DE2064597A1 - - Google Patents

Description

AGFA-GEVAERTAG

PATENT DEPARTMENT

LEVERKUSEN

2 Dec 9, 1970

Process for the preparation of aromatic azides

The invention relates to a new process for the preparation of azidobenzal compounds.

Aromatic azido or! »! Azido compounds have technical Importance as a crosslinking agent for photo-crosslinkable layers on certain polymeric compounds. For example, you can use a imagewise crosslinking of layers of chlorinated or cyclized rubber in the presence of chalcondiazides as Achieve crosslinking agents. Such aromatic azido or diazido compounds are generally acidic Condensation of p-azidobenzaldehyde with various compounds, e.g. with cyclohexanone or methylcyclohexanone, methyl aryl ketones under alkaline or acidic conditions or m-azidocinnamaldehydes, azidoacetophenones or the like Connections made.

In all the examples given, the azido compounds described by condensation of azidobenzaldehyde or similar azidocarbony! compounds are obtained. Most of these Compounds, especially azidobenzaldehydes, are extremely explosive substances and can only be used if they are observed can be produced with great effort by security measures. In addition, many viewed it as relatively stable Azido compounds sometimes lead to severe explosions for no apparent reason (cf. Nach. Chem. Techn. 18, 1970, No. 2).

The invention has for its object new process for preparing aromatischeη azido or diazido finding that the preparation of such compounds in

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allow easy and safe way.

There has now been a process for the preparation of azidobenzal compounds found, after which the nitro compounds corresponding to the desired azido compounds are first condensed, the condensation products catalytically with Raney-Jickel / Hydrazine hydrate reduced to the amino compounds and after diazotization with sodium azide to the azido compounds be convicted.

In the process according to the invention, there are no dangerous intermediate stages, and extraordinarily good ones are obtained Yields of the azidobenzal compounds suitable as crosslinking agents for light-crosslinkable polymer layers. The end)} Products of the process according to the invention are due to their significantly higher molecular weight than, for example, azidobenzalaldehyde much less dangerous and relatively easy to use.

In the method of reducing the nitro compounds to the corresponding amines used in the process according to the invention, the carbonyl groups and double bonds present in the molecule are left unchanged. This avoids yield losses in this process stage. Alcohols, ethers and ketones can be used as solvents for the reduction. Dioxane and tetrahydrofuran have proven to be particularly suitable. And there were also ψ PROBLEM-free reduction in ketones, for example acetone, in which one has to expect a reaction with hydrazine hydrate under hydrazone or Azinbildung performed. In these cases, a solution or suspension of the nitro compound with Raney oil in acetone is introduced and an aqueous solution of hydrazine hydrate is added dropwise. In all cases, a 3-5 molar excess of hydrazine hydrate was used

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BATH ORIGINAL

worked on a nitro group.

The amino compounds thus obtained can then very easily by diazotization in aqueous solution and reaction of the diazonium salt solutions with sodium azide in the corresponding Azido compounds transferred to earth.

Nitroarylaldehydes are used as the nitro compounds for the first stage, the condensation, of the process according to the invention such as nitrobenzaldehyde or nitrocinnamaldehyde. These are condensed with compounds that are reactive with aldehyde groups Contain methylene group. These include primarily aliphatic, cycloaliphatic, aromatic or mixed Ketones such as cyclohexanone, alkyl-substituted cyclohexanones, in particular methyl or ethyl cyclohexanone, also Acetone, acetophenone, nitroacetophenone or malonic acid, resp. their derivatives.

The amino compounds obtained after the reduction stage are known to be diazotized and then converted into the mono- or bisazido compounds by reaction with sodium azide convicted.

example 1

4 _< 4'-dinitro-dibenzal-cyclohexanone

The suspension of
150 g p-nitrobenzaldehyde in
500 ml of alcohol and
60 g of cyclohexanone is added dropwise at about 20 ° C

(Water cooling) with
50 ml 25 percent Sodium hydroxide solution added. With a slight increase in temperature, the p-nitrobenzaldehyde is lost

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in solution. A short time later, the condensation product precipitates. The mixture is stirred for a further 90 minutes and filtered off with suction and washed with hot methanol.

Yield: 130 g (72 96)
M.p .: 202-205 ° C

4,4'-diamino-dibenzal-cyclohexanone

g 4,4'-dinitro-dibenzal-cyclohexanone are dissolved at 70 ⁰ C in ml of dioxane. Then one adds about g Raney nickel (Raney nickel was aspirated and still f moist balanced) are added and dropped at 70 ⁰ C

within 60-90 min

ml 25 percent Hydrazine hydrate (VK-Nr .: 02-830) into the solution.

The Raney nickel is then filtered off and the solvent is stripped off in vacuo except for a small residue. The crystalline 4,4 · diamino-dibenzal-cyclohexanone is filtered off with suction and dried.

Yield: 75 g (90%)
M.p .: 182-185 ° C

4,4'-diazido-dibenzal-cyclohexanone

g 4,4'-diamino-dibenzal-cyclohexanone (WLL 2273)

very pure powdered and in

ml conc. Hydrochloric acid entered. Then a solution of

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Diazotized 40 g of sodium nitrate in 100 ml of water and stirred for half an hour at 0-5 ⁰ C. The clearest possible solution should be created. (It may be necessary to filter cold.)

In the clear tetrazonium salt is then at 0-5 ⁰ C slowly under vigorous stirring, a solution of

36 g of sodium azide instilled in 125 ml of water (under the surface). After the addition of azide is complete, stirring is continued at 0-5 ° C. until no further evolution of gas occurs is watching. It is then filtered off with suction and washed with alcohol.

Yield: 81 g (92 %)
Mp. 144 ⁰ C

Example 2;

Analogously to Example 1, 4-methylcyclohexanone is obtained from 4-methylcyclohexanone 2,6-di (4'-azidobenzal) -4-methylcyclohexanone.

Example 3:

That by condensation of p-nitrobenzaldehyde with p-nitroacetophenone 4,4'-Dinitrochalcone can be converted according to Example 1 into 4,4'-Diazidochalcone. Orange needles of m.p. 119

'C.

Example 4:

The product obtainable by condensation of p-nitrobenzaldehyde with acetone 4,4'-dinitro-dibenzalacetone can according to Example 1 into the 4 _f 4'-diazido-dibenzalacetone of mp. Over lead 156 ⁰ C.

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Example 5;

The product obtainable by condensation of p ~ nitrocinnamaldehyde with acetone 4,4'-Dinitrocinnamalaceton can be in accordance with Example 1 in 4,4 ^I -diazido "dicinnamalacetone transfer. M.p.

Example 6;

_{The 2 s} 6-di (4'-nitrocinnamal) -4-methylcyclohexanone obtainable by condensation of 4-methylcyclohexanone with p-nitrocinnamaldehyde can be converted into 2,6-di (4'-azidociimamal) -4-methylcyclohexanone according to Example 1 .

Example 7 s P-nitrocinnamylideneacetic acid;

p-nitrocinnamaldehyde and

Malonic acid can be removed by gently warming it in on the water bath

least. Pyridine dissolved. The mixture is then treated dropwise with piperidine for 5 hours at room temperature and 5 hrs. Then stirred at 120-140 ⁰ C. After the evolution of gas has ceased, the mixture is cooled with ice water, and the precipitate which has separated out is filtered off with suction and washed thoroughly with acetone.

Yields 218 g
Mp. 275 ⁰ G

500 G ml 263, , 5 g 1000 ml 5.5

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P-nitrocinnamylideneacetic acid ethyl ester:

g p-nitrocinnamylideneacetic acid are added dropwise under Stir with

ml of thionyl chloride are added. At an oil bath temperature of 100 ⁰ C for 5 hours was refluxed until the end of the HCl evolution.. The excess thionyl chloride is then stripped off in vacuo. The last residues are displaced by distillation after adding benzene. The residue is dissolved in

ml of absolute pyridine and then ml of absolute alcohol are added dropwise. It is then refluxed for 3 hours boiled, cooled in ice water, vacuumed on the suction filter and washed well.

M.p .: 120-122 ° C from alcohol Yield: 144.5 g

^C ber. 62 , 0 ^H ber. 5 , 83 ^N ber. 6th , 28

^{C found} 63.5 ^{H found} . 5.7 ^{N found} . 6.20

ethyl p-aminocinnamylidenessi ^ acid ester:

g p-Nitrocinnamylidenessigsäureäthylester are in ml of dioxane dissolved, mixed with Raney nickel and by the dropwise addition of

ml of 25% hydrazine hydrate reduced at 70 °. After filtering and stripping off the solvent, 107.5 g (98 %) of ethyl p-aminocinnamylideneacetate remain.

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Mp .: 90-92 ⁰ C

^C calc. 71.9 ^{C found} . 71.9

^H calc. 6.9 ^{H found} . 7.3

N r N « r

ber. 6.5 gex. o, 5

From this, after the diazotization and reaction of the filtered diazonium salt solution, the equivalent amount is obtained Sodium azide ethyl p-azidocinnamylideneacetate.

Example 8:

150 g of p-methoxyacetophenone and

151 g of p-nitrobejrizaldehyde are in

ml of alcohol suspended and at room temperature with 100 ml of 10 percent. Sodium hydroxide solution added. After a short time divorced the 4-nitro-4'-methoxychalcone is selected. The mixture is stirred for a further 2 hours, filtered off with suction, washed with alcohol and recrystallized.

Mp .: 168 ⁰ C

150 g of the A-nitro-4 ^l -methoxychalkons obtained in this way are dissolved in 750 ml of dioxane and, after heating to 80 ° C., 15 g of Raney nickel are added. Then within

of 30 min by slowly adding dropwise 70 ml of hydrazine hydrate (100 %) . The mixture is stirred for 15 minutes, the Raney nickel is filtered off and the dioxane solution is stirred into ten times the amount of ice water. From the precipitated 4-amino-4'-methoxychalcone, 4-azido-4'-methoxychalcone is obtained by diazotizing and reacting the diazonium salt solution with sodium azide.

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Example 9:

In analogy to Example 8, from p-nitrobenzaldehyde and m-Methoxycetophenon the corresponding 4-azido ~ 3-methoxychalcone of mp. 75-76 ⁰ C,

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Claims (2)

Claims AJ Process for the preparation of condensed azidobenzal compounds, characterized in that the aromatic nitro compounds corresponding to the desired azido compounds which contain an aldehyde group on the core or on one side chain are condensed with compounds which contain a methylene group which is reactive with aldehyde groups, then catalytically with Raney nickel and hydrazine hydrate reduced to the amino compounds and converted into the azido compounds after diazotization with sodium azide. 2. The method according to claim 1, characterized in that nitrobenzaldehyde or nitrocinnamaldehyde or their homologues condensed with aliphatic, cycloaliphatic or aromatic ketones or with malonic acid or its derivatives will. A-G 754 20982S / 1199