Pyrroline jV-oxide

The A pyrroline-jV-oxides (50) undergo violently exothermic reactions with DMAD in the absence of solvent.95 In ether at room temperature, unstable products (51) that rearrange exothermically to the pyrrolines (52) are formed this ring fission recalls that of isoxazolium salts.96 With unsymmetrical acetylenes, two modes of cycloaddition are possible. Propiolic acid adds to 50 (R = H), giving an unstable solid... 

Pyrrolinediones polymerization, 1, 273 2- rroline-4,5-diones synthesis, 4, 143 3 -Py rroline-2,5-diones polymers, 1, 294 Pyrrolines JV-oxide... 

A -Piperideine-JV-oxides and A -pyrroline-Af-oxides were obtained together with dimeric products by oxidation of iV-hydroxypiperidines and AT-hydroxypyrroli-... 

Topaquinone (TPQ), the oxidized form of 2,4,5-trihydroxyphenylalanine (TOPA), is the cofactor of copper-containing amine oxidases. The following model compounds have been prepared in order to understand the catalytic function of TPQ the jV-pivaloyl derivative of 6-hydroxydopamine in aqueous acetonitrile [38] topaquinone hydantoin and a series of 2-hydroxy-5-alkyl-l,4-benzoquinones in anhydrous acetonitrile (o- as well as />-quinones) [39] 2-hydroxy-5-methy 1-1,4-benzoquinone in aqueous system [40] and 2,5-dihydroxy-1,4-benzoquinone [41]. Reaction of model compounds with 3-pyrrolines revealed why copper-quinopro-tein amine oxidases cannot oxidize a secondary N [42], The studies clearly showed that certain model compounds do not require the presence of Cu for benzylamine oxidation whereas TPQ does [38,40] the aminotransferase mechanism proceeds via the -quinone form [39] the 470 nm band can be ascribed to a 71-71 transition of TPQ in />-quinonic form with the C-4 hydroxyl ionized but hydrogen bonded to some residue [40] hydrazines attack at the C-5 carbonyl, forming an adduct in the azo form [41], Electrochemical characterization has been carried out for free TPQ [43],... 

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