Synthesis of 2,3‐quinolinedicarboxylic acid

Maulding, Donald R.

doi:10.1002/jhet.5570250634

Cited by 24 publications

(13 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…N -Ethylmaleimide ( 2b ) was obtained from Janssen Chimica and crystallized from ether. N -Propyl- and N -butylmaleimide ( 2c,d ) were synthesized according to the literature . Demineralized water was distilled twice in a quartz distillation unit.…”

Section: Methodsmentioning

confidence: 99%

Effects of the Hydrophobicity of the Reactants on Diels−Alder Reactions in Water

1998

View full text Add to dashboard Cite

To assess the importance of the hydrophobicity of different parts of diene and dienophile on the aqueous acceleration of Diels-Alder reactions, second-order rate constants have been determined for the reactions of cyclopentadiene (1), 2,3-dimethyl-1,3-butadiene (4), and 1,3-cyclohexadiene (6) with N-methyl-, N-ethyl-, N-propyl-, and N-butylmaleimide (2a-d) in different solvents. All these reactions are accelerated in water relative to organic solvents as a result of enhanced hydrogen bonding and enforced hydrophobic interactions during the activation process. The beneficial influence of water as compared to 1-propanol on the rate of the Diels-Alder reaction of 4 with 2a-d increases linearly with the length of the alkyl chain of 2. In contrast, for the reaction of both 1 and 6 with 2a-d, no such effect was observed. This difference can be explained by a hydrophobic interaction between the methyl groups of 4 and the N-alkyl group of 2 during the activation process. In the reactions of 1 and 6, lacking the methyl substituents, this interaction is not possible and elongation of the alkyl chain from ethyl onward does not result in an additional acceleration by water. The enhanced hydrophobicity near the reaction center of dienes 4 and 6 compared to 1 results in an increased aqueous acceleration of the Diels-Alder reactions of the former dienes with 2a. These data indicate that an increase in the hydrophobicity close to the reaction center in the diene has a much more pronounced effect on the rate acceleration in water than a comparable increase in hydrophobicity in the dienophile further away from the reaction center. The Gibbs energies of transfer of initial state and activated complex of the Diels-Alder reactions under study have been determined. As expected, for all reactions the initial state in water is destabilized compared to that in 1-propanol. This destabilization becomes more pronounced when the nonpolar character of diene (close to the reaction center) or dienophile (distant from the reaction center) is increased. Likewise, an increase in the nonpolar character of 2 results in a destabilization of the activated complex. In contrast, addition of methyl or methylene units to the diene is not accompanied by a significant destabilization of the activated complex in water as compared to 1-propanol. We conclude that hydrophobic groups near the reaction center seem to lose their hydrophobic character completely in the activated complex of the Diels-Alder reaction, whereas more distant groups retain their nonpolar character throughout the reaction.

show abstract

Section: Methodsmentioning

confidence: 99%

Effects of the Hydrophobicity of the Reactants on Diels−Alder Reactions in Water

1998

View full text Add to dashboard Cite

show abstract

“…1 5). 28 The pyridone LIX, readily available from acetoacetamide and diethyl ethoxymethyleneoxalacetate, was brominated and reduced to give LX, which on treatment with triethylamine cyclized to the hydroxydihydrofuran derivative LXI. Acetylation and subsequent elimination yielded the furanopyridine diester LXJI.…”

Section: Other Heterocyclic Dicarboxylic Acidsmentioning

confidence: 99%

Imidazolinone herbicides: Synthesis and novel chemistry

Wepplo¹

1990

Pestic. Sci.

View full text Add to dashboard Cite

A B S T R A C TThe imidazolinone herbicides were prepared from reaction of an amethylvaline fiagment with an o-dicarboxylic acid. Early syntheses were completed through an imide amide intermediate, such as l o r X V , followed by further cyclization to 2,s-diones It1 or XXI. Reaction of these diones with nucleophiles led to imidazolinones IV and V. The signijicant and interesting activity of these compounds led to new and versatile methods of synthesis, including resolution of the a-methylvaline fragments, development of a metallation-carboxylation route, a one-step picoline to imidazolinone route, and several pyridine and fused-ring pyridine syntheses.

show abstract

“…While there are many examples of the preparation of quinolines via electrocyclic ring closures followed by elimination of a leaving group to regain aromaticity, 46−52 there are very few examples that afford quinolines fused to five- 53,54 and six-membered rings, 55,56 Since both the methylated imidazoles (Z)-2-[1-methyl-2phenyl-4-(phenylimino)-1H-imidazol-5(4H)-ylidene]malononitrile ( 16) and (Z)-2-[1-methyl-2-phenyl-5-(phenylimino)-1H-imidazol-4(5H)-ylidene]malononitrile (17) were in our possession, these were also independently thermolyzed to give 1-methyl-2-phenyl-1H-imidazo [4,5-b]quinoline-9-carbonitrile ( 26) and 3-methyl-2-phenyl-3H-imidazo [4,5-b]quinoline-9-carbonitrile ( 27) in high yields, respectively (Scheme 10).…”

Section: Resultsmentioning

confidence: 99%

Reactions of Tetracyanoethylene withN′-Arylbenzamidines: A Route to 2-Phenyl-3H-imidazo[4,5-b]quinoline-9-carbonitriles

2013

View full text Add to dashboard Cite

Eight 2-phenyl-3H-imidazo[4,5-b]quinoline-9-carbonitriles 15 are prepared in four steps from N'-arylbenzamidines 11 and tetracyanoethylene (TCNE) in ~70-90% yields. The transformation involves the initial formation of N-aryl-N'-(1,2,2-tricyanovinyl)benzamidines 12 in 87-99% yields, which in MeCN undergo a 5-exodig cyclization to give the 2-[1-aryl-5-imino-2-phenyl-1H-imidazol-4(5H)-ylidene]malononitriles 13 in 84-92% yields, while in MeOH the (Z)-2-[2-phenyl-4-(arylimino)-1H-imidazol-5(4H)-ylidene]malononitriles 14 are formed in 85-94% yields. The imidazoles 14 can also be prepared directly from imidazoles 13 via a Dimroth rearrangement in either neat MeOH or in DCM with DBU. Subsequent thermolysis of imidazoles 14 in diphenyl ether affords 2-phenyl-3H-imidazo[4,5-b]quinoline-9-carbonitriles 15 in near quantitative yields. Mechanistic rationale is provided for all transformations.

show abstract

Synthesis of 2,3‐quinolinedicarboxylic acid

Cited by 24 publications

References 8 publications

Effects of the Hydrophobicity of the Reactants on Diels−Alder Reactions in Water

Effects of the Hydrophobicity of the Reactants on Diels−Alder Reactions in Water

Imidazolinone herbicides: Synthesis and novel chemistry

Reactions of Tetracyanoethylene withN′-Arylbenzamidines: A Route to 2-Phenyl-3H-imidazo[4,5-b]quinoline-9-carbonitriles

Contact Info

Product

Resources

About