Effect of microwave pretreatment on the color degradation kinetics in mustard greens (Brassica juncea)

In the present work, the impact of microwave pretreatment on the thermal degradation of color (chlorophylls) in mustard greens was studied. The drying experiments were conducted in the range of temperatures from 50 to 80°C. The degradation in the levels of chlorophylls has been quantified using Hunter color values (L*, a*, and b*) and calculating total color difference (ΔE). From the color results, the changes in color values (L*, a*, and b*) were observed as inappreciable, and changes in ΔE were found to be increased during drying. Analysis of kinetic data displayed a first-order reaction kinetics for chlorophyll degradation. Arrhenius equation was used to calculate the activation energies for rate constants, and it has been varied from 13.3 to 27.4?kJ/mol. Thermodynamic parameters, enthalpy of activation (ΔH^#), and entropy activation (ΔS^#) were found to be in the range of 1.40–2.63?J/mol and ?293 to ?305?J/mol?·?K, respectively. The data from the present work revealed that the microwave pretreatment of mustard greens remarkably influenced the retention of chlorophylls in the final dehydrated powder.     

Design,Synthesis, and Biological Evaluation of Tetrahydro-α-carbolines as Akt1 Inhibitors That Inhibit Colorectal Cancer Cell Proliferation

A series of densely functionalized THαCs were designed and synthesized as Akt1 inhibitors. Organocatalytic [3+3] annulation between indolin-2-imines 1 and nitroallylic acetates 2 provided rapid access to this pharmacologically interesting framework. In vitro kinase inhibitory abilities and cytotoxicity assays revealed that compound 3 af [(3S*,4S*)-4-(4-bromo-2-fluorophenyl)-9-methyl-3-nitro-1-tosyl-2,3,4,9-tetrahydro-1H-pyrido[2,3-b]indole] was the most potent Akt1 inhibitor, and mechanistic study indicated that compound 3 af suppressed the proliferation of colorectal cancer cells via inducing apoptosis and autophagy. Molecular docking suggested that the indole fragment of 3 af was inserted into the hydrophobic pocket of Akt1 protein, and the H-bond between 3 af and residue Lys179 also contributed to the stable binding. This article provides an efficient strategy to design and synthesize biologically important compounds as novel Akt1 inhibitors.     

A fallacy in the definition of ΔH*

When a color differs from the reference, it is desirable to ascribe the difference to differences in the perceptual attributes of hue, chroma, and/or lightness through psychometric correlates of these attributes. To this end, the CIE has recommended the quantity ΔH* as a psychometric correlate of hue as defined by ΔH* = [(ΔE*)² - (ΔL*)² - (ΔC*)²]^1/2, where the correlates correspond to either the 1976 CIELAB or CIELUV color spaces. Since ΔH* is defined as a “leftover,” this definition is valid only to the extent that ΔE* comprises exclusively ΔL*, ΔC*, and ΔH* and that ΔL*, ΔC*, and ΔH* are mutually independent compositionally, both psychophysically and psychometrically. It will be shown that as now defined ΔH* lacks psychometric independence of chroma and always leads to incorrect hue difference determination. Such a deficiency causes problems, especially in the halftone color printing industry, since it can suggest an incorrect adjustment for the hue of the inks. A revised definition herein of ΔH* provides a psychometric hue difference independent of chroma, valid for large and small psychometric color differences regardless of chroma. However, for small chromas, the seldom used metric ΔC might be a better color difference metric than ΔH* because complex appearance effects make the perceptual discrimination of lightness, chroma, and hue components more difficult than for high chromas.     

Design,synthesis, antibacterial and antifungal activity of novel spiro-isoxazolyl bis-[5,5′]thiazolidin-4-ones and spiro-isoxazolyl thiazolidin-4-one-[5,5′]-1,2-4 oxdiazolines

The synthesis of novel isoxazolyl 1,6-dithia-4,9-diazaspiro[4.4]nonane-3,8-diones (4a–h) and isoxazolyl 1-oxa-6-thia-2,4,9-triazaspiro[4.4]non-2-ene-8-ones (5a–h) analogs is described. Reaction of N-1-\{3-methyl-5-[(E)-2-aryl-1-ethenyl]-4-isoxazolyl}-2-chloroacetamide (2) with aryl isothiocyanates yielded 3,3-methyl-5-[(E)-2-aryl-1-ethenyl]-4-isoxazolyl-2-(arylimino)-1,3-thiazolan-4-ones (3). Cyclocondensation of 3 with mercaptoacetic acid furnished novel isoxazolyl-1,6-dithia-4,9-diazaspiro[4.4]nonane-3,8-diones (4a–h). Cycloaddition of 3 with benzonitrile oxides afforded novel isoxazolyl 1-oxa-6-thia-2,4,9-triazaspiro[4.4]non-2-ene-8-ones (5a–h). Compounds 4a–h and 5a–h showed significant biological activity against all the standard strains.     

Direct coloration of textiles with photochromic dyes. Part 1: Application of spiroindolinonaphthoxazines as disperse dyes to polyester,nylon and acrylic fabrics†

1,3,3‐Trimethylspiroindoline‐2,3′‐3H‐naphth[2,1‐b][1,4]oxazine ( 1a ) and 6′‐piperidino‐1,3,3‐trimethylspiroindoline‐2,3′‐3H‐naphth[2,1‐b][1,4]oxazine ( 1b ) were applied as disperse dyes to polyester, nylon and acrylic fabrics. Under optimised dyeing conditions, photochromic fabrics were produced which, on irradiation with ultraviolet or exposure to sunlight, turned blue ( 1a) or blueish‐purple ( 1b ). Dye 1a showed enhanced photochromic colour change performance compared with dye 1b . The photochromic colour build was highest on nylon and lowest on acrylic fabric. The colour change properties and the technical performance (wash fastness and photostability) of the photochromic fabrics were evaluated using specifically adapted colour measurement methods. The data were analysed in terms of variation of lightness, a*, b*, chroma, hue angle and ΔE, colour difference before and after exposure, and K/S curves as a function of irradiation time. The fabrics generally showed good wash fastness. Although the colour build‐up decreased with exposure to the Xenotest fadeometer, some residual photochromism remained after prolonged exposure.     

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.     

Enzymes in organic synthesis. 27. Lipase-Catalyzed Synthesis of (5R,6S)-6-Acetoxyalkan-5-olides – homologues of the mosquito oviposition attractant pheromone

Sixteen homologous (5R*,6S*)-6-hydroxyalkan-5-olides rac- 5 and their acetoxy derivatives rac- 6 were synthesized from the corresponding methyl (Z)-alk-5-enoates 3 by osmium(VIII) oxide catalyzed cis-hydroxylation to the dihydroxy esters rac- 4 and hydrolysis of these esters followed by lactonization. Pancreatin-catalyzed lactonization of the dihydroxy esters rac- 4 afforded enantiomerically enriched hydroxy lactones ent- 5 , five of which were obtained enantiomerically pure by recrystallization. Acetylation of the 6-hydroxyalkan-5-olides rac- 5 by vinyl acetate catalyzed by the lipase SP 526 provided enantiomerically enriched 6-acetoxyalkan-5-olides 6 with an enantiomeric excess of more than 90% in nine cases. These compounds are known as mosquito oviposition attractant pheromone ( 6h ) or its homologues.     

Discovery of Affinity-Based Probes for Btk Occupancy Assays

Bruton's tyrosine kinase (Btk) is an attractive target for the treatment of a wide array of B-cell malignancies and autoimmune diseases. Small-molecule covalent irreversible Btk inhibitors targeting Cys481 have been developed for the treatment of such diseases. In clinical trials, probe molecules are required in occupancy studies to measure the level of engagement of the protein by these covalent irreversible inhibitors. The result of this pharmacodynamic (PD) activity provides guidance for appropriate dosage selection to optimize inhibition of the drug target and correlation of target inhibition with disease treatment efficacy. This information is crucial for successful evaluation of drug candidates in clinical trials. Based on the pyridine carboxamide scaffold of a novel solvent-accessible pocket (SAP) series of covalent irreversible Btk inhibitors, we successfully developed a potent and selective affinity-based biotinylated probe 12 (2-[(4-{4-[5-(1-{5-[(3aS,4S,6aR)-2-oxo-hexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanamido}-3,6,9,12-tetraoxapentadecan-15-amido)pentanoyl]piperazine-1-carbonyl}phenyl)amino]-6-[1-(prop-2-enoyl)piperidin-4-yl]pyridine-3-carboxamide). Compound 12 has been used in Btk occupancy assays for preclinical studies to determine the therapeutic efficacy of Btk inhibition in two mouse lupus models driven by TLR7 activation and type I interferon.     

Synthesis, Spectroscopic Characterization and Structures of Tributyltin(IV) 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoates. Toxicity Studies on the Second Larval Instar of the Anopheles stephensi Mosquito Larvae

A series of tributyltin(IV) complexes of 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoates have been investigated by ¹H, ¹³C, ¹¹⁹Sn NMR, IR and ¹¹⁹Sn M?ssbauer spectroscopic techniques in combination with elemental analyses. Single crystal X-ray crystallography of Bu₃Sn[O₂CC₆H₄{N=C(H)C₆H₃-2-OH(N=NC₆H₄CH₃-4)}-p] reveals a distorted tetrahedral structure which is further supported by ¹¹⁹Sn M?ssbauer data. Toxicity studies of the tributyltin(IV) complexes along with their ligands 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoic acids on the second larval instar of the Anopheles stephensi mosquito larvae are also reported.     

Design of gem‐Difluoro‐bis‐Tetrahydrofuran as P2 Ligand for HIV‐1 Protease Inhibitors to Improve Brain Penetration: Synthesis,X‐ray Studies,and Biological Evaluation

The structure‐based design, synthesis, biological evaluation, and X‐ray structural studies of fluorine‐containing HIV‐1 protease inhibitors are described. The synthesis of both enantiomers of the gem‐difluoro‐bis‐THF ligands was carried out in a stereoselective manner using a Reformatskii–Claisen reaction as the key step. Optically active ligands were converted into protease inhibitors. Two of these inhibitors, (3R,3aS,6aS)‐4,4‐difluorohexahydrofuro[2,3‐b]furan‐3‐yl(2S,3R)‐3‐hydroxy‐4‐((N‐isobutyl‐4‐methoxyphenyl)sulfonamido)‐1‐phenylbutan‐2‐yl) carbamate ( 3 ) and (3R,3aS,6aS)‐4,4‐difluorohexahydrofuro[2,3‐b]furan‐3‐yl(2S,3R)‐3‐hydroxy‐4‐((N‐isobutyl‐4‐aminophenyl)sulfonamido)phenylbutan‐2‐yl) carbamate ( 4 ), exhibited HIV‐1 protease inhibitory K_i values in the picomolar range. Both 3 and 4 showed very potent antiviral activity, with respective EC₅₀ values of 0.8 and 3.1 nM against the laboratory strain HIV‐1_LAI. The two inhibitors exhibited better lipophilicity profiles than darunavir, and also showed much improved blood–brain barrier permeability in an in vitro model. A high‐resolution X‐ray structure of inhibitor 4 in complex with HIV‐1 protease was determined, revealing that the fluorinated ligand makes extensive interactions with the S2 subsite of HIV‐1 protease, including hydrogen bonding interactions with the protease backbone atoms. Moreover, both fluorine atoms on the bis‐THF ligand formed strong interactions with the flap Gly 48 carbonyl oxygen atom.     

Bornane with integrated push–pull butadienes

The {3-[bis(alkylthio)methylene]-1,7,7-trimethyl-bicyclo[2.2.1]hept-2-ylidene}malononitriles ((1R,4S)- 2 , (1S,4R)- 2 and (1R,4S)- 3 ) were prepared starting from 1,7,7-trimethyl-bicyclo[2.2.1]hept-2-ylidenemalononitriles (1R, 4R)- 1 and (1S,4S)- 1 ) arisen from (+)-, (–)-camphor. The reaction of (1R,4S)- 2 with bromine yielded the (1S,8R)-8,11,11-trimethyl-3-methylthio-5-oxo-4-thiatricyclo-[6.2.1.0^2,7]undeca-2,6-diene-6-carbonitrile ( 8 ) after hydrolysis of the initially formed (1S,8R)-6-cyano-8,11,11-trimethyl-3-methylthio-4-thia-tricyclo[6.2.1.0^2,7]undeca-2,6-diene-5-iminium bromide ( 7 ).     

Synthesis of 6‐amino acid substituted 4,6,7,12‐tetrahydro‐4‐oxoindolo[2,3‐a]quinolizines

In the presence of Na₂CO₃ (1S,3S)‐ and (1R,3S)‐1‐(2,2‐dimethoxyethyl)‐2‐(1,3‐dioxobutyl)‐3‐(1,3‐dioxo‐butyl)oxymethyl‐1,2,3,4‐tetrahydrocarboline ( 1 ) were transformed into (1S,3S)‐ and (1R,3S)‐1‐(2,2‐dimethoxyethyl)‐2‐(1,3‐dioxobutyl)‐3‐hydroxymethyl‐1,2,3,4‐tetrahydrocarboline ( 2 ), which were cyclized to (6S)‐3‐acetyl‐6‐hydroxymethyl‐4,6,7,12‐tetrahydro‐4‐oxoindolo[2,3‐a]quinolizine ( 4 ), via(6S,12bS)‐ and (6S,12bR)‐3‐acetyl‐2‐hydroxyl‐6‐hydroxymethyl‐1,2,3,4,6,7,12,12b‐octahydro‐4‐oxoindolo[2,3‐a]quinoline ( 3 ). (6S)‐ 4 was coupled with Boc‐Gly, Boc‐L‐Asp(β‐benzyl ester), or Boc‐L‐Gln to give 6‐amino acid substituted (6S)‐3‐acetyl‐4,6,7,12‐tetrahydro‐4‐oxoindolo[2,3‐a]quinolizines 5a , 5b , or 5c , respectively. After the removal of Boc from (6S)‐ 5a (6S)‐3‐acetyl‐6‐glycyl‐4,6,7,12‐tetrahydro‐4‐oxoindolo[2,3‐a]quinolizine ( 6 ) was obtained. The anticancer activities of (6S)‐ 5 and (6S)‐ 6 in vitro were tested.     

Efficient Asymmetric Synthesis of 2,6‐Disubstituted 2H‐Dihydropyrans via a Catalytic Hetero‐Diels–Alder/Allylboration Sequence

[4+2] Cycloaddition of (E)‐3‐borylacrolein 1 with ethyl vinyl ether, catalysed by chromium complex (1R,2S) or (1S,2R) 2 , led to the corresponding cycloadducts with high diastereo‐ and enantioselectivities. Further reaction with aldehydes offers an attractive asymmetric route to synthetically useful substituted 3,4‐dihydro‐2H‐pyrans.     

From Overcrowded Polycyclic Aromatic Enes to Semifullerenes

Bi-9H-fluoren-9-ylidene (2) and bi-4H-cyclopenta[def]phenanthren-4-ylidene (5) are potential starting materials for the preparation of bowl-shaped fragments of fullerenes. Semiempirical MNDO-PM3 calculations of C₂₆H_n and C₃₀H_n (n = 12, 14, 16) species 2-12 are used to analyze energetic effects on the dehydrocyclization and isomerization reactions of these species. Oxidative photocyclizations on Z-2,2′-bridged derivatives of 2 and 5 are briefly outlined.     

Color stability of denture shade tabs is affected by exposure to daylight and decontamination protocols

The purpose of this study was to investigate the effect of light exposure and decontamination protocols on the color stability of denture shade guide tabs. Fifty tabs for shades 62, 66, and 69 (Biotone IPN, Dentsply Sirona) were submitted to baseline L*a*b* measurements (EasyShade, Vita), separated into 5 experimental groups (n = 10), and subjected to one of the following conditions: G1–distilled water (DW‐H₂O)–control; G2 ?70% alcohol; G3–sodium hypochlorite 1% (NaClO); G4–no light exposure; G5–natural light exposure for 6 months. The experimental conditions were designed to simulate 6 months of clinical use. After the test period, final color measurements were recorded. The mean tristimulus coordinate difference (ΔL*,Δa*,Δb*) and total color difference values () were analyzed using 2‐way ANOVA and the Tukey test, α = .05. G2 (alcohol) produced less (P < .05) color change in shade 69 than G3 (NaClO). G5 (light exposure) affected the color stability for all shades, producing a statistical difference (P < .05) from G4 (no light exposure). It was concluded that natural light changes the color stability of the shade guides and that decontamination with 70% alcohol had the least impact on the color stability of the shade guide tabs.     

Enantiospecific Effect of Pulegone and Pulegone-Derived Lactones on Myzus persicae (Sulz.) Settling and Feeding

The effect of pulegone chiral center configuration on its antifeedant activity to Myzus persicae was examined. Biological consequences of structural modifications of (R)-(+)- and (S)-(−)-pulegone, the lactonization, iodolactonization, and incorporation of hydroxyl and carbonyl groups were studied, as well. The most active compounds were (R)-(+)-pulegone (1a) and δ-hydroxy-γ-spirolactones (5S,6R,8S)-(−)-6-hydroxy-4,4,8-trimethyl-1-oxaspiro[4.5]decan-2-one (5b) and (5R,6S,8S)-6-hydroxy-4,4,8-trimethyl-1-oxaspiro[4.5]decan-2-one (6b) derived from (S)-(−)-pulegone (1b). The compounds deterred aphid probing and feeding at preingestional, ingestional, and postingestional phases of feeding. The preingestional effect of (R)-(+)-pulegone (1a) was manifested as difficulty in finding and reaching the phloem (i.e., prolonged time preceding the first contact with phloem vessels), a high proportion of probes not reaching beyond the mesophyll layer before first phloem phase, and/or failure to find sieve elements by 20% of aphids during the 8-hr experiment. The ingestional activity of (R)-(+)-pulegone (1a) and hydroxylactones 5b and 6b resulted in a decrease in duration of phloem sap ingestion, a decrease in the proportion of aphids with sustained sap ingestion, and an increase in the proportion of aphid salivation in phloem. δ-Keto-γ-spirolactone (5R,8S)-(−)-4,4,8-trimethyl-1-oxaspiro[4.5]decan-2,6-dione (8b) produced a weak ingestional effect (shortened phloem phase). The postingestional deterrence of (R)-(+)-pulegone (1a) and δ-hydroxy-γ-spirolactones (5R,6S,8R)-(+)-6-hydroxy-4,4,8-trimethyl-1-oxaspiro[4.5]-decan-2-one (5a), 5b, (5S,6R,8R)-6-hydroxy-4,4,8-trimethyl-1-oxaspiro[4.5]decan-2-one (6a), 6b, and δ-keto-γ-spirolactone 8b prevented aphids from settling on treated leaves. The trans position of methyl group CH₃–8 and the bond C5–O1 in lactone 6b appeared to weaken the deterrent activity in relation to the cis diastereoisomer (5b).     

Color distribution of maxillary primary incisors in Korean children

The purpose of this study was to investigate the color distribution of maxillary primary incisors measured with a colorimeter. The subjects were 100 Korean children aged 2–5 with total number of 400 teeth. A spot measurement intraoral colorimeter was used to determine the color of maxillary primary central and lateral incisors at labial central area. The CIE L*, a*, b* value of each tooth and color difference (ΔE) among each other were calculated and analyzed. The range of L*, a*, and b* values, regardless of the type of teeth, was 72.7–84.9, ?0.6 to 4.9, and 4.7–15.0, respectively. Mean value (SD) of L*, a*, and b* for maxillary primary incisors was 78.6 (2.3), 1.2 (0.9), and 9.6 (1.8), respectively. Boys showed more red (higher a* value) and less yellow (lower b* value) hue than girls in the central incisors (P < 0.05). Mean color difference (ΔE) (SD) between two values which selected from overall 400 L*, a*, b* values measured (n = ₄₀₀C₂) was 3.9 (1.8) with 95% confidence interval range of 3.86–3.89, and most of them were found to be present around the previously reported clinical acceptability thresholds (ΔE = 2.7–6.8). Because mean intraperson ΔE (SD) was 3.0 (1.6) with 95% confidence interval range of 2.86–3.12, most colors among primary incisors in the same person were presumably difficult to discern by naked eye (ΔE < 3.7). Age influenced L* and b* values significantly, but the correlation coefficients were not high (r = ?0.182 for L* of central incisors, P < 0.01; r = 0.188 for b* of central incisors, P < 0.01; and r = 0.143 for b* of lateral incisors, P < 0.05). The present study showed somewhat higher color coordinates than the previous reports which based on primary anterior teeth in other ethnic groups. The results of this study could be used for the color modification of esthetic materials for primary teeth. © 2009 Wiley Periodicals, Inc., Col Res Appl, 2010.     

Discovery of Aporphine Analogues as Potential Antiplatelet and Antioxidant Agents: Design,Synthesis, Structure–Activity Relationships,Biological Evaluations,and in silico Molecular Docking Studies

To explore the potential of aporphine alkaloids, a novel series of functionalized aporphine analogues with alkoxy (OCH₃, OC₂H₅, OC₃H₇) functional groups at C1/C2 of ring A and an acyl (COCH₃ and COPh) or phenylsulfonyl (SO₂Ph and SO₂C₆H₄‐3‐CH₃) functionality at the N6 position of ring B of the aporphine scaffold were synthesized and evaluated for their arachidonic acid (AA)‐induced antiplatelet aggregation inhibitory activity and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free‐radical‐scavenging antioxidant activity, with acetylsalicylic acid and ascorbic acid as standard references, respectively. The preliminary structure–activity relationship related to AA‐induced platelet aggregation inhibitory activity results showed that the aporphine analogues 1‐[1,2,9,10‐tetramethoxy‐6a,7‐dihydro‐4H‐dibenzo[de,g]quinolin‐6(5H)‐yl]ethanone and 1‐[2‐(benzyloxy)‐1,9,10‐trimethoxy‐6a,7‐dihydro‐4H‐dibenzo[de,g]quinolin‐6(5H)‐yl]ethanone to be the best compounds of the series. Moreover, the DPPH free‐radical‐scavenging antioxidant activity results demonstrated that the aporphine analogues 1,2,9,10‐tetramethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, 2‐ethoxy‐1,9,10‐trimethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, 1‐ethoxy‐2,9,10‐trimethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, 2,9,10‐trimethoxy‐6‐(methylsulfonyl)‐1‐propoxy‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, and 1‐(benzyloxy)‐2,9,10‐trimethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline were the best compounds of the series. Moreover, in silico molecular docking simulation studies of the active analogues were also performed.     

Enantiospecific synthesis of (3S,6R)-3-hydroxy-1,7-dioxaspiro[5.5]undecane and its (4R)-4-hydroxy isomer [minor components of olive fruit fly (Dacus oleae) sex pheromone]

The synthesis of (3S,6R)-3-hydroxy-1,7-dioxaspiro[5.5]undecane (8) and its (4R)-4-hydroxy isomer (11) from (3R,4S,6R)-3,4-dihydroxy-1,7-dioxaspiro[5.5]undecane (1), obtained from D-fructose, has been accomplished by regioselective deoxygenation at C-4 and C-3, respectively, of the appropriately protected derivatives.Enantiospecific synthesis of spiroacetals. Part III. For Part II, see Izquierdo et al. (1991).     

Diastereo‐ and Enantioselective Synthesis of Chiral Pyrrolidine‐Fused Spirooxindoles via Organocatalytic [3+2] 1,3‐Dipolar Cycloaddition of Azomethine Ylides with Maleimides

In the presence of a Cinchona alkaloid‐based squaramide organocatalyst, the [3+2] cycloaddition of isatin‐derived azomethine ylides with maleimides proceeded readily, thus delivering the desired pyrrolidine‐fused spirooxindoles in 61–89% yields with >20:1 dr and 12 to >99 % ee. The absolute configuration of 5‐chloro‐1,5′‐dimethyl‐3′‐phenyl‐3′,3a′‐dihydro‐2′H‐spiro[indoline‐3,1′‐pyrrolo[3,4‐c]pyrrole]‐2,4′,6′(5′H,6a′H)‐trione was unambiguously determined by means of X‐ray single crystal structure analysis. The reaction mechanism was hypothesized to account for the enantioselective formation of 5‐chloro‐1,5′‐dimethyl‐3′‐phenyl‐3′,3a′‐dihydro‐2′H‐spiro[indoline‐3,1′‐pyrrolo[3,4‐c]pyrrole]‐2,4′,6′(5′H,6a′H)‐trione.