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Aryl Halides to Thiophenols using Thiourea

Jap. Pat. 63-203632, translated by 6079_Smith_W_II
(format & minor edits by metanoid)
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...I've been having a bit of trouble with this one -- the scan quality of the document is not very good in either of the versions I have, there are some complicated (to me) run-on sentences, whine whine excuses etc etc... mainly the problem is I still suck at Japanese.

Here's the meat of the patent, the experimental part... I'll tackle the rest of it in a bit, as it does look interesting.


Patent JP63203632, 1988-08-23
Inventors: TSUJII YASUHIRO; UENISHI HISAYOSHI, KIMURA TOKIYA
Applicant: ISHIHARA SANGYO KAISHA LTD
Application:JP19870035316 19870218
IPC: C 07 B 45/06; C 07 D 213/70

(Skipping summary description, theory stuff for now ...)

Example of Execution 1

181.5g 2-chloro-3-trifluoromethylpyridine and 114g thiourea were dissolved in 91g acetic acid, and reacted at 90 degrees C for 1 hour.

After the end of this reaction, and after the reaction mixture cooled, 600ml of 20% sodium hydroxide solution was thrown in; next the aqueous layer was washed with methylene chloride and afterwards the pH of the solution was adjusted to 6-7 with hydrochloric acid; the formed crystals were separated, washed, and dried, to obtain 166g 2-mercapto-3-triflouromethylpyridine (yield 92.7%). Furthermore, in this reaction process bad odors were not generated.

Comparison example

A reaction was performed in a similar manner to Example of Execution 1 above with the exeptions that the 91g of acetic acid was replaced with 1l of ethanol, the reaction temperature was 80 instead of 90 degrees C, and the reaction time was 26 hours instead of 1 hour. 98.9g of the target compound was obtained (yield 55%) upon completion of this halide compound and thiourea reaction. Also, in this reaction process a bad odor was generated.

Examples of Execution 2-15

These were performed in the manner of Example of Execution 1, with the raw materials used shown in the following Table 1-1, and the reaction conditions shown in Table 1-2; results are shown in Table 1-2.


Table 1-1
Example
of
Exec.
No.
Raw materials
Halide substance Specific Carboxylic Acid thiourea
Type Quantity(g) Type Quantity(g) Quantity(g)
2 2-chloro-5-trifluoromethylpyridine 200 acetic acid 100 167
3 2-chloro-3-trifluoromethylpyridine 363 50% acetic acid
aqueous soln.
360 228
4 2-fluoro-3-trifluoromethylpyridine 16.5 acetic acid 16 15.2
5 2-bromo-3-methylpyridine 17.2 acetic acid 8 15.2
6 2-chloro-5-hydroxycarbonylpyridine 10 acetic acid 10 7.8
7 2-chloro-5-aminocarbonylpyridine 5.0 acetic acid 10 4.9
8 2-chloro-5-cyanopyridine 4.0 acetic acid 4 4.4
9 2-chloro-5-nitropyridine 10.0 acetic acid 5 9.6
10 2,3,5-trichloropyridine 36.5 acetic acid 18 22.8
11 2-bromopyridine 10.0 acetic acid 5 9.6
12 5-bromo-2-chloropyridine 10.0 acetic acid 10 7.7
13 5-bromo-3-methylene thiazole 3.0 acetic acid 10 2.6
14 benzylbromide 4.5 acetic acid 5 4.4
15 2-bromothiazole 6.0 acetic acid 6 5.6

Table 1-2
Example of Exec. No. Reaction Condition of Alkaline Substance Goal Substance
Reaction Temp (C) Reaction Time (Hours) Alkali Type Alkali Quantity (g) Species Yield (%)
2 70-80 1.3 NaOH 174 2-mercapto-5-trifluoromethylpyridine 88.3
3 95-100 1 NaOH 310 2-mercapto-3-trifluoromethylpyridine 94.3
4 110 6 NaOH 14 2-mercapto-3-trifluoromethylpyridine 59
5 95 1 NaOH 15 2-mercapto-3-methylpyridine 53.6
6 95 1 NaOH 20 2-mercapto-5-hydroxycarbonylpyridine 83.3
7 95 0.3 NaOH 10 2-mercapto-5-aminocarbonylpyridine 91.6
8 85 2 NaOH 5 2-mercapto-5-cyanopyridine 94.1
9 90 0.5 NaOH 10 2-mercapto-5-nitropyridine 90
10 100 2 NaOH 30 2-mercapto-3,5-dichloropyridine 73.3
11 70 2 NaOH 9.5 2-mercapto-pyridine 95
12 80 0.3 NaOH 8 5-bromo-2-mercaptopyridine 98
13 75 2 NaOH 8 3-methyl-5-mercaptoisothiazole 96
14 80 1 NaOH 3 benzylthio alcohol 92
15 80 0.5 NaOH 7 2-mercaptothiazole 95

Similarly with the exception of the halide substance, from for example 2-bromopyrazine, 3-bromopyridazine, 4-bromo-1-methylimidazole, 2-bromo oxazole, 5-bromo-4-nitro-isoxazole, 5-bromo-1-methyl-4-nitropyrazole, 3-bromo-1,2,4-triazole, and 2-bromotriazine, used in the reaction of Examples of Execution 1-15 above, 2-mercaptopyrazine, 3-mercaptopyridazine, 4-mercapto-1-methyl-imidazole, 2-mercapto oxazole, 5-mercapto-4-nitroisoxazole, 5-mercapto-1-methyl-4-nitropyrazole, 3-mercapto-1,2,4-triazole, and 2-mercaptotriazine would be obtained.


{Invention conclusion....)


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