JPS585192B2 - Methyl vinyl sulfide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing methyl vinyl sulfide.

Methyl vinyl sulfide directly converts this into 7/L41-/L
The resulting alkylated compound can be decomposed to obtain ketones [Kondo: Organic Synthetic Chemistry 31, 1011 (1973), K. Osima et al.
al ; J-kner-Chem, Soc, 2
694 (1973)).

Methyl vinyl sulfide is a useful intermediate substance that has many uses because its Li salt can be used for carbonylation, addition of epoxides, etc.

Conventionally, a phosphorus compound was used, butyl lithium (Bu
Li) A method for producing vinyl sulfide by reacting a ketone or aldehyde in the presence of a catalyst is known [Kondo et al.
Organic Synthetic Chemistry 31.1013-1014 (1973))
.

However, this known method uses MeSC as a phosphorus compound.
This method is carried out using a compound such as HP(OMe)2, and the yield of this phosphorus compound itself is low, and it is difficult to obtain.

Moreover, BuLi used as a catalyst is industrially labor-intensive to manufacture and is difficult to obtain.

This known method is therefore difficult to implement industrially.

Furthermore, since BuLi is used as a catalyst in this method, a low temperature (0 DEG C. to -10 DEG C.) is required, and there are difficulties in controlling the temperature.

The present invention provides a method for producing methyl vinyl sulfide, which allows methyl vinyl sulfide to be obtained industrially easily and extremely smoothly.

That is, the present invention general formula (In the formula, R represents a hexyl group or a phenyl group.

) [wherein R is the same as in general formula (I)] This is a new method for producing methyl vinyl sulfide, which can easily obtain the desired product by simply thermally decomposing monoalkyl formaldehyde dimethyl mercaptan S oxide under specific conditions. .

The monoalkyl formaldehyde dimethyl mercaptan S oxide used in the method of the present invention is obtained by reacting FAMSO [Nippon Soda registered trademark, formaldehyde dimethyl mercaptal S oxide] with an alkyl halide such as benzyl bromide or hexyl bromide. is a substance,
The starting materials of the present invention are easily available and can be used to effectively obtain the target product, methyl vinyl sulfide.

Furthermore, the present invention has the advantage of not requiring ketones or aldehydes as in conventional methods.

The above-mentioned FAMSO is a compound that has been attracting attention recently because aldehydes can be obtained by decomposing its monoalkylated product, but it has the disadvantage that it is difficult to synthesize its dialkylated product, making it impossible to obtain asymmetric ketones. [J, B, Riohman et al.
rahedron Lett, 35, 3267, 32
71.

3275 (1973), K., Ogura, G.
Tsuchihashi, 'Tetrahedro
nLett, 3151 (1971), Kokura, Dobashi; Proceedings of the 30th Annual Meeting of Japan Chemical Society 1lI2032 (1974)
), G, 5chill and P, R, Jone
s :communications.

5 synthesis 117 (1974)).

Methyl vinyl sulfide obtained by the method of the present invention can be led to an asymmetric ketone, and therefore, the present invention has great industrial significance as it opens the door to producing asymmetric ketones from FAMSO.

Currently, not only dialkyl FAMSO, which is difficult to synthesize, but also monoalkyl FAMSO, which is easy to synthesize, is difficult to purify by distillation under reduced pressure, and it is difficult to directly synthesize ketones from alkyl FAMSO.

In contrast, the present invention thermally decomposes monoalkyl FAMSO to produce methyl vinyl sulfide, which can be easily purified by distillation, and further converts this into dialkyl methyl vinyl sulfide, opening the door to intermediates for ketone synthesis. .

Next, the method of the present invention will be explained in more detail.

The reaction temperature varies depending on the pressure, and is usually about 90°C or about 20°C.
0°C, and suitably about 140 to about 160°C.

In order to obtain methyl vinyl sulfide, which is the object of the present invention, it is sufficient to simply heat monoalkyl FAMSO at the above temperature and normal pressure. You can get things.

The resulting methylvinyl sulfide cis, tran
It is a mixture of s and usually 6 trans isomers and 4 cis isomers.
System system 0 percentage.

As shown above, the present invention provides a novel method for producing methyl vinyl sulfide. In order to obtain the raw material of the present invention, the present inventors converted halogen from formaldehyde dimethyl mercaptal S oxide (FAMSO'). We also found a new method for deriving monoalkyl FAMSO using an alkyl compound; this will be explained below.

The reaction is generally represented by the following formula.

Here, R is the same as in the above general formula (1).

However, this reaction conventionally uses NaH as a catalyst.

KH was used.

However, such catalysts have drawbacks from the viewpoint of industrial implementation, such as the risk of ignition, being difficult to handle, and causing problems in work.

As a result of study, the present inventor found that the above-mentioned method can be achieved by using a complex such as Na-naphthalene, K-naphthalene, Li-naphthalene, etc. as a catalyst, which is synthesized from naphthalene and an alkali metal such as metallic Na and has no risk of ignition. It has been found that monoalkyl FAMSO can be synthesized in an industrially significant manner despite having the following drawbacks.

Reference examples for the synthesis of monoalkylated products from FAMSO are shown below, followed by examples of the present invention.

Reference example [Synthesis of monoalkylated product of FAMSO] (1
) Under N2 flow, under ice cooling, 1 equivalent of FAMSO 124 g
A previously prepared THF solution containing 1.2 to 1.3 equivalents of Na-naphthalene is gradually added dropwise to 300 rnl of dry tetrahydrofuran solution and stirred for 2 to 3 hours to form a salt.

Furthermore, under water cooling, 1.2 equivalents of n-hexyl bromide was added as the halogen alkyl, and the mixture was stirred at room temperature for 6 hours.

The formed salt was filtered and monohexyl FAMSO TH
A F solution was obtained.

Yield 70% (yield 72% using K-naphthalene), ■R of monohexyl FAMSO; νs = 01030 cm
-1, NMR (δ1nCC14) 3.40, m, 1
H: 2.60, S, 3H: 2.18°S, 3
H; 1.40. m, 10H; 1.00. m.

H0 (2) FAMSO62g (0.05eq.), benzyl bromide 10.3g (0.06eq.), metallic sodium 1.2g (0.05eq.), naphthalene 7.7g (0.05eq.)
The target product, phenylacetaldehyde dimethyl mercaptal S-
Oxide (8.8 g, yield 82%) was synthesized.

Phenyl FAMSO's ■R; C6H5-1500cm
-1. 5=o1030cm-1; NMR(δin
CC14) 7.20, S, 5H; 3.55゜m, 1H; 2.65, m, 5H; 2.10, S,
3H0 Example [Production of methyl vinyl sulfide] (1)
A tetrahydrofuran solution containing 1 equivalent of 208 g of monohexyl FAMSO obtained in Reference Example (1) was thermally decomposed at 140 to 160°C under reduced pressure (20 to 30 mm of mercury) in a N2 stream.

The yield of methylvinyl sulfide obtained by cutting the tongue is 11
5 g, the boiling point was 84-b, and the yield was 80% of the theoretical value.

CiS body (40%), m/e144 (M+); IR
, δC-H7720cm-1; trans body (60%
), m/el 44 (M+) tδC-N93
0cIrL-1; NMR, CiS body 5.50, m
, 2H; trans body, 6. OOt rn t 2
H0(2) Phenyl FAMSO obtained in Reference Example (2)
10.7 g (0.05 equivalents) was thermally decomposed in the same manner as in (1), and the yield of the cis, trans mixture of methylstyryl sulfide obtained was 7.2 g (yield 96%). there were.

This mixture was fractionally distilled (C): boiling point 122-123
°C/15MHg, ■): 123-b Cis-methylstyryl sulfide was obtained by fractionation using a gas chromatograph, and trans-methylstyryl sulfide was obtained from the fraction.

cis body m/e150; IR, c6H51495cm
-1; trans body m/e1 50; IR,
C/C6H5-1500cm-1, δC-H930cm
-1; NMR, cis form 7.30. S, 5H; 6, 30
, m, 2H: 2.35, S, 3H; t
rans body 7.30. S, 5H; 6.50. m, 2H;
2.35. S.

H9

Claims (1)

[Claims] 1 Monoalkyl formaldehyde dimethyl mercaptal S oxide represented by the general formula (in the formula, R represents a hexyl group or a phenyl group) is thermally decomposed at a temperature of 90°C or higher under normal pressure or reduced pressure. A method for producing methyl vinyl sulfide represented by the general formula [wherein R is the same as in general formula (1)].