Unexpected retro-Michael reaction of (−)-(1′S,4aS,8aR)- and (+)-(1′S,4aR,8aS)-4a-ethyl-1-(1-phenylethyl)octahydroquinolin-7-ones

An unexpected retro-Michael reaction of (−)-(1′S,4aS,8aR)-and (+)-(1′S,4aR,8aS)-4a-ethyl-1-(1′-phenylethyl)octahydroquinolin-7-ones 1 and 2 is described. In addition, a diastereospecific intramolecular Michael reaction of 3·HCl and 4·HCl is reported.     

A New Approach to the Construction of Pyrrolizidine and Indolizidine Skeleton: Enantioselective Synthesis of (1S, 7aS)-1-hydroxypyrrolizidine and (1S, 8aS)-1-hydroxyindolizidine

Pyrrolizidineandindolizidineareconunonstructura1elementsofmanynaturallyoccurringalkaloidsfoundinplantsandmicroorganisms.Thediverseandpotentbiologicalactivitiesofthesealkaloidshavedrawnmuchattentioninthestudiesoftheirpharmacologyandpreparation'.Ingeneral,mostconventionalsyntheticmethodologiesinvolvedthefinalformationofoneortwoC-Nbondsofpyrrolizidineandindolizidineskeleton'.andtheseresultedintheinefficientprotectinggroupchemistry,especiallywithrespecttohandlingtheaminoresidueTherefore.themostef…     

(2S,3aR,7aS)-八氢-1H-吲哚-2-甲酸苄酯的合成

通过合成路线的改进以及合成工艺的优化,方便高效地得到了抗高血压药物群多普利的关键中间体(2S,3aR,7aS)-八氢-1H-吲哚-2-甲酸苄酯.产品结构及绝对构型通过NMR及HPLC进行表征,与文献报道的数据完全一致.最终以99%的对映选择性及13.2%的产率得到目标化合物.为群多普利关键中间体的合成提供了一条可工业化的途径.     

3-((1R,3aS,3aS,10aR)-十氢-(1H,4H)-吡啶并[1,6]萘啶-1-基)丙-1-胺的合成

以廉价易得的苦参碱为起始原料,经过开环、酯化反应、水解等步骤,得到4-((3aS,3aS,10aR)-2-(叔丁氧基羰基)十氢-(1H,4H)-吡啶并[1,6]萘啶-1-基)丁酸(5)。5再经过Curtius重排反应,得到叔丁基(1R,3aS,3aS,10aR)-1-(3-(((苄氧基)羰基)氨基)丙基)八氢-(1H,4H)-吡啶并[1,6]萘啶-2(3H)-羧酸叔丁酯(6)。然后,6脱去Cbz基团得到(1R,3aS,3aS,10aR)-1-(3-氨基丙基)八氢-(1H,4H)-吡啶并[1,6]二氮杂萘-2(3H)-羧酸叔丁酯(7),最后,7脱去Boc基团成功得到苦参碱衍生物的重要中间体3-((1R,3aS,3aS,10aR)-十氢-(1H,4H)-吡啶并[1,6]萘啶-1-基)丙-1-胺(8),总收率28%。目标化合物和中间体的结构经¹H NMR, ¹³C NMR和HR-MS确证。      

光学纯的(4S, 8R)-和(4S, 8S)-1- 烯-8, 9-二醇的改进合成法

本文提出了一个改进的合成两个光学异构纯的94S)-1- 烯-8, 9-二醇的方法,其优点是简便、有效, 适于克量级制备。     

光学纯的(4S, 8R)-和(4S, 8S)-1- 烯-8, 9-二醇的改进合成法

本文提出了一个改进的合成两个光学异构纯的94S)-1- 烯-8, 9-二醇的方法,其优点是简便、有效, 适于克量级制备。     

光学纯的(4S,8R)-和(4S,8S)-1-■烯-8,9-二醇的改进合成法

本文提出了一个改进的合成两个光学异构纯的(4S)-1-■烯-8,9-二醇的方法,其优点是简便、有效,适于克量级制备.     

Synthesis and Crystal Structure of N-[（3aR,4R,4aR,5aS,6S,6aS）-1,3-Dioxooctahydro-4,6-ethenocyclopropa[f]isoindol-2（1H）-yl]-3-（trifluoromethyl）phenylmethanimine

The crystal structure of the title compound(C19H15F3N2O2,Mr = 360.33) was determined by single-crystal X-ray diffraction.The crystal belongs to triclinic,space group P1,with a = 6.5604(7),b = 13.9614(16),c = 18.1790(18) ,α = 102.749(7),β = 97.542(6),γ = 94.355(4)°,V = 1600.5(3) 3,Z = 4,Dc = 1.495 g/cm3,λ(MoKα) = 0.71070,F(000) = 744,μ(MoKα) = 0.122 mm-1,R = 0.0434 and wR = 0.1051.A total of 7590 unique reflections were collected,of which 5429 with |F|2 ≥ 2σ|F|2 were observed.The two cyclohexene rings in the molecule adopt boat-boat conformations with the deviations of ring atoms C(9) and C10 from the C(5)/C(6)/C(7)/C(8) plane(Ⅰ) by 1.1204(0.0023) and 1.1132(0.0023) ,respectively,whereas from the C(2)/C(3)/C(5)/C(8) plane(Ⅱ) by 1.1627(0.0022) and 1.1818(0.0021) ,respectively.In the cyclopropane and lactam rings,atoms C(11) and N(1) point towards the double bond of C(9)-C(10) and the dihedral angle between the ring plane(Ⅲ) containing C(1),C(2),C(3) and C(4) and plane(IV) consisting of C(6),C(7) and C(11) is 55.76(0.07)°.The dihedral angles between planes Ⅳ and Ⅰ and Ⅱ and Ⅲare 63.58(0.07)° and 58.10(0.06)°,respectively.The dihedral angle between the benzene ring C(13)～ C(18) and plane Ⅳ is 42.41(0.06)°.     

Synthesis and biological activity of the (−)-(2R,3S,4S)-3-azido-4-methoxy-2-(1′S-methoxy-2′-azido)ethyl-thiolane

A stereospecific ring contraction reaction, promoted by NaN₃, was detected starting from a thiepane derivative obtained from d-sorbitol, an inexpensive alcohol sugar. The major polyfunctionalized thiolane derivative obtained was investigated as a potential glycosidase inhibitor.     

(8R,8aS)-及(8R,8aR)-8-羟基-5-吲哚里西啶酮的不对称合成:两个有用的羟基吲哚里西啶合成砌块

以3-苄氧基哌啶-2,6-二酮衍生物20为起始原料,分别合成了两类新的合成砌块(8R,8aS)-及(8R,8aR)-8-羟基-5-吲哚里西啶酮19a/19b和15a/15b.19a/19b的合成是基于反式非对映立体选择性还原烷基化反应(dr=93:7),接着经4步转化而成;而化合物15a/15b的制备则以双烯29的RCM反应为关键步骤,再经顺式立体选择性催化氢化(dr=91:9)反应完成.此外,还原化合物15a得到了(8R,8aR)-8-羟基-5-吲哚里西啶18.     

Synthesis and Characterization of Two Chiral Cadmium Coordination Compounds Constructed from (1S,1′S)-1,1′-(4-amino-4H-1,2,4-triazole-3,5-diyl)diethanol

Two chiral cadmium coordination compounds,(S)-[Cd(deoatrz)2 Cl2](1)and(S)[Cd(deoatrz)2 (NO3)2](2)(deoatrz=(1S,1 S)-1,1-(4-amino-4H-1,2,4-triazole-3,5-diyl)diethanol),are reported.Both 1 and 2 are mononuclear,crystallizing in tetragonal P41212 chiral space group with Z=2.For1,a=11.520(3),b=11.520(3),c=15.175(1),V=2013.6(1)3,Mr=527.7,Dc =1.741 g/cm 3,μ=1.386mm-1,F(000)=1064,the final GOF=1.05,R=0.0147 and wR=0.0433 for1932 observed reflections with I>2σ(I).For 2,a=12.201(3),b=12.201(3),c=15.027(4),V=2237.1(1)3,Mr=580.8,Dc=1.725 g/cm 3,μ=1.047mm-1,F(000)=1176,the final GOF=1.00,R=0.0201 and wR=0.0415 for 2408 observed reflections with I>2σ(I).Compounds 1 and 2 are connected into three-dimensional supramolecular networks through hydrogen bonding interactions.     

(3aS,6aR)-1,3-二苄基-4-氢-4H-呋喃[3,4-d]咪唑-2,4(1H)-二酮在离子液体中的酶催化水解反应

D,L-(3 aS,6 aR)-1,3-二苄基-4氢-4H-呋喃[3,4-d]咪唑-2,4(1H)-二酮在BM ImBF4离子液体中,于45℃酶催化水解反应8 h得D-式异构体,收率45.0%,e.e.值90.4%。     

(+)-(1S,2S,5R)-8-联苯薄荷醇的合成

以(R)-( )-pu legone为起始原料,经1,4-加成,还原两步反应合成了手性辅助试剂( )-(1S,2S,5R)-8-联苯薄荷醇及其差向异构体(-)-(1R,2S,5R)-8-联苯薄荷醇,总产率95%。其结构经1H NMR,13C NMR,IR,MS和X-射线衍射仪表征。     

An efficient and stereoselective synthesis of (2S,1′S,2′S)-2-(carboxycyclopropyl) glycine (LCCG-I): conformationally constrained l-glutamate analogues

Conformationally restricted metabotropic glutamate receptor agonist (2S,1′S,2′S)-2-(Carboxycyclopropyl) glycine (LCCG-I) 1 have been efficiently synthesized in a stereoselective manner. A convenient five step synthesis of 1 from readily available (−)-dimenthyl (1S,2S)-cyclopropane-1,2-dicarboxylate 5 in 49% overall yield is described.     

Synthesis and Characterization of Polymethacrylates,Polyacrylates, and Poly(Methylsiloxane)S Containing 4-[S(-)-2-Methyl-1-Butoxy]-4′-(ω-Alkanyl-1-OXY)-α-Methylstilbene Side Groups

Abstract

The synthesis and characterization of polymethacrylates, polyacrylates, and poly(methylsiloxane)s containing 4-[S(-)-2-methyl-1-butoxy]-4′-(ω-alkanyl-1-oxy)-α-methylstilbene side groups with ω-alkanyl from 11-undecanyl to 2-ethyl are presented. According to both differential scanning calorimetry and thermal optical polarized microscopy analyses, the poly(methylsiloxane)s containing 1-octyl and 1-hexyl as ω-alkanyl groups exhibit enantiotropic S _A and S _C* mesophases. All other polymers display only an enantiotropic S _A mesophase.     

Synthesis and Crystal Structure of 1′-Methyl-4′- (4-chlorophenyl)-1H-indole-3-spiro-2′-pyrrolidine- 3′-spiro-4'-(2'-phenyloxazole)-2,5'(3H,4'H)-dione

The title compound (C26H20ClN3O3) has been synthesized by 1,3-dipolar cycloaddition reaction from isatin, sarcosine and (Z)-4-(4-chlorobenzylidene)-2-phenyloxazol-5(4H)-one through a one-pot procedure, and its structure was confirmed by IR, 1H NMR, elemental analysis and single-crystal X-ray diffraction analysis. The crystal belongs to the triclinic system, space group P1, with a = 9.3903(19), b = 11.398(2), c = 12.603(3) , α = 83.495(3), β = 68.988(3), γ = 67.178(3)°, V = 1160.1(4) 3, Z = 2, Mr = 457.90, Dc = 1.311 g/cm3, μ = 0.198 mm-1, F(000) = 476, the final R = 0.0489 and wR = 0.1144 for 3109 observed reflections with I > 2σ(I).     

Asymmetric synthesis of (−)-(1R,7aS)-absouline

The most efficient and concise asymmetric synthesis of (?)-(1R,7aS)-absouline to date, which was accomplished in eight steps and 20% overall yield from commercially available starting materials, is described. The doubly diastereoselective conjugate addition of lithium (S)-N-benzyl-N-(α-methylbenzyl)-amide to an enantiopure α,β-unsaturated ester derived from l-proline was employed as the key step. Subsequent hydrogenolytic N-debenzylation and acid-promoted cyclisation of the resultant β-amino ester produced the 1-aminopyrrolizidin-3-one scaffold, then reduction with DIBAL-H was followed by DCC-mediated coupling with (E)-p-methoxycinnamic acid to complete the synthesis of (?)-(1R,7aS)-absouline.     

Synthesis and Anti-HIV Activity of Trisubstituted (3′R, 4′R)-3′,4′- Di-O-(S)-camphanoyl-(+)-cis-khellactone (DCK) Analogs

In our prior studies,3′,4′-di-O-(S)-camphanoyl-(+)-cis-khellactone(DCK,1,Figure1)and its derivatives including mono-and di-substituted DCK analogs were identified as a novel class of potent anti-HIV agents1-4.Because of its high potency and efficient syn-thesis,4-methyl-DCK25was chosen as a drug candidate for preclinical studies.How-ever,the low solubility and poor oral bioavailability of4-methyl-DCK limited its further development.Because high molecular hydrophobicity might be one re…