Hydrochloric Acid → HCID 12378164, compound

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Reaction Steps

The following procedure is typical of that used to prepare the various azacoumarins. 7-Hydroxy-1,4-dimethyl-1,2,3,4-tetrahydro-1,8-naphthyridine (0.19 g.), 1.2 ml. of ethyl trifluoroacetoacetate, 50 mg. of anhydrous zinc chloride, and 10 ml. of absolute ethanol were refluxed for 40 hours. The cooled solution was poured with stirring into 50 ml. of water plus 3 ml. of hydrochloric acid; the yellow precipitate was filtered, washed with water, and dried (0.31 g., 95%). Solvent used for recrystallization, melting point, fluorescence data and analytical data are summarized in the table below. The 1H nmr spectral data (deuteriochloroform, 100 MHz) on the analogous 6,8,9-trimethyl derivative are: δ1.37 (d, 6H, CH3CH), 1.47 (m,1H, H7b), 2.10 (dt, 1H, H7a,J=13 Hz, J=4 Hz), 2.80 (m, 1H, H6), 3.20 (s, 3H, NCH3), 3.70 (m, 1H, H8), 6.38 (s, 1H, H3), 7.41 (q, 1H, H5, JH5 --CF3 =~1.5 Hz).

Provenance & Evidence