Patent GB-672741-A (GB)
Title: Improvements in or relating to coumarin compounds, to methine dyes containing coumarin nuclei and to the preparation of such dyes
Inventor: KENDALL JOHN DAVID
IPC: C09B23/02
Filed: 1949-10-20
Abstract: Dye intermediates of the general formula <FORM:0672741/IV (b)/1> wherein D1 completes a benzene ring, are prepared by reacting a compound of the formula <FORM:0672741/IV (b)/2> with a lower alkyl ester of cyanacetic acid at high temperature in the presence of a basic compound.  3 - Cyano - 4 - methylcoumarin is prepared by heating together o-hydroxyacetophenone, ethyl cyanacetate, and triethylamine. 3-Cyano-4-methyl-7-hydroxycoumarin is similarly prepared.ALSO:Dyes of the general formula <FORM:0672741/IV (c)/1> wherein D1 completes a benzene ring, D2 completes a 5- or 6-membered heterocyclic ring system, and R2 is alkyl or aralkyl, are prepared by condensing a compound of the general formula <FORM:0672741/IV (c)/2> with a compound of the general formula <FORM:0672741/IV (c)/3> wherein X is an acid radical and R is alkyl.  Methine - [2 - (3 - methyldihydrobenzthiazole)] - [4-(3-cyanocoumarin)] is prepared by refluxing together 3-cyano-4-methylcoumarin, 2-methylthiobenzthiazole methiodide, ethanol, and triethylamine.  Methine - [2 - (3 - ethyldihydrobenzthiazole)] - [4 - (3 - cyanocoumarin)], methine - [2 - (1 - ethyldihydroquinoline)] - [4 - (3 - cyanocoumarin)], methine - [2 - (3 - methyltetrahydrothiazole)] - [4 - (3 - cyanocoumarin)], methine - [2 - (3 - methyl - 5 - methylthio - 1 : 3 : 4 - dihydrothiodiazole)] - [4 - (3 - cyanocoumarin)], methine - [2 - (3 - methyldihydrobenzthiazole)] - [4 - (3 - cyano - 7 - hydroxycoumarin)], and methine - [2 - (1 - methyldihydroquinoline)] - [4 - (3 - cyano - 7 - hydroxycoumarin)] are similarly prepared.  Dyes of the general formula <FORM:0672741/IV (c)/4> where D1, D2, and R2 are as before, are prepared by condensing an intermediate of the second general formula above with an intermediate of the general formula <FORM:0672741/IV (c)/5> wherein X is an acid radical and Q an alkylthioether, amino, or substituted amino (e.g. acetamino or acetanilido) group.  Trimethine - [2 - (1 : 3 : 3 - trimethyldihydroindole)] - [4 - (3 - cyanocoumarin)] is prepared by refluxing together 3-cyano-4-methylcoumarin, 2 - (b  - methylthiovinyl) - 3 : 3 - dimethylindolenine methiodide, ethanol, and triethylamine. Trimethine - [2 - (3 - methyldihydrobenzoxazole)] - [4 - (3 - cyanocoumarin)], trimethine - [2 - (3 - methyldihydrobenzthiazole)] - [4 - (3 - cyanocoumarin)], trimethine - [4 - (1 - ethyldihydroquinoline)] - [4 - (3 - cyanocoumarin)], trimethine - [2 - (1 : 3 : 3 - trimethyldihydroindole)] - [4 - (3 - cyano - 7 - hydroxycoumarin)], and trimethine - [2 - (3 - methyldihydrobenzthiazole)] - [4 - (3 - cyano - 7 - hydroxycoumarin)] are similarly prepared.  Dyes of the general formula <FORM:0672741/IV (c)/6> wherein R3 is an alkyl group, are prepared by condensing an intermediate of the second general formula with a compound of the general formula <FORM:0672741/IV (c)/7> wherein X is an acid radical and R is an alkyl group.  b  - Methylthiotrimethine - [2 - (3 - ethyldihydrobenzthiazole)] - [4 - (3 - cyanocoumarin)] is prepared by refluxing together 3-cyano-4-methylcoumarin, 2-b -di-(methylthio)-vinylbenzthiazole ethiodide, ethanol, and triethylamine.  3-Cyano-4-methyl-7-hydroxycoumarin has a strong bluish fluorescence and can be applied to textile fabrics to impart a whitening effect or to render the colour more brilliant.