8-羟基喹啉衍生物及其金属配合物的合成与光致发光特性

设计合成了三种新型的8-羟基喹啉衍生物配体: 5-[(4-E-苯乙烯基)-苯甲亚胺基]-8-羟基喹啉(1), 5-[(4-溴-2-氟)-苯甲亚胺基]-8-羟基喹啉(2)和N-乙基-3-[2-(8-羟基喹啉基)-乙烯基]咔唑(3), 以及它们相应的金属配合物, 产物经质谱(MS)、元素分析(EA)、红外光谱(IR)、紫外光谱(UV)、核磁共振氢谱(¹H NMR)进行表征, 并测定了它们的荧光性质. 结果与8-羟基喹啉比较表明, 5位和2位取代8-羟基喹啉衍生物的荧光发生了明显的红移. 同时测定了配合物(3)₂Zn的荧光寿命, 结果表明, N-乙基-3-[2-(8-羟基喹啉基)-乙烯基]咔唑锌配合物表现出较长的荧光寿命.     

Five new nortropane alkaloids and six new amino acids from the fruit of Morus alba LINNE growing in Turkey

Investigation of the constituents of the fruits of Morus alba LINNE (Moraceae) afforded five new nortropane alkaloids (1-5) along with nor-psi-tropine (6) and six new amino acids, morusimic acids A-F (7-12). The structures of the new compounds were determined to be 2alpha,3beta-dihydroxynortropane (1), 2beta,3beta-dihydroxynortropane (2), 2alpha,3beta,6exo-trihydroxynortropane (3), 2alpha,3beta,4alpha-rihydroxynortropane (4), 3beta,6exo-dihydroxynortropane (5), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (7), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid (8), (3R)-3-hydroxy-12-1(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (9), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid (10), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-hydroxymethyl-piperidin-1-yl]-dodecanoic acid-3-O-beta-D-glucopyranoside (11), and (3R)-3-hydroxy-12-[(1R,4S,5S)-4-hydroxy-5-methyl-piperidin-1-yl]-dodecanoic acid (12) on the basis of spectral and chemical data.     

Cycloaddition of 1-Aryl-3-trimethylsiloxy-1,3-butadienes in the Synthesis of Natural Quinone Analogs

7-Hydroxy-5-(2-methoxyphenyl)-2-methyl-6-R-1,4-naphthoquinones, 8-hydroxy-1-(2-methoxyphenyl)-3-oxo-1,2,3,4-tetrahydro-9,10-anthraquinone, and 2-ethoxycarbonyl-8-hydroxy-1-(2-methoxyphenyl)-3-trimethylsiloxy-1,1a,4,4a-tetrahydro-9,10-anthraquinone were synthesized by reactions of 1-(2-methoxyphenyl)-2-R-3-trimethylsiloxy-1,3-butadienes with 2-bromo-5-methyl-1,4-benzoquinone and juglone. 1-Aryl-2-ethoxycarbonyl-3-trimethylsiloxy-1,3-butadienes reacted with 1,4-naphthoquinone to afford 1-aryl-2-ethoxycarbonyl-3-hydroxy-9,10-anthraquinones and their 4,4a-dihydro derivatives.     

Anthraquinones with antiplasmodial activity from the roots of Rennellia elliptica Korth. (Rubiaceae)

Dichloromethane root extract of Rennellia elliptica Korth. showed strong inhibition of Plasmodium falciparum growth in vitro with an IC?? value of 4.04 μg/mL. A phytochemical study of the dichloromethane root extract has led to the isolation and characterization of a new anthraquinone, 1,2-dimethoxy-6-methyl-9,10-anthraquinone (1), and ten known anthraquinones: 1-hydroxy-2-methoxy-6-methyl-9,10-anthraquinone (2), nordamnacanthal (3), 2-formyl-3-hydroxy-9,10-anthraquinone (4), damnacanthal (5), lucidin-ω-methyl ether (6), 3-hydroxy-2-methyl-9,10-anthraquinone (7), rubiadin (8), 3-hydroxy-2-methoxy-6-methyl-9,10-anthraquinone (9), rubiadin-1-methyl ether (10) and 3-hydroxy-2-hydroxymethyl-9,10-anthraquinone (11). Structural elucidation of all compounds was accomplished by modern spectroscopic methods, notably 1D and 2D NMR, IR, UV and HREIMS. The new anthraquinone 1, 2-formyl-3-hydroxy-9,10-anthraquinone (4) and 3-hydroxy-2-methyl-9,10-anthraquinone (7) possess strong antiplasmodial activity, with IC?? values of 1.10, 0.63 and 0.34 μM, respectively.     

Phenolic glycosides from Pyrola japonica

Five new phenolic glycosides, 2-beta-D-glucopyranosyloxy-5-hydroxyphenylacetic acid methyl ester (4), 4-hydroxy-2-[3-hydroxy-3-methylbutyl]-5-methylphenyl beta-D-glucopyranoside (5), 4-hydroxy-2-[(E)-4-hydroxy-3-methyl-2-butenyl]-5-methylphenyl beta-D-glucopyranoside (7), 4-hydroxy-2-[(2E,6Z)-8-beta-D-glucopyranosyloxy-3,7-dimethylocta-2,6-dien-1-yl]-5-methylphenyl beta-D-glucopyranoside (8), and 2,7-dimethyl-1,4-dihydronaphthalene-5,8-diol 5-O-beta-D-xylopyranosyl(1-->6)-beta-D-glucopyranoside (10), were isolated from the whole plants of Pyrola japonica (Pyrolaceae), together with androsin, (-)-syringaresinol glucoside, homoarbutin, pirolatin, hyperin, monotropein and chimaphilin.     

Synthesis and antimicrobial activity of some derivatives of (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid hydrazide

(7-Hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid hydrazide (2) was prepared from (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid ethyl ester (1) and 100% hydrazine hydrate. Compound 2, is the key intermediate for the synthesis of several series of new compounds such as Schiff's bases 3a-l, formic acid N'-[2-(7-hydroxy-2-oxo-2H- chromen-4-yl)acetyl] hydrazide (4), acetic acid N'-[2-(7-hydroxy-2-oxo-2H-chromen-4- yl)-acetyl] hydrazide (5), (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid N'-[2-(4- hydroxy-2-oxo-2H-chromen-3-yl)-2-oxoethyl] hydrazide (6), 4-phenyl-1-(7-hydroxy-2- oxo-2H-chromen- 4-acetyl) thiosemicarbazide (7), ethyl 3-{2-[2-(7-hydroxy-2-oxo-2H- chromen-4-yl)-acetyl]hydrazono}butanoate (8), (7-hydroxy-2-oxo-2H-chromen-4-yl)- acetic acid N'-[(4-trifluoromethylphenylimino)methyl] hydrazide (9) and (7-hydroxy-2- oxo-2H-chromen-4-yl)acetic acid N'-[(2,3,4-trifluorophenylimino)-methyl] hydrazide (10). Cyclo- condensation of compound 2 with pentane-2,4-dione gave 4-[2-(3,5- dimethyl-1H-pyrazol-1-yl)-2-oxoethyl]-7-hydroxy-2H-chromen-2-one (11), while with carbon disulfide it afforded 7-hydroxy-4-[(5-mercapto-1,3,4-oxadiazol-2-yl)methyl]-2H- chromen-2-one (12) and with potassium isothiocyanate it gave 7-hydroxy-4-[(5- mercapto-4H-1,2,4-triazol-3-yl)methyl]-2H-chromen-2-one (14). Compound 7 was cyclized to afford 2-(7-hydroxy-2-oxo-2H-chromen-4-yl)-N -(4-oxo-2-phenylimino- thiazolidin-3-yl) acetamide (15).     

Antiangiogenic polyketides from Peperomia dindygulensis Miq

Two new polyketides: 2Z-(heptadec-12-enyl)-4-hydroxy-3,4,7,8-tetrahydro-2H-chromen-5(6H)-one (1) and 2-(heptadec-12-enyl)-5-hydroxy-5,6,7,8-tetrahydrochromen- 4-one (2), together with eleven known compounds: 4-hydroxy-2-[(3,4-methylenedioxy- phenyl)tridecanoyl] cyclohexane-1,3-dione (3), oleiferinone (4), 4-hydroxy-2-[(3,4- methylenedioxyphenyl)undecanoyl]cyclohexane-1,3-dione (5), 4-hydroxy-2-[(11-phenyl- undecanoyl)cyclohexane-1,3-dione (6), proctorione C (7), surinone C (8), 5-hydroxy- 7,8,4'-trimethoxyflavone (9), 5-hydroxy-7,8,3',4'-tetramethoxyflavone (10), 5-hydroxy- 7,3',4'-trimethoxyflavone (11), 5,8-dihydroxy-7,3',4'-trimethoxyflavone (12) and cepharanone B (13) were isolated from the whole plant of Peperomia dindygulensis Miq. Their structures were elucidated by spectroscopic methods, including 2D-NMR techniques. Compounds 2, 3, 5 and 8 inhibited human umbilical vein endothelial cell (HUVEC) proliferation and compounds 5 and 8 sharply suppressed HUVEC tube formation.     

Studies on the constituents of Broussonetia species. VII. Four new pyrrolidine alkaloids, broussonetines M, O, P, and Q, as inhibitors of glycosidase, from Broussonetia kazinoki SIEB

Four new pyrrolidine alkaloids, broussonetines M, O, P, and Q, were isolated from the branches of Broussonetia kazinoki SIEB, (Moraceae). Broussonetines M, O, P, and Q were formulated as (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(10S)-10,13-dihydroxy-tri decyl]pyrrolidine (1), (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(E)9-oxo-13-hydroxy-3- tridecenyl]pyrrolidine (2), (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(E)10-oxo-13-hydroxy-3-++ +tridecenyl]pyrrolidine (3), and (2R,3S,4R,5R)-2-hydroxymethyl-3-hydroxy-4-(beta-D-glucopyranosyloxy++ +)-5-[10-oxo-13-(beta-D-glucopyranosyloxy)tridecyl]pyrrolidine (4) respectively, by spectroscopic and chemical methods. 1-4 inhibited beta-glucosidase, beta-galactosidase and beta-mannosidase.     

Schiff’s base phenol-hydrazone derivatives as colorimetric chemosensors for fluoride ions

Two new chromogenic receptors 4-nitro-2-[(phenylhydrazoimino)methyl]phenol (1) and 4-nitro-2-[(4-nitrophenylhydrazoimino)methyl]phenol (2) containing a nitro group as a signalling unit and OH and NH groups as binding sites have been synthesized and characterized by spectroscopic techniques and XRD. Both receptors show colorimetric responses and UV-vis spectral changes in the presence of fluoride ions in organic solvents.     

Synthesis of 5-hydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-ones: selective antagonists of muscarinic (M3) receptors

Two approaches to tetrahydro-[1H]-2-benzazepin-4-ones of interest as potentially selective, muscarinic (M(3)) receptor antagonists have been developed. Base promoted addition of 2-(tert-butoxycarbonylamino)methyl-1,3-dithiane with 2-(tert-butyldimethylsiloxymethyl)benzyl chloride gave the corresponding 2,2-dialkylated 1,3-dithiane which was taken through to the dithiane derivative of the parent 2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-one by desilylation, oxidation and cyclisation via a reductive amination. After conversion into the N-tert-butyloxycarbonyl, N-toluene p-sulfonyl and N-benzyl derivatives , hydrolysis of the dithiane gave the N-protected tetrahydro-[1H]-2-benzazepin-4-ones . However, preliminary attempts to convert these into 5-cycloalkyl-5-hydroxy derivatives were not successful. In the second approach, ring-closing metathesis was used to prepare 2,3-dihydro-[1H]-2-benzazepines which were hydroxylated and oxidized to give the required 5-hydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-ones. Following preliminary studies, ring-closing metathesis of the dienyl N-(2-nitrophenyl)sulfonamide gave the dihydrobenzazepine which was converted into the 2-butyl-5-cyclobutyl-5-hydroxytetrahydrobenzazepin-4-one by hydroxylation and N-deprotection followed by N-alkylation via reductive amination, and oxidation. This chemistry was then used to prepare the 2-[(N-arylmethyl)aminoalkyl analogues , , and . N-Acylation followed by amide reduction using the borane-tetrahydrofuran complex was also used to achieve N-alkylation of dihydrobenzazepines and this approach was used to prepare the 5-cyclopentyl-5-hydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-one and the 5-cyclobutyl-8-fluoro-5-hydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-one . The structures of 2-tert-butyloxycarbonyl-4,4-propylenedithio-2,3,4,5-tetrahydro-[1H]-2-benzazepine and (4RS,5SR)-2-butyl-5-cyclobutyl-4,5-dihydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepine were confirmed by X-ray diffraction. The racemic 5-cycloalkyl-5-hydroxy-2,3,4,5-tetrahydro-[1H]-2-benzazepin-4-ones were screened for muscarinic receptor antagonism. For M(3) receptors from guinea pig ileum, these compounds had log(10)K(B) values of up to 7.2 with selectivities over M(2) receptors from guinea pig left atria of approximately 40.     

Synthesis of 9-[(2-hydroxy-1-phosphonylethoxy)ethyl]guanine, 1-[(2-hydroxy-1-phosphonylethoxy)ethyl]cytosine and 9-[(2-hydroxy-1-phosphonylethoxy)ethyl] adenine

The acyclic nucleoside phosphonate analogues, 9-[(2-hydroxy-1-phosphonylethoxy)ethyl]guanine 6 , 1-[(2-hydroxy-1-phosphonylethoxy)ethyl]cytosine 7 and 9-[(2-hydroxy-1-phosphonylethoxy)ethyl]adenine 8 , have been prepared by the coupling of a tosylate of the phosphonate side chain 12 with a purine or pyrimidine base followed by deprotection of the blocking groups.     

Fluorescence signaling of aromatic oxoanion inclusion within metal-ion activated molecular receptor complexes formed from 2-(9-anthracenylmethylamino)ethyl-appended cyclen

Our observations that 1-[2-[(9-anthracenylmethylamino)ethyl)-4,7,10-tris[(2S)-2-hydroxy-3-phenoxypropyl]-1,4,7,10-tetraazacyclododecane, L¹, complexes Cd(II) to form fluorescent [CdL¹]²⁺ which undergoes a fluorescence change when it acts as an aromatic anion receptor complex has caused us to explore further the potential development of an interesting sequestration/sensor system. Accordingly, three new, octadentate, fluorescent, macrocyclic ligands, 1-[2-[(9-anthracenylmethyl)((2S)-2-hydroxy-3-phenoxypropyl)amino]ethyl]-4,7,10-tris[(2S)-2-hydroxy-3-phenoxypropyl]-1,4,7,10-tetraazacyclododecane, (L²), 1-[2-[(9-anthracenyl-methyl)((2S)-2-hydroxy-3-(4??-methyl)phenoxypropyl)amino]ethyl]-4,7,10-tris[(2S)-2-hydroxy-3-(4??-methyl)phenoxypropyl]-1,4,7,10-tetraazacyclododecane, (L³), and 1-[2-[(9-anthracenylmethyl)((2S)-2-hydroxy-3-(4??-t-butyl)phenoxypropyl)amino]ethyl]-4,7,10-tris[(2S)-2-hydroxy-3-(4??-t-butyl)phenoxypropyl]-1,4,7,10-tetraazacyclododecane, (L⁴), have been prepared with a view to using their metal complexes to study aromatic anion sequestration. The eight-coordinate Cd(II) complexes of L² and L³, [CdL²](ClO₄)₂·5H₂O and [CdL³](ClO₄)₂·2H₂O·2Et₂O are both capable of acting as receptors for a range of aromatic oxoanions. This is demonstrated by perturbation of the anthracene derived fluorescence emission intensity as the guest aromatic oxoanion and the receptor complex combine. In 20% aqueous 1,4-dioxane the receptor complex/aromatic oxoanion association constants are in the range of 10^3.2 M^?1 (guest = p-hydroxybenzoate) to 10^7.3 M^?1 (guest = 3,4,5-trihydroxybenzoate).     

1,7-dithioxo systems. Reaction of 3-[(5,5-dimethyl-3-thioxocyclohex-1-en-1yl)sulfanyl]-5,5-dimethylcyclohex-2-ene-1-thione with 2-aminoethanol and ethane-1,2-diamine

The reaction of 3-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)sulfanyl]-5,5-dimethylcyclohex-2-ene-1-thione with 2-aminoethanol involves cleavage of the sulfide bond with formation of 3-[(2-hydroxyethyl)-amino]-5,5-dimethylcyclohex-2-ene-1-thione as the major product. The reaction of the same sulfide with ethane-1,2-diamine gave previously unknown 3-({2-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)amino]ethyl}-amino)-5,5-dimethylcyclohex-2-ene-1-thione.     

Chiral Cyclopentane-Based Mimics of D-myo-Inositol 1,4,5-Trisphosphate from D-Glucose

Two routes from D-glucose to chiral, ring-contracted analogs of the second messenger D-myo-inositol 1,4,5-trisphosphate are described. Methyl alpha-D-glucopyranoside was converted by an improved procedure into methyl 4,6-O-(p-methoxybenzylidene)-alpha-D-glucopyranoside (6) and thence into methyl 2-O-benzyl-3,4-bis-O-(p-methoxybenzyl)-alpha-D-gluco-hexodialdopyranoside (1,5) (14) in four steps. In the first ring-contraction method 14 was converted into methyl 2-O-benzyl-6,7-dideoxy-3,4-bis-O-(p-methoxybenzyl)-alpha-D-gluco-hept-6-enopyranoside (1,5) (15), which on sequential treatment with Cp(2)Zr(n-Bu)(2) followed by BF(3).Et(2)O afforded a mixture of (1R,2S,3S,4R,5S)-3-(benzyloxy)-4-hydroxy-1,2-bis[(p-methoxybenzyl)oxy]-5-vinylcyclopentane (16) and its 4S,5R diastereoisomer 17. Removal of the p-methoxybenzyl groups of 16 and subsequent phosphorylation and deprotection afforded the first target compound, (1R,2R,3S,4R,5S)-3-hydroxy-1,2,4-tris(phosphonooxy)-5-vinylcyclopentane (3). In the second route, intermediate 14 was subjected to SmI(2)-mediated ring contraction to give (1R,2S,3S,4R,5S)-3-(benzyloxy)-4-hydroxy-5-(hydroxymethyl)-1,2-bis[(p-methoxybenzyl)oxy]cyclopentane (20). Benzylation of 20 provided (1R,2S,3S,4R,5S)-3-(benzyloxy)-6-[(benzyloxy)methyl]-4-hydroxy-1,2-bis[(p-methoxybenzyl)oxy]cyclopentane (22) and (1R,2S,3S,4R,5S)-3,4-bis(benzyloxy)-5-(hydroxymethyl)-1,2-bis[(p-methoxybenzyl)oxy]cyclopentane (21), which were elaborated to the target trisphosphates (1R,2R,3S,4R,5S)-3-hydroxy-5-(hydroxymethyl)-1,2,4-tris(phosphonooxy)cyclopentane (4) and (1R,2S,3R,4R,5S)-1,2-dihydroxy-3,4-bis(phosphonooxy)-5-[(phosphonooxy)methyl]cyclopentane (5), respectively. Both 3 and 4 mobilized intracellular Ca(2+), but 4 was only a few fold less potent than D-myo-inositol 1,4,5-trisphosphate, demonstrating that effective mimics can be designed that do not bear a six-membered ring.     

Iridoids and anthraquinones from the Malaysian medicinal plant,Saprosma scortechinii (Rubiaceae)

A further investigation of the leaves and stems of Saprosma scortechinii afforded 13 compounds, of which 10 are new compounds. These were elucidated as the bis-iridoid glucosides, saprosmosides G (1) and H (2), the iridoid glucoside, 6-O-epi-acetylscandoside (3), and the anthraquinones, 1-methoxy-3-hydroxy-2-carbomethoxy-9,10-anthraquinone (4), 1-methoxy-3-hydroxy-2-carbomethoxy-9,10-anthraquinone 3-O-beta-primeveroside (5), 1,3-dihydroxy-2-carbomethoxy-9,10-anthraquinone 3-O-beta-primeveroside (6), 1,3,6-trihydroxy-2-methoxymethyl-9,10-anthraquinone (7), 1-methoxy-3,6-dihydroxy-2-hydroxymethyl-9,10-anthraquinone (8), 1,3,6-trihydroxy-2-hydroxymethyl-9,10-anthraquinone 3-O-beta-primeveroside (9), and 3,6-dihydroxy-2-hydroxymethyl-9,10-anthraquinone (10). Structure assignments for all compounds were established by means of mass and NMR spectroscopies, chemical methods, and comparison with published data. The new anthraquinones were derivatives of munjistin and lucidin.     

Studies on the constituents of Broussonetia species VIII. Four new pyrrolidine alkaloids, broussonetines R, S, T, and V and a new pyrroline alkaloid, broussonetine U, from Broussonetia kazinoki Sieb

Four new pyrrolidine alkaloids, broussonetines R, S, T, and V and a new pyrroline alkaloid, broussonetine U were isolated from the branches of Broussonetia kazinoki SIEB. (Moraceae) in low yield. Broussonetines R, S and T were formulated as (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(1R)-1-hydroxy-3-[6-(4-hydroxybutyl)-cyclohexy-2-on-1(6)-enyllpropyl] pyrrolidine (1), (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(1R,10S)-1,10,13-trihydroxytridecyl] pyrrolidine (2), (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(1R,5S)-1,5, 13-trihydroxy-10-oxo-tridecyl] pyrrolidine (3). And broussonetines U and V were proposed to be (2S,3S,4S)-2-hydroxymethyl-3, 4-dihydroxy-5-(9-oxo-13-hydroxytridecyl)-5-pyrroline (4), (2R,3S,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(E)-9-oxo-13-hydroxy-3-tridecenyl] pyrrolidine (5), respectively, by spectroscopic and chemical methods.     

Synthesis of 5-substituted 5-hydroxy-2-pyrrolidones, metabolites of the antipsychotic benzamide remoxipride

This paper describes the synthesis of 5-[(3-bromo-2,6-dimethoxybenzamido)-methyl]-5-hydroxy-2-pyrrolidon e (3) and its 1-ethyl analogue 2, two urinary metabolites of the dopamine D-2 antagonist remoxipride [1, (S)-3-bromo-N-[(1-ethyl-2-pyrrolidinyl)methyl]-2, 6-dimethoxybenzamide]. Two synthetic schemes leading to a common intermediate, 5-benzamido-4-oxopentanoic acid 4, were developed. This key intermediate permits conversion into either metabolite. Reaction of 4 with isobutyl chloroformate furnished a mixed carbonic anhydride, which upon treatment with ethylamine or ammonia gave the 4-oxopentanamides 5 and 6, respectively. Ring-closure afforded the corresponding 5-hydroxy-2-pyrrolidones 2 and 3.     

Beta-hydroxy-gamma-lactones as chiral building blocks for the enantioselective synthesis of marine natural products

The enantioselective synthesis of trans-(+)-laurediol, (2S,3S,5R)-5-[(1R)-1-hydroxy-9-decenyl]-2-pentyltetrahydro-3-furanol, and (2S,3S,5S)-5-[(1S)-1-hydroxy-9-decenyl]-2-pentyltetrahydro-3-furanol are described. In addition, a formal synthesis of trans-(-)-kumausyne is also developed. All the synthetic procedures have in common the use of enantiomerically enriched beta-hydroxy-gamma-lactones, easily available by Sharpless asymmetric dihydroxylation (AD) from the suitable beta,gamma-unsaturated ester. The use of Katsuki-Sharpless asymmetric epoxidation (AE) as an additional enantioselective reaction provides cyclic compounds of high enantiomeric purity.     

Studies on modified benzotriazoles as photostabilizers for poly(vinyl chloride)

It has been found that modified benzotriazoles: (2-(2-hydroxy-3-chlormethylacetamid-5-methylphenyl)2H-benzotriazole, 2-(2-hydroxy-3[(N,N-di-n-butyl)acetamidmethyl]-5-methyl-phenyl)2H-benzotriazole and 2-(2-hydroxy-3[(N,N-di-n-octyl)acetamidmethyl]-5-methyl-phenyl)2H-benzotriazole) have photostabilizing properties similar to those of Tinuvin P (2-(2-hydroxy-5-methylphenyl)2H-benzotriazole) for the photo-oxidative degradation of PVC under 3665 and 2537 A. The migration rate of stabilizers in a polymer matrix is decreased by introducing long chain groups. The possible mechanism of photosensitization is discussed.     

Transformation of 1-(acyl)(2-haloethyl)amino-9,10-anthraquinones into 1-(2-acyloxyethylamino)-9,10-anthraquinones

Acylation of 1-(2-haloethylamino)-9,10-anthraquinones gave 1-[(2-haloethyl)(aroyl, hetaroyl, or acetyl)amino]-9,10-anthraquinones which were converted into the corresponding 1-[2-(aroyloxy, hetaroyloxy, or acetoxy)ethylamino]-9,10-anthraquinone on keeping in dimethylformamide. According to the experimental data (including those obtained by kinetic study), the transformation involves intramolecular migration of the acyl group through aziridinium or oxazolidinium intermediates.