Quinolines, amino-, reaction with

The wide variety of ketomethylene and amino ketone monomers that could be synthesized, and the abiUty of the quinoline-forming reaction to generate high molar mass polymers under relatively mild conditions, allow the synthesis of a series of polyquinolines with a wide stmctural variety. Thus polyquinolines with a range of chain stiffness from a semirigid chain to rod-like macromolecules have been synthesized. Polyquinolines are most often prepared by solution polymerization of bis(i9-amino aryl ketone) and bis (ketomethylene) monomers, where R = H or C H, in y -cresol with di-y -cresyl phosphate at 135—140°C for a period of 24—48 h (92). 

The Friedlander quinoline synthesis combines an a-amino aldehyde or ketone (1) with another aldehyde or ketone with at least one methylene a to the carbonyl (2) to furnish a substituted quinoline. The reaction can be promoted by acid, base, or heat. 

The isomeric thiazolo[5,4-g]quinoline skeleton was prepared from 6-chloro-quinoline-5,8-dione hydrochloride by reaction with thiourea, resulting in the 2-amino-4,9-dioxo-4,9-dihydroderivative 42 (91CCC1919). 

The proposed structure of 97 isolated from broiled sardines was confirmed by straightforward synthesis starting from5,6-diaminoquinolines. After reaction with cyanogen bromide it afforded the 2-amino-imidazo[4,5-/]quinolines 99 (R = H, Me), which was then converted into its 3-A-methyl derivative 100 by... 

Alkylpyridines are aminated preferentially at the 2-position, but reaction is slower than in the parent system. Quinoline is difficult to aminate and only a low yield of 2-aminoquinoline (32%) is obtained from reaction with sodamide in toluene. When dimethylaniline is employed as solvent, 2-amino-3,4-dihydroquinoline (24%) becomes the major product, and the yield of 2-aminoquinoline drops to 7%. The best yields of 2-aminoquinoline (53-69%) have been obtained by using barium or potassium amide in liquid ammonia. Use of the potassium salt also produces a 10% yield of the 4-amino isomer. The... 

The same authors have also reported the synthesis of 2-amino quinolines46, Scheme 5.28. Secondary amines were reacted with aldehydes to form enamines subsequent addition of 2-azidobenzophenones initially forms triazoline intermediates, which undergo a thermal rearrangement and intermolecular base-catalysed cyclocondensation to produce 2-amino quinolines. The reactions were run at 180°C for 10 min (the time includes 3 min required for enamine formation) to give the products in 57-100% yields. 

As already indicated, the chemistry of terminal borylene complexes is as yet almost unexplored. In addition to the photochemically induced borylene transfer, which was already discussed in Chapter 3.2, studies of the reactivity of terminal borylene complexes are restricted to two recent reports by Roper.147,148 The base-stabilized borylene complex [Os (=BNHC9H6N)Cl2(CO)(PPh3)2] (26) undergoes a reaction with ethanol to yield the ethoxy(amino)boryl complex [Os B(OEt)NHCgH6N Cl(CO) (PPh3)2] (35) according to Eq. (13) with a 1,2-shift of the quinoline nitrogen atom from the boron to the osmium center. The alcoholysis of 26 indicates that even the boron atom in base-stabilized borylene complexes displays some electrophilic character—a fact already predicted by a theoretical study.117... 

Oxidative amination, using a Cun-catalyst was reported to take place on treatment of 6-hydroxyquinoline with secondary amines in a methanol solution, 8-R2N-quinoline-5,6-dione being obtained. So besides a SNH (amino) reaction at C-8, a SNH(oxo) reaction occurs at C-5 (Scheme 11) (90CPB2841). A similar reaction was found earlier with 5-hydroxybenz-imidazoles (Scheme 11) (78KGS1680)... 

Aromatic primary amines are not only binucleophiles at the amino group, but they also exhibit the properties of C,N-binucleophiles. Their reactions with internal perfluoroolefins lead to quinoline derivatives (98JFC(88)169, 94JCS(CC)134, 98T4949). Thus the reaction of aniline with 2//-heptafluorobut-2-ene yields phenyl(2-trifluoromethylquinolin-4-yl) amine (00ZOR109) when the reaction is carried out with the tetrafluoro-ethylene trimer, it leads to 2-trifluoromethyl-3-(l-N-phenylimino-2,2,2-trifluoroethyl)-4-(N-phenylamino)quinoline (98JFC(88)169). 

Specialized diazo transfer reactions have also been reported (Scheme 33 and Equation (18)), but their preparative value is limited. For example, JV-ethylbenzothiazolium azide (164) and 2,6-diaminopyridine affords 5-aminotriazolo[4,5-Z>]pyridine (5p) <78HCA108>. Since the reaction is sensitive to the pKa of the aminoheterocycles employed, the process has limited applicability. The highly specific colorimetric assay for oj-amino acids, which is based on a reaction with quinoline-3-diazonium tetrafluoroborate (166), affords l-substituted-[l,2,3]triazolo[4,5-c]quinolines (167)... 

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