DE2013557B - Process for the preparation of N- (p-aminobenzenesulfonyl) methyl carbamate - Google Patents

Description

The present invention relates to a new method for the production of N- (p-aminobenzenesulfonyl) -methylcarbamate, a product of the formula

H, N

-SO ₇ NHCOOCH ₃

(I)

as well as its alkali and alkaline earth salts, their herbicidal properties in the French patent 1 340 297 and its addition 84 273 are described

There are also a number of manufacturing processes there described

It was now em new process for the preparation of N- (p-aminobenzenesulfonyl) methyl carbamate and its alkali and alkaline earth salts are found to give a yield much higher than those the previously known method is, leads and enables Exceeding yields of 90% of theory

The inventive method for the preparation of N- (p-Ammobenzenesulfonyl) -methylcarbamat der formula

H ₇ N

₂ -NH-CO-Q-CH ₃

and its alkali and alkaline earth salts, is characterized in that em sulfanilamide salt of formula

30th

H ₇ N

J V

SO ₇ NH

in which M is an alkali metal or alkaline earth metal atom and η is 1 when M is an alkali metal atom and 2 when M is an alkaline earth metal atom means, represents, with 1 to 1.2 moles of dimethyl carbonate per mole of sulfamlamide under anhydrous Conditions in methanol at a temperature not exceeding the boiling point of the mixture, preferably in the presence of 0.05 to 0.15 moles of a hydride, alcoholate or amide of an alkali or alkaline earth metal, per mole of sulfamlamide and optionally the alkali or alkaline earth salt obtained by known methods m the free N - (p - aminobenzenesulfonyl) methyl carbamate converted

According to a preferred embodiment, one performs the reaction at a temperature between 25 and 65 ° C is preferably performs the conversion even at the reflux temperature of the mixture or in the vicinity of this temperature, for example at 65 ⁰ C., which allows very good yields in the shortest possible time, ie 8 to 24 hours

In general, the lower the reaction temperature, the longer the period of time required to achieve high yields. For example, at 25 ^° C., a reaction time of a few days (3 to 4) may be required in order to achieve a yield of more than 90%

It is preferred to have the reaction in the presence a small proportion (for example 0.05 to 0.15 moles per mole of the compound of formula II) an alkali or alkaline earth derivative, preferably an alkali derivative, such as, for example, a hydride (e.g. sodium hydride), an alcoholate (ζ Β sodium methylate), of an amide (e.g. Natnumamid) to add. These compounds accelerate the reaction

The sulfamlamide salts of the general formula II can be done in situ by adding sulfamlamide to a solution of an alkali or alkaline earth alcoholate, preferably using a small excess of alcoholate (e.g. 1.05 to 1.15 mol of sodium alcoholate per mole of sulfamlamide) to be produced. This gives the small amount at the same time to alkali or alkaline earth derivatives, the utility of which has been noted above

After the reaction, the methanol can be removed by adding water and distillation The aqueous solution thus obtained is for the herbicide concentrates can be used, which are intended, for example, for atomization. They can be used if desired treat with products containing calcium ions contain (such as calcium hydroxide or chloride) to reduce the carbonates that may be present can remove this is not necessary if one has used the calcium salt of sulfanamide or a calcium derivative or both of these were already used in the production

This removal of carbonates from the solution is desirable in order to avoid the precipitates could occur if the concentrates are diluted with hard water before use

You can also remove the salt by filtering or decanting after concentrating the solution or else isolate by evaporating the solution to dryness, if desired under reduced pressure The salt of N- (p-aminobenzenesulfonyl) methyl carbamate can also be added by adding a salt Salting out the same alkali or alkaline earth metal, however, this isolation process is for manufacturing of sodium salt is not convenient

If you have the N- (p-aminobenzenesulfonyl) -methylcarbamate wants to preserve itself, it is sufficient to use an acid (such as hydrochloric acid) to add and the product obtained by filtration or Separate decanting

The N- (p-ammobenzenesulfonyl) methyl carbamate obtained by the process according to the invention can be a small proportion, the m of the order of 5 percent by weight among the preferred Reaction conditions, on N- (p-methoxycarbonylaminobenzenesulfonyl) - contain methyl carbamate, which is formed as a reaction by-product

It is not necessary to disconnect this product, as it has herbicidal properties similar to those of N - (p - aminobenzenesulfonyl) - methylcarbamate analogous, but less effective for the same weight, can, however, if desired this by-product by dissolving the reaction product in a dilute aqueous solution of a Acid, Filti ieren and reprecipitation of N- (p-aminobenzenesulfonyl) -methylcarbamats separate by adjusting the pH of the solution to about 3

The production of N- (p-methoxycarbonylaminobenzenesulfonyl) -methylcarbamate is achieved by increasing the proportion of the alkali or alkaline earth derivative favored in the mixture or by increasing the proportion of dimethyl carbonate

For this reason, it is preferable to use the above Quantities for the alkali metal or alkaline earth derivative and for the dimethyl carbonate are preferred not to exceed far

There may be a little unreacted in the end product Sulphanilamide remain that you duich Washing with water can remove the presence of a small percentage of sulfanilamide (e.g. on the order of 3 percent by weight) makes the unpurified N- (p-ammobenzenesulfonyl) methyl carbamate not useless as a herbicide, and therefore it is generally not required to remove the sulfanilamide

It has surprisingly turned out that the reaction between the Sulfamlar Rudsalz and the thin methyl carbonate is carried out satisfactorily only in methanol

If you have other solvents, such as other alcohols (e.g. ethanol, isopropanol and n-butanol), ketones (e.g. methyl ethyl ketone and Methyl isobutyl ketone), dioxane and glycols (ζ Β Ethylene glycol) is used, so you can not get commercially valuable yields of compound the Formula I obtained

It is known that dialkyl carbonates can be added Transfer of wet nurses to the appropriate Can use N-substituted alkyl carbamates (N Bortnick u Mitarb, J Am Chem Soc [1956] 78, 4358, German patent specification 122 096) According to Houben-Weyl, methods of organic Chemie, Vol. 8 (1952), p. 139, it is known that only one carbalkoxy group is used with dialkyl carbonate in diamines to introduce

That for the transfer of primary wet nurses N-substituted methyl carbamates most commonly used Product is methyl chloroformate which like that Dimethyl carbonate is a derivative of carbonic acid From Example 9 of British Patent 1,040,541 it can be seen that when sulfanilamide is reacted with a limited amount of methyl chloroformate using diethylamine as an acid acceptor 4-amino group is quantitatively acylated and the major part of the reaction product p-methoxycarbonylaminobenzenesulfonylamide is and that only em is present in a small proportion of the Ammo part of the sulfonamide group with the formation of N-ip-methoxycarbonylaminobenzenesulfonyty-methylcarbamate acylated It would therefore have been expected that the process according to the invention would be the same Way to p-methoxycarbonylammobenzenesulfonylamide as the main reaction product and possibly a small amount of N- (p-methoxycarbonylammobenzenesulfonyl) - methyl carbamate was driving

The fact that the methoxycarbonyl radical is preferentially attached to the sulfamido group low formation of N- (p-methoxycarbonylaminobenzenesulfonyl) methyl carbamate, is surprising and unexpected, since the ammo group is in the p-position for the acylation is freely accessible

If you have the N- (p-Ammobenzenesulfonyl) -methylcarbamat in the form of the free base, it can be used as a herbicide, if desired in alkali or alkaline earth salts according to one of the m the first addition 84 273 to the French patent specification 1,340,297

The method according to the invention offers the following advantages

1 It is a one-step process in which only Products used are the usual commercial products or can easily be formed from such in situ

2. The procedure is easy to use in seSner

3 The reaction can be carried out in concentrated solution carried out, which means a high production, based on the volume of the device,

enables

4 The direct reaction product, the alkali or Alkaline earth salt of N-m-Ammobenzenesulfonyl) -methylcarbamats, is in the form of an aqueous Get solution that goes directly into the herbicide concentrates can be used without prior isolation of the active substance required

5 The process gives high yields ar one Product with a degree of purity suitable for its use as a herbicide without any further Suitable for cleaning,

6 The usual protection of the ammonia residue by a Protecting group, such as an acyl group, is not required for the product of Formula II.

hch j

7 The reaction takes place in basic medium, what the selection of the apparatus facilitates

None of the previously known methods has these advantages

Known under the term »used here Methods «are to understand the procedures that hitherto used for this purpose or described as such in the literature

The following examples illustrate the process the invention

In these examples! the above, provisions carried out as follows

Determination with nitrite

The content of primary amino residues is determined by titration nut (an O.ln natnumnite solution The result is as N- (p-Ammoberizolsulfonyi) -methylcarbamate printed out In this attempt, the entire amount of unreacted Sulphanilamide is also a factor

Non-aqueous provision

The content of sulfonyl carbamate is determined

residues by titration of a solution of the product in anhydrous dimethylformamide with emer 0, In solution of lithium methylate in

an anhydrous

Methanol-toluene mixture

The result is printed out as N- (p-ar | iinobenzenesulfonyl) methyl carbamate
In this determination the sulfanilamide is not determined, but at the same time the N- (p-methoxycarbonylammobenzenesulfonyl) -methylcarbamite that may be present is determined

Determination of the sulfanilamide content by thin layer chromatography (D -C)

The content of unreacted sulfanilamide is made by using thin layer chromatography of silica gel and a ^ a fluorescent Pigment determined as an indicator

One brings a spot of

solution of the sample and developed

gram in the case of Examples 1 to 11 with a

Mixture of 15 volume parts methanol and 80 volume

report chloroform and for Examples 12 to 17 a mixture of 20 parts by volume of glacial acetic acid and 80 parts by volume of chloroform amide in Examples 1 to 17 and on N- (p-meth-

thanohschen Lct the chromato-

oxycarbonylamiriobenzolsulfonyO-methylcarbamatim The case of Examples 15 and 17 is compared with standardized solutions in ultraviolet light definitely.

These three tests enable the purity of the product to be assessed.

example 1

86 g (0.5 mol) of sulfanilamide are added to one Solution of 0.575 mol of sodium methylate in methanol (prepared by dissolving 13.2 g of sodium in 150 ml of anhydrous methanol) to Man heated with stirring for 35 minutes under reflux conditions 54 g (0.6 mol) of dimethyl carbonate are then added and the mixture is heated under reflux conditions for 16V2 hours

The reaction mixture is distilled. When 89 ml of distillate (the methanol and the unreacted Contains dimethyl carbonate, which can be reused) Add 200 ml of water to the residue and continue distillation until the temperature of the mixture is reached 95 ° C (48.5 ml distillate). Then cool down to room temperature.

The pH of the mixture is adjusted to 7 cm by adding 7 ml of concentrated hydrochloric acid The mixture is inoculated with a little sulfanilamide and stirred for 1 hour. There is no separation of sulfanilamide solid. The mixture is clarified by filtration. You sit under constant agitation 37.5 ml of concentrated hydrochloric acid are added in order to obtain a pH of 3. The precipitate formed is filtered off off, wash it three times with 100 ml of water each time and dry it.

108.5 g of N- (p-aminobenzenesulfonyl) methyl carbamate are obtained (Yield: 94.3% of theory, based on the sulfanilamide)

Properties of the product obtained (continued)

Melting point

140.5 ⁰ C
(Zers)
97.5%

Determination with nitrite. .

Determination in non-aqueous

Medium 96.6%

Sulfanilamide content through

D.-C about 1%

0.035 mol of dimethyl carbonate has been recovered.

The N- (p-aminobenzenesulfonyl) methyl carbamate was also prepared from 0.5 moles of sulfanilamide as outlined above produced, however, the reaction times, the amount of dimethyl carbonate and that of the sodium methylate were varied

The results are shown in the table below indicated (in all of these experiments the amount of methanol used is 150 ml with the exception from example 4, in which it is 100 ml)

at
game Dimethyl
carbonate
(Mole) sodium
methylate
(Mole) Reaction
time
(Hours) Generated
N- (p-ami-
nobenzol
sulfonyl) -
methyl-
carbamate
(G) Yield,
based
on the
Sulfanil
amide
(%) 2
3
4th 0.6
0.6
0.55 0.575
0.575
0.538 8th
10
20th 105.1
105.6
100.8 91.5
91.9
87.9

example

Melting point
( ⁰ C)

139

138.5

137.5

determination With Nitnt

95.2
94.4
95.0

determination in non-water medium

97.5
96.5
95.8

Recovered dimethyl carbonate (mole)

Recovered sulfanilamide

0.04

0.045

0.02

Gebalt

Sulfanilamide by D-C

0 0 0

In Examples 5 and 6, the procedure described in Example 1 was repeated as a whole, however, the dimethyl carbonate was added in two fractions

Example 5

86 g (0.5 mol) of sulfanilamide are added to a methane solution of 0.5 mol of sodium methylate, prepared by dissolving 11.5 g of sodium in 150 ml of anhydrous methanol, added and heated 25 minutes under reflux conditions. 45 g (0.5 mol) of dimethyl carbonate are added. One heats up 36 hours under reflux conditions, 9 g (0.1 mol) of dimethyl carbonate being added after 4 hours

It is distilled until 93.5 cm ^{3 of} distillate is obtained (which contains the methanol and the unreacted dimethyl carbonate, which can be reused) 200 ml of water are added and the mixture is concentrated until the temperature of the mixture has reached 95 ° C ( 49 ml of distillate) 50 ml of water are added to the mixture, the mixture is cooled to room temperature and the pH is adjusted to 7 by the addition of concentrated hydrochloric acid (9.7 ml). A little sulfanilamide is added and the mixture is then stirred for 1 hour. It is filtered and a small amount of unreacted sulfanilamide (5.3 g, 0.03 mol) is recovered. 35.5 ml of hydrochloric acid are added to the filtrate with stirring to obtain a pH of 3. The precipitate formed is washed six times with 50 ml of water each time and dry it. 90.2 g of N- (p-aminobenzenesulfonyl) methyl carbamate (yield: 78.4%, based on the sulfanilamide) with the following properties are obtained

Melting point. ..

Determination with nitrite

Determination in non-aqueous

medium

Sulfanilamide content through

D-C. . about

139 ⁰ C (dec) 99.5%

98.9% 2%

0.035 moles of dimethyl carbamate were recovered

Example 6

The procedure is as in Example 5, except that 0.5 mol Sulfanilamide, 0.6 mole of dimethyl carbonate and 0.525 mole of sodium methylate are used and the Response time is 20 hours.

94 g of N - (ρ - ammobenzenesulfonyl) methyl carbamate are obtained (Yield 81.7% based on the sulfanilamide) with the following properties

Melting point

Determination with nitrite
Determination in non-aqueous

medium
Sulfanilamide content through

D -C about

139 ⁰ C (dec) 99.2%

95.7% 3%

4.0 g (0.023 mol) of sulfanilamide were recovered

Example 7

The procedure is as in Example 5, using 0.5 mol of sulfanilamide, sodium salt, 0.6 mol of dimethyl carbonate and 0.075 mol of sodium methylate and with a reaction time of 22% ₂ hours

105.2 g of N- (p-aminobenzenesulfonyl) methyl carbamate are obtained (Yield 91.7% based on the sulfanilamide) with the following properties

Melting point

Determination with nitrite
Determination in non-aqueous

medium
Sulfanilamide content through

D -C about

138 ° C (dec) 94.9%

96.2% 2%

0.045 moles of dimethyl carbonate were recovered

Example 8

The procedure is as in Example 1 with 0.5 mol of sulfanilamide Potassium salt, 0.6 mol of dimethyl carbonate and 0.075 mol of sodium methylate in one reaction time of 20 hours

95.9 g of N- (p-aminobenzenesulfonyl) methyl carbamate are obtained (Yield 83.1%, based on the sulfanilaintd) with the following properties

Melting point

136 ° C (dec) 96.1%

45

Determination with nitrite
Determination in non-aqueous

Medium 93.9%

Sulfanilamide content through

D-C about 9%

amate from F = 141 ⁰ C (Z; rs) with the following properties

Determination with Nitrr 100.0% Determination of the mighty water

Medium, 99.4%

Sulfanilamide by DjC <0.5%

Example 9

The procedure is as in Example 1 with 0.5 mol of sulfanilamide, sodium salt, 0.6 mol of dimethyl carbonate and 0.075 mol of magnesium methylate with a reaction time of 220 ₂ hours. 102.5 g of N - (p - Ammobenzolsulifonyj) - methyl carbamate (yield 89 2%, based on the sulfanilamide) with the following properties

Melting point

Determination with nitrite
Determination in non-wa

medium
Sulfanilamide content

D-C

There were 0.08 moles of Di
won

B eιspi

One works as in the example
from 0.5 moles of magnesium salt;
situ from sulfanilamide and 1 \
provided), 0.6 mole of dimethyla
Magnesium methylate at e
21 hours You get 63
sulfonyl) methyl carbamate (Ai
on the sulfanilamide) with i

Melting point

Determination with nitrite
Determination in non-wa.

medium
Sulfanilamide content

D-C

0.025 moles of dimethyl carbonate were recovered

The resulting product is purified to obtain lost as follows 25 g of crude N- (p-aminobenzenesulfonyl) methylcarbamate in 250 ml of 1N-hydrochloric acid at 20 to 25 ⁰ C.

A small amount of insoluble product is recovered by filtration, mainly from N- (p-Methoxycarbonylaminobenzenesulfonyl) methyl carbamate consists of washing four times with 5 ml of water each time

Combine the filtrate and the wash waters and adjusts it to pH 3 with 10N sodium hydroxide solution

The product is obtained by filtering and washing it three times with 10 ml of water each time and dry it Man get em N- (p-aminobenzenesulfonyl) -methylcarbigem

urch

14O ⁰ C (Zeis) 98.7%

97.5%

about

ethyl carbonate back

1 10

el 1 using

of sulfanilamide (in

agnesmmmethyl.it hot

■ bonat and 0.0375 mol

he response time of

g N- (p-ammobenzene-

s yield 55.3% based on

Ienden properties

138 ° C (dec) 101.7%

igem

arch

94.9%

There were 0.17 moles of E.
0.18 mole sulfanilamide back

about 12% methyl carbonate and

play 8 described methoc
N - (p - aminobenzenesulfonyl)

The product obtained was after the two

It was rhymed with methylcarbamate

142.5 ⁰ C 99.8%

receive the following properties

Melting point
Determination with nitrate
Determination in non-water

medium
Sulfanilamide du

D-C

Example

You work like in the example
of the sodium salt of sulfane
situ from 0.5 mole sulfanilamide
methylate), 0.6 mol dimethyl approx
Natnumamide in one reaction

; won

according to

eh

11th

99 4% <0.5%

5 prepared using the amide (0.5 mol in nd Natr umbonat and 0.075 mol tiszeit number of _19/2 hours, maintaining 104.8 g of N- (p ^ minobenzolsulfo, iyl) -

109544/387

ίο

IO

methyl carbamate (yield 91.3% based on the sulfanilamide) with the following properties

Melting point 138 ^° C

Determination with nitrite 94.2% determination with low water

Medium 96.8% content of sulfanilamide through

D-C. <5%

Example 12

The procedure is as in Example 1 with 0.5 mol Lithium salt of sulfanilamide (in situ from sulfanilamide and lithium methylate produced), 0.6 mol of dimethyl carbonate and 0.075 mol of lithium methylate a reaction time of 16 hours

108.5 g of N- (p-ammobenzenesulfonyl) methyl carbamate are obtained (yield 94.0%, based on sulfanilamide) with the following properties

Melting point

Determination with nitrite
Determination in non-aqueous

medium
Sulfanilamide content through

D-C <0.5%

0.06 mole of dimethyl carbonate was recovered

Example 13

The procedure is as in Example 1 with 0.5 mol of potassium salt of sulfanilamide (prepared in situ from sulfanilamide and potassium methylate), 0.6 mol of dimethyl carbonate and 0.075 moles of potassium methoxide with a reaction time of 16 hours

81.9 g of N - (p - ammobenzenesulfonyl) methyl carbamate are obtained (yield 71.2%, based on the Sulfanilamide) with the following properties

Melting point. . . 134.5 ° C

Determination with nitrite. 97.1%
Determination in non-aqueous

Medium. 94.5%
Sulfanilamide content through

D-C ... 6%

Example 14

The procedure is as in Example 1 with 0.5 mol of calcium salt of sulfanilamide (prepared in situ from sulfanilamide and calcium methylate), 0.6 mol of dimethyl carbonate and 0.0375 mol of calcium methylate in 1 liter of methanol with a reaction time of 66 hours

35 g of N - (p - aminobenzenesulfonyl) methyl carbamate are obtained (Yield: 30.5% based on the sulfanilamide) with the following properties

14O ⁰ C 25th Melting point. 142 ° C (Zers) Determination with Nitnt 99.8% 95.2% Determination in multi-water medium 97.8% 99.9% Sulfanilamide content through D-C 2%

0.31 moles of dimethyl carbonate and 0.20 moles of sulfanilamide were recovered

Example 15

The procedure is as in Example 1 with 0.5 mol of sulfanilamide, 0.575 mol of sodium methylate and various molar proportions of dimethyl carbonate, the methanol was used as the solvent and the reaction time was 20 hours fraud

The results are shown in the table below cited

Dimethyl
carbonate
(Mole) N- (p-aminobenzene-
sulfonyO-methyl-
carbamate
(G) Yield (based on
on the sulfanil
amide)
(%) determination
with nitrite
(%) determination
in mchtwassngem
medium
(%) Sulfanil content
amid by DC
(X) Salary of minor
products through
DC
(%) 0.5
0.75
1.0 98.5
111.1
113.4 85.7
96.6
98.6 96.6
90.4
87.8 98.2
97.3
96.9 1
<ε1
<1 1
10
20th

N-ip-methoxycarbonylammobenzenesulfonylI-methylcarbamate was formed at the same time. No sulfanilamide was recovered
In all of these experiments the melting point was 14O ⁰ C (decomposition)

example

The procedure is as in Example 1 with 0.5 mol of sulfanilamide, 0.575 mol of sodium methylate, 0.6 mol of dimethyl carbonate and methanol as the solvent, the temperature in the experiments after addition of the dimethyl carbonate from the reflux temperature (65 ° C) to the temperatures given in the table below has been modified

temperature
( ⁰ C) reaction time
(Hours) N- (p-aminobenzene-
sulfonyl) methyl
carbamate
(G) Yield,
related to
Sulfanilamide
(%) determination
with nitrite
(%) determination
in mchtwassngem
medium
(%) Sulfanil content
amid by DC
(%) 50
40 to 45
25th
25th 20th
20th
20th
90 107.1
101.7
42.4
92.6 93.1
88.4
36.9
80.5 99.2
98.8
97.7
101.1 97.5
98.1
97.4
97.6 «El
«El
1
<rl

The melting point was in all cases 14O ⁰ C (dec)

No sulfanilanud was recovered in the first two attempts, but wui [de in the latter two Attempts sulfanilanud recovered, 0.28 and 0.04 moles, respectively

example

The procedure is as in Example 1 with 0.5 mol of sulfanil arm, 0.6 mol of dimethyl carbonate and variable proportions of sodium methylate, methanol being used as the solvent. The reaction times are

wore 16 to 20 hours N- (p-amino-
benzenesulfonyl) - Yield,
based on the Melting point determination determination
in non-water I. stop
Ifanilamide Content of
By-product methyl carbamate
(G) Sulfamlamide of the product
( ⁰ C) with nitrite medium raw D-C by D-C 81.5 70.8 139 100.1 96.2 Si 3 <! 94.0 81.7 139 99.2 95.7 d 3 1 The results are given in the table below 102.7 89.3 139 96.9 97.7 2 1 Sodium methylate 108.5 94.3 140.5 97.5 96.6 <1 Jl (Mole) 108.4 94.3 138 91.8 98.4 <1 6th 0.500 111.8 97.2 137 82.3 92.9 1 If 0.525 88.0 76.5 123 80.8 83.2 5 10 0.550 0.575 0.600 0.750 1.0

The by-product consists of N- (p-methoxycarbonylammobenzenesulfonyl) - methyl carbamate There were 0.07 moles, 0.024 moles and 0.073 moles of sulfanilamide, respectively recovered when the amount of sodium methylate was 0.500, 0.525 and 1.00 mol No sulfanilamide was recovered in the other experiments

Example 18

172 g (1.0 mol) of sulfanilamide are added to a solution of sodium methylate (1.150 mol) in methanol (prepared by dissolving 26.5 g of sodium in 300 ml of anhydrous methanol) heated to man with stirring for 1 hour under reflux conditions 108 g (1.2 mol) of dimethyl carbonate are then added and heated for 17 hours under reflux conditions. Then 180 ml of distillate are distilled (which contains the methanol and the unreacted dimethyl carbonate, which are reused can) are obtained, 400 ml of water are added and the distillation is started under reduced pressure continued, taking care that the temperature of the medium remains below 95 ° C until one only water (428 ml of distillate) wins During the distillation, water (80 ml) is added to produce a To avoid significant reduction in the volume of the liquid The final volume of the mixture is 350 ml

It takes 175 ml of the mixture and stirring it with 6 g of calcium chloride for 30 minutes at 50 ⁰ C. The insoluble component which is composed mainly of Calcmmcarbonat, the mixture in the heat is removed washes by filtration, the residue nut 5 ml water and combined the Filtret with the washing liquid one holds 169 ml (217.7 g) of a solution of the sodium salt of N- (p-ammobenzenesulfonyl) methyl carbamate

This solution is used as a herbicide concentrate for the Can be used by atomizing

The determination with nitrite shows a content of 60.6% of N- (p-ammobenzenesulfonyl) methyl carbamate, which corresponds to a yield of 89.2% on the sulfanilamide, corresponds to The solution has a residual carbonate content of 0.1% (Weight / volume) expressed as sodium carbonate, and a cajlcium content of 23 parts each Million auf The N- (p-Ammotbenzenesulfonyl) -methylcarbamate isolated from a sample of the solution by acidification melts at 139.2 ° O (dec) and has a Content when determined in a non-aqueous medium of 98.8%. I.

In this example, the calcium chloride can be replaced by an equivalent amount of calcium oxide (CaI-ciumhydroxyd) corresponding to 13.5 g per 0.5 mol of sulfanilamide used replace ^

Example 19

86 g (0.5 mol) of sulfanilamide are added to a solution of 0.575 mol of potassium methylate in methanol, prepared by dissolving 22.45 g of potassium in 200 ml of methanol. 0.6 mol) of dimethyl carbonate and heated for 40 hours under reflux conditions. Distillation. When 140 ml of distillate (which contains the methanol and the unreacted dimethyl carbonate, which can be reused) has been obtained, 57 ml of water are added and the distillation is continued, until the temperature of the mixture has reached 95 ^° C. (66 ml of distillate), water being constantly added so that the volume remains constant (66 ml)

One cools on rooms *
the pH of the mixture
concentrated hydrochloric acid (14.7
inoculated with a little sulfanilam
It precipitates sulfanilamide that
wins and with 20 ml of water! washes. The filtrate is combined with the wash water and it is made up to with an aqueous 40% (weight / volume) potassium hydroxide solution
molphthalein alkaline Then d
reduced pressure

If you add 86 ml of distillate
the residue to 40 ⁰ C

temperature and adjusts by adding

1) to 6 a. And stir for 1 hour, in by filtering

mschlag of Tbytil is found under

has on, cools b and sets the

Adjust the pH of the mixture to 8 by adding concentrated hydrochloric acid (4.3 ml)
the mixture to 40 ⁰ C and sets;

one. Add 2 g of potassium chloride

to The potassium salt of N- (p-aminobenzene-

sulfonyl) -methylcarbamats from is cooled to 5 ° C., stirred for 1 hour at 5 ° C and the precipitate is suctioned off with suction is dried to completion at 6O ⁰ C and obtained 105.2 g Kahumsalz of N - (p - Ammobenzolsulfonyl) - methyl carbamate, which contains potassium chloride (yield 49.8% of theory, based on the sulfamlamide).

Testing with nitrite
Chloride content

63.4%

(calculated as
Potassium salt)
36.1%

(calculated as
Potassium chloride)

The N- (p-Ammobenzenesulfonyl) -methylcarbamate released from the potassium salt melts at 144 ⁰ C (decomposition) (test with nitrite 99.5%, titer in non-aqueous medium 97.4%)

As before, a second fraction of 19.2 g of the potassium salt of N- (p-aminobenzenesulfonyl) methyl carbamate is isolated from the filtrate (yield 13.2% of theory, based on the sulfamlamide, test with nitrite 91.8%, calculated as Kahumsalz, Chlondgehalt 6.7%, calculated as potassium chloride) the potassium salt of the liberated N- (p-Ammobenzolsulfonyl) methylcarbamate melts (141.3 ⁰ C (dec) examination with nitrite 98.2%, titer in medium nichtwaßngem 97 , 3%)

0.066 moles of dimethyl carbonate and 7.9 g (0.046 moles) of sulfanilamide were recovered

Example 20

0.5 mol of the calcium salt of the sulfanilamide is heated (produced in situ from sulfamlamide and calcium methylate), 0.6 mol of dimethyl carbonate and 0.0375 mol of calcium methylate in 1 l of methanol for 103 hours under reflux conditions

After 23, 46 and 48 hours of heating, 500 ml are distilled (then 470 ml of methanol are contained), 250 ml (then 240 ml of methanol are contained) or 145 ml (then 140 ml of methanol are contained) of solvent After each distillation, dimethyl carbonate is added to the reaction mixture in an amount added, which is equivalent to the amount contained in the distillate m

The reaction mixture is then distilled, after 89 ml (consisting of methanol and unreacted dimethyl carbonate, which can be reused) have passed over, 200 ml of water and then 31 g (0.29 mol) of anhydrous sodium carbonate are added to the residue and the distillation so long, until the temperature of the mixture to 95 ° C is reached is then cooled to 6O ⁰ C and filtered from the precipitated calcium carbonate and the filtrate is cooled to room temperature and adjusted to pH by addition of concentrated hydrochloric acid to 7 em then inoculated to the mixture with a small amount of sulfamlamide and stirred for 1 hour, no sulfamlamide precipitates. Then it is filtered and 37.5 ml of concentrated hydrochloric acid is added to the clear mixture with stirring, a pH of 3 being established. The resulting filter is filtered Precipitate, washed three times with 100 ml of water and dried. 101.4 g of N- (p-aminobenzenesulfonyl) methylcarba are obtained mat (yield 88.2% of theory, based on the Sulfamlamid) of melting point 141 ⁰ C (with decomposition)

Determination with nitrite 103.5%

Determination in non-aqueous
Medium with lithium methylate 96.5%

Content of sulfamlamide through

D-C 10%

0.04 moles of dimethyl carbonate were recovered, sulfamlamide was not recovered

25 g of N prepared as described above - (p - Ammobenzolsulfonyl) - methylcarbamate lost it at 20 to 25 ⁰ C m 250 ml ln-hydrochloric acid is filtered from a small amount of insoluble products off and washed four times with 5 ml of water The combined filtrates and Wash solutions are adjusted to a pH value of 3 by adding 10n sodium hydroxide solution. The precipitate obtained in this way is filtered off, washed three times with 10 ml of water and dried Melting point 141 ⁰ C (with decomposition)

Determination with nitrite 98.5%

Determination in non-aqueous

Medium with lithium methylate 97.3%
Content of sulfamlamide through

D-C less than 0.1%

Example 21

The procedure is as in Example 19, but stirred 2V2 hours at 5 ⁰ C after the addition of potassium chloride to salt out the potassium salt of N - (p - Ammobenzolsulfonyl) - methylcarbamate and hollows to 5 ° C. The precipitate thus obtained is filtered, the filter dried and sucked dry at 6O ⁰ C are obtained, 156.8 g Kahumsalz of N - (p - Ammobenzolsulfonyl) - methylcarbamate mixed with potassium chloride (yield 87.9% of theory, based on the Sulfamlamid taking into account the Kahumchloridgehalts)

Determination with nitrite as
Potassium salt of the N- (p-amino-

benzenesulfonyl) methyl carbamate 69.5%

Chlorine content as potassium chloride 24.8%

The Kahumsalz of free N- (p-Ammobenzolsulfonyi) methylcarbamate melted at 141 ⁰ C (with decomposition)

Determination with nitrite 94.2%

Determination in non-aqueous
Medium with lithium methylate 95.9%

A second deposit was not isolated
0.02 mol of dimethyl carbonate were recovered. Sulfamlamide was not recovered. No unreacted sulfamlamide could be precipitated by acidification with 14.7 ml of concentrated hydrochloric acid and inoculation with an insufficient amount of sulfanilamide. It was therefore not filtered

In the above, the reaction between the salt of the sulfanilamide of the formula II and the Dimethyl carbonate in methanol only at atmospheric pressure It can be seen that this reaction also occurs under a pressure higher than atmospheric pressure can be carried out and that in this case the boiling point of the mixture is consequently increased

Claims (2)

Claims 1 Process for the preparation of N (p-aminobenzenesulfonyl) methyl carbamate the formula SO ₂ - NH - CO - O - CH ₃ and its alkali and alkaline earth salts, thereby characterized in that em sulfanilamide salt the formula H ₂ N SO ₂ NH in which M denotes an alkali or alkaline earth metal atom and η denotes the value 1 when M denotes an alkali metal atom and the value 2 when M denotes an alkaline earth metal atom, with 1 to 1.2 moles of dimethyl carbonate per mole of sulfanilamide under anhydrous conditions in methanol at a temperature of at most the boiling point of the mixture, preferably in the presence of 0.051 to 0.15 mol of a hydride, alcoholate or JAmids of an alkali or alkaline earth metal, per mole of sulfanilamide and, if necessary, the alkali metal or alkaline earth metal obtained by known methods: in the Free N- (p-Ammobenzenesulfonyl) -methylcarbamat transferred 2 The method according to claim 1, characterized in that the reaction is carried out at a temperature between 25 and 65 ° C 109544/387