Cinnoline Aldehydes and Ketones

Most of the more recently reported data on these C-acylcinnolines and A-acylated hydrocinnolines have been discussed previously in this book, as indicated in the following paragraphs. 

These acylcinnolines have been made by primary synthesis (see Chapter 1), Reissert-type addition to cinnoline (Section 2.1.3), oxidation of alkylcin-nolines (Section 2.2.2), displacement of halogeno substituents (Section 3.2), hydrolysis of dihalogenomethylcinnolines (Section 3.2), N-acylation of tautomeric cinnolinones (Section 4.1.2.2), oxidation of extranuclear hydro-xycinnolines (Section 4.2), or as illustrated here. 

4-Methoxycinnoline was converted into 3-lithio-4-methoxycinnoline (52) and thence by direct formylation into 4-methoxy-3-cinnolinecarbaldehyde (53) 

4-MethylcinnoIine (54) underwent reductive acetylation to give 1,2-diacetyl-4-methyl-1,2-dihydrocinnoline (55) [electrolytic, AC2O, Me2NCHO a physicochemical study without isolation) 4-phenylcinnoline behaved simi-larly].  

These reactions of acylcinnolines have been covered already reduction to alkylcinnolines (Section 2.2.1), some cyclocondensations (Section 4.1.2.2), and reduction to extranuclear hydroxycinnolines (Section 4.2). Their oxidation to cinnolinecarboxylic acids appears to be unrepresented in the more recent literature. Some other reactions are illustrated in the examples that follow. 

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Cinnoline Aldehydes and Ketones conditions for controlled hydrolysis of the cyano group ]... 

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