Novel compounds possessing potent cAMP and cGMP phosphodiesterase inhibitory activity. Synthesis and cardiovascular effects of a series of imidazo[1,2-a]quinoxalinones and imidazo[1,5-a]quinoxalinones and their aza analogs

Davey, David D.; Erhardt, Paul; Cantor, Elinor H.; Greenberg, S; Ingebretsen, W. R.; Wiggins, J. M.

doi:10.1021/jm00113a002

Cited by 44 publications

(21 citation statements)

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“…A similar approach to imidazo[1,2-a]quinoxalinones (7, R = OH) has been described recently by reaction of 5 with 1,1'-carbonyldiimidazole [17]. In conclusion, we presented a straightforward four-step sequence to imidazo[1,2-a]quinoxalines which allows the easy introduction and variation of substituents in the 4-position.…”

Section: ____________________________________________________________mentioning

confidence: 77%

Synthesis of 4-substituted imidazo[1,2-a]quinoxalines

Lamberth¹

1999

J. prakt. Chem.

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[6,7] and triazolo [4,3-a]quinoxalines [8,9] have been described, which enable the selective and diverse substitution of the 4-position, this is not the fact for imidazo[1,2-a]quinoxalines. Known procedures for the preparation of imidazo[1,2-a]quinoxalines either start from 2-chloroquinoxalines [10,11], in which a future 4-substituent would have to be installed already in the starting material, or use the intramolecular condensation of 2-methyl or 2-formyl substituted 1-(2-aminophenyl)imidazoles [12,13] with no possibility for the introduction of a 4-function. Only one example in the patent literature describes an appropriate approach to 4-substituted imidazo[1,2-a]quinoxalines, based on the intramolecular ring closure between an acylamino function and the 2-position of an 1-arylsubstituted imidazole [14]. Unfortunately, the application of this method was limited so far, because many products are formed in extraordinary low yields. Herein we present an improved procedure, by which the amount of phosphorus oxychloride in the key step could be reduced dramatically, resulting in increased yields of the products.The synthesis starts with the known copper oxide catalyzed arylation of imidazole with 1-fluoro-2-nitrobenzene (3). The PROCEDURES/DATA _________________________________________________________________ 492

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Section: ____________________________________________________________mentioning

confidence: 77%

Synthesis of 4-substituted imidazo[1,2-a]quinoxalines

Lamberth¹

1999

J. prakt. Chem.

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“…This fact indicates that the nitro group is on the atom C(8), rather than on C(7), since in this case the diagnostical signal for the proton H(9) would have resonate as a doublet of dou blets with J ≈ 8.5 and J ≈ 2.5 Hz. 28, 34 In contrast to the reactions given above, the condensation of ester 7b with 4 nitro 1,2 phenylenediamine (3c) proceeds slower and to be completed requires reflux of the reaction mixture for 4 h, which is due to the strong electron withdrawing power of the nitro group decreasing the reactivity of 1,2 phe nylenediamine 3c. The structure of selenazolo[3,4 a]qui noxaline 13b formed was confirmed by X ray diffraction analysis (Fig.…”

Section: Methodsmentioning

confidence: 99%

Polyfused nitrogen-containing heterocycles 23. Methyl 4-hydroxy-3-phenyl-5-phenyl(alkyl)-2-phenyliminoselenazolidine-4-carboxylates and selenazolo[3,4-a]quinoxalin-4(5H)-one derivatives on their basis

et al. 2009

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Condensation of methyl phenyl(alkyl)halopyrotartrates with N,N´ diphenylselenourea leads to the formation of methyl 4 hydroxy 3 phenyl 5 phenyl(alkyl) 2 phenyliminoselenazolidine 4 carboxylates, which undergo reaction with 1,2 phenylenediamines to give selenazolo [3,4 a]quinoxalin 4(5H) ones.Key words: N,N´ diphenylselenourea, phenyl and alkylhalopyruvates, methyl 4 hydroxy 3 phenyl 5 phenyl(alkyl) 2 phenyliminoselenazolidine 4 carboxylates, selenazolo[3,4 a]qui noxalin 4(5H) ones, IR spectroscopy, NMR spectroscopy, X ray diffraction.During the last thirty years, organoselenium com pounds are under intensive study in the field of synthetic organic chemistry and pharmacology, which is due to their high reactivity 2-8 and wide range of biological and pharmacological activity, 2,8-11 including antiviral, 2,9,10 antibacterial, 2,9,10 antifungus, 2,9 antioxidant, 9,10 anti prolifiration, 12,13 and antitumor. 9,14-16 Derivatives of 1,3 selenazolidine 1 are of special interest among sele nium containing organic compounds, 16-19 the study of pharmaceutical potential of which showed a possibility to use these compounds as inhibitors of NO synthase, 20,21 antimutagenes, 22 and cancer preventing agents. 23-26From the point of view of developing methods for the synthesis and study of pharmacological activity, the most prospective are selenazolidines corresponding to the struc ture 1. For the most of them, a common feature is the presence of exocyclic double bond C=O, C=N, or C=C at the second position. The presence of other substituents in 1,3 selenazolidines 1 makes their synthesis and the search for new pharmacologically useful compounds more difficult.Earlier, we have suggested (Scheme 1) a method for the synthesis of various thiazolo[3,4 a]quinoxalines 4 from 1,2 phenylenediamines 3 and structurally related to selenazolidines 1 methyl 4 hydroxy 3,5 diphenyl * For Part 22, see Ref. 1 ** Dedicated to Academician O. N. Chupakhin on the occasion of his 75th birthday. X = C(CN)CO 2 Et, O, NH; R = H, Alk, Ar; R´ = H, Alk, CO 2 H; R″ = H, Alk 2 phenyliminothiazolidine 4 carboxylate (2), 27-30 as well as its aryl and hetaryl analogs. 29,31 However, synthetic possibilities of this reaction remain still little studied. 29-31 Scheme 1 R = R´ = H (a); R = H, R´ = Me (b); R = H, R´ = NO 2 (c)

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“…The imidazo[1,5-a]quinoxaline ring system is a common structure in medicinal chemistry, and is readily constructed by treatment of 1-(2-aminoaryl)imidazoles with 1,1 0 -carbonyldiimidazole 45 …”

Section: Electrophilic Substitutionmentioning

confidence: 99%