The Electrochemical Reduction of Compounds with the Group. III as-Triazines

1972 ◽  
Vol 50 (10) ◽  
pp. 1581-1590 ◽  
Author(s):  
Jean Pinson ◽  
Jean-Pierre M'Packo ◽  
Nicole Vinot ◽  
Joseph Armand ◽  
Philippe Bassinet
Keyword(s):  
Electrochemical Reduction ◽  
Group Iii ◽  
Dihydro Derivative

The electrochemical reduction of as-triazines 3-one or -thione leads to a 1,4-dihydro derivative which rearranges into a 4,5-dihydro compound which is further reducible to an imidazolone or a tetrahydro as-triazine 3-one. In the case of simple as-triazine the 1,4-dihydro compound rearranges either to a 1,2- or to a 4,5-dihydro compound. This last derivative can be reduced to an imidazole or a tetrahydro as-triazine. The mechanisms are discussed.

Chemical and electrochemical reduction of pyrazino[2,3-g]quinoxalines and of their benzo and dibenzo derivatives; the structure of fluorindine and the formation of tetraanion

1987 ◽  
Vol 65 (7) ◽  
pp. 1619-1623 ◽  
Author(s):  
Joseph Armand ◽  
Line Boulares ◽  
Christian Bellec ◽  
Jean Pinson
Keyword(s):  
Electrochemical Reduction ◽  
Catalytic Hydrogenation ◽  
Radical Anion ◽  
Reversible Systems ◽  
Restricted Class ◽  
Dihydro Derivative ◽  
Successive Formation

The structure of fluorindine is established by nmr as the 5,14-dihydroquinoxalino[2,3-b]phenazine. The catalytic hydrogenation of 2,3-di(p-methoxyphenyl)pyrazino[2,3-b]phenazine 2a leads to the 6,11-dihydro derivative 4a. The electrochemical reduction in an hydroorganic medium furnishes 4a and then the 1,4,6,11-tetrahydro derivative 8a. In dry DMSO the voltammogram shows four monoelectronic reversible systems corresponding to the successive formation of a radical anion, dianion, radical trianion, and tetraanion. Thus 2a appears as a new example of the very restricted class of compounds leading to tetraanions upon electrochemical reduction. The catalytic hydrogenation of 2,7-diphenylpyrazino[2,3-g]quinoxaline 1a or the reaction of LiAlH4 with 1,2,7,8-tetramethylpyrazino[2,3-g]quinoxaline 1b leads to 1,2,3,4-tetrahydro compounds. The electrochemical reduction of 1a and 1b in hydroorganic medium leads successively to 1,4-dihydro and then to 1,4,6,9-tetrahydro compounds which undergo a further rearrangement. In dry DMSO 1a and 1b behave differently from 2a: one only observes two reversible monoelectronic systems.

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

1988 ◽  
Vol 66 (6) ◽  
pp. 1500-1505 ◽  
Author(s):  
Joseph Armand ◽  
Line Boulares ◽  
Christian Bellec ◽  
Jean Pinson
Keyword(s):  
Electrochemical Reduction ◽  
Catalytic Hydrogenation ◽  
Polarographic Wave ◽  
Dihydro Derivative

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 7,8-dimethylpyrido[3,4-b]quinoxaline 2. The electrochemical reduction of 1 and 2 in hydroorganic medium gives the 5,10-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. AlLiH4 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 5,10-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-b]quinoxaline. In the case of 2, 4,6,7-trimethylpyrido[3,4-b]quinoxaline is obtained.

Ultrastructural Lesions Produced by Alcohol and Sucrose in the Heart and Liver of C57BL Mice

1970 ◽  
Vol 28 ◽  
pp. 208-209
Author(s):  
K.K. SEKHRI ◽  
C.S. ALEXANDER ◽  
H.T. NAGASAWA
Keyword(s):  
Osmium Tetroxide ◽  
Male Mice ◽  
Alcohol Group ◽  
Group Iii ◽  
Group I ◽  
C57bl Mice ◽  
Group Ii

C57BL male mice (Jackson Lab., Bar Harbor, Maine) weighing about 18 gms were randomly divided into three groups: group I was fed sweetened liquid alcohol diet (modified Schenkl) in which 36% of the calories were derived from alcohol; group II was maintained on a similar diet but alcohol was isocalorically substituted by sucrose; group III was fed regular mouse chow ad lib for five months. Liver and heart tissues were fixed in 2.5% cacodylate buffered glutaraldehyde, post-fixed in 2% osmium tetroxide and embedded in Epon-araldite.

The Quantitative Ultrastructure of the Heart Muscle of Japanese Quail by Hypergravitation, Hypodynamy and Combination

1990 ◽  
Vol 48 (3) ◽  
pp. 188-189
Author(s):  
Anton Bózner ◽  
Mikuláš Gažo ◽  
Jozef Dostál
Keyword(s):  
Japanese Quail ◽  
Heart Muscle ◽  
Relative Size ◽  
Combination Group ◽  
Control Group ◽  
Group V ◽  
Group Iii ◽  
Space Flights ◽  
Group I ◽  
Quantitative Ultrastructure

It is anticipated that Japanese quail /Coturnix coturnix japonica/ will provide animal proteins in long term space flights. Consequently this species of birds is of research interest of international space program INTERCOSMOS. In the year 1987 we reported on an experiment /2/ in which the effect of chronic acceleration of 2 G hypergravitation, the hypodynamy and the simultaneous effect of chronic acceleration and the location in the centre of the turntable of the centrifuge on the protein fractions in skeletal muscles was studied. The ultrastructure of the heart muscle was now in this experiments examined as well.Japanese quail cockerels, aged 48 days were exposed to 2 G hypergravitation /group IV/ in a 6,4 m diameter centrifuge, to hypodynamy /group III/ and their combination /group V/, respectively for 6 days / Fig.1/. The hypodynamy in group III was achieved by suspending the birds in jackets without contact the floor. The group II was located in the centre ofthe turntable of the centrifuge. The control group I. was kept under normal conditions. The quantitative ultrastructure of myocard was evaluated by the methods of Weibel/3/ - this enables to determine the number, relative size and volume of mitochondria volume of single mitochondria, defficiency of mitochondrial cristae and volume of myofibrils.

Recent work on group III antimonides and arsenides

Physica ◽  
1954 ◽  
Vol 3 (7-12) ◽  
pp. 1065-1067
Author(s):  
H HROSTOWSKI ◽  
M TANENBAUM
Keyword(s):  
Recent Work ◽  
Group Iii

In Situ X-Ray Absorption Studies of the Electrochemical Reduction of Hydroxocobalamin

1997 ◽  
Vol 7 (C2) ◽  
pp. C2-619-C2-620 ◽  
Author(s):  
M. Giorgett ◽  
I. Ascone ◽  
M. Berrettoni ◽  
S. Zamponi ◽  
R. Marassi
Keyword(s):  
Electrochemical Reduction ◽  
X Ray ◽  
Absorption Studies ◽  
X Ray Absorption

Heterogeneity and Immunochemical Properties of Anti-β2-glycoprotein I Autoantibodies

1998 ◽  
Vol 80 (09) ◽  
pp. 393-398 ◽  
Author(s):  
V. Regnault ◽  
E. Hachulla ◽  
L. Darnige ◽  
B. Roussel ◽  
J. C. Bensa ◽  
...  
Keyword(s):  
Fluid Phase ◽  
Anticardiolipin Antibodies ◽  
Dual Reactivity ◽  
Group Iii ◽  
Important Group ◽  
Epitope Specificity ◽  
Glycoprotein I ◽  
Group I ◽  
Group Ii ◽  
Sufficient Concentration

SummaryMost anticardiolipin antibodies (ACA) associated with antiphospholipid syndrome (APS) are directed against epitopes expressed on β2-glycoprotein I (β2GPI). Despite a good correlation between standard ACA assays and those using purified human β2GPI as the sole antigen, some sera from APS patients only react in the latter. This is indicative of heterogeneity in anti-β2GPI antibodies. To characterize their reactivity profiles, human and bovine β2GPI were immobilized on γ-irradiated plates (β2GPI-ELISA), plain polystyrene precoated with increasing cardiolipin concentrations (CL/β2GPI-ELISA), and affinity columns. Fluid-phase inhibition experiments were also carried out with both proteins. Of 56 selected sera, restricted recognition of bovine or human β2GPI occurred respectively in 10/29 IgA-positive and 9/22 IgM-positive samples, and most of the latter (8/9) were missed by the standard ACA assay, as expected from a previous study. Based on species specificity and ACA results, IgG-positive samples (53/56) were categorized into three groups: antibodies reactive to bovine β2GPI only (group I) or to bovine and human β2GPI, group II being ACA-negative, and group III being ACA-positive. The most important group, group III (n = 33) was characterized by (i) binding when β2GPI was immobilized on γ-irradiated polystyrene or cardiolipin at sufficient concentration (regardless of β2GPI density, as assessed using 125I-β2GPI); (ii) and low avidity binding to fluid-phase β2GPI (Kd in the range 10–5 M). In contrast, all six group II samples showed (i) ability to bind human and bovine β2GPI immobilized on non-irradiated plates; (ii) concentration-dependent blockade of binding by cardiolipin, suggesting epitope location in the vicinity of the phospholipid binding site on native β2GPI; (iii) and relative avidities approximately 100-fold higher than in group III. Group I patients were heterogeneous with respect to CL/β2GPI-ELISA and ACA results (6/14 scored negative), possibly reflecting antibody differences in terms of avidity and epitope specificity. Affinity fractionation of 23 sera showed the existence, in individual patients, of various combinations of antibody subsets solely reactive to human or bovine β2GPI, together with cross-species reactive subsets present in all samples with dual reactivity namely groups III and II, although the latter antibodies were poorly purified on either column. Therefore, the mode of presentation of β2GPI greatly influences its recognition by anti-β2GPI antibodies with marked inter-individual heterogeneity, in relation to ACA quantitation and, possibly, disease presentation and pathogenesis.

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