Iron II oxalate

An early synthesis of pyrido[3,4-6]quinoxalines involved cyclization by strong heating of o-aminoanilinopyridinamine derivatives, e.g. (418) to give (419) (49JCS2540). In a related reaction, o-nitroanilinopyridines (420) were cyclized to pyrido-[2,3-6]- or -[3,4-6]-quinoxa-lines (421) by reduction with iron(II) oxalate, probably via a nitrene intermediate (74JCS(P1)1965). 

The oxide (prepared at 300°C) bums in air above 200°C, while the finely divided oxide prepared by reduction may be pyrophoric at ambient temperature [1]. That prepared by thermal decomposition under vacuum of iron(II) oxalate is also pyrophoric [2],... 

Iron overload, ascorbic acid and, 25 770 Iron(II) oxalate dihydrate, 14 547-548 Iron oxide(s), 14 541-542... 

Iron Iron(II) oxalate Fe(C204).2H20 Fe11 - Absorbs in infrared... 

Methods which are principally of use when other reducible substituents are absent include catalytic hydrogenation, use of metals and acid, iron(II) oxalate (61CJC2134), sodium borohy-dride and lithium aluminum hydride (70CCC2802). 

Preparation of Iron(II) Oxide, a. First prepare iron(II) oxalate. To do this, pour an ammonium oxalate solution into 20 ml of a Mohr .s salt solution up to the complete precipitation of the iron. Wash the precipitate several times with water by decantation, next filter it on a Buchner funnel, wash off sulphate ions, and dry it at 100 °G. 

A variety of pyrrole ring closure reactions are conveniently formulated as proceeding via nitrene intermediates, although it is doubtful whether a free nitrene is involved. Pyrolysis of o-nitrobiphenyls with iron(II) oxalate (61T(16)80), or reduction under milder conditions with triethyl phosphite (65JCS4831) or tris(trimethylsilyl) phosphite (79TL375), leads to the carbazole, as does the pyrolysis or photolysis of 2-azidobiphenyls (Scheme 3) (75JA6193). 

Nitro groups can function as precursors for nitrenes this deoxygenation is usually brought about by triethyl phosphite iron(II) oxalate has also been used for this purpose. The transformations of such nitrenes attached to thiophene are discussed below. 

Chemically pure Fe can be prepared by reduction of pure iron oxide (which is obtained by thermal decomposition of iron(II) oxalate, carbonate, or nitrate) with H2, by electrodeposition from aqueous solutions of Fe salts, or by thermal decomposition of Fe(CO)5. 

The iron(II) oxalate catalyzed rearrangement of 3-substituted diphenyldiazenes (R = Cl, OMe, Ph) gives 2,7-disubstituted phenazines 1 in low yields. 

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