US3678042A - Process for the manufacture of aryloxazoles - Google Patents

Process for the manufacture of aryloxazoles Download PDF

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US3678042A
US3678042A US862442A US3678042DA US3678042A US 3678042 A US3678042 A US 3678042A US 862442 A US862442 A US 862442A US 3678042D A US3678042D A US 3678042DA US 3678042 A US3678042 A US 3678042A
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carbon atoms
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Erich Matter
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BASF Schweiz AG
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D263/00—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings
    • C07D263/52—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems
    • C07D263/54—Benzoxazoles; Hydrogenated benzoxazoles
    • C07D263/56—Benzoxazoles; Hydrogenated benzoxazoles with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached in position 2
    • C07D263/57—Aryl or substituted aryl radicals
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D263/00—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings
    • C07D263/52—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems
    • C07D263/62—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems having two or more ring systems containing condensed 1,3-oxazole rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D263/00—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings
    • C07D263/52—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems
    • C07D263/62—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems having two or more ring systems containing condensed 1,3-oxazole rings
    • C07D263/64—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems having two or more ring systems containing condensed 1,3-oxazole rings linked in positions 2 and 2' by chains containing six-membered aromatic rings or ring systems containing such rings

Definitions

  • ABSTRACT The invention provides a new process for preparation of Oct. 7, 1968 Switzerland ..14932/68 aryloxazoles y g closure reaction between an y y amino benzene and a carboxylic acid.
  • the improvement over [52] U.S. Cl. ..260/240 CA, 260/307 D known processes consists in performing the reaction in a [51] [Ill- Cl. ..C07tl 85/48 step heating procedure and in the presence of small amounts [58] Field of Search ..260/240 D, 307D f ifi i f r bl non-aromatic cyclic nitrogen bases, having a P -value of at least 7.
  • References Cited are valuable optical whitening agents.
  • aryloxazoles that is to say oxazoles of which the two adjacent carbon atoms of the oxazole ring at the same time are ring members of an aromatic-carbocyclic six-membered ring, are appropriately manufactured from o-hydroxyaminoaryl compounds and carboxylic acids.
  • This process is characterized in that the reaction of the reagents is carried out in the presence of less than stoichiometric amounts of a nitrogen base from the group of (a) secondary or tertiary, cyclic, nonaromatic nitrogen bases or (b) the primary or secondary aminobenzenes or (c) the primary or secondary, aliphatic or cycloaliphatic, amines or (d) basic nitrogen compounds which contain the atom grouping of formula IIIII C N/ ⁇ N at least once, as well as in the presence of small amounts of boric acid, by first heating the reaction mixture to temperatures of at least 150 C and then, with gradual increase of temperature, to temperatures of at least 200 C.
  • a nitrogen base from the group of (a) secondary or tertiary, cyclic, nonaromatic nitrogen bases or (b) the primary or secondary aminobenzenes or (c) the primary or secondary, aliphatic or cycloaliphatic, amines or (d) basic nitrogen compounds which contain the atom grouping of
  • a minimum temperature of 150 C for the first reaction stage denotes a temperature in the range of between 150 and about 200 C, whilst the upper limit for the temperature range applicable from 200 C onwards is set by the incipient decomposition of the reagents and reactionproducts.
  • One embodiment of this process consists of carrying out the reaction of the reagents in the presence of less than stoichiometric amounts of a nitrogen base from the group of the (a) secondary or tertiary, cyclic, non-aromatic nitrogen bases, or (b) the primary or secondary aminobenzenes, or (c) the primary or secondary aliphatic or cycloaliphatic amines, as well as small amounts of boric acid, by heating the reaction mixture initially to temperatures of at least 150 C and then, with gradual increase to temperatures of at least 200 C.
  • a nitrogen base from the group of the (a) secondary or tertiary, cyclic, non-aromatic nitrogen bases, or (b) the primary or secondary aminobenzenes, or (c) the primary or secondary aliphatic or cycloaliphatic amines, as well as small amounts of boric acid
  • one of the essential characteristics of this process is the use of selected nitrogen bases, whilst another criterion is the use, connected therewith, of less than stoichiometric amounts of these nitrogen bases.
  • possible amounts of nitrogen base are quite generally those lying between, say, 0.05 and 20, preferably 0.5 to 10, percent by weight, relative to aminophenol to be employed.
  • significantly lower amounts of nitrogen base are normally employed, since the nitrogen base evidently possesses a catalytic effect.
  • larger amounts are, within the framework of the above-mentioned limits, without harmful effect on the course of the reaction, they are normally superfluous and uneconomical.
  • nitrogen bases with a pK-value of at least 7 which are preferentially to be employed.
  • the reaction defined above in the presence of such nitrogen bases as belong to the group of the (a) secondary or tertiary, cyclic, non-aromatic, S-membered to 8-membered nitrogen bases containing one to two ring nitrogen atoms, or the (b) primary or secondary aminobenzenes or the (c) primary or secondary aliphatic amines with one to 12 carbon atoms and one to three amino groups.
  • nitrogen bases of the nature defined which have a pK-value of at least 7 (measured in ethylene glycol monomethyl ether/water).
  • the especially preferred process is to be defined in that according to it (1) a carboxylic acid from the series of the (i) dicarboxylic acids of benzene, naphthalene, stilbene, thiophene or furane, (ii) monocarboxylic acids of benzene or diphenyl, or (iii) of the aliphatic dicarboxylic acids having a carbon atom chain of 4 carbon atoms, is reacted with (2) a hydroxyarylamino compound of formula wherein R denotes the phenyl group or a residue C I-1 and occupies the positions 4 or 5, and n represents an integer from 1 to 5, in the presence (3) of a nitrogen base having a pK-value of at least 7, from the series of the (x) secondary or tertiary, cyclic, non-aromatic nitrogen bases containing one to two rings with five or six ring members and one to two ring nitrogen atoms
  • secondary or tertiary cyclic non-aromatic nitrogen bases are to be understood as compounds of which the secondary or tertiary nitrogen atoms, respectively, are present as ring members.
  • these non-aromatic nitrogen-heterocyclic compounds possess six ring members, but it is also entirely possible to employ compounds containing five, seven and eight ring members (for example bicyclic types). Furthermore one is usually dealing with compounds with one to two ring nitrogen atoms.
  • S-membered nitrogen bases of this nature are for example pyrrolidine, pyrazolidine, imidazolidine and its N-alkyl derivatives, and typical representatives of 6-membered nitrogen bases are the piperidines and piperazines as well as their N- alkyl derivatives, and also morpholine types.
  • the bicyclic types such as for example tetrahydroquinoline or bicyclic endoalkyl types such as quinuclidine and l,4-diazabicyclo-[2,2,2]- octane should be mentioned as examples.
  • Primary and secondary aminobenzenes can in principle be used, though they produce lower yields because of their pK- value being low in most cases. They are represented by bases such as aniline, toluidines, xylidines, phenylenediamines and their N-alkyl derivatives and compounds of analogous structure. in general one is here dealing with monoamines or diamines.
  • alkylamines straight-chain or branched with one to 12 carbon atoms and one to three amino groups of primary or secondary nature are preferentially used.
  • polyalkylenepolyamines for example diethylenetriamine or triethylenetetramine
  • aliphatic amines with hydroxyl groups for diethanolamine
  • alkoxy groups for diethanolamine
  • dialkylaminoalkylamines dialkylaminoalkylamines
  • cycloaliphatic amines there should here be understood those of which the amino group is bonded to a cycloaliphatic ring (for example cyclohexylamine).
  • the reaction according to the present process inherently takes place in two stages, that is to say condensation to give the acyl compound first occurs, and a ring closing reaction occurs in a second stage. Accordingly, the reaction mixture is first heated to temperatures of at least 150 C to about 200 C and is only thereafter (after a certain dwell time, depending on the nature of the reagents) brought to the minimum temperature of about 200 C required for the ring closing reaction, with the temperature being raised slowly.
  • the practical working range for the ring closing reaction stage is about 200 to 260 C, but it is entirely possible to exceed 260 C if the components are sufficiently heat-stable.
  • aliphatic carboxylic acids are used as starting substances, they contain two carboxylic acid grOups and at least four carbon atoms.
  • the bridge member between the two carboxylic acid groups can be a branched or unbranched, saturated or unsaturated, aliphatic hydrocarbon residue. This residue can however further contain substituents, for example halogen atoms such as chlorine, amino groups, alkoxy groups such as methoxy and especially hydroxyl groups.
  • substituents for example halogen atoms such as chlorine, amino groups, alkoxy groups such as methoxy and especially hydroxyl groups.
  • aliphatic dicarboxylic acids adipic acid, dichlorosuccinic acid, tartaric acid, aspartic acid, thiomalic acid, but especially succinic acid, fumaric acid and malic acid may be mentioned.
  • bridge member between the two carboxylic acid groups can also occur on carrying out the present process, for example splitting off of a further molecule of water from tartaric acid and malic acid or splitting off of ammonia from aspartic acid, whereby carbon-carbon double bonds are produced.
  • the process according to the invention is particularly valuable for the reaction of cyclic-aromatic carboxylic acids.
  • the ring systems can contain one or two carboxylic acid groups and two or preferably one carbocyclic or heterocyclic ring.
  • Carbocyclic rings are aromatic, as is the case for naphthalene-, diphenyland benzene-mono-carboxylic and dicarboxylic acids.
  • Heterocyclic rings preferably contain five ring members, namely 4 carbon atoms and an oxygen or sulphur atom.
  • Monocyclic benzene-, furaneor thiophenecarboxylic acids can especially be used.
  • heterocyclic rings and above all the aromatic carbocyclic rings can, additionally to the carboxylic acid groups, contain yet further substituents, for example halogen atoms such as bromine or chlorine, alkyl groups with one to four carbon atoms such as methyl, ethyl,
  • a preferred embodiment of the present invention consists in reacting a carboxylic acid component which represents a carboxylic acid, containing one to two carboxyl groups, of benzene, diphenyl, naphthalene, stilbene, styrene, thiophene or furane, or the analogues of these carboxylic acids containing one to three alkyl groups having one to four carbon atoms each, or an aliphatic dicarboxylic acid containing 4 carbon atoms, in approximately equivalent amount with an o-hydroxyaminophenol which can optionally be substituted by one to three alkyl groups with one to 18 carbon atoms, an alkoxy group with one to four carbon atoms, a carbalkoxy group with one to 12 carbon atoms, a halogen atom or a phenyl group.
  • a carboxylic acid component which represents a carboxylic acid, containing one to two carboxyl groups, of benzene, diphenyl, naphthal
  • aromatic-cyclic carboxylic acids which are possible starting materials there may be mentioned: naphthalene-lor -2-carboxylic acid, naphthalene-1,4- or l,5-dicarboxylic acid, diphenyl-4,4-dicarboxylic acid, stilbene-4,4-dicarboxylic acid, cinnamic acid, benzene carboxylic acid, 3- or preferably 4-methylbenzenecarboxylic acid, benzene-1,3- or preferably -1,4-dicarboxylic acid, furane-2- carboxylic acid, thiophene-Z-carboxylic acid, 3,4- dimethylthiophene-2,5-dicarboxylic acid, 3,4-diphenylthiophene-2,5-dicarboxylic acid, diphenyl-4-carboxylic acid, 5- phenyl-thiophene-Z-carboxylic acid and furane-2,5-dicarboxylic acid
  • the present process requires hydroxyaminoaryl compounds which contain the hydroxyl group and the (primary) amino group in an adjacent position to one another.
  • Possible substances are for example 1,2- or 2,l-hydroxyaminonaphthalenes or preferably o-hydroxyaminobenzenes which may contain yet further substituents, for example a halogen atom such as chlorine, an alkoxy group such as methoxy or ethoxy, a phenyl group, an alkyl group such as methyl, ethyl, isopropyl, tertiary butyl or 1,1,15,3- tetramethylbutyl, and also two methyl groups.
  • Preferred substances are o-hydroxyaminobenzene which does not contain any further substituents, and o-hydroxyaminobenzenes which as further substituents contain one to two alkyl groups, an alkoxy group, a halogen atom or a phenyl group.
  • Important substances amongst these are the o-hydroxyaminobenzenes of formula (I) [see above], wherein, in this formula, the phenyl group representing R is preferably in position 5, whilst the group -(C,, ,H is preferably in position 4, that is to say hydroxyaminobenzenes of formulas l a) no (lb) are predominantly employed.
  • the reaction according to the present process is carried out in a diluent which as such must be liquid at the temperatures of the entire process and which does not participate in the reaction. At the same time it is however in no way necessary for all the products occuning in the reaction, that is to say the reagents used as starting substances, intermediate stages and final substances, to be largely or even completely dissolved.
  • the carboxylic acid amides which as a rule are formed as an intermediate can be sparingly soluble to practically insoluble in such a diluent without this having a disadvantageous effect.
  • the diluent should be present also at the high temperature at the end of the course of the reaction, it is advisable to use such an inert organic solvent for diluting the reaction mixture as has a boiling point of at least 200 C under normal pressure. Admittedly it is also possible to use a diluent or solvent boiling at lower temperatures at the start of the reaction, to allow this to distil off and to replace it at the correct time by a higher-boiling diluent or solvent, and water can even be used as the first diluent; however, economic reasons alone as a rule suggest working from the start with a high-boiling diluent which does not have to be replaced or renewed.
  • tetrahydronaphthalene mixtures of diphenyl and diphenyl-ether and especially trichlorobenzenes
  • trichlorobenzene mixtures such as are commercially available can also be used without difficulty.
  • the reaction is preferably carried out in the presence of a diluent which represents a halogenobenzene, preferably a trichlorobenzene, alkylbenzene, halogenated alkylbenzene, partially hydrogenated naphthalene or chlorinated naphthalene, which is liquid at room temperature and boils at not less than 200 C, or diphenylether or diphenyl.
  • a diluent which represents a halogenobenzene, preferably a trichlorobenzene, alkylbenzene, halogenated alkylbenzene, partially hydrogenated naphthalene or chlorinated naphthalene, which is liquid at room temperature and boils at not
  • the catalyst for splitting off water is employed in the usual amounts, that is to say about 0.5 to percent of boric acid, calculated relative to the amount by weight of the condensation components.
  • the nitrogen base and the carboxylic acid are first of all allowed to act on one another.
  • the base and the carboxylic acid can first of all be stirred with one another in the diluent, the hydroxyaminoaryl compound and the catalyst for splitting off water added, and the mixture then slowly heated further until the acid amide is first formed and thereafter ring closure takes place at an even higher temperature.
  • a simpler and particularly advantageous procedure is first to warm a mixture which has been obtained by combining the nitrogen base with a carboxylic acid of the indicated composition and a hydroxyaminoaryl compound of the indicated composition in a liquid diluent to temperatures of 150 to 200 C until approximately one molecule of water has been split off per molecule of hydroxyaminoaryl compound, and then to complete the reaction by heating to even higher temperatures, up to about 260 C, with water being continuously removed by distillation.
  • antioxidants such as for example amylphenol has proved particularly advantageous. This not only increases the yield but also greatly represses the formation of by-products which act as fluorescence extinguishers, that is to say increases the purity of the final products.
  • the carboxylic acid amide is formed in the first stage of the present process and the oxazole in the second stage.
  • the minimum temperature at which the second stage takes place can show certain differences from case to case within the specified limits. It is advisable to allow the two reaction stages to take place successively, that is to say not to warm the mixture beforehand to the ring closing temperature before the carboxylic acid amide has substantially formed.
  • the oxazoles are obtained in very the present process.
  • the product can be dissolved in a six-fold amount of trichlorobenzene, treated at C with an adsorbent, clarified by filtration and concentrated.
  • the pale yellow crystals, having a melting point of 223 C, are completely precipitated by adding isopropanol.
  • the yield is 96.3 percent, and when using only 1 g of N-methylpiperidine a yield of 95.4 percent is achieved.
  • EXAMPLE 6 2,5-Di-[benzoxazolyl-(2')]-thiophene A mixture of 600 g of trichlorobenzene, 220 g of l-hydroxy- 2-aminobenzene, 172 g of 2,S-thiophenedicarboxylic acid, 6 g of boric acid and 3 g of ethylethanolamine is heated with exclusion of air, as in the previous examples. The 2,5-di- [benzoxazolyl-(2)]-thiophene is obtained in a yield of 301 g or 94.6 percent of theory. Melting point 220 C. If 3 g of diethylamine are used as the amine additive, a yield of 95.3 percent of theory is obtained.
  • EXAMPLE 7 2,5-Di-[benzoxazolyl-(2)]-thiophene A mixture of 600 g of trichlorobenzene, 218 g of l-hydroxy- 2-aminobenzene, 173.5 g of2,5-thiophenedicarboxylic acid, 6 g of boric acid and 3 g of piperazine is heated with exclusion of air in accordance with Example 1, and worked up. The yield is 295 g or 92.7 percent of theory.
  • aminoethylpiperazine is used in the following mix: 600 g of trichlorobenzene, 220 g of l-hydroxy-Z-aminophenol, 172 g of 2,5-thiophenedicarboxylic acid, 6 g of boric acid and 3 g of aminoethylpiperazine, the above-mentioned reaction product is obtained in a yield of 299 g or 94.2 percent of theory.
  • EXAMPLE 8 2,5-Di-[benzoxazolyl-(2)]-thiophene A mixture of 600 of trichlorobenzene, 219 g of l-hydroxy- Z-aminobenzene, 172 g of 2,S-thiophenedicarboxylic acid, 6 g of boric acid and 3 g of ethylenediamine is heated in accordance with Example 1, with exclusion of atmospheric oxygen.
  • the dibenzoxazolylthiophene is obtained in a yield of 91.2 percent oftheory. Melting point 218 C.
  • EXAMPLE 10 2,5-Di-[benzoxazolyl-(2)l-thiophene
  • the dibenzoxazolylthiophene is obtained in a yield of 89.5 percent by reaction, in accordance with the instruction of Example l, of 600 g of trichlorobenzene, 218 g of l-hydroxy-2- aminobenzene, 173.5 g of 2,S-thiophenedicarboxylic acid, 5 g of boric acid and 3 g of tetrahydroquinoline. Melting point 220 C.
  • EXAMPLE 1 1 2,5-Di-[5-tert.butylbenzoxazolyl-(2)]-thiophene
  • a mixture of 266 g of l-hydroxy-2-amino-4-tertiary butylbenzene, 138.5 g of 2,5-thiophenedicarboxylic acid, 6 g of boric acid, 350 g of trichlorobenzene and 2 g of piperidine is heated to 210 C over the course of 4 hours with exclusion of air. The temPerature is raised to 220 C over the course of a further hour and finally the mixture is stirred at 220 to 222 C for 3 hours.
  • the crystal sludge is filtered off at room temperature, washed with a total of 900 g of isopropanol and dried in a vacuum drying cabinet.
  • the 2,5-di-[5-tert.butylbenzoxazolyl-(2')]-thiophene is obtained in the form of pale yellow luminous crystals, in a yield of 327 g or 95 percent oftheory. Melting point 199 to 200 C.
  • EXAMPLE 12 2-(4-Methylphenyl)-5-tertiary butyl-benzoxazole A mixture of 272 g oF p-toluic acid, 330 g of lhydroxy-Z- amino-4-tert.butylbenzene, 10 g of boric acid, g of trichlorobenzene and 3 g of piperidine is stirred with complete exclusion of air and heated to 200 C over the course of 4 hours. At 150 C a mixture of water and piperidine begins to distil olf.
  • the temperature is raised to 220 C over the course of a further hour and the mixture is finally stirred for a further 2 hours at 220-225 C. After cooling to 120 C, 200 g of isopropanol are allowed to run in.
  • the mixture is cooled to C and the crystal sludge is filtered off on a porcelain suction filter.
  • the crystals are washed with a total of 350 g of cold isopropanol.
  • the yield is 481 g or 90.6 percent of theory. Melting point of the white greyish-tinged crystals: 1 14 C.
  • a mixture of 205.5 g of diphenyl-4-carboxylic acid, 109 g of 1-hydroxy-2-aminobenzene, 5 g of boric acid, 750 g of trichlorobenzene and 2 g of methylpiperidine is heated to 210 C over the course of 4 hours with stirring and exclusion of air. The temperature is raised to 220 C over the course of a further hour and the mixture is finally stirred for 3 hours at 220 to 225 C.
  • the crystal sludge is filtered off and washed with isopropanol.
  • the desired product is obtained in the form of almost colorless crystals in a yield of 229 g. Melting point 139.4 to 139.6 C.
  • EXAMPLE 14 2,5-Di-[benzoxazolyl-(2)]-furane
  • a mixture of 220 g of 1-hydroxy-2-aminobenzene, 156 g of 2,5-furanedicarboxylic acid, 5 g of boric acid, 600 g of trichlorobenzene and 3 g of piperidine is heated to 210 C over the course of 4 hours with exclusion of air.
  • a mixture of water and piperidine beings to distil off at about 150 C.
  • the temperature is raised to 220 C over the course of a further hour and the mixture finally stirred for 2 hours at 220 to 225 C.
  • 135 ml of distillate containing 65 ml of trichlorobenzene are collected.
  • EXAMPLE 15 1,2-Di-[benzoxazolyl-( 2 ]-ethane A mixture of 220 g of 1-hydroxy-2-aminobenzene, 118 g of succinic acid, 600 g of trichlorobenzene, 5 g of boric acid, and 3 g of piperidine is heated to 210 C over the course of 4 hours with exclusion of air, and the temperature is raised to 220 C over the course of a further hour.
  • the mixture is stirred for 2 hours at 220 to 225 C and 400 g of isopropanol are carefully added at about 150 C.
  • the product is filtered off at room temperature, washed with isopropanol and dried in a vacuum drying cabinet.
  • the yield of di-benzoxazolyl-ethane is 97.3 percent of theory. Melting point l92.7 to 193 C.
  • EXAMPLE l6 A mixture of 166 g of terephthalic acid, 220 g of l-hydroxy- Z-aminobenzene, 5 g of boric acid, 400 g of trichlorobenzene and 3 g of piperidine is heated to 210 C over the course of 4 hours. The greenish suspension is heated to 215 C over the course of a further hour, whereby a thick brown sludge is produced. Finally the mixture is stirred for 2 hours at 215 C. 400 g of isopropanol are allowed to run in at 150 C. The product is filtered off at room temperature, washed with isopropanol and dried in vacuo.
  • the yield is 318 g or 95.4 percent of theory. Melting point 340 C.
  • EXAMPLE l7 2,5-Di-[benzoxazolyl-(2')]-thiophene
  • a mixture of 219 g of l-hydroxy-2-aminobenzene, 172 g of 2,S-thiophenedicarboxylic acid, 600 g of trichlorobenzene, 6 g of boric acid and 3 g of N-methylpyrrolidine is heated to 220 C over the course of 5 hours with exclusion of air and is stirred for 3 hours at this temperature.
  • a golden brown solution is obtained, into which 400 g of isopropanol are allowed to run carefully at about 150 C.
  • the product is filtered off at room temperature and carefully washed with isopropanol.
  • the yellow crystals are dried in a vacuum drying cabinet at to C.
  • the di-benzoxazolyl-thiophene is obtained in a yield of 308.4 g or 96.9 percent of theory. Melting point 220 C.
  • EXAMPLE l8 2,5-Di-[benzoxazolyl-(Z')]-thiophene A mixture of 219 g of l-hydroxy-2-aminobenzene, 172 g of 2,5-thiophenecarboxylic acid, 6 g of boric acid, 600 g of trichlorobenzene and 1.5 g of diethylenetriamine is heated in the reaction vessel, with exclusion of air, to 220 C over the course of 5 hours and is finally stirred for 3 hours at 220 C.
  • the desired product is obtained in a yield of 300 g or 94.5 percent of theory. Melting point 219 to 2 l 9.4 C.
  • EXAMPLE l9 2,5-Di-[benzoxazolyl-(2')]-thiophene
  • a mixture of 220 g of l-hydroxy-2-aminobenzene, 172 g of 2,S-thiophenedicarboxylic acid, 600 g of trichlorobenzene, 6 g of boric acid and 1.5 g of 1,4-diaza-bicylco[2,2,2]-octane is heated to 220 C over the course of 5 hours with exclusion of air.
  • the mixture is stirred for 3 hours at 220 to 222 C, isopropanol is added at C, and the product filtered off at room temperature.
  • the yellow crystals are rinsed with isopropanol and dried.
  • the dibenzoxazolyl-thiophene is obtained in a yield of 305.9 g or 96.2 percent of theory. Melting point: 219.2 to 219.6 C.
  • EXAMPLE 20 2,5 -Di-[ benzoxazolyl-( 2 ]-thiophene a. 219 g of l-hydroxy-2-aminobenzene, 172 g of 2,5- thiophenedicarboxylic acid, 600 g of 1,2,4-trichlorobenzene, 6 g of boric acid and 2 g of pyrrolidine are heated to 210 C over the course of 4 hours, with exclusion of air. The mixture is heated to 220 C over the course of a further hour and is kept at this temperature for 3% hours.
  • EXAMPLE 21 2,5-Di-[benzoxazolyl-( 2')]-thiophene a.
  • a mixture of2l9 g of 1-hydroxy-2-aminobenzene, 172 g of 2,5thiophenedicarboxylic acid, 600 of trichlorobenzene, 6 g of boric acid and 2 g of aminoguanidine bicarbonate is heated to 220 C over the course of 4 hours with exclusion of air and stirred for 4 hours at this temperature.
  • 400 g of methanol are carefully allowed to run in at 100 C and the product is filtered off at room temperature, washed with methanol and dried in a vacuum drying cabinet. Yield: 305 g of pale yellow crystals of melting point 221 C.
  • EXAMPLE 22 2,5-Di-[benzoxazolyl-(2)]-thi0phene A mixture of 219 g of 1-hydroxy-2-aminobenzene, 172 g of 2,5-thiophenedicarboxylic acid, 600 g of trichlorobenzene, 6 g of boric acid and 2 g of diethylamine is heated to 220 C over the course of 4 hours with complete exclusion of air and is kept at this temperature for 4 hours. In the course thereof a mixture of diethylamine, water and trichlorobenzene distils off.
  • the di-(benzoxazolyl)-thiophene is obtained in the form of light yellow crystals in a yield of 308.1 g or 97.1 percent of theory. Melting point: 222 C.
  • EXAMPLE 23 2,5-Di-[benzoxazolyl-(2)]-thiophene a.
  • a mixture of 219 g of l-hydroxy-2-aminobenzene, 172 g of 2,S-thiophenedicarboxylic acid, 600 g of trichlorobenzene, 6 g of boric acid and 2 g of dimethylamine hydrochloride is heated with exclusion of air as described in the preceding example and is stirred for 4 hours at 220 C.
  • the batch is mixed with 400 g of isopropanol, and the crystals are filtered off at room temperature and washed with isopropanol.
  • Di-(benzoxazolyl)-thiophene is obtained in a yield of 305.1 g or 96.0 percent of theory. Melting point: 221 C. b. If instead of dimethylamine hydrochloride 2 g of methylamine hydrochloride are employed, the reaction product is obtained in a yield of 301.3 g.
  • EXAMPLE 24 Manufacture of l,4-di[benzoxazolyl-(2')]-naphthalene
  • a mixture of 6.5 g (0.03 mol) of 1,4-naphthalenedicarboxylic acid, 6.87 g (0.063 mol) of o-aminophenol, 0.18 g of boric acid, ml of distilled trichlorobenzene and 0.06 g of piperidine is heated over the course of 90 minutes to 160 C in a sulphonation flask having a water separator, under a nitrogen atmosphere. The temperature is raised to 220 over the course of a further 2 hours, with slight distillation starting from about 180 C onwards and a clear solution forming at 205 C.
  • EXAMPLE 25 10.8 g of naphthalene-2,6-dicarboxylic acid,'18.5 g of 3- hydroxy-4-aminodiphenyl, 0.1 g of piperidine, 0.3 g of boric acid and 100 ml of a mixture of 73 percent of diphenyl-ether and 27 percent of diphenyl are stirred with exclusion of air and heated to 240 C over the course of4 hours. 0.5 g of boric acid anhydride are added to the light brown suspension which is heated to 255 C and stirred for one hour at 255 to 260 C.
  • an aryloxazole comprising the reaction of a carboxylic acid selected from the group consisting of i. a dicarboxylic acid of benzene, naphthalene, stilbene,
  • iii an aliphatic dicarboxylic acid having a carbon chain of four carbon atoms, with an approximate equivalent amount of a hydroxyarylamino compound ofthe formula wherein R denotes the phenyl group or a residue (C,, H and occupies positions 4 or 5, and n represents a number from 1 to 5, in the presence ofa halogenobenzene, an alkylbenzene, a partially hydrogenated naphthalene or chlorinated naphthalene which is liquid at room temperature and boils at not less than 200 C, diphenylether or diphenyl, and in the presence of small amounts of boric acid, by first heating the reaction mixture to temperatures of at least C and then, with gradual increase in temperature, to temperatures of at least 200 C, wherein the improvement comprises carrying out said reaction in the presence of a nitrogen base selected from the group consisting of a. a secondary or tertiary, cyclic, non-aromatic nitrogen base containing one to two rings with five to eight ring
  • styrene, thiophene or furane or the analogues of these carboxylic acids containing one to three alkyl groups with one to four carbon atoms each, or an aliphatic dicarboxylic acid containing four carbon atoms, is reacted in approximately equivalent amount with an o-hydroxyaminophenol which can optionally be substituted by one to three alkyl groups with one to 18 carbon atoms, an alkoxy group with one to four carbon atoms, a carbalkoxy group with one to 12 carbon atoms, a halogen atom or a phenyl group.
  • an o-hydroxyaminophenol which can optionally be substituted by one to three alkyl groups with one to 18 carbon atoms, an alkoxy group with one to four carbon atoms, a carbalkoxy group with one to 12 carbon atoms, a halogen atom or a phenyl group.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
  • Heterocyclic Carbon Compounds Containing A Hetero Ring Having Nitrogen And Oxygen As The Only Ring Hetero Atoms (AREA)
US862442A 1968-10-07 1969-09-30 Process for the manufacture of aryloxazoles Expired - Lifetime US3678042A (en)

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CH1493268A CH514616A (de) 1968-10-07 1968-10-07 Verfahren zur Herstellung von Arylenoxazolen

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4454322A (en) * 1982-02-23 1984-06-12 Atochem Process for the preparation of 2-benzoxazolone and derivatives from ortho-nitrophenols and carbon monoxide
US4921964A (en) * 1989-03-01 1990-05-01 Eastman Kodak Company Process for the preparation of stilbene derivatives

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL37633A (en) * 1970-09-10 1975-08-31 Merck & Co Inc 2-(4-(2-benzoxazolyl)phenyl)alkanoic acid derivatives
CN114591316B (zh) * 2022-03-14 2024-09-20 黄石市利福达医药化工有限公司 一种2,5-双(苯并噁唑-2-)呋喃的制备方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3095421A (en) * 1960-08-11 1963-06-25 Ciba Ltd Bis-azolyl-tetrahydrothiophene compounds
US3135762A (en) * 1961-01-19 1964-06-02 Ciba Ltd Bis(benzoxazolyl)thiophene compounds
US3136773A (en) * 1961-11-27 1964-06-09 Ciba Ltd New 2, 5-dibenzoxazolyl-thiophene derivatives
US3293258A (en) * 1964-06-19 1966-12-20 Ciba Ltd Certain 1-(2-benzoxazolyl)-4-(2-naphthoxazolyl)-benzene compounds
US3427307A (en) * 1962-06-09 1969-02-11 Hoechst Ag Benzoxazole optical brighteners

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3095421A (en) * 1960-08-11 1963-06-25 Ciba Ltd Bis-azolyl-tetrahydrothiophene compounds
US3135762A (en) * 1961-01-19 1964-06-02 Ciba Ltd Bis(benzoxazolyl)thiophene compounds
US3136773A (en) * 1961-11-27 1964-06-09 Ciba Ltd New 2, 5-dibenzoxazolyl-thiophene derivatives
US3427307A (en) * 1962-06-09 1969-02-11 Hoechst Ag Benzoxazole optical brighteners
US3293258A (en) * 1964-06-19 1966-12-20 Ciba Ltd Certain 1-(2-benzoxazolyl)-4-(2-naphthoxazolyl)-benzene compounds

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4454322A (en) * 1982-02-23 1984-06-12 Atochem Process for the preparation of 2-benzoxazolone and derivatives from ortho-nitrophenols and carbon monoxide
US4921964A (en) * 1989-03-01 1990-05-01 Eastman Kodak Company Process for the preparation of stilbene derivatives

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FR2020034A1 (de) 1970-07-10
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NL6915094A (de) 1970-04-09
GB1272134A (en) 1972-04-26
CH514616A (de) 1971-10-31
BE739878A (de) 1970-04-06

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