Substituted Heterocyclic Methine Dyes

This invention relates to disperse dyes for the dyeing of synthetic fibers such as cellulose acetate, triacetate, polyamide and especially polyester and its blends, which have the general formula ##STR4## in which R.sub.1 and R.sub.2 may be the same or different and are selected from hydrogen, aryl, benzyl, cyclohexyl, and C.sub.1 -C.sub.6 alkyl which may be substituted by Cl, CN, OC.sub.2 H.sub.4 OC.sub.2 H.sub.5, C.sub.1 -C.sub.4 alkoxy, aryl, ##STR5## (in which the aryl, and the C.sub.1 -C.sub.10 alkyl of the preceding substituent, may be substituted by Cl, Br, CN, NO.sub.2, CO--alkyl, CO--aryl, alkoxy, aryloxy, CO--O--alkyl or CO--O--aryl), ##STR6## NHCONHPh, OCONHPh, phthalimido, succinimido or mercaptobenzthiazolyl, and R.sub.1 and R.sub.2 may form a 5- or 6-membered ring with the ##STR7## which ring may or may not contain a S, N, or O atom; R.sub.3 is H, Cl, Br, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy; R.sub.2 and R.sub.3 may form a 5 or 6 membered ring preferably substituted by 1-3 methyl groups; R.sub.4 is H, Cl, Br, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy; and R.sub.5 is selected from 3-pyridyl, 3-benzisothiazolyl, 2-benzothiazolyl, 2-benzoxazolyl, 2-quinoxalyl, 2-quinazolinonyl, 2-1,3,4-oxadiazolyl, 2-1,3,4-thiadiazolyl and 2-thienyl, which R.sub.5 heterocycles may be substituted by Cl, Br, NO.sub.2, CN, aryl, aryl substituted by Cl, Br, NO.sub.2 or CN, C.sub.1 -C.sub.4 alkyl or COOR.sub.6 wherein R.sub.6 is C.sub.1 -C.sub.4 alkyl or aryl.

The dyes produce yellow to scarlet shades on hydrophobic textile fiber including polyesters, polyamides and cellulose esters and show unexpected improvements in one or more of such properties as fastness to light, wash, ozone, gas such as oxides of nitrogen, perspiration, crock, sublimation, dyeability at unusually low energy levels to deep shades and exhibit excellent build, pH stability, bloom resistance, leveling, migration, dye bath exhaustion, dye transfer, heat stability on polyamide and the like, over such prior art as disclosed in U.S. Pat. Nos. 4,077,962; 4,016,191; 4,006,178; 3,917,604; 3,240,783; 3,247,211; 3,595,863; 3,453,280; 2,766,233; 2,850,520; and Japanese J7-4023-806.

The dyeing of the fiber with the dyestuffs according to the invention is appropriately carried out from an aqueous suspension in the presence of carriers between 80.degree. and 100.degree. C., in the absence of carriers at between 100.degree.-130.degree. C., or using the so-called thermofixing process at 180.degree.-230.degree. C. The printing of the materials can be carried out by steaming the goods, printed with the new dyestuffs, in the presence of a carrier at temperatures between 80.degree. and 110.degree. C., or in the absence of a carrier at 110.degree.-140.degree. C., or also by treating the goods which have been printed with the new dyestuffs, according to the thermofixing process at 180.degree.-230.degree. C.

This invention will be further illustrated by the following examples although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention.

4-Formyl N-ethyl-N-(.beta.-cyanoethyl) aniline (0.404 g, 0.002 mole) was dissolved in ethyl alcohol (10 ml). To this was added 5-chloro-benzoxazolyl-2-acetonitrile (0.385 g, 0.002 mole) and piperidine (0.1 ml) and the mixture was warmed on a steam bath for 15 min. After cooling overnight the orange crystalline product was collected by filtration and air dried. The dye was ball milled in the presence of a lignin sulphonate dispersing agent for 24 hours and the resulting dispersion was applied to polyester fiber by dyeing at 130.degree. for 1 hour. It gave a deep yellow dyeing of excellent color strength and fastness to light. Similar dyeings prepared in dyebaths buffered from pH 4-8 also gave high strength dyeings indicating the dye had excellent pH stability.

4-Formyl N-ethyl N-(2'-phthalimidoethyl) m-toluidine (1.68 g., 0.005 g. mole) was dissolved in ethyl alcohol (40 ml). To this was added 2-quinoxalyl acetonitrile (0.85 g., 0.005 g. mole) with stirring, and piperidine (0.2 ml) was added and the mixture left at room temperature overnight. The orange crystalline product was collected by filtration, washed with a little cold ethanol and dried. The dye was ball milled in the presence of a lignin sulphonate dispersing agent for 24 hours and the resulting dispersion was applied to polyester fibre by dyeing at 130.degree. for 1 hour. It gave a deep yellow dyeing of excellent color strength and fastness to light. Similar dyeings prepared in dyebaths buffered from pH 4-8 also gave high strength dyeings indicating the dye had excellent pH stability.

By application of the synthetic procedures outlined in Example 1, the following dyes were prepared. When applied by a procedure similar to the above dyeing description they give high strength dyeings on polyester textile fibers.

The following table gives further examples and specifies the heterocyclic aldehyde which is reacted with the methylene active cyano compound.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.