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The synthesis and properties of pyrrolo[1,2-a]pyrazines are reviewed.

Recyclization of 3-alkylpyrrolo[1,2-a]pyrazinium salts in the presence of base afforded derivatives of 6-aminoindolizine. Rearrangement of 1,3-dialkylpyrrolo[1,2-a]pyrazinium salts proceeded in two directions, giving rise to both 6- and 8-aminoindolizines, though the latter predominated in terms of yield. In the absence of alkyl substituents at positions 1 and 3 the pyrazine ring was cleaved on treatment with base, yielding derivatives of 2-acylpyrrole.

A method for synthesis of pyrazinol[1,2-a]indoles with alkyl substituents in position 1 was developed based on indole and isomerization recyclization of their quaternary salts into 9-aminopyrido[1,2-a]indole derivatives was conducted.

The recyclization of pyrrolo[1,2-a]pyrazinium salts under the influence of a base leads to 8-aminoindolizine derivatives and is a new method for the synthesis of indolizines, as well as the first example of the Kost—Sagitullin rearrangement in the pyrazine series.

We have investigated the effects of surface copper diffusion on the creep of large-grain nickel (average grain size about 20 m) and submicron crystalline nickel (grain size about 0.3 m). For both structural states of nickel we find an acceleration of creep over its value in vacuum, and an increase in plasticity during creep when copper has diffused deeply into the nickel from the surface. The temperature range over which these effects are observed in the submicron nickel is nearly 300° lower than that for the large-grain samples. This result is probably due to a significant increase in the grain-boundary and bulk diffusion coefficients of copper in submicron nickel when compared with large-grain nickel.

Rearrangement of the methyl iodides of 1- and 3-alkyl-substituted pyrrolo[1,2-a]pyrazines in the presence of various alkylamines afforded a mixture of 8- and 6-aminoindolizines, respectively, with and without exchange of the methylamine fragment. The ratio of the products of direct and exchange recyclization was dictated by the size of the N-alkyl substituents in the reagent and starting salt. Rearrangement of the 1-alkylpyrrolo[1,2-a]pyrazinium salts proceeded via the breaking of the C(3) -N(2) bond, and rearrangement of the 3-alkylpyrrolo-[1,2-a]pyrazinium salts via the breaking of the C(1) -N(2) bond.

furnishing tricyclic structures (V)

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.