A facile approach to the synthesis of novel 2-diethylaminocinchomeronic dinitriles, which are found to be fluorescent both in the solution and in a solid states, was developed. Absorption, fluorescence and solvatochromic properties as well as a crystal structure of the synthesized compounds were investigated.It was found that the 2-diethylaminocinchomeronic dinitrile derivatives with methoxy groups in the aryl moiety possess the most intensive emission in nonpolar solvents with fluorescence quantum yields up to 0.59.

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SHORT COMMUNICATIONSAccording to published data, tetracyanoethylene reacts with ketones in the presence of a catalytic amount of hydrochloric acid to give 4-oxoalkane-1,1,2,2-tetracarbonitriles [1,2]. It is also known that concentrated hydrochloric acid reacts with 4-oxoalkane-1,1,2,2-tetracarbonitriles to produce 2-chloropyridine-3,4-dicarbonitriles [3]. These data suggest that 2-chloropyridine-3,4-dicarbonitriles could be prepared via one-pot procedure, i.e., without isolation of 4-oxoalkane-1,1,2,2-tetracarbonitriles, which should make their preparation simpler and less expensive.In fact, three-component reaction of tetracyanoethylene with the corresponding ketone Ia-If (aliphatic, aromatic, or heterocyclic) and hydrochloric acid in 1,4-dioxane afforded substituted 2-chloropyridine-3,4-dicarbonitriles IIa-IIf in 86-97% yield. The structure of compounds IIa-IIf was confirmed by IR, 1 H NMR, and mass spectra. ensured higher yield and shorter reaction time. Compounds IIb and IId-IIf were not reported previously.2-Chloro-5,6-dimethylpyridine-3,4-dicarbonitrile (IIa). Tetracyanoethylene, 0.64 g (0.005 mol), was added to a solution of 0.45 g (0.006 mol) of butan-2-one in 10 ml of 1,4-dioxane, 5 ml of concentrated hydrochloric acid was then added, and the mixture was stirred for 1-2 h at 60-70°C. When the reaction was complete (TLC), the mixture was diluted with water, and the precipitate was filtered off, washed with water and propan-2-ol, and recrystallized from propan-2-ol. Yield 0.85 g (89%), mp 72-74°C [3]. IR spectrum, ν, cm -1 : 2233 (C≡N), 1561, 1535 (C=C). 1 H NMR spectrum, δ, ppm: 2.56 s (3H, CH 3 ), 2.68 s (3H, CH 3 ). Mass spectrum: m/z 191 (I rel 57%). Found, %: C 55.98; H 3.15; N 21.58. C 9 H 6 ClN 3 . Calculated, %: C 56.41; H 3.16; N 21.93. M 191.62.Compounds IIb-IIf were synthesized in a similar way. 2-Chloro-5-ethyl-6-methylpyridine-3,4-dicarbonitrile (IIb). Yield 0.95 g (93%), mp 46-48°C. IR spectrum, ν, cm -1 : 2234 (C≡N), 1554 (C=C). 1 H NMR spectrum, δ, ppm: 1.19 t (3H, CH 3 , J = 8 Hz), 2.66 s (3H, CH 3 ), 2.86 q (2H, CH 2 , J = 8 Hz). Mass spectrum: m/z 205 (I rel 45%). Found, %: C 57.98; H 3.15; N 20.02. C 10 H 8 ClN 3 . Calculated, %: C 58.41; H 3.92; N 20.43. M 205.65. 2-Chloro-5,6,7,8-tetrahydroquinoline-3,4-dicarbonitrile (IIc). Yield 1.05 g (97%), mp 95-96°C [3]. IR spectrum, ν, cm -1 : 2222 (C≡N), 1539 (C=C). 1 H NMR spectrum, δ, ppm: 1.90 m (4H, CH 2 ), 2.89 t (2H, CH 2 , J = 6 Hz), 3.09 t (2H, CH 2 , J = 6 Hz). Mass spectrum: m/z 217 (I rel 100%). Found, %: C 59.96; R 1 = R 2 = Me (a); R 1 = Me, R 2 = Et (b); R 1 R 2 = (CH 2 ) 4 (c), (CH 2 ) 6 (d); R 1 = Ph, R 2 = H (e); R 1 = 2-thienyl, R 2 = H (f).

A facile approach to the synthesis of novel 2‐(N‐cycloamino)cinchomeronic dinitriles showing intense photoluminescence both in solution and solid state was developed. Absorption, fluorescence and solvatochromic properties were investigated. It was found that the 2‐(N‐cycloamino)cinchomeronic dinitrile derivatives containing conjugated aryl moiety show intense emission in nonpolar solvents with fluorescence quantum yield up to 0.8.