Electrochemical reduction of pyridopyrazines

Armand, Joseph; Chekir, Khaled; Pinson, Jean

doi:10.1139/v78-294

Cited by 25 publications

(8 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Besides, our results are in good agreement with the reduction scheme which we had proposed for the pyrazino[2,3-blpyrazines (10). In this last case the dihydro derivatives were too oxidizable to be isolated; by analogy with what is observed in the case of quinoxalines we had assigned a 1,4-(or 5.8-) dihydro structure to these compounds and had excluded a 1 3 -(or 4,8-) structure.…”

Section: Electrochemical Reductionsupporting

confidence: 90%

Chemical and electrochemical reduction of pyrazino[2,3-b]quinoxalines

Armand¹,

Boulares²,

Chekir³

et al. 1981

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

JOSEPH ARMAND, LINE BOULARES, KHALED CHEKIR, and CHRISTIAN BELLEC. Can. J . Chem. 59, 3237 (1981). The hydrogenation of 2,3-dimethylpyrazino[2,3-blquinoxaline 1 and 2-phenylpyrazino[2,3-b]quinoxaline 2 leads to the corresponding 5,lO-dihydroderivatives 3b and 4b. LiAlH, reduction of 2, of 2.3-dimethyl-6,7-diphenylpyrazino[2,3-b]pyrazne 8 and 2,6,7-triphenylpyrazino[2,3-blpyrazine 9 furnishes the corresponding 1,2,3,4-tetrahydroderivatives 7,10, and 11. NaBH, reduction of 2 leads to a mixture of 4b and 7. In hydroorganic medium 1 and 2 are electrochemically reduced to 36 and 46 with which they form a redox system. Although the synthesis of pyrazino[2,3-blquin-1). The reduction products of 1 and 2 have two oxalines has been investigated (1) neither their amino protons which are readily exchanged by chemical nor their electrochemical reduction has addition of D,O so that the isomeric structures been studied.shown below have to be considered:We report the hydrogenation, the reduction with LiAlH, and NaBH,, and the electrochemical reduction of compounds 1 and 2. Concerning the electrochemical reduction, the presence of two condensed pyrazine rings made possible two reaction paths, either a reduction into a 1,4-(or 5.10-) dihydro derivative as in the case of pyrazines, or a behaviour similar to that of flavines leading to a 1 3 -(or 4, lo-) dihydro compound. HydrogenationIn the presence of Pd/C, hydrogenation of 1 and 2 leads to the dihydro derivatives 3b and 4b, the structures of which were determined by nmr (Table k I A rapid equilibrium on the nmr time scale of the two tautomers 3c and 3c' cannot be excluded on the grounds of the nmr spectrum. However, acetylation gives a diacetylated compound to which the nmr spectrum permits assigning the 1 ,Cdiacetyl-1 ,4-dihydro structure or the 5,lO-diacetyl-5,lOdihydro structure (see Experimental). Thus, the reduction product of 1 must have a plane of symmetry, which rules out structure 3c. Structures 3a and 3b can be discriminated by examination of the chemical shifts. The aromatic protons of 1,2,3,4-tetrahydrophenazine 5 give evidence of a multiplet

show abstract

Section: Electrochemical Reductionsupporting

confidence: 90%

Chemical and electrochemical reduction of pyrazino[2,3-b]quinoxalines

Armand¹,

Boulares²,

Chekir³

et al. 1981

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The reduction of quinoxalines in aprotic media produces the radical species [11][12][13][14], and is different from that in protic media [15][16][17][18][19][20][21][22]. For this reason, 98% H 2 SO 4 was used to adjust the solution pH and to act as the proton source of the electrochemical reaction.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical behavior of conjugated quinoxaline derivatives

Wang

Ramaraj

Okajima

et al. 2004

Journal of Electroanalytical Chemistry

View full text Add to dashboard Cite

“…'H-nmr spectra were recorded on a Bruker WH80, a Varian A60, and a Bruker 250 MHz spectrometer using tetramethylsilane (TMS) as internal standard. The apparatus and techniques used for the electrochemical studies and pH measurements have been described previously (6). All the potentials are referred to the saturated-calomel electrode (SCE); the temperature of the solutions was 20°C.…”

Section: Methodsmentioning

confidence: 99%

“…After 4 h of stirring at room temperature, the mixture was poured into 80 mL of water. The precipitate was filtered, washed with water, and dried to give 215 mg of 1,2-or 3,4-dihydro-2,3-diphenylpyrido[2,3-blpyrazine, 13 (6). With the same work-up but after stirring 72 h, 226 mg of cis-1,2,3,4-tetrahydro-2,3-diphenylpyrido-[3,4-blpyrazine, 14 (6), was obtained.…”

Section: Electrolysis Of 2 Preparation Ofmentioning

confidence: 99%

Preparation, chemical and electrochemical reduction of pyrido[2,3-b]quinoxalines and pyrido[3,4-b]quinoxalines

Armand¹,

Boulares²,

Bellec³

et al. 1988

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

. Can. J. Chem. 66, 1500 (1988). The reaction of 2,3-diaminopyridine with the dimeric 4,5-dimethylcyclohexa-3,5-dien-1,2-dione gives 7, 8-dimethylpyrido[2,3-b]quinoxaline, 1, in good yields; in the same way 3,4-diaminopyridine gives the 7,s-dimethylpyrido[3,4-blquinoxaline 2. The electrochemical reduction of 1 and 2 in hydroorganic medium gives the 5,lO-dihydro compounds 6 and 7; 1 and 2 present a single 2e-polarographic wave, in contrast to phenazine which shows two monoelectronic waves. The catalytic hydrogenation of 1 and 2 gives 6 and 7 and does not involve the pyridinic ring as in the case of pyridopyrazines. A1LiH4 does not react with 2 but 1 is reduced into the 1,2-dihydro derivative 8. The behavior of 1 and 2 is thus different from that of pyridopyrazines (which give the 1,2,3,4-tetrahydro compounds) and from that of phenazine (which gives the 5,lO-dihydro derivative). NaBH4 reacts with pyridopyrazines to give, according to the substituents, 1,2-or 5.6-dihydro or 1,2,3,4-tetrahydro derivatives. Methylmagnesium chloride reacts with 1 to give a mixture of 2-methyl-1,2-dihydro, 2,6,7-trimethyl, and 4,6,7-trimethylpyrido[2,3-blquinoxaline. In the case of 2, 4,6,7-trimethylpyrido[3,4-blquinoxaline is obtained.JOSEPH ARMAND, LINE BOULARES, CHRISTIAN BELLEC et JEAN PINSON. Can. J. Chem. 66, 1500 (1988). L'action de la diamino-2,3 pyridine sur la dimethyl-4,5 cyclohexadikne-3,5 dione-1,2 sous forme dimkre fournit avec un bon rendement la dimethyl-7,8 pyrido[2,3-blquinoxaline 1. En utilisant la diamino-3,4 pyridine on obtient la dimethyl-7,8 pyrido[3,4-blquinoxaline 2. En milieu hydroorganique la reduction Clectrochimique de 1 et 2 foumit les derives dihydro-5,10 : 6 et 7; 1 et 2 presentent une seule vague polarographique de 2e-contrairement i la phtnazine qui donne deux vagues monoClectroniques. L'hydrogknation catalytique de 1 et 2 foumit 6 et 7 et ne conceme donc pas le noyau pyridine comme dans le cas des pyridopyrazines. A1LiH4 est sans action sur 2 alors que 1 fournit le derive dihydro-1,2 : 8; le comportement de 1 et 2 diffkre de celui des pyridopyrazines (qui donnent des derives tetrahydro-1,2,3,4) et de la phknazine (qui foumit le derive dihydro-5,lO). Avec NaBH4 1 fournit un melange de 6 et 8 tandis que 2 donne le derive tetrahydro-1,2,3,4. L'action de NaBH4 sur les pyridopyrazines a kt6 egalement 6tudiCe : selon la nature du substituant des derives dihydro-1,2, tetrahydro-1,2,3,4 ou dihydro-5,6 sont obtenus. Le chlorure de m&thylmagntsium conduit dans le cas de 1 i un melange de derive dihydro-1,2 methyl-2, de trimethyl-2,6,7 pyrido with 2-formyl-3 -aminoquinoxaline (4). The few pyrido [3,4-b]quinoxalines which are known have been obtained by cyclization of 3-amino-4-(2-aminoani1ino)pyridine (5) or of 3-amino-4-(2-aminoto1uidino)pyridine (3). In view of the rather low yields and the complicated experiments, we looked for alternative routes to prepare these compounds. W e reacted 2,3-and 3,4-diaminopyridine with a quinone: 4,5-dimethylcyclohexa-3,5-dien-1,2-dione. When the quinone is used as a monomer, ...

show abstract

Electrochemical reduction of pyridopyrazines

Cited by 25 publications

References 2 publications

Chemical and electrochemical reduction of pyrazino[2,3-b]quinoxalines

Chemical and electrochemical reduction of pyrazino[2,3-b]quinoxalines

Electrochemical behavior of conjugated quinoxaline derivatives

Preparation, chemical and electrochemical reduction of pyrido[2,3-b]quinoxalines and pyrido[3,4-b]quinoxalines

Contact Info

Product

Resources

About