GB1566985A - Process for the preparation of azo dyestuffs - Google Patents

Description

(54) PROCESS FOR THE PREPARATION OF AZO DYESTUFFS (71) We, BAYER AKTIENGESELLSCHAFT, a body corporate organised under the laws of the Federal Republic of Germany, of Leverkusen, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement::- The present invention relates to an improved process for the preparation of azo dyestuffs, which are free from sulpho groups, of the formula

wherein Rl denotes a hydrogen or halogen atom or an alkyl, aryl, alkoxy, alkoxycarbonyl or alkylthio radical, R2 denotes a hydrogen atom or an alkyl, aralkyl, aryl or aromatic heterocyclic radical and K denotes the radical of a coupling component, it being possible for the abovementioned radicals optionally to carry further non-ionic substituents.

Most of the dyestuffs of the formula (I) are known, and they have hitherto been prepared by diazotising a 4-cyano-5-amino-pyrazole and coupling the diazotisation product with an appropriate coupling component. (Compare U.S. Patent Specification 3,336,285 and DOS (German Published Specification) 2,600,036).

However, this process has a number of disadvantages.

Thus, for example, not only are the aminocyanopyrazoles obtainable in moderate yields (2965% according to the U.S. Patent Specification cited above), but they are also difficult to diazotise under normal conditions. Furthermore, the corresponding diazonium salts are so unstable that both the diazotisation and the coupling must without fail be carried out in an organic medium, and in spite of this dyestuff yields of only about 70% are obtained.

It has now been found that the dyestuffs of the formula (I) can be prepared in significantly better total yields when 4 - halogeno - 5 - amino - pyrazoles, which are accessible in a more simple manner, are diazotised, preferably in an aqueous-mineral acid medium, the diazotisation products are combined with coupling components to give dyestuffs of the formula

wherein X represents halogen, preferably bromine, and R1, R2 and K have the abovementioned meaning, and the substituent X in the dyestuffs is replaced by the cyano group by means of a nucleophilic replacement reaction.

The halogen/cyano replacement, to be carried out in suitable solvents by means of metal cyanides, is in itself known and is described, for example, in the following patent literature: U.S. Patent Specification 3,962,209, 3,821,195 and 3,876,621.

Suitable solvents are all the solvents which have hitherto been described for halogen/cyano replacement. Possible solvents here are polar protic solvents, such as monoalkyl ethers of ethylene glycol or diethylene glycol, and above all polar aprotic solvents, for example, carboxylic acid amides and lactams which are optionally alkylated on the nitrogen, dialkylsulphoxides, trialkyl phosphates, hexaalkylphosphoric acid triamides and carboxylic acid nitriles.

Examples which may be mentioned are: glycol monomethyl ether, glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, tetramethylurea, dimethylsulphoxide, tetramethylene sulphone, triethyl phosphate, hexamethylphosphoric acid triamide or acetonitrile. Water can also be used.

It can sometimes be advantageous to carry out the replacement reaction in the presence of organic bases, for example pyridine or imidazole.

In general, the reaction temperatures are between 20 and 1800C, temperatures between 40 and 1200C being preferred.

The reaction times are between 10 minutes and 2 to 3 hours.

Suitable metal cyanides are, in particular, Cu(I)CN alone or a mixture of Zn(CN), and Cul(I)CN, which are either employed as such or are produced only in the reaction medium, for example from coppery salts and alkali metal cyanides.

The working up can be carried out by various methods; thus, for example, it is possible to precipitate the dyestuff from the cyano replacement mixture by adding water or a Cl to Ct alcohol, such as methanol or ethanol, and thereafter, if necessary, to de-copper the reaction product by an oxidative route by, for example, stirring it with an oxidising agent, preferably iron-III salts, in aqueous hydrochloric acid. Thereafter, the product is filtered off and dried.

In this manner, the dyestuffs of the formula (I) are obtained in outstanding yields in high purity and with very good coloristic properties.

The new process is particularly suitable for the preparation of dyestuffs of the formula

wherein R1 and R2 have the abovementioned meanings, R1 denotes hydrogen, halogen, alkyl, alkoxy, aryloxy, alkylcarbonylamino, aralkyl carbonylamino, cydoalkylcarbonylamino, arylcarbonylamino, aromatic hetero cydic-carbonylamino, alkoxycarbonylamino, alkylsulphonylamino, aryl sulphonylamino, aminocarbonylamino- CN, CF3, carbamoyl, dialkylamino carbonyl, alkoxycarbonyl, sulphamoyl, dialkylaminosulphonyl or alkyl sulphonyl, R, denotes hydrogen, alkyl, alkoxy or aryloxy, R5 denotes hydrogen, alkyl, aralkyl or aryl and R6 denotes hydrogen, alkyl, aralkyl or cycloalkyl, or wherein R4 and R5 as well as R, and R6, together with the N atom, can form a 5 membered or 6-membered heterocyclic ring.

The alkyl and alkoxy radicals mentioned above in any connection (that is to say, for example, also alkylsulphonyl or alkoxycarbonyl) are preferably to be understood as radicals with 114 C atoms which can be optionally monosubstituted by OH, CN, halogen, C1---C4-alkoxy or C1C5-alkoxycarbonyloxy, whilst the aryl or aryloxy radicals are preferably understood as phenyl or phenoxy radicals which are optionally monosubstituted to trisubstituted by Cl, Br, NO2, CN, alkoxy (C1-C4) or alkyl (C,4).

Suitable halogen atoms are, above all, Br and Cl.

Suitable cycloalkyl radicals are cyclohexyl and cyclopentyl radicals.

Suitable hetaryl radicals are, inter alia, pyridyl, thienyl and furyl.

Suitable heterocyclic rings which R2 and Rs can form are the pyrrolidine, piperidine and morpholine rings. Suitable heterocyclic rings which R4 and R form are the tetrahydroquinoline and benzmorpholine rings.

The 4-halogeno-5-aminopyrazoles required for the preparation of the compounds of the formula (II) are obtained in a manner which is in itself known by halogenating, preferably brominating, the corresponding pyrazoles which are unsubstituted in the 4-position, most of which are known from the literature. This reaction can be carried out almost quantitatively.

In contrast to the cyanopyrazoles, the diazotisation of the aminohalogenopyrazoles can be quite successfully carried out in the customary aqueous media, preferably sulphuric acid and phosphoric acid. The coupling is also carried out in the customary manner, preferably in an aqueous medium.

As a rule, yields of over 90% of theory are obtained in both reaction steps.

Suitable coupling components are those of the benzene, naphthalene, indole, pyridine, pyrazole and tetrahydroquinoline series, but preferably N-substituted p-aminoarylene radicals, and in particular anilines of the formula

wherein R,--R, have the abovementioned meaning.

Coupling components of the formula indicated above wherein R, represents one of the acylamino radicals mentioned further above, preferably an alkylcarbonylamino radical, are very particularly suitable.

The process claimed may be illustrated in more detail with the aid of the following examples.

Example 1.

16.1 g of 5 - amino - 4 - bromo - 3 - methyl - 1 - phenyl - pyrazole in 30 ml of concentrated sulphuric acid are diazotised with 11.7 ml of 45% strength nitrosylsulphuric acid at 0--5"C. 13.5 g of N,N - diethyl - N' - acetyl - m - phenylenediamine are dissolved in 50 ml of water and 10 ml of concentrated hydrochloric acid and the solution is cooled to 0--50C. The solution from the diazotisation and sodium acetate solution (10% strength) are run into this solution, whilst simultaneously controlling the temperature (05 C), in a manner such that the pH value is kept at S3. The coupling is effected virtually instantaneously. After the coupling, the mixture is neutralised with about 17% strength sodium carbonate solution and the dyestuff is filtered off.

Yield: 28.8 g of dyestuff (96% of theory).

When dyed onto polyester, a reddish-tinged orange results.

The diazo component can be prepared according to Liebigs Annalen der Chemie 339, 144.

5 g of the bromine dyestuff are dissolved in 30 ml of dimethylformamide and 1 ml of pyridine, and 1 g of copper-I cyanide is added. After stirring the mixture at 1000C for 3 hours, it is discharged onto water and the product is filtered off. The dyestuff of the formula

is de-coppered by stirring with iron-III chloride in aqueous hydrochloric acid.

Yield: 4.1 g of dyestuff (=92% of theory).

Polyester is dyed by this dyestuff in bluish-tinged red shades with very good fastness properties.

Further dyestuffs which correspond to the general formula

are obtainable with similarly good yields analogously to Example 1 and are listed in the table which follows (in which the symbol " " denotes a phenyl radical):

e 0 f Z v le le S s g e e t v . < .< h 00 &commat; o o ux h h I O hrl h h h h B g :s psa OiD O ax H oH X o > XQO tq tSH X a) O Cl P H Q H to g bO h = = q bO I d w d b h d bD o a > < O oH ZD = 0H 0 H-d0 Htt HH OS-,10 = U PW h > > 4 h h hM Q Ph &num; &num; MR U hCr k k k ku Pk o, cu M ap P B 2 h h ;roD e O o g red 4 bO g g bO t 5 " 4' H , , . 5 ,{i 1 )P) 3Q | O red as owz Z w Z < oSH 7 II h ottst ti lt 8 . o o k hOO k yr 9 " N CH3 H C5 C2H5 I' scarlet e Xt 4' 4' H aN-Xv 11 4' 4' Y H . = i. II 12 . N . oa13 ci'5 c5 reddish-tinged orange bluish 13 " 4' COcR3 fl St 'I red Icu 5 3 tinged red 15 4' 4' 4' H CH2 reddish-tinged orange bluish 16 U Y aY UiS 4' c2Hs yellowish-tinged tscina1edetred 17 '1 4' 4' oc5 4' 4' r bluish 18 m 3 x c 8 8 f x B 8 = 19 Ft 4' ls02CH3 Ii 4' 4' II II 'I U 4 U S s m s r %: E} r t a s = s S o s o ~ eq v uo tD b X a

cg < bD 4 I a 90 S ç O Pv H S M H H o 0 > O O O o o = b o V O > h h el Sq bX t g e a O O O *~l ~ bO bO bO 91 4X g g CH401 C5 = = = yellowish-tinged yell" owis' h-tinged "3 u 22 e g g - = = h o = 23 " h NO2013 H h orange, reddish-tinged red Uk O, Q, P PM bD ,n bO l) bO bO 24 " 013 H C5 s kk k O o O~ 0 25 " a!3 NHCOCH3 H 'I reddish-tinged red o > Ui = Y a 8 e 28 u -012201 NHOCH3 H 5' Y u II It I? E 5' -Br O3 H 5' N orange scarlet t f g 8 g n o s O n Ct; 6 r = t s O ~ e v U

wE ç H O h h t1 t etl g (d O4} h h O ZD bO bll bO bO ' h h h h 30 O O COCH3 H C5 k k k k 0 0 0 0 I a a a 32 < < < 33 NHCOC!3 H -CH2O6H5 C2H5 reddish-tinged orange A o' ra a, ra m Io a, U N N bO 1 1 b0 ,1 f;;i = a, k co k kokko k cn o h O h h O h 0 o 35 N u, H C5 C5 reddish-tinged orange 'S 36 55 t UN N m N NHSO2013 H N N II II II g 4 C6H5 COCH3 H N S " tI It "a m s: e 8 ?C) Y, f m 013 H x x m n o W go O O ~ rt v e e b ea a O Z X n n n n v n v > n n Nw v

d ^S +1 0 o O ss h ,&num; sS ,1 d 'S S d b e d 'S n oS > s o a = = o e ~ = H~s V4Jd h.D4Jh h X h h ,04 > o 42 6H5 HCOCH3 H C5 C5 reddish-tinged orange red Y N h h g 0 tinged red o Ii 013 N a) og b bD t W t e r h n A N H N 4 o j 4 ori +r % P, 8 46 N E hz N N orange 47 1 II S O m 4a N N N N N S' U SI II 49 -sOH3 C5 H N N orange scarlet 50 3Y 5 N e c t r t r I J r E e t N L L I t 8 *br SI U N S' U S' S' 53 N 'I N N N S' S' S' IS 3 N N carlet bluish 3S | r Ng4 ei=- dk ys= O N t 0 t n v) v

X 0 I Vl g g t +re ffi h 1w O: k k I( kl %a hd ac ma, me, ric. 55 d C6H5 = = H C2H5 ==== orange red U O h n 43 h , 4) M, ho 9 " 6H5 H " 9= reddish-tinged orange S' v S = !l M oh ho 59 N II g 'I I' scarlet bluish a) 60 N N}ISO2CH3 1! '1 " b!l 02 a h " C2H'4 zD 4 4) B n A 62 E 5H6 X o o o ro o QE P M bo 6 63 h a e N a j4OCH3 h h SI k ak k h h O O h O h O ao h o cJ o o 2HA6Hs c2H5 Oo II Cl C32 '" u It = = < 24OO5 orange red O, U: 9 Oe U C1 d t e Xn Z Xn 3h C2H5 67 NuNs = = H N = y xG y v V y y V II ~ < 69 N 6H -NX < 0a13 !i 'I II II V)lrV)r t t r tL 2rP 71 N = ~ iV r t I H s r s: II II 0 m X: N N C2}!4COOC2HS II SI t I' NO2flr OC! I, C2II49C21! 8 b}uirp,O0h0 u =o S=o S m Xv e U '" = = S osuN? uNy ?7 y ? y X muE tS U B V .o n o b es O ~ G o z tn uz 0 W ç W ç W > b rW rv

Colour o the Colour of qd ow B n0 a e d estuff = == k oa o s: e a} . .~ ~ II Ii h fi 3 b9 OhO = = N =. rI.cX ,5 h V e O f tt \ Y Y Y s ue S S V V o tS ≈ t > Y Y z v b b WHAT WE CLAIM IS:1. A process for the production of an azo dyestuff of the general formula

in which R1 denotes a hydrogen or halogen atom or an alkyl, aryl, alkoxy, alkoxycarbonyl or alkylthio radical, R2 denotes a hydrogen atom or an alkyl, aralkyl, aryl or aromatic heterocyclic radical and K denotes the radical of a coupling component, it being possible for the abovementioned radicals optionally to carry further non-ionic substituents, in which a halogenoazo dyestuff of the general formula

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   Colour o the Colour of qd ow B n0 a e d estuff = == k oa o s: e a} . .~ ~ II Ii h fi 3 b9 OhO = = N =. rI.cX ,5 h V e O f tt \ Y Y Y s ue S S V V o tS ≈ t > Y Y z v b b WHAT WE CLAIM IS:1.A process for the production of an azo dyestuff of the general formula

   in which R1 denotes a hydrogen or halogen atom or an alkyl, aryl, alkoxy, alkoxycarbonyl or alkylthio radical, R2 denotes a hydrogen atom or an alkyl, aralkyl, aryl or aromatic heterocyclic radical and K denotes the radical of a coupling component, it being possible for the abovementioned radicals optionally to carry further non-ionic substituents, in which a halogenoazo dyestuff of the general formula

   in which X denotes a halogen atom, and R,, R2 and K have the above mentioned meanings, is reacted with a metal cyanide, the halogen atom X being replaced by a cyano group.
2. 2. A process according to Claim 1, in which the halogenoazo dyestuff of formula (II) as defined in Claim 1, is prepared by diazotising a corresponding 4-halogeno-5amino-pyrazole and coupling the diazotisation product with a coupling component KH, in which K has the same meaning as in Claim 1.
3. 3. A process according to Claim 2, in which the diazotisation is carried out in aqueous medium.
4. 4. A process according to any of the foregoing claims, in which the compound of formula (II) is a compound of the general formula

   in which R1 and R2 have the same meanings as in Claim 1, X denotes a halogen atom, Rs denotes a hydrogen or halogen atom or an alkyl, alkoxy, aryloxy, alkyl carbonylamino, aralkylcarbonylamino, cycloalkylcarbonylamino, arylcarbonyl amino, aromatic heterocyclic-carbonylamino, alkoxycarbonylamino, alkyl sulphonylamino, arylsulphonylamino, aminocarbonylamino, CN, CF,, carb amoyl, dialkylaminocarbonyl, alkoxycarbonyl, sulphamoyl, dialkylamino sulphonyl or alkylsulphonyl radical, R, denotes a hydrogen atom or an alkyl, alkoxy or aryloxy radical, R6 denotes a hydrogen atom or an alkyl, aralkyl or aryl radical and Rss denotes a hydrogen atom or an alkyl, aralkyl or cycloalkyl radical in which R4 and R5 as well as R, and R6, together with the N atom, can form a 5 membered or 6-membered heterocyclic ring.
5. 5. A process according to Claim 4, in which R3 denotes an alkylcarbonylamino radical.
6. 6. A process according to any of the foregoing claims, in which X denotes a bromine atom.
7. 7. A process according to any of the foregoing claims in which the metal cyanide is CuCN alone or a mixture of CuCN and Zn(CN),.
8. 8. A process according to Claim 1, when carried out substantialy as described in any one of the Examples.
9. 9. An azo dyestuff of formula (I) as defined in Claim 1, when produced by the process of any of the foregoing claims.