy-2(E)-hexenoate 16, which was converted into L-(-)-forosamine 18. 相似文献
12.
Wei ZL Sakamuri S Petukhov PA George C Lewin NE Blumberg PM Kozikowski AP 《Organic letters》2002,4(13):2169-2172
[structures: see text] Both (2S,5R,6R)- and (2S,5R,6S)-6-hydroxy-8-(1-decynyl)benzolactam-V8 were designed and synthesized as PKC modulators. Biological assays reveal the (6R)-ligand to be 20-fold more potent than its (6S)-counterpart in binding to PKC alpha. 相似文献
13.
(3R,4aR,5S,6R)-6-Hydroxy-5-methylramulosin (1) was isolated from a culture of a sterile mycelium, which was derived from the green alga, Codium fragile, along with (-)-5-methylmellein (2), (-)-5-hydroxymethylmellein (3), and (-)-(3R,4R)-cis-4-hydroxy-5-methylmellein (4). The absolute configuration of 1 was determined by the NMR data along with the lactone sector rule by circular dichroism (CD). Compound 1 exhibited moderate cytotoxic activity against HeLa cells. 相似文献
14.
(1R,2S,3S,4S)-(6-O-Acetyl-1,2-O-isoproplidene-3,5-dideoxy-a-D-glucofuranoso)1,3,5-trihydro-2,3-oxathiaindene-2,2-dioxide (C_(11)H_(16)O_8S,M_r=308.30) was synthesized and structurally characterized by NMR,MS and single-crystal X-ray diffraction.It belongs to the triclinic system,space group P1 with a=7.0836(14),b=10.832(2),c=14.895(3) (A),α=96.01(3),β=98.85(3),γ=108-59(3)°,V=1055.8(4) (A)~3,Z=3,D_c=1.455 g/cm~3,F(000)=486,μ=0.264 mm~(-1),the final R=0.0360 and wR=0.0712.It is a tricyclic sultone derivative composed of three five-membered rings. 相似文献
15.
A synthesis and the determination of the absolute configuration of (?)-(1S, 3R′ 6R, 8R)-2, 7-dioxa-isotwistane ( 13 ) and (?)-(1R, 3R, 6R, 8R)-2, 7-dioxa-twistane ( 14 ) is described. The results for 14 are compared with those for carboeyclic (+)-twistane ( 2 ) of known chirality. 相似文献
16.
The title compound(4aR,7aS)-6-benzyl-1-((R)-2-(2-chlorophenyl)-4,5-dihydrothiazole-4-carbonyl)-hexahydro-5H-pyrrolo[3,4-b]pyridine-5,7(6H)-dione(C24H22ClN3O3S)w... 相似文献
17.
The title compound (9S,13R,14S)-7,8-dehydro-4-(4'-bromo-benzyloxy)-3,7-dime- thoxy-17-methyl-morphinan-6-one monohydrate (O-4-bromobenzylsinomenine) was synthesized by the reaction of (9S, 13R, 14S)-7,8-dehydro-4-hydroxy-3,7-dimethoxy- 17-methyl-morphinan-6-one with 4-bromobenzyl alcohol.Its chemical structure was determined by X-ray single-crystal diffraction.The crystal belongs to the monoclinic system, space group P2<,1> with a = 8.890(2), b = 14.757(4), c = 9.205(2) (A), β = 91.577(4)°, C<,26>H<,30>BrNO<,5>, M<,r> = 516.42,μ = 1.740 mm<'-1>, V = 1207.2(5) (A)<'3>, Z = 2, D<,c> = 1.421 mg/m<'3>, F(000) = 536, R = 0.0785 and wR = 0.1889. 相似文献
18.
A general enantioselective approach to jasmonoid fragrances: synthesis of (+)-(1R,2S)-methyl dihydrojasmonate and (+)-(1R,2S)-magnolione 总被引:2,自引:0,他引:2
Methyl dihydrojasmonate 1 and magnolione 3 are of both academic and industrial interest. In this paper, we describe a flexible, high-yielding route to diastereomerically pure (+)-cis-(1R,2S)-methyl dihydrojasmonate 1 and the first synthesis of (+)-cis-(1R,2S)-magnolione 3, both with enantiomeric excesses up to 93%. The two syntheses diverged from the same advanced intermediate 5, readily available from the enantioenriched hydroxymethyl delta-lactone (-)-(3aS,4S,6aR)-6. The olfactory properties of (1R,2S)-1 and (1R,2S)-3 are reported. 相似文献
19.
以2-溴丙酸和N-叔丁氧羰基-O-苄基-L-丝氨酸为起始试剂首先制得N-(2-溴丙基)-O-苄基-L-丝氨酸(BPBS), 在N,N-二甲基甲酰胺(DMF)/三乙胺(Et3N)溶剂中80 ℃经9 h后BPBS发生分子内环化反应生成(3S,6S)-3-苄氧甲基-6-甲 基-吗啉-2,5-二酮[(3S,6S)-BMMD]及(3S,6R)-BMMD共存体, 产率70%. 将所制得的共存体以乙酸乙酯为重结晶溶剂, 采用微分重结晶法, 经4次“溶解-部分重结晶”操作循环制得两种纯光学构型的(3S,6S)-BMMD和(3S,6R)-BMMD. 将两种光学纯双手性中心的BMMD分别溶于乙酸乙酯, 室温下培养得(3S,6S)-BMMD和(3S,6R)-BMMD的单晶体, 以X射线衍射法测定上述两种BMMD的分子结构. 相似文献
20.
Concellón JM Rivero IA Rodríguez-Solla H Concellón C España E García-Granda S Díaz MR 《The Journal of organic chemistry》2008,73(15):6048-6051
The transformation of enantiopure (2R,4R)- and (2S,4S)-N,N-dibenzyl-1,2:4,5-diepoxypentan-3-amine, 1 and 2, into the corresponding enantiopure (3S,5S)- and (3R,5R)-3,5-dihydroxy-3-aminopiperidines, 3 and 4 respectively, is described. The opening of the two epoxide rings with a range of amines takes place with total regioselectivity and high yields, in the presence of LiClO4. A mechanism to explain this transformation is proposed. 相似文献