Facile Total Synthesis of Three Natural 1,7-Diaryl-4-hepten-3-ones

Linear 1,7-diarylheptanoids (Ar¹-C₇-Ar²) are a large group of interesting natural products isolated from plants belonging to Alinia,Curcuma, Zingiber, Alnua,Centridobium and Acer genera used as traditional medicines in some oriental countries¹. Pharmacological experiments exhibited that some of them had many physiological actions such as anti-inflammatory, antifungicial, antioxidative,antihepatotoxic activities and so on². Three natural compounds 1³, 2⁴ and 3⁵ (gingerone C) having 1,7-diaryl-4-hepten-3-one skeleton were isolated from the rhizomes of Alpinia offocinarum, the wood of Alnus japonica and the rhizomes of Zingiber officinale respectively. Their structures were elucidated as 1,7-diphenylhept-4-en-3-one(1), 1,7-bis(4-hydroxyphenyl)hept-4-en-3-one(2) and 1-(3-hydroxyl-4-methoxyphenyl)-7-(4-hydroxyphenyl)hept-4-en-3-one(3) by spectral method. Herein, we wish to report facile total synthesis of these three natural compounds. Their synthetic routes were shouwn in scheme.     

Anionic Cyclization Approach to Hexahydrobenzo[b] furan-3-one and Hexahydro-1H-3-indolone:Application to Total Syntheses of Natural Products

Hexahydrobenzo[b]furan-3-one(3) and hexahydro-1H-3-indolone (4) are potentially useful intermediates for total synthesis of natural products, such as the hexahydrobenzofuran unit (5) of avermectins and pancracine (6). Anionic cyclization approach toward (3) and (4) have been developed. Their application to the total synthesis of (5) and (6) will be presented.     

Novel Enone-benzene Rearrangement of 4,4-Dialkylcholest-5-en-3-ones to Ring-B Aromatic Steroidal Hydrocarbons Catalysed by p-Toluenesulfonic acid

Under acidic conditions, α,α-dimethyl-β,γ-unsaturated cyclohexanones undergoes an enone-benzene rearrangement leading to aromatic derivatives^1-4. We recently run an enone-benzene rearrangement of 4,4-dimethyl-cholest-5-en-3-one (1a) catalysed by montmorillonite K-10 to give 1,3,4-trimethyl-19-norcholesta-1,3,5(10)-triene (2a) in moderate yield accompanying intractable mixture of hydrocarbons as by products⁵. Repetition of this reaction by employing TsOH as a catalyst, 2a was obtained in 65% yield and a new product, 6-methyl-3-isopropyl-A,19-dinorcholesta-6,8,10(5)-triene (3a), was also isolated in 25% yield. The formation of 3a has not been reported in earlier studies^1-5. Herein we report the novel enone-benzene rearrangement of 4,4-dialkylcholest-5-en-3-ones (1a~d) leading to ring-B aromatic steroidal hydrocarbons (3a~d) catalysed by TsOH (Scheme 1).     

On the thermal behaviour of palladium (II) macrocyclic polycatenars

Polycatenar saturated macrocycles 1,10-bis[3,4,5-tris(4-dodecyloxy)benzoy1]-1,10-diaza-4,7,13,16-tetrathiacyclo-octadecane (3b) and 1,10-bis[3,4-bis(4-dodecyloxy)benzoy1] -1,10-diaza-4,7,13,16-tetrathiacyclo-octadecane (3d) reacted with [Pd(MeCN)₄][BF₄]₂ led to the cationic complexes [4b][BF₄]₂ and [4d][BF₄]₂, respectively. Complexes [4b][BF₄]₂ and [4d][BF₄]₂ showed smectic mesomorphism on heating as confirmed by small angle X-ray diffraction. A concurrent, irreversible structural change of the complex cations was observed and a tentative explanation is suggested.     

Ferroelectric liquid crystals with fluoro- and aza-fluorenone cores: the effect of stereo-polar coupling

The chiral fluorenone mesogens (R)-1-fluoro-2-(2-octyloxy)-7-(4-undecyloxybenzoyloxy)fluoren-9-one (2) and (R)-2-(2-octyloxy)-7-(4-undecyloxybenzoyloxy)-3-azafluoren-9-one (3) were synthesized using a combined ortho-directed and remote metalation strategy, which also incorporates a Suzuki-Miyaura crosscoupling step. These compounds form chiral SmC* liquid crystal phases with reduced polarizations (P _o) of +475 and +332 nC cm^-2 at 10 K below the Curie point, respectively. These values are considerably larger than that previously reported for the unsubstituted fluorenone (R)-2-(2-octyloxy)-7-(4-undecyloxybenzoyloxy)fluoren-9-one (1), which is +111 nC cm^-2 at 10 K below the Curie point. Molecular modelling based on the Boulder model suggests that the larger polarizations result from a conformational bias of the fluorenone core dipole moment along the polar axis of the SmC* phase caused by stereo-polar coupling with the chiral 2-octyloxy side chain.     

A Luminescent Metal-Organic Framework with LON Topology for Highly Effective Fluorescence Sensing of Fe3+ and TNP

Aluminescent Ag-based metal-organic framework(1) has been synthesized and its structure has been characterized. Compound 1 was fabricated using the Ag⁺ and bbimb^2‒ ligands and manifestes a rare LON topology. Compound 1 is selective not only in detecting traces of Fe³⁺ and 2,4,6-trinitrophenol(TNP) via luminescence quenching, but also demonstrates high selectivity in the presence of other competitors. Compound 1’s K_sv values towards Fe³⁺ can reach as high as 9.3×10³ L/mol, which is higher than those of several other MOF materials. It is also a recyclable luminous sensor with the potential to be utilized for detecting TNP. Hence, based on its characteristics, compound 1 can be regarded as a prospective luminescence sensor for detecting Fe³⁺ and TNP.     

The synthesis and liquid crystalline behaviour of 2-(4-n-alkoxyphenyl)-5-methylpyridines

We have synthesized a new series of polyphenylene compounds with a pyridine ring, 2-(4-n-alkoxyphenyl)-5-methylpyridines (CH₃C₅H₃NC₆H₄OC_iH_2i1) (1a-i; the carbon number, i, of the alkoxy group is 1-9), and studied their phase transitions and mesogenicity using DSC and polarizing microscopy. In the homologous series of 1a-i, no mesomorphic phase appeared for i=1-5 and only a monotropic nematic phase was observed for i=6-9. The mesomorphic potential is relatively weaker for the 1a-i than for the 2a-i and 3a-i homologues, which are pyridine-containing three- and four-ring similar systems. This lowering of the mesogenicity may be due to the lack of a phenyl ring between the pyridine ring and the methyl group in the 1a-i homologues.     

The substituent effect on mesomorphic properties of 4-octyloxyphenyl 4-(4-R-3-nitrobenzoyloxy)benzoates and 4-(4-octyloxybenzoyloxy)phenyl 4-R-3-nitrobenzoates

The thermal properties of 4-octyloxyphenyl 4-(4-R-3-nitrobenzoyloxy) benzo-ates (1) and 4-(4-octyloxybenzoyloxy)phenyl 4-R-3-nitrobenzoates (2) have been examined, where R = hydrogen, halogens, alkyl and alkoxy groups. The derivatives of compound 1 incorporating hydrogen, halogens, methoxy and nitro groups show a smectic A phase having a bilayer arrangement, and the others with a long alkoxy group show the S_A phase with the monolayer arrangement. The derivatives of compound 2 incorporating halogens, and the nitro group show the S_A phase with the monolayer arrangement. The alkoxy derivatives show a smectic C phase as well as the nematic phase. The nitro group at the lateral position tends to increase the ratio of the S_A-N transition temperature to the N-I. The effect of the nitro group on the smectic properties has been discussed in terms of the structural and electrostatic nature of the nitro group.     

Liquid crystalline photoconductors

The influence of molecular order as well as of orientation of charge carrier units on photoconductivity has been investigated for the liquid crystal photoconductors H5T (1), thiadiazole (2) and oxadiazole (3). The discotic H5T (1) and both smectic systems 2 and 3 exhibit a higher photocurrent in the highly ordered mesophase than in the polycrystalline or isotropic state. For 1, results concerning charge carrier transport mechanism and Dember effect are given indicating an electronic charge transport comparable with the one known for single crystalline anthracene.     

Synthesis and properties of optically active 1,3-diols and their derivatives as chiral dopants for ferroelectric liquid crystals

New chiral dopants β-hydroxy ketones 1, 1,3-diols 2, 1,3-dioxanes 3 and 1,3-dioxan-2-ones 4 were designed and synthesized. Reaction of (R)-1,2-epoxyoctane with carbanions derived from 2-(4-substituted phenyl)-1,3-dithianes followed by hydrolysis of the resulting hydroxy dithianes afforded 1. Reduction of 1 gave the diols 2, which yielded 3 upon acetalization and 4 upon carbonation. The syn isomers of 2, 3, and 4 exhibited larger spontaneous polarizations, when applied as chiral dopants, than the anti isomers or hydroxy ketones 1.     

Two Zinc(Ⅱ) Complexes Based on 7rany-(1R,2R)-cyclohexanediamine: Molecular Structure Analyses and Preparation of Composite Membrane

Two novel complexes Zn2(chda)2(TPA)Cl2(1) and [Zn(chda)2(H2O)2](TPAXH2O)2(2)[chda is a chiral ligand of trans-(1R,2R)-cyclohexanediamine, H2TPA is terephthalic acid] were synthesized at room temperature. The molecular structures of complexes 1 and 2 were identified by single-crystal X-ray diffraction measurement. The results showed that complex 1 had a binuclear structure, each Zn(Ⅱ) ion was four coordinated by two N atoms of chda, one O atom of TPA and one Cl atom, to construct a distorted tetrahedral geometry. For complex 2, the Zn(Ⅱ) ion was six coordinated by two chda molecules and two water molecules to form a ZnN4O2 octahedral geometry. Complexes 1 and 2 further extended into three-dimensional supramolecular frameworks by hydrogen-bonding interactions. Hirshfeld surface analysis and fingerprint plots were used to further analyze the contribution of diflerent intermolecular interactions. Further, a composite membrane [Zn(chda)2(H2O)2](TPA)(H2O)2/CA was prepared by adding 10%(mass fraction) of complex 2 into cellulose acetate using acetone/chloroform( V:V-1:1) as solvent.     

Mesogenic properties of cycloalkylmethyl 4-(4'-octoxybiphenyl-4-carbonyloxy)benzoate

Four analogous compounds, cyclohexylmethyl 4-(4'-octoxybiphenyl-4-carbonyloxy)benzoate (2), cyclopentylmethyl 4-(4'-octoxybiphenyl-4-carbonyloxy)benzoate (3), cyclobutylmethyl 4-(4'-octoxylbiphenyl-4-carbonyloxy)benzoate (4) and cyclopropylmethyl 4-(4'-octoxylbiphenyl-4-carbonyloxy)benzoate (5) were prepared. They all exhibit SmA, SmC and SmX phases.     

New liquid crystal compounds ( )-4-[5-(2-Methylbutyl)-1,3-dioxan-2-yl]phenyl 4-alkoxybenzoate

New liquid crystal compounds, (+)-4-[5-(2-methylbutyl)-1,3-dioxan-2-yl] phenyl 4-alkoxybenzoates (5), were synthesized. The mesomorphic behaviour of these compounds is compared with that of (+)-4-(5-alkyl-1,3-dioxan-2-yl)-phenyl 4-(2-methylbutoxy)benzoates (6). While compounds 6 exhibited a chiral smectic C phase, the corresponding compounds 5 did not. This might mean that for the appearance of a chiral smectic C phase in these types of compounds, it is necessary that the carbonyl and the chiral groups exist at nearby positions. Transition temperatures to those isotropic state for compounds 5 were lower than those for compounds 6. This result is common in both cases of (+)-4-alkoxycarbonylphenyl-4-[5-(2-methylbutyl)-1,3-dioxan-2-yl]benzoates (7), and (+)-4-(2-methylbutoxy-carbonyl)phenyl 4-(5-alkyl-1,3-dioxan-2-yl)-benzoates (8).     

K3PO4-promoted Cyclopropanation of Electron-deficient Alkenes with 2-Bromo-1,3-propanedione Compounds

An easy and efficient method for the synthesis of multisubstituted cyclopropane derivatives from electron-deficicent alkenes with 2-bromo-1,3-propanedione compounds was described. For this method, ethyl α-cyanocinnamate derivatives 1 and β,β-dicyanostyrene derivatives 4 can all smoothly react with 2-bromo-1,3-propanedione compounds 2 to afford the corresponding multisubstituted cyclopropane derivatives 3 and 5 in good to excellent yields(up to 100%) promoted by anhydrous K₃PO₄ in DMF at room temperature, respectively. A possible mechanism of this reaction was proposed. Structures of all the products were confirmed by ¹H NMR, ¹³C NMR and HRMS.     

First Total Synthesis of (-)-4-O-(6'-Hydroxy-7'(9')-Dehydro-6',7,-Dihydrogeranyl)-Coniferyl Alcohol

Some Ligularia species have long used as folk remedies due to their antibiotic, antiphlogistic and antitumor activities.¹ Compound 1,² a novel coniferyl alcohol, was isolated from ligularia duciformis(Compoitae). The geometrical structure of 1,determined by spectroscopic techniques, was corresponded to 4-o-(6,-hydroxy-7'(9')-dehydro-6',7'-dihydrogeranyl)-coniferyl alcohol. But its absolute configuration at C-₆,has not yet been determined. Herein, we report the total synthesis of (6'S)-(-)-1 from Geraniol 2 through 9 steps (Scheme 1).     

Solvothermal Syntheses and Characterization of Three One-dimension Cadmium Selenidoarsenates [Ni(1,2-dap)3][As2CdSe4],[Zn(1,2-dap)3][As2CdSe4] and [Ni(en)3][As2CdSe4]

Three new cadmium selenidoarsenates,[Ni(1,2-dap)3][As2CdSe4](1)(1,2-dap=l,2-diaminopropane),[Zn( 1,2-dap)3][As2CdSe4](2) and [Ni(en)3][As2CdSe4](3)(en=ethylenediamine), were synthesized under solvothermal conditions. And they are isostnictural and monoclinic crystalls. As seen from their structures, they exhibited one-dimensional(1D) chains composed of [As2CdSe4]^2- anions and [TM(amine)3]^2+(TM=Ni,Zn;amine=1,2-dap, en) cations. Their absorption edges are 2.32, 1.84 and 2.38 eV and they show the properties of the semiconductor. These compounds were also characterized by means of single-crystal X-ray ditlraction(XRD), powder X-ray diflraction (PXRD), solid-state optical absorption spectrometry, and so on.     

Facile Synthesis of (±)-2,6-Dimethethyl-6-hydroxy-2,7-octadienoic Acid and its Methyl Ester and Amide (Acacialactam)

The monoterpenoid acid 1, which is a component of some traditional medicine such as Gymnocladus chinensis baillon in glycoside form,¹ was recently isolated from Artemisia sieberi in Iran in free form.². Its structure has been established to be (E)-2,6-dimethyl-6-hydroxy-2,7-octadienoic acid (1) by chemical and spectroscopic analysis. Its methyl ester derivative 2,was isolated from the antibacterial extracts of the leaves of Piper aduncum³ as well. Acacialactam, a natural product isolated from the seeds of Acacia concinna DC.(Legunninosae) used in folk medicine of several tropical countries for treating some skin diseases, was assigned structure 4 by Sekine et al⁴ on the basis of its physical and spectral properties.     

Design,synthesis and biological activity of some novel benzimidazole derivatives against Coxsackie virus B_3

A series of novel benzimidazole derivatives was synthesized and their anti-Coxsackie virus B_3(CVB_3) activity was evaluated in VERO cells.Compounds 9 and 10 exhibited better inhibitory activity than those of ribavirin(RBV) with IC_(50) values of 5.30 and 1.06μg/mL,respectively.     

Synthesis ofα-D-GlcpNAc-（1→2）-[α-D-ManpNAc-（1→3）-]α-L-Rhap-（1→2）-α-L-Rhap-（1→3）-α-L-Rhap,the repeating unit of O10 antigen from Acinetobacter baumannii

An efficient synthesis ofα-D-GlcpNAc-（1→2）-[α-D-ManpNAc-（1→3）-]α-L-Rhap-（1→2）-α-L-Rhap-（1→3）-α-L-Rhap（1）, the repeating unit of the O10 antigen from Acinetobacter baumannii was achieved via sequential assembly of the building blocks,p- methoxylphenyl 2,4-di-O-benzoyl-α-L-rhamnopyranoside（2）;2-O-allyloxycarbonyl-3,4-di-O-bcnzoyl-α-L-rhamnopyranosyl tri- chloroacetimidate（3）;4-methoxylphenyl 3-O-allyloxycarbonyl-4-O-benzoyl-α-L-rhanmopyranoside（4）;2-azido-3-O-benzoyl-2- deoxy-4,6-O-isopropylidene-α-D-mannopyranosyl trichloroacetirnidatc（5）;2-azido-3,4,6-tri-O-benzoyl-2-deoxy-α,β-D-glucopyr- ano syl trichloroacetimidatc（6）.The total yield of 1 from 4 was 4.7%.     

Crystal-smectic E mesophases in a series of 2-(4-n-alkylphenyl)indenes

A series of 2-(4-n-alkylphenyl)indenes (3) with different alkyl substituents (CH₃ to C₁₀H₂₁) were synthesized and systematically characterized using differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction compared with 2-phenylindene (3a). Depending on the alkyl chain length, highly ordered crystal-smectic E mesophases were observed and confirmed by X-ray diffraction for the derivatives 3h-3k with heptyl to decyl chains (n = 6-9). For 3f with a pentyl side chain (n = 4), an X-ray crystal structure analysis was carried out.