Most of the compounds have physiologically active properties, and their biological properties are often attributed to the heteroatoms contained in their molecules, and most of these heteroatoms also appear in cyclic structures. A Journal, Acta Poloniae Pharmaceutica called Synthesis of new derivatives of 1,2,5-triazepino[1,2-a]cinnoline. II. Synthesis of haloacyl derivatives of 4-oxo-1,2,3,4-tetrahydrocinnoline, Author is Kwapiszewski, Wincenty; Stanczak, Andrezej; Groszkowski, Stefan, which mentions a compound: 137195-33-6, SMILESS is O=C1CNNC2=C1C=CC=C2.[H]Cl, Molecular C8H9ClN2O, Quality Control of 2,3-Dihydrocinnolin-4(1H)-one hydrochloride.
Stirring 1,2,3,4-tetrahydrocinnolin-4-one (I) with BrCH2COCl (II) in H2O at 0° gave 76% III (X = Br, R = R1 = R2 = H). III (X = Cl, R1 = R2 = H; R = Cl, Me, MeO; R = R1 = H, R2 = Cl, Me; R = H, R1 = R2 = MeO) were prepared analogously in 49-74% yields from the appropriately substituted I and ClCH2COCl (IV). When I and II were refluxed 10 h in C6H6, diacetylation occurred to give 67% V (X = Br, R1 = R2 = H). V (X = Cl, R1 = R2 = MeO; R1 = H, R2 = Cl, Me) were prepared analogously. V (X = Cl, R1 = R2 = H) was obtained from the corresponding III and IV in the presence of Et3N. Refluxing I 10 h with ClCH2CH2COCl in C6H6 gave 54% VI, which was also obtained as a byproduct when a similar reaction was carried out at 0° in CHCl3; the main product (60% yield) was 2-(3-chloropropionyl)-1,2,3,4-tetrahydrocinnolin-4-one.
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Reference:
Cinnoline – Wikipedia,
Cinnoline – an overview | ScienceDirect Topics