Baker's yeast reduction of α-(alkoxycarbonylamino)acetophenones and Lipase-catalysed resolution of 2-(alkoxycarbonylamino)-1-arylethanols

Enzymatic reduction of α-(alkoxycarbonylamino)acetophenones with baker's yeast afforded optically active (R)-2-(alkoxycarbonylamino)-1-arylethanols. However, the reduction of α-(benzyloxycarbonylamino)-4-methoxyacetophenone ( 3c ) with immobilized baker's yeast gave (S)-2-(benzyloxycarbonylamino)-1-(4-methoxyphenyl) ethanol. The lipase PS-catalysed transesterification of 2-(allyloxycarbonylamino)-1-arylethanols ( 5 ) using vinyl acetate as an acyl donor resulted in the formation of (S)-2-(allyloxycarbonyl-amino)-1-arylethyl acetates [( S )- 9 ] and (R)-2-(allyloxycarbonylamino)-1-aryle-thanols [( R )- 5 ].     

(S)-2-(ethyl propionate)-(O-ethyl xanthate)- and (S)-2-(Ethyl isobutyrate)-(O-ethyl xanthate)-mediated RAFT polymerization of vinyl acetate

(S)-2-(Ethyl propionate)-(O-ethyl xanthate) (X1) and (S)-2-(Ethyl isobutyrate)-(O-ethyl xanthate) (X2) were used as the reversible addition-fragmentation chain transfer (RAFT) agents for the radical polymerization of vinyl acetate (VAc). The former showed the better chain transfer ability in the polymerization at 60°C. Kinetic study with both RAFT agents showed pseudo-first order kinetics up to around 85% monomer conversion. Molecular weight of the resulting polymer increased linearly with increase in the monomer conversion up to around 85%. The observed molecular weights calculated from ¹H-NMR spectrum [M_n(NMR)] are close to the corresponding theoretical molecular weights [M_n(theor)]. The corresponding polydispersity index (PDI) of the resulting polymers remained almost constant at around 1.2 up to ∼ 65% monomer conversion and then increased gradually with the further increase in the monomer conversion. Chain-end analysis of the resulting polymers by ¹H-NMR showed clearly that polymerization started with the radical forming out of the xanthate mediator. The negligible homo-chain extension and the hetero-chain extension involving synthesis of poly(VAc)-b-poly(NVP) diblock copolymer were occurred. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Oxidation of aroylthioureas during their reactions with 2,3-diphenylcyclopropenone resulting in (E/Z)-3-(aroylthioureido)-2-phenylcinnamic acids

Isolated (E/Z)-3-(aroylthioureido)-2-phenylcinnamic acids have been obtained from the reactions of N-substituted-aroylthioureas with 2,3-diphenylcyclopropenone in acetic acid. The abnormal behavior of the reaction was described as due to nucleophilic addition of N ³ followed by hydrolysis, ring opening and oxidation processes.     

Synthesis of 2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine-1-oxide and its hydrazones

An efficient method for preparation of earlier unknown S-oxide of 2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine by oxidation of 2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine hydrochloride with hydrogen peroxide in H₂O or EtOH/H₂O followed by the reaction mixture neutralization with Na₂CO₃ has been described. Interaction of the S-oxide with acetaldehyde, butanal, benzaldehyde, 4-methoxybenzaldehyde and 4-pyridinecarboxaldehyde in EtOH, C₆H₆, in the mixture of acetonitrile and ethanol or ethanol and benzene affords the unknown hydrazones, N-organylmethylidene-2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine-1-oxides.     

Reactivity of (1′ S )-1-(1′-phenyl-ethyl)-4-hydroxy-piperidin-2-one with Lawesson's reagent

The study of the reactivity of diasteromeric mixture (1′S)-1-(1′-phenyl-ethyl)-4-hydroxy-piperidine-2-one 2 with the Lawesson's reagent in different conditions is described.     

Synthesis, structure and magnetic properties of the first copper(II) complex with an (E)-4-aryl-4-oxo-2-butenoato ligand

A new binuclear Cu(II) complex with an (E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoato ligand (L) was successfully synthesized and characterized by elemental analysis and IR-spectroscopy. The structures of (E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoic acid (HL), and the corresponding (tetrakis)-μ-[(E)-4-(2,4-diisopropylphenyl)-4-oxo-2-butenoato]-bis(ethanol)-copper(II) complex, [Cu₂L₄(C₂H₅OH)₂], were determined by single crystal X-ray analyses and are preliminarily discussed. This is the first complex of a transition metal with ligand L, as well as the first determined crystal structure of a metal complex with this type of ligand. Analysis of the magnetic susceptibility measurements of the isolated [Cu₂L₄(C₂H₅OH)₂] · H₂O complex shows the existence of a strong anti-ferromagnetic intradimer coupling, with an exchange integral value 2J of −260 cm⁻¹.     

N-(2-methylpropyl)-(E,E)-2,4-decadienamide a mosquito larvicide fromAchillea millefolium L.

A methanol extract ofAchillea millefolium L. showed activity against 24-hr-old larvae ofAedes triseriatus. Bioassay- and TLC-monitored fractionation yielded a neutral fraction which was refined further by column chromatography to afford the antilarvalN-(2-methlpropyl)-(E,E)-2,4-decadienamide which was identified by spectral methods and through comparisons with a synthesized sample. Isolated and synthesized amides at 5 ppm resulted in 98 and 100% mortality of 24-hr-oldA. triseriatus larvae. TheN-(2-methylpropyl)-amides of decanoic and (E)-2-decenoic acids showed the same order of antilarval activity asN-(2-methylpropyl)-(E,E)-2,4-decadienamide, butN-(2-methylpropyl)sorbamide was inactive.     

Kinetics of Photo-isomerization and Photo-degradation of 2-Hydroxy-5-methylbenzophenone (E)- and (Z)-Oximes

The kinetics of photo-isomerization and photo-degradation of 2-hydroxy-5-methylbenzophenone (E)- and (Z)-oximes in ethanol, octane, toluene and a mixture of octane and toluene under exposure to UV light was studied. The products of the photo-isomerization/photo-degradation of both oximes are similar but the conversion rate and amount of photo-degradation products of 2-hydroxy-5-methylbenzophenone (Z)-oxime are much higher. Also the photo-degradation of the (Z)-isomer is quicker than its photo-isomerization to the (E)-isomer. The photo-isomerization and photo-degradation kinetic models were developed for both oximes. The formulated kinetic model contains 12 reaction rate constants which have been estimated from experimental data. Good agreement was found between experimental and predicted data. © 1997 SCI.     

Biological activity of (3R,5S,6R)- and (3S,5R,6S)-3,5-dimethyl-6-(methylethyl)-3,4,5,6-tetrahydropyran-2-one,a pheromone ofMacrocentrus grandii (Goidanich) (Hymenoptera: Braconidae)

In a previous study we reported identification of (3R*,5S*,6R*)-3,5-dimethyl-6-(methylethyl)-3,4,5,6-tetrahydropyran-2-one as a component of the pheromone ofMacrocentrus grandii Goidanich. The lactone was present in male and female wasps, and laboratory and field bioassays demonstrated that both sources of the lactone elicit flight initiation, upwind anemotaxis, and casting in male wasps. In the present study, the synthetic (3R,5S,6R)- and (3S,5R,6S)-lactone enantiomers (RSR andSRS, respectively) were bioassayed for biological activity. In wind tunnel studies theSRS enantiomer elicited flight initiation, upwind anemotaxis, and casting by male wasps comparable to lactone derived from male and female wasps. Flight response to theRSR enantiomer averaged 14 percent of theSRS enantiomer. No specific ratio of the stereoisomers was found more attractive than theSRS enantiomer alone. Field studies demonstrated theSRS enantiomer was active alone in attracting male wasps. When paired with (Z)-4-tridecenal (a previously identified female-derived sex pheromone), theSRS enantiomer yielded a synergistic response comparable to (Z)-4-tridecenal plus female-derived lactone.     

Chemoenzymic synthesis of optically active 3-methyl- and 3-butylphthalides

Optically active (S)-3-methylphthalide was synthesized by the enzymic reduction of 2-iodoacetophenone using baker's yeast, followed by palladium-catalysed carbonylation under carbon monoxide. With enzymic reduction using baker's yeast, however, 2-bromo- or 2-iodovarelophenones were not reduced, even after 25 days. On the other hand, the enantioselective hydrolysis of α-alkylated 2-halobenzyl acylates using pig liver esterase, horse liver esterase or lipase from Candida rugosa resulted in the formation of (R)-α-alkylated 2-halobenzyl alcohol and (S)-acylate, and the following palladium-catalysed carbonylation of the products yielded the (R)- and (S)-3-alkylated phthalides, respectively.     

Synthesis of polyfunctionally substituted pyridine-2-(1H)-thiones containing a sulfone moiety

1-Phenyl-2-(phenylsulfonyl)ethanone (1) reacts with DMFDMA to give enamine 2, which upon treatment with cyanothioacetamide affords 3-cyano-5-benzenesulfonyl-4-phenylpyridine-2(1H)-thione (4), a compound that can also be obtained by the reaction of 1-benzenesulfonyl-1-benzoyl-2-ethoxyethene (3) with cyanothioacetamide. The reaction of 2-thiocarbamoylacetamide (8a) and N-phenyl-2-thiocarbamoylacetamide (8b) with 3-aryl-2-benzenesulfonylacrylonitrile (9a– c) affords 10a–f. The methylation of 10d–f with methyl iodide results in the formation of S-methyl derivatives (12a–c). Compound 12c can be obtained by the reaction of 13 with 9c.     

Improvement in the synthesis of 2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(Z)-methoxyiminoacetic acid 2-benzothiazolyl thioester

2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-(Z)-methoxyiminoacetic acid 2-benzothiazolyl thioester(III), an important intermediate of the fourth generation cephalosporins, was efficiently synthesized by reacting 2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(Z)-methoxyiminoacetic acid (I) with 2,2′-dibenzothiazole disulfide (II) in the presence of triphenylphosphine. Effects of reaction time, temperature, solvents, catalysts and feeding molar ratio on the yield and quality of products were investigated, and an improved procedure suitable for industrial production was established. Using 1,2-dichloroethane as solvent, triphenylphosphine as reducer, and triethylamine as catalyst, n(I): n(II): n(triphenylphosphine)51.0: 1.0: 1.0, the product was obtained at room temperature in 98.1% yield. The purity of the product without further purification is 98.7% determined by HPLC method. This procedure could be a suitable alternative to the traditional processes because of its easy handling, high yield and low cost. __________ Translated from Fine Chemicals, 2007, 24(8): 816–819 [译自:精细化工]     

(Z,Z)-4,7-tridecadien-(S)-2-yl acetate: sex pheromone of Douglas-fir cone gall midge,Contarinia oregonensis

Our objectives were to identify and field test the sex pheromone of female Douglas-fir cone gall midge, Contarinia oregonensis (Diptera: Cecidomyiidae). Coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone extract revealed a single compound (A) that elicited responses from male antennae. Hydrogenation of pheromone extract, followed by renewed GC-EAD analysis, revealed a new EAD-active compound with chromatographic characteristics identical to those of tridecan-2-yl acetate on five fused silica columns (DB-5, DB-210, DB-23, SP-1000, and Cyclodex-B). Syntheses, chromatography, and retention index calculations of all possible tridecen-2-yl acetates suggested that the candidate pheromone A was a tridecadien-2-yl acetate with nonconjugated double bonds. Synthetic candidate pheromone component (Z,Z)-4,7-tridecadien-2-yl acetate (Z4Z7) cochromatographed with A on all analytical columns and elicited comparable antennal activity. In GC-EAD analyses that separated the enantiomers (Z,Z)-4,7-tridecadien-(S)-2-yl acetate (2S-Z4Z7) and (Z,Z)-4,7-tridecadien-(R)-2-yl acetate (2R-Z4Z7) with baseline resolution, only 2S-Z4Z7 as a component in a racemic standard or in pheromone extract elicited antennal responses. In Douglas-fir seed orchards, sticky traps baited with 2S-Z4Z7 captured male C. oregonensis, whereas 2R-Z4Z7 was behaviorally benign. Comparable catches of males in traps baited with racemic Z4Z7 (50 g) or virgin female C. oregonensis suggested that synthetic pheromone baits could be developed for monitoring C. oregonensis populations in commercial Douglas-fir seed orchards.     

(E)- and (Z)-6-nonen-2-one: Biosynthetic precursors ofEndo- andexo-brevicomin in two bark beetles (Coleoptera: Scolytidae)

The ability of (E)- and (Z)-6-nonen-2-one to serve as precursors of the common scolytid pheromonesEndo- andexo-brevicomin was examined in vivo. When mountain pine beetles (MPB),Dendroctonus ponderosae Hopkins, or western balsam bark beetles (WBBB),Dryocoetes confusus Swaine, were exposed to [6,7-D₂](E)-6-nonen-2-one, theEndo-brevicomin produced was enriched with two deuterium atoms per molecule (as determined by GC-MS), indicating that (E)-6-nonen-2-one served as a precursor of this pheromone. Similarly, when the beetles were exposed to [4,4-D₂](Z)-6-nonen-2-one, theexo-brevicomin produced was enriched with two deuterium atoms per molecule. Evidence in support of biological relevance of the latter observation include: (1) (Z)-6-nonen-2-one was found in the volatiles of male MPBs and WBBBs, indicating that this is a natural metabolite; (2) theexo-brevicomin produced by MPB was shown to be of natural (+) chirality by complexation chromatography; and (3) female WBBBs and MPBs (which are not known to produceexo-brevicomin) produced significantly lessexo-brevicomin when exposed to the precursor than did the males.     

Synthese und Reaktionen chiraler,von (R)-(−)-bzw. (S)-(+)-2-Methoxymethylpyrrolidin abgeleiteter Dithiocarbamate

Synthesis and Reactions of Chiral Dithiocarbamates Derived from (R)-(−)- or (S)-(+)-2- The synthesis, diastereoselective alkylation reactions, dithiocarboxylation, and aldol condensation of several substituted methyl (R¹ CH₂) (S)-2-(methoxymethyl)-pyrrolidine-1-dithiocarboxylates (S)- 2 and of the corresponding (R)-derivatives (R)- 2 are described. The new enantiomeric dithiocarbamates (S) -2a – e , and (R) -2a – d are obtained by reaction of (S)-(+)-[(S) -1 ] or (R)-(−)-2-(methoxymethyl)-pyrrolidine [(R) -1 ], respectively, with carbon disulfide in dry methanol/anhydrous sodium acetate and the appropriate alkylating agent. The cyclic ketene dithioacetals (S) -3 and (R) -3 are formed by dithiocarboxylation procedure of (S) -2a and (R) -2a whereas (S) -6 and (R) -6 are obtained by aldol reaction with isobutyraldehyde. (S)- 2c , d and (R) -2c , d react in a diastereoselective manner after deprotonation with n-BuLi or LiTMP/LiBr at −78°C in THF with alkyl halides to the enantiomeric compounds 4a /ent -4a, 4b /ent -4b and 5 /ent -5 , respectively.     

Novel type of sex pheromone structure identified fromStigmella malella (Stainton) (Lepidoptera: Nepticulidae)

Short-chain unsaturated chiral methyl carbinols are identified as a new class of lepidopteran pheromone components. The natural female-produced pheromone of the banded apple pigmyStigmella malella (=Nepticula malella) (Stainton) (Lepidoptera: Nepticulidae) was identified to be a mixture of (S)-(E)-6,8-nonadien-2-ol and (S)-(Z)-6,8-nonadien-2-ol. For monitoring traps, a 10:3E:Z blend at 100–1000 µg is recommended. It is suggested that pheromones with similar structures may be specific to Nepticulidae and other related microlepidopteran families.     

Copper-Catalyzed Diazidation of Allenes: Access to 3-(Azidomethyl)-2H-Azirines

A class of 3-(azidomethyl)-2H-azirine has been obtained through a copper-catalyzed diazidation of allenes and a subsequent azirination involving vinyl azides. A variety of functional groups in the allenes are well tolerated, providing a series of 3-(azidomethyl)-2H-azirine motifs in 51%-93% yields (26 examples).     

(5Z,9Z)-3-alkyl-5-methylindolizidines fromSolenopsis (Diplorhoptrum) species

The alkaloidal venom components of two species of thief ants,Solenopsis (Diplorhoptrum) species AA andS. (Diplorhoptrum)conjurata have been found to contain (5Z,9Z)-3-hexyl-5-methylindolizidine and a mixture of (5Z,9Z)-3-ethyl-5-methylindolizidine andcis-2-methyl-6-nonyl-piperidine,trans-2-methyl-6-nonylpiperidine,cis-2-methyl-6-undecylpiperidine, and hexadecanoic acid.Monomorium pharaonis was similarly investigated and found to contain the indolizidine and pyrrolidines previously described (Ritter et al., 1977b). Both indolizidines were synthesized along with their stereoisomers and separated by preparative gas chromatography. Spectral studies revealed the stereochemistry to be 5Z,9Z in both cases. The stereochemistry of 2-butyl-5-pentylpyrrolidine inM. phaeronis has also been established. Biosynthetic relationships are discussed.     

(Z)-9-tetradecen-1-ol acetate

(Z)-9-Tetradecen-1-ol acetate [(Z)-9-TDA], identified originally as the sex pheromone of the fall armyworm,Spodoptera frugiperda (J.E. Smith), acted as a secondary sex pheromone when it was tested in sticky traps in field tests. Low-level synergism was obtained when 2 and 10% quantities of (Z)-9-TDA were added to 100 g of (Z)-9-dodecen-1-ol acetate, which is now considered the primary sex pheromone.Lepidoptera: Noctuidae.In cooperation with the University of Georgia College of Agriculture Experiment Stations, Coastal Plain Station, Tifton, Georgia 31794.Mention of a proprietary product does not constitute endorsement by the USDA.     

Enzymatic Transesterification of 3,7-Dimethyl-4,7- octadien-1-ol Using Lipases

Enzymatic transesterification of (±)-3,7-dimethyl-4,7-octadien-1-ol ( 1 ) using various lipases and vinyl esters resulted in the formation of (S)-(+)-1-acyloxy-3,7-dimethyl-4,7-octadiene ((S)- 2 ) and (R)-(-)-3,7-dimethyl-4,7-octadien-1-ol ((R)- 1 ). Cyclization of (R)- 1 with iodine afforded (4R)-(-)-cis-4-methyl-2-(2-methyl-1-propenyl)tetrahydropyran ((-)-rose oxide). © 1997 SCI.