Quinoline chromophore

HPLC methods were developed for the detection and isolation of the free and Fe(III) complexed forms of the siderophores, pseudobactins, containing a pyrimido[l,2-a]quinoline chromophore (93JPR157 94MI1, 94MI2). A microbial siderophore and its Fe(III) complex were analyzed by means of HPLC with amperometric detection (93MI4). 

The syntheses of pyrimido[l,2-a]quinoline chromophore of pseudobactins are depicted in Schemes 6 and 7 (88MI4 90JOC4246). When allyloxycarbonyl and phthaloyl protective groups were used, then along with pyrimido[l,2-a]quinoline derivatives 410 and 411, tetracyclic 412, corresponding to the chromophore of azobactin, was formed (Scheme 6). Pyrimido[l,2- ]quinoline (413) was obtained in good yield when 2,2,2-... 

For leather, the quinoline chromophore, prepared by condensation of quinoline derivatives with phthalic anhydride or similar substances, is of some interest. The mainly yellow or red compounds are sulfonate d and yield valuable dyes for leather, e.g., C.I. Acid Yellow2, 47010 (15). 

Another related example is 52 [157], which is a tetra-substituted cyclen ligand with four quinoline receptor moieties capable of sensing protons in a similar manner to 50. The lanthanide emission was found to be switched on in highly acidic conditions, with a luminescent enhancement of over 300-fold. Luminescent enhancement was attributed to an enhancement in the population of the Si and subsequent Ti excited states of the quinoline chromophore when in acidic media. A bell-shaped pH profile was found to exist at pH 1.8-3.5, whereas at more acidic pH the emission was switched off. 

The symmetry of the bisphenethylisoquinoline molecule is such that reductive cleavage of 0,0-dimethylmelanthioidine (17) with sodium in liquid ammonia afforded almost exclusively the one phenolic isoquinoline 18 (12, 13) which showed a negative first Cotton effect. Previous knowledge (14, 15) of ORD measurement on tetrahydroiso-quinoline chromophores established the illustrated R-configuration and indicated that the molecule is in a head-to-tail arrangement. 

Oligopeptide antibiotics and siderophores from Pseudomonas fluorescens and P. aeruginosa. The pyri-mido[ 1,2-a]quinoline chromophore is responsible for the yellow-green color and fluorescence of P. 

Through these experiments, it was confirmed that pseudanVII was biosynthesized from an anthranilyl CoA unit and an unbranched chain that was derived through the polyketide biosynthetic pathway. The remaining part of the quinoline chromophore was derived from malonyl CoA [1]. During the experiments regarding the biosynthesis of this alkaloid, it was found that about twice the level of radioisotope was incorporated when [2-i C] acetate was fed compared with the experiments when ace-... 

Ozonolysis of 5,8,9-trihydroxy-2,3-dihydro-l//-pyrimido[l, 2-n]quinoline-3-carboxylic acid (420), obtained from isopyoverdin isolated from Pseudomonas putida BTPl by acidic hydrolysis, gave l-2,4-diaminobutyric acid, which confirmed the hypothesis that heterocyclic chromophores 1 and 4 of pyoverdin and isopyoverdin, respectively, could have the same precursor, and the configuration at C(3) should be 5 (97ZN(C)549). 

ZN(C)153, 00ZN(C)323, 00ZN(C)857, 01MI2, 01MIP4, 01TL5849). 5-Amino-8,9-dihydroxy-2,3-dihydro-l//-pyrimido[l,2-u]quinoline-3-carboxylic acid moiety 4 was also identified as a chromophoric moiety of certain... 

Ar-quinolin-2-yl)imino]propionates by injection or sublimation at 530°C yielded a mixture of 3-amino- and 3-ethoxy-l//-pyrimido[l,2-rz]quinolin-l-ones <2004AJC577>. An oxidative cascade for the biomimetic formation of the pyoverdine chromophore was supported by incubation of 2-[(4-hydroxyphenyl)- and 2-[(2-(3,4-dihydroxipheny-l)ethyl]-l,4,5,6-tetrahydropyrimidines with polyphenol oxidase or Pseudomonas extract to afford a mixture of 8,9-dihydroxy-2,3-dihydro- and -2,3,5,6-tctrahydro-l //-pyrimido[ 1,2- ]quinolines <20030L2215>. Oxidation of 2-[(2-(3,4-dihydroxiphenyl)ethyl]-l,4,5,6-tetrahydropyrimidine with MnOz gave a similar result. 

Quinoid-type chromophoric structures, reactions of, 21 36-37 Quinoline (QI), 12 723, 725-726 soluble dyes, 7 373t Quinoline-4-carboxylic acids, 21 190 Quinoline derivatives, 21 196-214 Quinoline-derived drugs, 21 197-198t Quinoline dyes, 21 196 Quinoline, formation of, 21 109. See also Quinolines... 

Taking advantage of the fact that the triplet state of metalloporphyrins with tetrabenzopor-phyrin (H2TBP or H2I, fig. 10) lies around 12 500 cm-1, a team from Minsk succeeded in sensitizing Ybm luminescence in solutions of [Yb(TBP)L], where L = Cl or acac (acetyl-acetonate), in several solvents like benzene, dimethylformamide (dmf), pyridine, quinoline or a mixture of octane and benzene (Kachura et al., 1974). Energy transfer from the porphyrin chromophore was ascertained by the excitation spectrum of the Ybm luminescence being identical to the absorption spectrum of the complex. In benzene, the quantum yield of... 

Another chromophore, 8-alkoxy-5-chloroquinoline, was appended to the narrower rim of a calix[4]arene triamide, 44a and 44b (see fig. 38). If Nd111, Er111, and Ybm nitrates are added to acetonitrile solutions of these receptors, quenching of the methoxy quinoline luminescence oc-... 

Phenylsulfonyl)furo[2,3- ]quinoline and its parent unsubstituted heterocycle were found to have very similar absorption maxima hence, the sulfone group does not provide an additional conjugative effect <83JOC774>. In addition, furo[2,3-/ quinoline and its isomeric furo[3,2-< ] counterpart were found to exhibit UV absorption maxima that are almost identical. An absorption maximum at 435 nm consistent with the presence of a 2H-1,4-benzothiazine chromophore was one of the key pieces of data that enabled the structure determination of compounds based upon the new 1,2-dihydro-3//,8//-pyrrolo[2,3-/z][l,4]benzothiazine skeleton <87T5357>. The UV spectrum of l,4-benzodioxano[6,7-c]furoxan was found to exhibit four characteristic band maxima in the 350-480 nm region <88JHC803>. 

Disperse dyes vary in the type of chromophore present and include azo, anthraquinone, nitro, methine, benzodifuranone, and quinoline based structures. Examples of the first three types are given in Table 13.4, and representative of the latter three types are C.I. Disperse Blue 354, C.I. Disperse Yellow 64, and C.I. Disperse Red 356. Most disperse dyes have azo ( 59%) or anthraquinone ( 32%) structures. Azo disperse dyes cover the entire color spectrum, whereas the important anthraquinone disperse dyes are mainly red, violet, and blue. The azo types offer the advantages of higher extinction coefficients (emax = 30,000-60,000) and ease of synthesis, and the anthraquinones are generally brighter and have better photostability (lightfastness). The key weaknesses associated with the anthraquinone dyes are their low extinction... 

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