Quinoline conversion

The effect of quinoline and phenanthrene additions to a n-hexadecane feedstock has been determined for a model four-component FCC catalyst by means of a MAT reactor with analysis of all products and characterisation of the coke produced. Both additions lead to an overall loss in conversion quinoline is considered to act as a poison while phenanthrene participates strongly in coke formation and the resultant coke becomes more aromatic in nature. The cracking propensity and associated coke formation have been measured for a series of FCC catalysts with differing compositions. Increasing amounts of zeolite in a matrix lead to increasing extents of conversion but with little effect on the extent of coke production. However, a pure zeolite gave a very high coke content. 

These compounds can be malodorous as in the case of quinoline, or they can have a plecisant odor as does indole. They decompose on heating to give organic bases or ammonia that reduce the acidity of refining catalysts in conversion units such as reformers or crackers, and initiate gum formation in distillates (kerosene, gas oil). 

The oxidative dehydration of isobutyric acid [79-31-2] to methacrylic acid is most often carried out over iron—phosphoms or molybdenum—phosphoms based catalysts similar to those used in the oxidation of methacrolein to methacrylic acid. Conversions in excess of 95% and selectivity to methacrylic acid of 75—85% have been attained, resulting in single-pass yields of nearly 80%. The use of cesium-, copper-, and vanadium-doped catalysts are reported to be beneficial (96), as is the use of cesium in conjunction with quinoline (97). Generally the iron—phosphoms catalysts require temperatures in the vicinity of 400°C, in contrast to the molybdenum-based catalysts that exhibit comparable reactivity at 300°C (98). 

Mechanistic studies on the formation of PPS from polymerization of copper(I) 4-bromobenzenethiolate in quinoline under inert atmosphere at 200°C have been pubUshed (91). PPS synthesized by this synthetic procedure is characterized by high molar mass at low conversions and esr signals consistent with a single-electron-transfer mechanism, the Sj l-type mechanism described earlier (22). 

Treatment of quinoline with cyanogen bromide, the von Braun reaction (17), in methanol with sodium bicarbonate produces a high yield of l-cyano-2-methoxy-l,2-dihydroquinoline [880-95-5] (5) (18). Compound (5) is quantitatively converted to 3-bromoquinoline [5332-24-1], through the intermediate (6) [66438-70-8]. These conversions are accompHshed by sequential treatment with bromine in methanol, sodium carbonate, or concentrated hydrochloric acid in methanol. Similar conditions provide high yields of 3-bromomethylquinoHnes. 

Nitrogen nucleophiles used to diplace the 3 -acetoxy group include substituted pyridines, quinolines, pyrimidines, triazoles, pyrazoles, azide, and even aniline and methylaniline if the pH is controlled at 7.5. Sulfur nucleophiles include aLkylthiols, thiosulfate, thio and dithio acids, carbamates and carbonates, thioureas, thioamides, and most importandy, from a biological viewpoint, heterocycHc thiols. The yields of the displacement reactions vary widely. Two general approaches for improving 3 -acetoxy displacement have been reported. One approach involves initial, or in situ conversion of the acetoxy moiety to a more facile leaving group. The other approach utilizes Lewis or Brmnsted acid activation (87). 

Imides (e.g. phthalimide) can be purified by conversion to their potassium salts by reaction in ethanol with ethanolic potassium hydroxide. Hie imides are regenerated when the salts are hydrolysed with dilute acid. Like amides, imides readily crystallise from alcohols and, in some cases (e.g. quinolinic imide), from glacial acetic acid. 

Until recent years the only syntheses of 3-hydroxy quinoline involved multistep processes, the last step of which consisted of the conversion of 3-aminoquinoline to 3-hydroxyquinoline via the diazonium salt. " Small quantities of quinoline have been oxidized to 3-hydroxyquinoline in low yields by using oxygen in the presence of ascorbic acid, ethylenediaminetetraacetic acid, ferrous sulfate, and i)hosi)halc buffer. The decarboxylation of 3-hydroxycinchoninic, acid in boiling nitrobenzene has been re-... 

The synthesis of meconin has been referred to already (p. 201). Cotarnine has been synthesised by Salway from myristicin (I) as a starting-point. This was transformed into jS-3-methoxy-4 5-methylenedioxy-phenylpropionic acid (II), the amide of which was converted by Hofmann s reaction into )S-3-methoxy-4 5-methylenedioxyphenylethylamine, and the phenylacetyl derivative (HI) of this condensed, by heating it in xylene solution with phosphoric oxide, giving rise to the two possible dihydroiso-quinoline derivatives. The first of these substances, 8-methoxy-6 7-methylenedipxy-1-benzyl-3 4-dihydroiioquinoline (IV), on conversion into the methochloride and reduction with tin and hydrochloric acid, gave... 

These results indicate that quinine and quinidine differ in structure from cinchonine and cinehonidine in containing a methoxyl group in position 6 in a quinoline nucleus. The identity of the other oxidation products, meroquinenine, cincboloiponic and loiponic acids, in all foiu" cases indicates that the second half of the molecule has the same structure in all four alkaloids. Further, this second half must be joined to the quinoline nucleus at position 4 by a group capable of conversion into carboxyl. 

Condensation of an aniline with a dione with loss of water provides enamine 16. Ketone protonation and cyclization forms 18 followed by loss of water provides quinoline 4. Some have suggested the formation of dication 19 as a requirement to cyclization. Cyclization of 19 to 20 and subsequent conversion to quinoline 4 requires loss of water and acid. Another rendering of the mechanism takes into account participation of an electron-donating group (EDG), which stabilizes intermediate 21. 

These effects are not entirely understood because cyclizations forming 5,8-dimethyl quinolines are not problematic as shown below by the conversion of 46 into 47. 

Analogous to the selectivity observed for the conversion of 48 into 50, pyridyl 51 formed enamine 52 which underwent cyclization to give 4-pyridyl-substituted quinoline 53. Again, imine formation first occurs on the less hindered ketone and subsequent cyclization on the more reactive carbonyl occurred in high yield. ... 

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 the Meth-Cohn quinoline synthesis, the acetanilide becomes a nucleophile and provides the framework of the quinoline (nitrogen and the 2,3-carbons) and the 4-carbon is derived from the Vilsmeier reagent. The reaction mechanism involves the initial conversion of an acylanilide 1 into an a-iminochloride 11 by the action of POCI3. The a-chloroenamine tautomer 12 is subsequently C-formylated by the Vilsmeier reagent 13 derived from POCI3 and DMF. In examples where acetanilides 1 (r = H) are employed, a second C-formylation of 14 occurs to afford 15 subsequent cyclisation and... 

Under the conditions of the attempted conversion of the indolenine 17 into the quinoline 18 most of the indolenine was recovered, but there was also formed a small amount of a hydrolysis product, o-acetamido-jS-chloro-a-methylstyrene (22), obtainable in good yield with aqueous ethanolic potassium hydroxide. By analogy with a similar sequence of reactions in the carbocyclic series the hydrolysis product 22 might possibly undergo acid-catalyzed cyclodehydration to the quinoline... 

In 1960 Rapoport and his co-workers found that some 2,2 -biquinoline is formed when quinoline w as used as a solvent for dehydrogenations in the presence of palladiuin-on-carbon catalyst, and they showed that several related bases (including pyridine) gave 2,2 -biai yls when refluxed at atmospheric pressure with a 5% pal-ladium-on-carbon catalyst. With a pyridine-to-catalyst ratio of 10 1, 11% conversion of pyridine to 2,2 -bipyridine was observed after heating for 24 hr. 

Calculated on the basis of recovered quinoline to avoid confusion with yields percentage conversions are given in parentheses. 

With quinoline and palladium-on-carbon the yields and conversions with different batches of catalyst were found to vary very widely but this matter has not been studied in detail, and similar data are still lacking for other quinolines. 

Sufficient data are not yet available to allow evaluation of the relative merits of palladium-on-carbon and degassed Raney nickel catalysts. Comparable yields of 2,2 -biquinolines have been obtained by both methods under suitable conditions but the percentage conversions with degassed Raney nickel have been found to be much lower, reflecting the extent of side reactions with this catalyst. However, work in this laboratory has shown that the reaction of quinoline with palladium-on-carbon is not free from complications for example, at least three products in addition to 2,2 -biquinoline have been detected by paper chromatography. 

Rhodium-on-carbon has also been found to bring about the formation of 2,2 -biquinoline from quinoline, the yield and the percentage conversion being similar to that obtained with palladium-on-carbon. On the other hand, rhodium-on-carbon failed to produce 2,2 -bipyridine from pyridine, and it has not yet been tried with other bases. Experiments with carbon-supported catalysts prepared from ruthenium, osmium, iridium, and platinum have shown that none of these metals is capable of bringing about the formation of 2,2 -biquinoline from quinoline under the conditions used with palladium and rhodium. ... 

In this connection the conversion of 8-hydroxy quinoline to 1-methyl-8-hydroxyquinolinium betaine (91)should also be men-... 

The Reissert method15—conversion of an isoquinoline to a 2-benzoyl-1,2-dihydroisoquinaldonitrile (Reissert compound), alkylation, and hydrolysis—has enjoyed wide success in the synthesis of benzyliso-quinoline and related alkaloids.16,17 In particular, aporphines are prepared conveniently by converting isoquinolines to I-(o-nitrobcnzyl)-isoquinolines via a Reissert sequence, followed by A7-alkylation, reduction, and Pschorr cyclization.17... 

The Suzuki reaction has been successfully used to introduce new C - C bonds into 2-pyridones [75,83,84]. The use of microwave irradiation in transition-metal-catalyzed transformations is reported to decrease reaction times [52]. Still, there is, to our knowledge, only one example where a microwave-assisted Suzuki reaction has been performed on a quinolin-2(lH)-one or any other 2-pyridone containing heterocycle. Glasnov et al. described a Suzuki reaction of 4-chloro-quinolin-2(lff)-one with phenylboronic acid in presence of a palladium-catalyst under microwave irradiation (Scheme 13) [53]. After screening different conditions to improve the conversion and isolated yield of the desired aryl substituted quinolin-2( lff)-one 47, they found that a combination of palladium acetate and triphenylphosphine as catalyst (0.5 mol %), a 3 1 mixture of 1,2-dimethoxyethane (DME) and water as solvent, triethyl-amine as base, and irradiation for 30 min at 150 °C gave the best result. Crucial for the reaction was the temperature and the amount of water in the... 

Cyclization of quinoline derivatives 57 in DMSO under the action of Cs2C03 at 85 °C afforded diesters 49 <1995T11125>. No cyclization product could be obtained when a piperazino group was present in 57 (Rz = piperazino). Cyclization in the presence of NaH gave a lower yield. When the potassium salt of 57 was used in the presence of 20 mol% of Cul, the conversion was almost quantitative, but the removal of the last traces of copper was difficult. When allyl ester 57 (R = Et, R1 = allyl, R2 = 4 - 7/-biu o ycarbonyl-l -pipcridinyl) was cyclized in DMSO in the presence of Cul and KOBuc at 50-55 °C for 0.5 h, then 100-105 °C for 6 h, the 3-ester 50 (R = Et, R1 = 4-tert-butoxycarbonyl-l-piperidinyl) was obtained in 32% yield. 

The reaction network for 5,6-benzoquinoline [101] has been proposed in a more detailed level than that of acridine. In this network, conversely to acridine network, only one primary hydrogenation product, l,2,3,4-tetrahydro-5,6-benzoquinoline, was identified, and in contrast to the quinoline case however, no aniline derivatives were detected. 

This section summarizes the literature on biodenitrogenation, with focus on BDN studies using quinoline, carbazole, pyridine and indole as model organonitrogen molecules. Research related to biodegradation (vs. nitrogen-specific conversion) of organonitrogen molecules is also considered, since it can be a viable option for relatively low-nitrogen feedstocks. 

The most widely studied N-compound is quinoline and a vast number of microorganisms have been considered for its conversion. As already discussed, the majority of... 

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