DE1051859B - Process for the preparation of pyrimidyl-2-sulfenomorpholides - Google Patents

Description

GERMAN

It is known that sulfenamides can be prepared by reacting sulfenic chlorides with amines. To the Example you have in this way phenylsulfenchloride and diethylamine to the corresponding sulfenamide according to the implemented the following reaction equation:

Method of manufacture
of pyrimidyl-2-sulfenomorpholides

-s-ci + hn;

CoH _s

C2H5 '>

-S-N-

CoH _s applicant:
Chemical works in Hüls
Corporation,
Marl (district of Recklinghausen)

However, such a process has the disadvantage that one of the often only accessible in unsatisfactory yield Sulfenchlorides, which are easily decomposable, sensitive to moisture and difficult to handle, run out got to. This method is also not generally applicable. So it has been shown that, for example, the production of 4-methylpyrimidyl-2-sulfenmorpholide is not satisfactory in the above manner succeed.

It is also known that sulfenamides can be obtained by reacting mercaptides with N-halogen derivatives of secondary amines (cf. Journal of organic chemistry, Vol. 14 [1949], p. 922). In particular, N-chloromorpholine reacted with 2-mercaptobenzothiazole in inert solvents to benzothiazole-2-sulfenmorpholide (cf. USA patent Re. 19 226 and German patent specification 950 465).

It has been found that pyrimidyl-2-sulfenomorpholides can be prepared in good yield and using readily available and convenient starting compounds if alkaline solutions of 2-mercaptopyrimidines are gradually introduced into N-halomorphs. Suitable solutions of alkali or alkaline earth metal hydroxides, eg. B. an aqueous or alcoholic solution. Suitable 2-mercaptopyrimidines are, for. B. 4-alkyl-, 4,5-dialkyl- and 4,5,6-trialkyl-2-mercaptopyrimidines, especially Dr. Walter Franke and Dr. Willi Ziegenbein, Marl (Kr. Recklinghausen), have been named as the inventor

4-methyl- and 4,6-dimethyl-2-mercaptopyrimidine or the corresponding aryl derivatives of pyriridine. These connections are e.g. B. by reacting thiourea with 1,3-dicarbonyl compounds convenient and accessible in good yield. The best N-halomorpholine to use is N-chlorine or N-bromomorpholine, but preferably N-chloromorpholine, which z. B. after that in "Journal of the American Chemical Society ", Vol. 72 (1950), p. 2280, indicated procedures conveniently and in quantitative yield can be.

The reaction is expediently carried out in such a way that an aqueous and / or an alcoholic solution of an alkali salt of a 2-mercaptopyrimidine is gradually introduced into an N-halogen morphon. The reaction takes z. B. for the following case the following course:

CH ₃ CH ₃

Ln,. ν Jk _x

■ ^χ ^ S-Na + Hai —N _{x y} 0 > ■ κ > —S —Ν:, O + NaHal

\ = _N / ^{X /} \ = _N / ^{X X}

It is surprising that compounds can be oxidized so easily to the corresponding disulfides by reaction with N-chloromorpholine, which is known to be a relatively strong oxidizing agent, not in the disulfide compounds but can actually form an S-N bond.

The process products are vulcanization accelerators and can be used as intermediates for pharmaceutical Industry can be used.

The parts given in the examples are parts by weight.

809 768/525

example 1

12.5 parts of 2-mercapto-4-methylpyrimidine are dissolved in 200 parts of water containing 4 parts of sodium hydroxide solution Solution brought. This solution is dissolved in 12.5 parts of N-chloromorpholine while stirring and initially cooling with ice dripped in. When the temperature no longer increases, the mixture is slowly heated to 30 to 40 ° C and maintain this temperature for 1 to 2 hours. The reaction mixture turns a light yellow-brown, and that The reaction product is largely separated out as a solid substance. The reaction mixture becomes exhaustive with Ether extracted, the ether solution dried over sodium sulfate and the solvent removed by distillation. After cooling, a solid, brownish residue remains (15 parts). By recrystallizing twice from aqueous methanol, 4-methylpyrimidyl-2-sulfenmorphohd is obtained in the form of almost white, fine needles, m.p. 93 to 94 ° C

The substance is soluble in ether f, methanol, chlorinated hydrocarbons such as carbon tetrachloride and chlorides ⁰ roform, benzene, and slightly soluble in water.

Example 2

40 parts of 2-mercapto-4-methylpyrimidine are dissolved in 800 parts of methanol containing 16 parts of sodium hydroxide, solved. The solution is dissolved in 40 parts of N-chloromorpholine while stirring and initially cooling with ice dripped in. When the heat of reaction subsides, the mixture is heated to 30 to 40 ° C. for a further 1 to 2 hours warmed up. Most of the sodium chloride that forms is precipitated during the reaction and becomes removed by filtration. The methanolic solution is then strongly concentrated, after Cooling in ice water and adding a small amount of water to the concentrated solution of the reaction product the 4-methylpyrimidyl-2-sulfenmorpholide crystallized out. After drying in a vacuum desiccator 55 parts of the reaction product are obtained, which is already quite pure (mp 90 to 92 ° C.). After two recrystallization from methanol-water (80:20 parts by volume) the substance melts at 93 to 94 ° C Mother liquor can still receive 2 parts of the substance.

45

Example 3

28 parts of 2-mercapto-4,6-dimethylpyrimidine are in 200 parts by volume of methanol, the 8 parts of sodium hydroxide contained, solved. The filtered solution is converted into 26 parts of N-chloromorpholine which has been pre-cooled to 0 ° C. while stirring and cooling with ice dripped in. The excretion of sodium chloride begins immediately. Towards the end of the implementation will the reaction mixture is heated to 30 to 40 ° C. for a further 1 to 2 hours. After that, sodium chloride is used (11 parts) filtered off and the methanolic filtrate evaporated to dryness in vacuo. One remains behind crystallized mass consisting of crude 4,6-dimethylpyrimidyl-2-sulfenmorpholide (37 parts). After recrystallization from a methanol - water mixture (70:30 parts by volume, the pure melts in white crystals accruing substance at 98 ° G.

To illustrate this with, for example, 4-methylpyrimidyl-2-sulfenmorpholide as a vulcanization accelerator compared to the benzothiazolyl-2-sulf enmorpho-Iid obtainable according to German patent specification 950 465 Technical progress achieved with both compounds were suitable and commonly used Test mixtures measurements carried out and their results summarized in the following tables.

Table 1

Dependence of the module and the breaking strength on pressure and time in the press

Scorch
and bakeout
in the press Benzthiazolyl
2-sulfenomorpholide
(at 300%
Strain) 4-methylpyrimidyl-
2-sulfenomorpholide
(at 300%
Strain) pressure
in at Time
in
Minutes module fracture
firm
speed
kg / cm ² module fracture
firm
speed
kg / cm ² 1.0 30th 22nd 80 6th 30th 1.0 45 64 245 13th 60 1.5 23 43 190 8th 45 1.5 35 74 260 43 175 2.0 15th 37 165 10 45 2.0 25th 73 250 48 190 3.0 10 36 175 27 125 3.0 20th 81 260 77 245 3.0 30th 79 245 85 245 3.0 60 63 205 77 220 3.0 90 60 205 75 210

Table 2

Dependence of the defo hardness on the vulcanization time

Defo hardness (DH) of the raw mixtures, tempered at 135 ° C

Time in minutes Benzthiazolyl
2-sulfenomorpholide 4-methylpyrimidyl-
2-sulfenomorpholide 15th 1200 1000 40 13,000 1400 50 19,000 9,000 55 20,000 11 500

Table 3

Dependence of the module and the breaking strength on pressure and time in the press

Scorch
and bakeout
in the press Benzthiazolyl
2-sulfen-
morpholid (at
300% elongation) 4-methylpyrimidyl-
2-sulfen-
morpholid (at
300% elongation) fracture fracture pressure
in at time in
Minutes module firm
speed
kg / cm ² module firm
speed
kg / cm ² 2 30th 22nd 100 40 53 180 5 10 60 83 185 51 155 3 30th 50 170 5 10 45 88 200 74 190 65 93 200 86 185

Thereafter, the temperature and time dependencies of the breaking strengths and defo-hardening result from the course corresponding samples for the 4-methylpyrimidyl-2-sulfenmorphoHdein very considerably delayed Use in vulcanization. (For the measurements, the results of which are given in Tables 2 and 3, was 2.4 times the amount of VulkamsationsbescUeuniger on which Table 1 is based.)

Claims (1)

Table 4 Abrasion losses according to DIN 53516 Anvulfca
and Au.
in the
pressure
in at nization
iheating
Press
time in
Minutes Benzt
2-su
morp
fresh liazole
window
holid
gcaicerc
8 days
Sour
fabric
plot 4-methyl]
2-su
morp
fresh jyrimidyl
window
holid
göd.ILcl L
8 days
Sour
fabric
plot 3 30] ö
45 3
Sr "
60 I.
90 years OO OO
OO 00 128
123 85
85 115
118 The use of 4-methylpyrimidyl-2-suKenmorpholid thus results in a reduction in the abrasion of the vulcanized products. Claim. Process for the preparation of pyrimidyl-2-sulfenmorpholiden, characterized in that one gradually introduces alkaline solutions of 2-mercaptopyrirnidines into N-halomorpholines. Considered publications: German Patent No. 950,465; U.S. Patent No. Re 19,286; Journal of organic chemistry, 14: 922 (1949). © 809768/525 2.59