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31.
Indole lactones 8 and 14 were synthesized as a means of functionalizing the 1-isopropyl substituent of the indole nucleus. Lactone 8 , upon reduction with diisobutylaluminum hydride, produces lactol 9 which behaves like a masked hydroxy aldehyde and undergoes a Horner-Emmons reaction with triethyl phosphonoacteate to give α,β-unsaturated ester 3 which possesses a hydroxyl group on the 1-isopropyl moiety. 相似文献
32.
Arosio D Fontanella M Baldini L Mauri L Bernardi A Casnati A Sansone F Ungaro R 《Journal of the American Chemical Society》2005,127(11):3660-3661
A high-affinity ligand of cholera toxin, the divalent glycocalix[4]arene 1, was obtained by exploiting a combination of structure-based design of glycomimetic monovalent ligands and affinity enhancements by multivalent presentation through a calix[4]arene scaffold. It exhibits a slightly higher affinity for the toxin than its natural ligand, the GM1 oligosaccharide. 相似文献
33.
The formation and stability of protonated diamines-carboxylic ligand complexes was studied potentiometrically (H(+)-glass electrode). Species formed are ALH(r) (A=cadaverine, putrescine, L=acetate, malate, tartrate, malonate, citrate, 1,2,3-propanetricarboxylate, 1,2,3,4-butanetetracarboxylate and glutamate; r=1...m+1, where m is the maximum degree of protonation of the carboxylic ligand), and their stability is a function of charges involved in the formation reaction. For the equilibrium H(i)A(i+)+H(j)L((j-z))=ALH((i+j-z))(i+j) the following linear relationships can be written: logK(1j)=-0.25+0.75 |j-z|, logK(2j)=0.50+0.90 |j-z| (by also considering some ethylenediamine and 1,2-diaminopropane complexes). Medium effects were considered. Comparison was made with analogous inorganic polyanion complexes. The simplest relationships -DeltaG(0)=6.5+/-0.3 and -DeltaG(0)=7.9+/-0.6 kJ mol(-1)n(-1) (n=number of possible salt bridges) were found for carboxylic and inorganic anions, respectively. 相似文献
34.
The reaction between ethyl o-fluorobenzoylacetate and cyclic imino ethers is described. The products, the corresponding 1,2-fused quinolines ( 13a-17a ), were isolated in good yields. In one instance the uncyclized condensation intermediate 18 was isolated and characterized. 相似文献
35.
Gary M. Coppola 《Journal of heterocyclic chemistry》1983,20(5):1217-1221
N-Methylisatoic anhydride reacts with the lithium enolates of esters to produce β-ketoesters 4 in nearly quantitative yield. Thermal cyclization of these relatively unstable intermediates afford the corresponding 3-substituted-4-hydroxy-1-methyl-2(1H)-quinolinones (5) in good yields. The reaction of the lithium enolate of 5-methyl-4-hexenoic acid ethyl ester ( 14 ) with various nuclear substituted isatoic anhydrides gives 4-hydroxyl-methyl-3-prenyl-2(1H)-quinolinones 8, 9 , and 18 which are highly desirable intermediates in the synthesis of a variety of quinoline alkaloids. Treatment of 18 with DDQ furnishes oricine in 73% yield. 相似文献
36.
2-Propynamides react with aryl isocyanates in the presence of triethylamine to give 5-methylene-2,4-imidazolidinediones 5 in good yields. If the propynamide contains a terminal trimethylsilyl group, Z-trimethylsilylidenehydantoin ( 7 ) is produced. 相似文献
37.
Gary M. Coppola 《Journal of heterocyclic chemistry》1983,20(2):331-336
Reactions of 1,3-disubstituted-2,3-dihydro-1,3,2-benzodiazaphosphorin-4 (1 H)-one 2-oxides ( 1 ) with various electrophiles were investigated. The treatment of 1 with aldehydes in the absence of a basic catalyst directlyafforded alcohols 7a-h in good yield. The product from the reaction of 1 with chloral, on treatment with sodium hydride, resulted in the formation of a dichloroepoxide ( 8 ). When 1 was allowed to react with isocyanates or isothiocyanates in the presence of triethylamine, amides 10a-e and thioamide 11 were produced in good yield. Compounds 1a and 1b were readily halogenated on their phosphorus atom by treatment with either carbon tetrachloride or carbon tetrabromide and triethylamine. The P-chloro compound 12a reacted with ethanol to furnish the P-ethoxy derivative 13 and, in an attempt to react 12a with bis (2-chloroethyl) amine, anhydride 14 was formed in high yield. Spectral data for the majority of the products are also discussed. 相似文献
38.
Young PM Price R Lewis D Edge S Traini D 《Journal of colloid and interface science》2003,262(1):298-302
Drug particulate interactions in pressurized metered dose inhalers (pMDI) may lead to a decrease in aerosolization efficiency and subsequent efficacy in patient treatment. The interactions between salbutamol sulfate (commonly used in Ventolin pMDIs) and a series of pMDI canister materials were investigated using the atomic force microscope (AFM) colloid probe technique. Approximately 4000 individual force-distance curves were determined for a drug probe and three surfaces (10 x 10 mum areas) in situ, in a model propellant. The area under each force-distance curve was integrated to obtain separation energy values. Median separation energy values followed the rank order borosilicate glass > aluminum > PTFE, suggesting PTFE to be the most suitable canister coating. 相似文献
39.
Alfredo Carrascull Claudia Grzona Daniela Lick Marta Ponzi Esther Ponzi 《Reaction Kinetics and Catalysis Letters》2002,75(1):63-68
The catalytic combustion of particulate material was studied on cobalt catalysts promoted with potassium using different supports for its preparation. Silica, aluminium oxides and hydroxides, zirconium oxide and hydroxide were used as supports. The catalytic activity for combustion depends on the type of support used, the higher activity corresponding to the supported catalyst on zirconium oxide. TPR studies indicate that the interaction metal/support allows to explain the higher activity of the CoK/SiO2 catalyst with respect to the CoK/Al2O3 but the high activity found in CoK/ZrO2is not explained by this interaction. In all cases the Co and K improved the performance of the catalysts. 相似文献
40.
A chiral supramolecular assembly encapsulates the two cationic ruthenium sandwich complexes [CpRu(eta(6)-C(6)H(6))](+) and [CpRu(p-cymene)](+). The host-guest complexes K(11)[CpRu(eta(6)-C(6)H(6)) subset Ga(4)L(6)] (2) and K(11)[CpRu(p-cymene) subset Ga(4)L(6)] (3) were characterized by one- and two-dimensional NMR techniques as well as by electrospray mass spectrometry. Encapsulation of the prochiral complex [CpRu(p-cymene)](+) by the chiral host renders enantiotopic protons diastereotopic as evidenced by (1)H NMR spectroscopy. 相似文献