Quinoline as reagent

Y Kiso, H Yajima. 2-Isobutoxy-l-isobutoxycarbonyl-l,2-dihydro-quinoline as a coupling reagent in peptide synthesis. J Chem Soc Chem Commun 942, 1972. 

The best reagent for selective reduction of alkynes to the cis alkene is the Lindlar catalyst.3 1 Palladium chloride (PdCl2) was precipitated on calcium carbonate (CaCOs) in acidic media and deactivated with lead tetraacetate [Pb(OAc)4] to give the named Pd-CaC03-Pb0 catalyst. Reduction of alkynes will stop at the cis alkene with little or no cis-trans isomerization. A variation uses quinoline as a poison, and this catalyst was used by Overman and co-workers to convert alkyne 378 to cis-alkene 379 as part of a synthesis of... 

An infrared method for the analysis of primary alcohols in polyglycols based on the reaction of the polyol with triphenylchloromethane is where the reagent consists of trityl chloride, with tris(dimethyl amino)phosphine oxide in quinoline as a solvent. This reagent is added to the sample, scanned from 3700 to 3100 cm to establish the total hydroxyl absorbance, and the reaction is then carried out in a glass-stoppered flask in a thermostatted bath at 75°C. At appropriate times, aliquots are removed and scanned, the absorbance being measured at 3280cm... 

Pyridine/alumina 17, 927 Pyridine borane —, reductions with — 16,113 Pyridine derivatives, 1,2,3,6-fefrahydro- 16, 855 Pyridine hydrochloride as reagent 17, 17, 793, 992 Pyridine ring (s. a. Quinoline ring)... 

Preparation of Isothiocyanates. Ethoxycarbonyl isothiocyanate (18), useful as a synthetic reagent for heterocyclic syntheses, can be prepared in excellent yield from the reaction of ethyl chloroformate (16) with sodium thiocyanate (17) using quinoline as a base catalyst (eq 9). Only trace amounts of the isomeric thiocyanates are formed in the reaction. In the absence of the base catalyst, only a moderate (65%) yield of the desired product is obtained, along with significant (10%) contamination by the isomeric ethoxycarbonyl thiocyanate. Pyridine can also be used as the catalyst here however, it reacts faster, which sometimes leads to undesired byproduct formation. 

The preparation of hydroquinoline derivatives is of great interest owing to their biological activity but, in many cases, their preparation has involved the tedious use of chiral auxiliaries and organometallic reagents.AgOTf has been used to activate phenyl chloroformate toward condensation with quinoline, as well as isoquinoline, for subsequent reaction with chiral allylsilanes, to give 2-allylated derivatives (eq 15). ... 

This mixture is known as Quinoline Yellow A [8003-22-3] (Cl 47000) and is most widely used with polyester fibers (109). Upon sulfonation, the water-soluble Quinoline Yellow S or Acid Yellow 3 [8004-92-0] (Cl 47005) is obtained. This dye is used with wool and its aluminum salt as a pigment. Foron Yellow SE-3GL (Cl Disperse Yellow 64) is the 3-hydroxy-4-bromo derivative. Several other quinoline dyes are commercially available and find apphcations as biological stains and analytical reagents (110). 

The Meth-Cohn quinoline synthesis involves the conversion of acylanilides 1 into 2-chloro-3-substituted quinolines 2 by the action of Vilsmeier s reagent in warmed phosphorus oxychloride (POCI3) as solvent. ... 

In another example treating anilines 40 with acetone under similar conditions gave the desired quinoline 41 as a single regioisomer. It has been reported that the addition of silylating reagents, in particular bis(trimethylsilyl)acetamide, may be beneficial for these types of substrates. ... 

The usual order found with halogenonitrobenzenes is F > Cl Br I, the order of Cl and Br being variable, just as in heteroaromatic reactivity. The position of fluorine is of interest the available data indicate that it is usually the same as for nitrobenzene derivatives. Thus, in acid hydrolysis the order F > Cl for 2-halogeno-quinolines can be deduced beyond doubt since the fluoro derivative appears to react in the non-protonated form and the chloro derivative to resist hydrolytic attack even in the protonated form under appropriate conditions (Section II,D, l,d). Furthermore, in the benzo-thiazole ring, fluorine is displaced by the CHgO reagent at a rate 10 times that for chlorine. ... 

The yield of hydroxylated products is always very low, and there are usually a number of by-products. For instance, side chains of aromatic nuclei are easily attacked, as shown by the formation of 5-hydroxymethyluracil from thymine. Breslow and Lukens measured both the amount of 3-hydroxyquinoline formed and the quinoline consumed during hydroxylation with Fenton s reagent and EDTA in the presence of several adducts (Table XII). 

Discussion. When a solution of an orthophosphate is treated with a large excess of ammonium molybdate solution in the presence of nitric acid at a temperature of 20-45 °C, a precipitate is obtained, which after washing is converted into ammonium molybdophosphate with the composition (NH4)3[P04,12Mo03]. This may be titrated with standard sodium hydroxide solution using phenolph-thalein as indicator, but the end point is rather poor due to the liberation of ammonia. If, however, the ammonium molybdate is replaced by a reagent containing sodium molybdate and quinoline, then quinoline molybdophosphate is precipitated which can be isolated and titrated with standard sodium hydroxide ... 

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