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

A synthesis of the enamine (−)-(1′S)-5-ethyl-1-(1′-phenylethyl)-1,2,3,4-tetrahydropyridine 4 and its application in a synthesis of (−)-(1′S,4aS,8aR)- and (+)-(1′S,4aR,8aS)-4a-ethyl-1-(1′-phenylethyl)-octahydroquinolin-7-ones 5 and 6 is described. In addition, an X-ray study of 6 is reported. Finally, the preparation of (+)-(4aS,8aR)-4a-ethyl-octahydroquinolin-7-one 7 is described.     

Synthesis of (4R,5S)-(−)- and (4S,5S)-(+)-L-Factors and Muricatacin from D-Glucose

Abstract

In connection with our projects on the synthesis of biologically active 5-hydroxyalkan-4-olides which have a chiral 2.3-diol unit,¹ we have carried out the synthesis of (4R,5S)-(?)- and (4R,5S)-(+)-L-factors (1).² the proposed autoregulators from Streptomyees griseus, and muricatacin (2),³ a biologically active constituent from the seeds of Annona muricata L. via 2.3-dihydroxy aldehydes derived from D-glucose. Hex-3-enofuranose4 was prepared by the elimination of thetriflate derived from D-glucose.     

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.     

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.     

A Convenient Approach to the Enantiopure (1S,2S,4S,5S)-and (1R,2S,4R,5S)-2,5-Bis(phenylmethyl)-1,4-diazabicyclo[2.2.2]-octane

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…     

Low-temperature dynamics of (S)-4-(1-methylheptyloxy)-4ʹ-cyanobiphenyl (8*OCB) and (S)-4-(2-methylbutyl)-4ʹ-cyanobiphenyl (5*CB) in disordered crystalline and glassy phases

The inelastic neutron scattering (INS) spectra were measured for two materials of chiral molecules: (S)-4-(1-methylheptyloxy)-4?-cyanobiphenyl (8*OCB) and (S)-4-(2-methylbutyl)-4?-cyanobiphenyl (5*CB), revealing solid state polymorphism with two partially disordered crystalline phases I and II and glassy state of liquid and of crystalline phase in each substance. The experiments were performed in the energy range up to 30 µeV in the temperature range from 4 to 35 K. For 8*OCB the elastic scans were measured as well up to 300 K illustrating well the phase diagram. For all solid phases of both substances in the µeV range of INS spectra, the existence of the excess density of vibrational states over that typical for fully ordered crystalline phases was evidenced. Contribution of this so-called boson peak occurred to be much larger in glass of isotropic phase than in the phase II and glass of phase I of 8*OCB, while for 5*CB it was larger in the phase I and glass of phase II than in glass of cholesteric phase. The quasi-elastic broadening of elastic peak corresponding to stochastic reorientations in the ns time scale was detected for both substances. Comparison of the results obtained for glassy and crystalline phases of 8*OCB and 5*CB compounds have been given and confronted with those obtained previously in meV energy range.     

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。     

First synthesis of (−)-(1R,4R)- and (+)-(1S,4S)-(7,7-dimethyl-2-methylene-bicyclo[2.2.1]hept-1-yl)-methanol: new fenchone-derived chiral auxiliaries

The treatment of (+)- or (−)-fenchones epoxides with 1:2 85% H₃PO₄:DMSO for 30 min at 20°C induced an enantiospecific Wagner–Meerwein rearrangement affording new C(10)-O-substituted camphor derivatives which could prove useful as chiral auxiliaries.     

Synthesis and Crystal Structure of (2S,2'S,4'R)-2-(1-Hydroxy-1-ethylpropyl)-1-[(1'-p-tosyl-4'-hydroxypyrrolidin-2'-yl)methyl]pyrrolidine

1 INTRODUCTION In recent years, chiral β-amino alcohols have attracted much attention due to their special bio- logical functions and catalytic activities. Chiral β- amino alcohol moieties are usually found not only in natural products (e.g., cinchona alkaloids, ephe- drine, toxal, etc.) with special biological activities[1, 2], but also critical structural segments of some syn- thesized biologically active compounds, such as adrenergic agonists or antagolist[3, 4] and inhibitors for HI…     

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 Structural Determination of (2R,4S,SS)-( )-Threo-5-(2,2-dichloroacetamido)-4-(4-nitrophenyl)-2-aryl-1,3-dioxanes

Acetalscanbesynthesizedinanumberofways.Themainproblemintheacetalformationinacidicmediumistoshifttheequilibriumtotherightbyremovalofthewaterformedduringthereactionl.Wesynthesized(2R,4S,SS)-( )-threo-5-(2,2-dich(4-nitrophenyl)-2-aryl-1,3-dioxanesbyacet...     

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.     

DiastereoselectiveandEnantioselectiveSynthesisof(1S,2S)-2-Ethyl-1-aminocyclopropaneCarboxylicAcid

During the last decade, 1-aminocyclopropanecarboxylic acid and its derivatives (ACCS) have attracted increasing attention of organic and bioorganic chemists due to their outstanding biological properties, ranging from antimicrobial, insecticidal, plant growth and fruit ripening controls, etc.1. Moreover, the three-membered carbocycle provides building blocks of unprecedented synthetic potential because it undergoes selective ring opening, ring enlargement or cycloaddition reactions2. The mo…     

Isolation,structural assignment and insecticidal activity of (−)-(1S,2R,3R,4S)-1,2-epoxy-1-methyl-4-(1-methylethyl)-cyclohex-3-yl acetate,a natural product from Minthostachys tomentosa

(−)-(1S,2R,3R,4S)-1,2-Epoxy-1-methyl-4-(1-methylethyl)-cyclohex-3-yl acetate has previously been identified as the active compound of Minthostachys tomentosa responsible for the insecticidal activity against Oncopeltus fasciatus. Its structure was initially assigned on the basis of spectral data. In order to confirm the structure and to define the stereochemistry, stereoselective synthesis of its enantiomer, (+)-(1R,2S,3S,4R)-1,2-epoxy-1-methyl-4-(1-methylethyl)-cyclohex-3-yl acetate, starting from (R)-(−)-piperitone, was carried out using a Sharpless reaction as the key step. The natural product is dextro-rotatory while the synthetic product is levo-rotatory. Measurements of insecticidal activities of the different steroisomers revealed that only the natural product is active.     

Synthesis and Crystal Structure of Spiro[1-bromo(S)-4-(R)-hydroxy-5-oxa-6-oxo-bicyclo[3.1.0]hexane-2,2''''-(3''''-diethyl-α-(S)-4''''''''-Cl-benzyloxyphosphonyl-4''''-(1R,2S,5R)-menthyloxybutyrolactone)]

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…     

Synthesis,mesomorphic and dielectric properties of 4-(cyanomethoxy)phenyl 4-alkoxybenzoates, 4-(cyanomethoxy)-4′-alkoxyazo- and -azoxybenzenes

Preparation methods were developed for homologs of 4-(cyanomethoxy)phenyl 4-alkoxybenzoates (C₇, C₈, C₉), 4-(cyanomethoxy)-4′-alkoxyazo (C₂, C₃, C₆), -azoxybenzenes (C₃, C₆) whose composition and structure were proved by elemental analysis and ¹H NMR spectra. 4-(Cyanomethoxy) group destabilizes the mesophase, consequently, only four among the compounds obtained exhibit the thermotropic nematic mesomorphism.     

Synthesis and structural characterization of camphanates of (−)-(2S3S,3S) and (+)-(2S,3R)-4-Phenyl-3-bromo-2-butanol diastereoisomers

The X-ray crystal structures of (–)-syn-4-phenyl-3-bromo-2-butyl camphanate (I) and (+-anti-4-phenyl-3-bromo-2-butyl camphanate (II) have been determined. Thesyn diastereoisomer of bromohydrin has the (2S,3S) absolute configuration whereas theanti diastereoisomer has the (2S,3R) absolute configuration. The crystallized derivatives I and II have been obtained by the reaction of each stereoisomer of bromohydrin, synthesized by reduction with baker's yeast, with (1S)-camphanic chloride. Crystal data: (I) C₂₀H₂₅BrO₄:M _w: 409.32; orthorhombic,P2₁2₁2₁;a=11.245(3),b=12.086(1),c=14.512(4) å; Z=4; finalR=0.053 for 1819 observed reflections. (II) C₂₀H₂₅BrO₄;M _w=409.32; monoclinic, P2₁;a=11.352(1),b=6.378(1),c=14.255(2) å,=110.38(1);Z=2; finalR=0.045 for 1672 observed reflections.     

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.