Carbazole containing benzopyrans

The present invention relates to novel benzopyrans which have a side chain in ring position 2, a process for their preparation and their use in pressure-sensitive or heat-sensitive recording systems.
We have found benzopyrans of the general formula I ##STR3## where R.sup.1 is unsubstituted or substituted C.sub.1 -C.sub.8 -alkyl, unsubstituted or substituted phenyl, C.sub.1 -C.sub.5 -alkoxy or halogen, X is a radical ##STR4## R.sup.2 is hydrogen or, together with R.sup.1, is C.sub.2 -or C.sub.3 -alkylene which is unsubstituted or substituted by C.sub.1 -C.sub.4 -alkyl, R.sup.3 is phenyl which is unsubstituted or substituted by C.sub.1 -C.sub.4 -alkyl (which in turn may be substituted by phenyl), cyclohexyl, halogen, C.sub.1 -C.sub.8 -alkoxy, C.sub.1 -C.sub.8 -mono- or dialkylamino (each of which in turn may be substituted by phenyl or chlorine), phenylamino (which in turn may be substituted by C.sub.1 -C.sub.8 -alkyl on the phenyl ring or on the nitrogen atom), pyrrolidino, piperidino or morpholino, and which furthermore may be substituted by C.sub.1 -C.sub.5 -alkyl, C.sub.1 -C.sub.5 -alkoxycarbonyl, C.sub.1 -C.sub.5 -dialkylaminocarbonyl, pyrrolidinocarbonyl, piperidinocarbonyl, morpholinocarbonyl, C.sub.1 -C.sub.8 -alkoxy or halogen; or is naphthyl which is unsubstituted or substituted by C.sub.1 -C.sub.4 -alkoxy; or is carbazol-3-yl or 1,2,3,4,4a,9a-hexahydrocarbazol-6yl, each of which may be substituted on the nitrogen atom by C.sub.1 -C.sub.5 -alkyl or benzyl, or is indol-3-yl, which may be substituted in ring position 1 and/or 2 by unsubstituted or phenyl-substituted C.sub.1 -C.sub.5 -alkyl; or is thiazol-5-yl which is substituted in ring position 2 by unsubstituted or phenyl-substituted C.sub.1 -C.sub.5 -mono- or dialkylamino, pyrrolidino, piperidino or morpholino and may be substituted in ring position 4 by C.sub.1 -C.sub.5 -alkyl, phenyl or chlorine, and R.sup.4 is hydroxyl, C.sub.1 -C.sub.5 -alkoxy, unsubstituted or substituted phenoxy, unsubstituted or substituted phenylsulfonyl, pyrrolidino, piperidino, morpholino or a radical of a CH-acidic compound, and the ring A may be fused to a benzo ring, may be substituted by C.sub.1 -C.sub.4 -alkyl, chlorine or bromine, or may be substituted in ring position 7 by C.sub.1 -C.sub.5 -mono- or dialkylamino (each of which in turn may be substituted by chlorine or phenyl), pyrrolidino, piperidino, morpholino, hydroxyl or C.sub.1 -C.sub.4 -alkoxy.
All alkyl groups occurring in the abovementioned radicals may be either straight-chain or branched.
In formula I, R.sup.1 is, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isoamyl, hexyl, heptyl, octyl, 2-ethylhexyl, phenyl which is unsubstituted or substituted by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or halogen, such as 4-methylphenyl, 2-methylphenyl, 4-ethylphenyl, 4-isopropylphenyl, 4-methoxyphenyl, 2-ethoxyphenyl, 4-chlorophenyl or 2,4-dichlorophenyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, fluorine, chlorine or bromine.
In formula I, R.sup.2 is, for example, hydrogen or, together with R.sup.1, is 1,2-ethylene, 1,2-propylene or 1,3-propylene.
In formula I, R.sup.3 is, for example, phenyl or, preferably, phenyl which is substituted in ring position 4 by methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, benzyl, 2-phenylethyl, cyclohexyl, fluorine, chlorine, bromine, methoxy, ethoxy, propoxy, isopropoxy, butoxy, pentyloxy, hexyloxy, 2-ethylhexyloxy, methylamino, ethylamino, isopropylamino, butylamino, 2-ethylhexylamino, benzylamino, 2-chloroethylamino, dimethylamino, diethylamino, dibutylamino, methylethylamino, di(2-ethylhexyl)-amino, anilino, 4-methylanilino, 4-ethylanilino, N-methylanilino, N-ethylanilino, pyrrolidino, piperidino or morpholino; or is, for example, 2,4-dimethylphenyl, 2-methoxycarbonyl-4-dimethylaminophenyl, 2-ethoxycarbonyl-4-dimethylaminophenyl, 2-dimethylaminocarbonyl-4-methoxyphenyl, 2-pyrrolidinocarbonyl-4-methylphenyl, 2-piperidinocarbonyl-4-dimethylaminophenyl, 2-morpholinocarbonyl-4-methylphenyl, 2,4-dimethoxyphenyl, 3,4-dimethoxyphenyl, 2-methoxy-4-dimethylaminophenyl, 2-methoxy-4-dibenzylaminophenyl, 2,4-dichlorophenyl, naphthyl, 4-methoxynaphthyl, carbazol-3-yl, N-methylcarbazol-3-yl, N-ethylcarbazol-3-yl, N-benzylcarbazol-3-yl, 1,2,3,4,4a,9a-hexahydrocarbazol-6-yl, N-methyl-1,2,3,4,4a,9a-hexahydrocarbazol-6-yl, N-ethyl-1,2,3,4,4a,9a-hexahydrocarbazol-6-yl, N-benzyl-1,2,3,4,4a,9a-hexahydrocarbazol-6-yl, indol-3-yl, 1-methylindol-3-yl, 1-ethylindol-3-yl, 1-benzylindol-3-yl, 1=(2-phenylethyl)indol-3-yl, 2-methylindol-3-yl, 1,2-dimethylindol-3-yl, 1-benzyl-2-methylindol-3-yl, 2-methylaminothiazol-5-yl, 2-dimethylaminothiazol-5-yl, 2-diethylaminothiazol-5-yl, 2-benzylaminothiazol-5-yl, 2-pyrrolidinothiazol-5-yl, 2-morpholinothiazol-5-yl, 4-methyl-2-dimethylaminothiazol-5-yl, 4-phenyl-2-benzylaminothiazol-5-yl or 4-chloro-2-piperidinothiazol-5-yl.
In formula I, R.sup.4 is, for example, hydroxyl, methoxy, ethoxy, propoxy, isopropoxy, sec-butoxy or pentyloxy; phenoxy which is unsubstituted or substituted by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or halogen, such as 2-methylphenoxy, 4-methylphenoxy, 3-methoxyphenoxy or 4-chlorophenoxy; phenylsulfonyl which is unsubstituted or substituted by C.sub.1 -C.sub.4 -alkyl or halogen, such as 4-methylphenylsulfonyl or 4-chlorophenylsulfonyl; pyrrolidino, piperidino or morpholino.
In formula I, R.sup.4 may furthermore be a radical of a CH-acidic compound, for example 2-(pyrrolidino, piperidino or morpholino)-cyclopent-1-en-1-yl or -cyclohex-1-en-1-yl; cyclohexane-1,3-dion-2-yl which is unsubstituted or monosubstituted or disubstituted in ring position 5 by C.sub.1 -C.sub.4 -alkyl, such as cyclohexane-1,3-dion-2-yl, 5-methylcyclohexane-1,3-dion-2-yl, 5-ethylcyclohexane-;b 1,3-dion-2-yl or 5,5-dimethylcyclohexane-1,3-dion-2-yl; benzoylmethyl; cyano; nitromethyl; 2,4,6-trihydroxypyrimid-5-yl; 1-phenyl-3-methylpyrazol-5-on-4-yl; 5-hydroxy-3,4-dichlorfuran-2-yloxy; or a radical ##STR5## where Y and Z are identical or different and independently of one another are each acetyl, benzoyl, C.sub.1 -C.sub.5 -alkoxycarbonyl or cyano, and, where Y is cyano, Z may furthermore be methyl, eg. bis-(acetyl-methyl, bis-(benzoyl)-methyl, bis-(methoxycarbonyl)-methyl, bis-(ethoxycarbonyl)-methyl, bis-(cyano)-methyl, acetyl-benzoyl-methyl, acetyl-methoxycarbonyl-methyl, benzoyl-ethoxycarbonyl-methyl, cyano-methoxycarbonyl-methyl or 1-cyanoeth-1-yl.
In formula I, the ring A may be substituted, for example, in ring position 6 or 8 by chlorine or bromine or in ring position 6 and 8 by chlorine. It may furthermore be substituted in ring position 7 by, for example, methyl, ethyl, propyl, isopropyl, butyl, hydroxyl, methoxy, ethoxy, isopropoxy, methylamino, ethylamino, propylamino, isopropylamino, butylamino, benzylamino, 2-chloroethylamino, dimethylamino, diethylamino, dibutylamino, dibenzylamino, methylethylamino, pyrrolidino, piperidino or morpholino. It may also be benzofused, for example as follows: ##STR6##
Preferred benzopyrans of the formula I are those in which R.sup.1 is C.sub.1 -C.sub.5 -alkyl, R.sup.2 is hydrogen, R.sup.3 is carbazol-3-yl or unsubstituted or substituted phenyl and R.sup.4 is a radical ##STR7##
The novel benzopyrans are advantageously obtained if a benzopyrylium compound of the formula II ##STR8## where R.sup.1 and the ring A have the above meanings and Y.sup..crclbar. is an anion, is reacted with an aldehyde of the formula III
R.sup.3 --CHO (III)
where R.sup.3 has the above meanings, in a molar ratio of from 1:0.8 to 1:1.2, in the presence of an inert solvent at from 20.degree. to 120.degree. C., preferably from 40.degree. to 80.degree. C., and, in a subsequent stage, the resulting dye salt of the formula IV ##STR9## where R.sup.1, R.sup.3, Y.sup..crclbar. and the ring A have the above meanings, is reacted with a compound of the formula V
R.sup.4 --H (V)
where R.sup.4 has the above meanings, in a molar ratio of from 1:1.1 to 1:2, in the presence of an inert solvent and of a base at from 20.degree. to 120.degree. C., preferably from 40.degree. to 80.degree. C.
Examples of suitable anions Y.sup..crclbar. are trichlorozincate, tetrachloroferrate(III), bisulfate, nitrate or halide, such as chloride or bromide. Trichlorozincate and tetrachloroferrate (III) are particularly preferred.
Examples of advantageously inert solvents are methanol, ethanol, propanol, isopropanol, butanol and isobutanol. Mixtures of these alcohols with aromatic hydrocarbons, such as toluene or xylene, may also be used as the reaction medium.
Examples of suitable bases for the reaction of the dye salt IV with the compound V are alkali metal and alkaline earth metal carbonates, such as sodium carbonate, potassium carbonate, magnesium carbonate or calcium carbonate, alkaline earth metal oxides, such as magnesium oxide or calcium oxide, and alkali metal alkanolates, such as sodium or potassium methylate, ethylate or butylate. In general, from 1 to 3 moles of base are added per mole of dye salt.
The benzopyrylium salts II, aldehydes III and compounds IV which are required for the novel process are known.
The benzopyrans according to the invention are pale or colorless compounds whose solutions in inert organic solvents, in contact with electron acceptors, give dyeings in yellow, orange, red or blue hues, depending on the substitution of the benzopyran. Examples of electron acceptors are carboxylic acids, mineral acids, kaolin, bentonite, activated clay, aluminum silicate, attapulgite or any clay, acidic polymeric materials, such as condensates based on phenol (and/or phenolsulfonic acids) and formaldehyde, as well as metal oxides or salts, such as zinc oxide, alumina, zinc chloride, iron stearate and cobalt naphthenate.
Because of these propertiesm, the novel compounds of the formula I are useful as dye precursors in pressure-sensitive and heat-sensitive recording materials.
For use in pressure-sensitive systems the novel benzopyrans are advantageously enclosed in microcapsules, in the form of solutions in organic solvents, eg. chloroparaffins, partially hydrogenated di- or terphenyl, alkylbenzenes, alkylnaphthalenes, alkylated dibenzylbenzenes, liquid paraffin, mineral oil or conventional lower-boiling solvents, such as xylene or toluene, and the carrier, eg. paper, is coated with these microcapsules. When the microcapsules are subjected to pressure and are in contact with electron acceptors, dye formation then takes place at the pressure point.
Suitable processes for the preparation of microcapsules are disclosed in, for example, U.S.-A-2 800, 457, U.S.-A-2 800,458, DE-A-2 119 933 and EP-A-26 914. It is also possible for the novel compounds to be finely dispersed in wax or oil/wax mixtures by the method described in U.S.-A-3 103,404, and carriers, such as films or paper, to be coated with these mixtures. The resulting pressure-sensitive materials are suitable for copying onto papers coated with electron acceptors, and can be removed after use, like carbon paper.
The novel benzopyrans can also be used as dye precursors in heat-sensitive recording materials which contain a binder, a dye precursor and an electron acceptor on a carrier. The structure of such heat-sensitive recording materials and the composition of the layers which produce the color under the effective heat are known (for example, DE-A-2 228 581 and DE-A-2 110 854), as are the processes and apparatuses which are used to produce the dye.

The examples which follow illustrate the invention.
EXAMPLE 1
(a) Synthesis of the Dye Salt
331 g (1 mole) of 2,3-dimethylbenzopyrylium trichlorozincate and 149 g (1 mole) of 4-dimethylaminobenzaldehyde in 1,500 ml of methanol were refluxed for 4.5 hours. After the mixture had cooled, the precipitated dye was filtered off under suction and washed with methanol.
Yield: 400 g (86.6% of theory). mp.: 242.degree.-244.degree. C.
The dye salt of the formula ##STR10## is obtained.
(b) Synthesis of the Dye Precursor
46 g (0.1 mole) of the dye salt prepared under (a) and 20 g of benzoylacetone (0.13 mole) in 500 ml of methanol were stirred in the presence of 22 g (0.2 mole) of sodium carbonate at 45.degree. C. The reaction mixture was then added to a mixture of 1,600 ml of toluene and 1,600 ml of water. The organic phase was separated off, treated with active carbon and filtered, and the filtrate was evaporated down. 500 ml of methanol were added, and the precipitate which formed was then filtered off under suction, washed with 200 ml of methanol and dried at 60.degree. C. under reduced pressure.
Yield: 34 g (76%). mp.: 165.degree.-167.degree. C.
A dye precursor of the formula ##STR11## was obtained.
The components of the formula ##STR12## which are listed in Table 1 can be obtained in a similar manner.
TABLE 1______________________________________ ColorExample R.sup.4 Mp. [.degree.C.] or .lambda..sub.max [nm]______________________________________ ##STR13## 270-272 blue3 CH(COC.sub.6 H.sub.5).sub.2 193-195 628.94 CH(CN).sub.2 194-196 628.95 CH.sub.2NO.sub.2 156-158 blue______________________________________
EXAMPLE 6
(a) Synthesis of the Dye Salt
331 g (1 mole) of 2,3-dimethylbenzopyrylium trichlorozincate and 223 g (1 mole) of N-ethylcarbazole-3-aldehyde in 2,600 ml of methanol saturated with HCl are refluxed for 3 hours. After the mixture had cooled, the precipitated dye was filtered off under suction and washed with methanol.
Yield: 453 g (84.6% of theory). mp.: 240.degree.-242.degree. C.
A dye salt of the formula ##STR14## was obtained.
(b) Synthesis of the Dye Precursor
16 g (0.03 mole) of the dye salt prepared under (a) and 5 g (0.038 mole) of ethyl acetoacetate in 250 ml of methanol were stirred in the presence of 7 g (0.066 mole) of sodium carbonate at 45.degree. C. The reaction mixture was then added to a mixture of 500 ml of toluene and 500 ml of water. The organic phase was separated off, treated with active carbon and filtered, and the filtrate was evaporated down. After the addition of 250 ml of methanol, the precipitate formed was filtered off under suction, washed with 70 ml of methanol and dried at 60.degree. C. under reduced pressure.
Yield: 10 g (67.6% of theory. mp.: 132.degree.-134.degree. C.
A dye precursor of the formula ##STR15## was obtained.
The components of the formula ##STR16## which are listed in Table 2 can be obtained in a similar manner.
TABLE 2______________________________________ ColorExample R.sup.4 Mp. [.degree.C.] or .sub.max [nm]______________________________________ ##STR17## 156-158 blue8 CH(COCH.sub.3).sub.2 147-149 607.49 ##STR18## 126-128 606.910 OH 154-157 606.411 CH(COOC.sub.2 H.sub.5).sub.2 182-184 pale blue12 CH(COC.sub.6 H.sub.5).sub.2 142-144 606.913 CH(CN).sub.2 241-243 607.414 ##STR19## 193-195 607.915 ##STR20## 187-189 607.916 CH.sub.2NO.sub.2 154-156 605.417 CH(COOCH.sub.3).sub.2______________________________________
The dye precursors of the formula ##STR21## which are listed in Table 3 can be obtained similarly to Examples 1 to 6.
TABLE 3__________________________________________________________________________Example R.sup.1 R.sup.3 R.sup.4 Mp. [.degree.C.] Color or .lambda..sub.max__________________________________________________________________________ [nm]18 CH.sub.3 ##STR22## ##STR23## 146-148 blue19 CH.sub.3 ##STR24## CH(COCH.sub.3).sub.2 142-144 pale lime green20 CH.sub.3 ##STR25## CH(COC.sub.6 H.sub.5).sub.2 144-146 642.421 CH.sub.3 ##STR26## ##STR27## 203-205 blue21 CH.sub.3 ##STR28## ##STR29## 203-205 blue22 CH.sub.3 ##STR30## CH(COCH.sub.3).sub.2 170-172 blue23 CH.sub.3 ##STR31## ##STR32## 144-148 green24 CH.sub.3 ##STR33## CH(COC.sub.6 H.sub.5).sub.2 189 632.425 CH.sub.3 ##STR34## ##STR35## 184-186 blue26 CH.sub.3 ##STR36## ##STR37## oil 672.9/631.427 CH.sub.3 ##STR38## ##STR39## 128-130 671.9/630.928 CH.sub.3 ##STR40## CH(COC.sub.6 H.sub.5).sub.2 132-134 672.9/630.429 CH.sub.3 ##STR41## CH(CN).sub.2 203-205 blue30 CH.sub.3 ##STR42## ##STR43## oil blue31 CH.sub.3 ##STR44## ##STR45## oil blue32 CH.sub.3 ##STR46## ##STR47## 154-156 blue33 CH.sub.3 ##STR48## OH 195 blue34 CH.sub.3 ##STR49## CH(COC.sub.6 H.sub.5).sub.2 178-180 519.335 CH.sub.3 ##STR50## CH(COCH.sub.3).sub.236 CH.sub.3 ##STR51## ##STR52##37 CH.sub.3 ##STR53## CH(COCH.sub.3).sub.2 165 reddish violet38 CH.sub.3 ##STR54## ##STR55## reddish violet39 CH.sub.3 ##STR56## CH(COCH.sub.3).sub.2 98-102 523.840 CH.sub.3 ##STR57## ##STR58## 159-160 reddish violet41 CH.sub.3 ##STR59## OH 136-140 pale red42 CH.sub.3 ##STR60## ##STR61## oil 542.843 CH.sub.3 ##STR62## OH 120-124 reddish violet44 CH.sub.3 ##STR63## CH(COCH.sub.3).sub.2 violet45 CH.sub.3 ##STR64## OH 210-216 violet46 CH.sub.3 ##STR65## CH(COCH.sub.3).sub.2 141-145 pink47 CH.sub.3 ##STR66## CH(COCH.sub.3).sub.2 oil orange48 CH.sub.3 ##STR67## OH oil orange49 CH.sub.3 ##STR68## CH(COCH.sub.3).sub.2 118 yellow50 CH.sub.3 ##STR69## ##STR70## 155 yellow51 CH.sub.3 ##STR71## ##STR72## 163-168 647.952 CH.sub.3 ##STR73## CH(COCH.sub.3).sub.2 oil blue53 CH.sub.3 ##STR74## ##STR75## oil blue54 CH.sub.3 ##STR76## ##STR77## 181-183 blue55 CH.sub.3 ##STR78## CH(COCH.sub.3).sub.2 130-132 blue56 CH.sub.3 ##STR79## CH(COC.sub.2 H.sub.5).sub.2 166-168 644.957 CH.sub.3 ##STR80## CH(CN).sub.2 221-223 643.958 CH.sub.3 ##STR81## CH(COCH.sub.3).sub.2 198-200 573.359 CH.sub.3 ##STR82## ##STR83## 134-137 violet60 CH.sub.3 ##STR84## ##STR85## blue61 CH.sub.3 ##STR86## ##STR87## 204-207 violet 549.3/583.862 CH.sub.3 ##STR88## ##STR89## oil blue63 CH.sub.3 ##STR90## ##STR91## oil blue64 CH.sub.3 ##STR92## ##STR93## oil blue65 CH.sub.3 ##STR94## OH 215 violet66 C.sub.2 H.sub.5 ##STR95## ##STR96## 148-150 blue67 C.sub.2 H.sub.5 ##STR97## CH(COCH.sub.3).sub.2 128-130 blue68 C.sub.2 H.sub.5 ##STR98## ##STR99## 166-168 blue69 C.sub.2 H.sub.5 ##STR100## CH(COCH.sub.3).sub.2 131-135 blue70 CH(CH.sub.3).sub.2 ##STR101## ##STR102## 157-159 blue71 CH(CH.sub.3).sub.2 ##STR103## CH(COCH.sub.3).sub.2 133-135 blue72 CH(CH.sub.3).sub.2 ##STR104## ##STR105## 153-155 633.473 CH(CH.sub.3).sub.2 ##STR106## CH(CN).sub.2 195-197 633.474 CH(CH.sub.3).sub.2 ##STR107## ##STR108## 129-131 sky blue75 CH(CH.sub.3).sub.2 ##STR109## CH(COCH.sub. 3).sub.2 148-150 sky blue76 CH(CH.sub.3).sub.2 ##STR110## CH(COCH.sub.3).sub.2 164-168 blue77 CH(CH.sub.3).sub.2 ##STR111## ##STR112## 118-120 605.478 CH(CH.sub.3).sub.2 ##STR113## CH(COC.sub.6 H.sub.5).sub.2 143-145 606.479 CH(CH.sub.3).sub.2 ##STR114## ##STR115## 141-143 pale blue80 CH.sub.2CH(CH.sub.3).sub.2 ##STR116## ##STR117## 140-142 blue81 CH.sub.2CH(CH.sub.3).sub.2 ##STR118## CH(COCH.sub.3).sub.2 oil blue82 CH.sub.2CH(CH.sub.3).sub.2 ##STR119## ##STR120## 163-165 pale blue83 CH.sub.2CH(CH.sub.3).sub.2 ##STR121## CH(COCH.sub.3).sub.2 oil greenish blue84 CH.sub.2CH(CH.sub.3).sub.2 ##STR122## CH(COCH.sub.3).sub.2 oil blue to bluish green85 ##STR123## ##STR124## CH(COCH.sub.3).sub.2 oil blue86 ##STR125## ##STR126## ##STR127## oil blue87 ##STR128## ##STR129## CH(COCH.sub.3).sub.2 oil blue88 ##STR130## ##STR131## ##STR132## oil blue89 ##STR133## ##STR134## ##STR135## 179-181 greenish blue90 ##STR136## ##STR137## CH(COCH.sub.3).sub.2 oil greenish blue91 ##STR138## ##STR139## OCH.sub.3 greenish blue92 ##STR140## ##STR141## ##STR142## oil greenish blue93 ##STR143## ##STR144## ##STR145## 180-182 blue94 ##STR146## ##STR147## ##STR148## 198-200 blue95 ##STR149## ##STR150## CH(COCH.sub.3).sub.2 162-164 blue96 OCH.sub.3 ##STR151## ##STR152## 182 blue97 OCH.sub.3 ##STR153## CH(COCH.sub.3).sub.2 168-170 blue98 OCH.sub.3 ##STR154## ##STR155## 100-112 blue99 OCH.sub.3 ##STR156## CH(COCH.sub.3).sub.2 oil blue100 OCH.sub.3 ##STR157## CH(COCH.sub.3).sub.2 183-185 blue__________________________________________________________________________
EXAMPLE 101
The following dye precursor was obtained similarly to Example 1: ##STR158##
EXAMPLE 102
(a) Synthesis of the Dye Salt
24 g (0.1 mole) of bis-(4-formylphenyl)-methylamine and 66 g (0.2 mole) of 2,3-dimethylbenzopyrylium trichlorozincate in 200 ml of methanol were refluxed for 3 hours, 200 ml of methylglycol were added and refluxing was then continued for a further 1/2 hour. The mixture was cooled, and the solvent was then separated off from the precipitated dye.
Yield: 66 g. mp.: 110.degree. C.
(b) Synthesis of the Dye Precursor
26 g (0.03 mole) of the dye salt prepared under (a) and 8 g (0.08 mole) of acetylacetone were heated at 50.degree. C. for 3 hours in the presence of 14 g (0.13 mole) of sodium carbonate in a mixture of 200 ml of methanol and 100 ml of toluene. The reaction mixture was then added to a mixture of 500 ml of toluene and 500 ml of water. The organic phase was separated off, treated with active carbon and filtered, and the filtrate was evaporated down. The residue was added dropwise to ice-cooled methanol, and the precipitate formed was filtered off under suction at 0.degree. C.
Yield: 7 g. mp.: 166.degree.-168.degree. C.
A dye precursor of the formula ##STR159## was obtained.
EXAMPLE 103
The dye salt prepared in Example 102a was used and the following dye precursor was obtained by a method similar to that described in Example 102b: ##STR160##
EXAMPLE 104
(a) Synthesis of the Dye Salt
66 g (0.2 mole) of 2,3-dimethylbenzopyrylium trichlorozincate and 33 g (0.1 mole) of ethylenebis-[N-ethyl-N-(4-formylphenyl)]-amine in 400 ml of methanol were refluxed for 4 hours. After the mixture had cooled, the precipitated dye was filtered off under suction and washed with methanol.
Yield: 82 g. mp.: 255.degree.-260.degree. C.
(b) Synthesis of the Dye Precursor
28.5 g (0.03 mole) of the dye salt prepared under (a) and 13 g (0.08 mole) of benzoylacetone were stirred under reflux for 7 hours in the presence of 15 g (0.14 mole) of sodium carbonate in a mixture of 350 ml of methanol and 100 ml of toluene. The reaction mixture was then added to a mixture of 500 ml of toluene and 500 ml of water. The organic phase was separated off, treated with active carbon and filtered, and the filtrate was evaporated down. The residue was diluted with methylglycol, and methanol was added. The precipitate formed was filtered off under suction, washed with methanol and dried at 60.degree. C. under reduced pressure.
Yield: 7 g. mp.: 132.degree.-140.degree. C.
A dye precursor of the formula ##STR161## was obtained.
EXAMPLE 105
(a) Synthesis of the Dye Salt
21.9 g (0.05 mole) of 2-cyclohexylidene-2,3,4,5-tetrahydroxanthylium trichlorozincate and 7.2 g (0.05 mole) of indoline-3-carbaldehyde in 320 ml of n-butanol were refluxed for one hour. The dye precipitated after the mixture had been cooled was filtered off under suction.
Yield: 21 g. mp.: 243.degree.-245.degree. C.
A dye salt of the formula ##STR162## was obtained.
(b) Synthesis of the Dye Precursor
9.7 g (0.02 mole) of the dye salt prepared under (a) and 2.7 g (0.027 mole) of acetylacetone in 100 ml of methanol were stirred in the presence of 4.7 g (0.044 mole) of sodium carbonate for 4 hours at 45.degree. C. The reaction mixture was then added to a mixture of 300 ml of toluene and 300 ml of water. The organic phase was separated off, treated with active carbon and filtered, and the filtrate was evaporated down. After the addition of 100 ml of methanol, the precipitate formed was filtered off under suction, washed with 40 ml of methanol and dried at 60.degree. C. under reduced pressure.
Yield: 5 g. mp.: 162.degree.-170.degree. C.
A dye precursor of the formula ##STR163## was obtained.

Carbazole containing benzopyrans

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