Hydrochloric Acid → HCID 178486309, compound

Participants

Reaction Conditions

Reaction Steps

20.9 g (0.11 mol) of naphthazarin (8) and 28.4 g of 1-methoxy-1,3-chclohexadiene (19) (technical grade, 70%, 0.177 mol) were refluxed in 330 ml of methylene chloride (temperature oil bath 50° C.). The course of the reaction was followed by means of TLC (ethyl acetate:n-hexane, 2:5). After evaporation 330 ml of pentane was added to the residue and the solution was stirred for 5 minutes. The solution was cooled to 0° C. and filtrated. The filtrate was rinsed with 2×50 ml of petroleum ether. The yield of the yellow/brown product was 30.0 g (91%). The crystals were taken up in a solution of 22.0 g (0.55 mol) of caustic soda in 825 ml of water. During half an hour air was passed through the solution while the solution was stirred. The colour of the solution changed from green to blue. The course of the reaction was followed by means of TLC (ethyl acetate:n-hexane, 2:5). After the reaction 46.2 ml of concentrated HCl (37%) was added to the solution. The product precipitated as a red solid which was filtered off. This compound was dried on a film evaporator (2 mm Hg) and in a vacuum dessicator (over P2O5) during at least one night. The yield of the red compound (20) was 27.0 g (91%). The overall yield was 83%. Melting point 239°-241° C. 1H-NMR (90 MHz, CDCl3, TMS internal standard): δ=1.39-1.92 ppm (4H, m, CH2 --CH2), δ=3,69 ppm (3H, s, OMe), δ=4,53 ppm (1H, m, H4), δ=6.40 ppm (1H, dd, J=5.6 Hz and J=8 Hz), δ=6.64 ppm (1H, dd, J=8 Hz and J=1.5 Hz), δ=7.12 ppm (2H, s, ArH), δ=12.60 ppm (1H, s, ArOH), δ=13.06 ppm (1H, s, ArOH).

Provenance & Evidence