Dicarboxylic acid anhydrides dinitriles

Treatment of quinoxaline-2,3-dicarboxylic acid anhydrides, diesters, or dinitriles with hydrazine monohydrate gives pyridazino[4,5-h]quin-oxalines (Scheme 7). ... 

The chemical transformation must not affect the stereogenic centers. Suitable acyclic candidates are compounds with easily convertible functional groups, such as diols, diamines, amino alcohols, dicarboxylic acids and so on. A number of procedures known before 1973 have been compiled, including conversion of diols and amino alcohols into sulfites or 1,3-dioxolanes by thionyl chloride, or acetalization with ketones31,1"319, as well as the conversions of dinitriles into imides320, dicarboxylic acids into cyclic anhydrides or imides321, and hydroxy acids into oxazolidones 322. 

Cyclic amino acids 139, when heated in acetic anhydride, probably form initially mesoionic oxazolium 5-oxides (munchnones) subsequent 1,3-dip olar cycloaddition of 1,2-dicyanocyclobutene, loss of carbon dioxide, and opening of the cyclobutane ring lead to dinitriles 140 (80JHC1593). Pyridone 141 is the by-product (together with an indolizine) of the mono-cyclic pyridone dicarboxylate and acrylic ester (73JHC77). 

Quinoxaline-2-carboxylic acid with thionyl chloride gives the acid chloride (79%), which undergoes the expected reactions.166 The gas-phase pyrolysis of quinoxaline-2,3-dicarboxylic anhydride (157) over a Nichrome coil gives o-phthalonitrile (158) (72%), probably via 2,3-quinoxalyne (159) which ring-cleaves, and the diisocyanide subsequently rearranges thermally to the dinitrile.167... 

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