JPS642571B2 - - Google Patents

Description

Detailed Description of _the Invention The present invention is based _on the general formula () α, ω-dihalogeno hydrocarbons represented by
Dehydrohalogenation selected from the group consisting of phosphoric acid hexamethyltriamide, lithium dicyclohexylamide, dimethyl sulfoxide, sodium ethylate-dimethyl sulfoxide and 1,5-diazabicyclo[5,4,0]undecene-5-dimethyl sulfoxide It is characterized in that dehydrohalogenation is carried out by using an approximately equimolar amount of a oxidizing agent with respect to the α,ω-dihalogeno hydrocarbon ().

This invention relates _to a method for producing monoalkenyl halides _represented by _the general formula ()

Conventionally, the compound represented by the general formula () has been obtained by halogenating the corresponding alkenyl alcohol, but many of the corresponding alkenyl alcohols are difficult and expensive to produce. There is also a method of adding hydrogen halide to diene hydrocarbon to synthesize monohalogenoalkenyls, but this reaction is limited to certain types of compounds and produces many by-products. The present invention uses an α,ω-dihalogeno hydrocarbon () having halogen atoms at both ends, which is easy to obtain industrially, as a raw material and dehydrohalogenates one molecule of the molecule to produce a monomer having double bonds. It was discovered that halogenoalkenyls () can be easily obtained.

To explain the present invention in more detail, specific examples of α,ω-dihalogeno hydrocarbons represented by the general formula () used as raw materials include 1,4-dichlorobutane, 1,4-dibromobutane, 1,4-
diiodobutane, 1,5-dichloropentane,
1,5-dibromopentane, 1,5-diiodopentane, 1,6-dichlorohexane, 1,6-dibromohexane, 1,6-diiodohexane,
1,7-dichloroheptane, 1,7-dibromoheptane, 1,7-diiodoheptane, 1,8-dichlorooctane, 1,8-dibromooctane,
Examples include 1,8-diiodooctane, and the target monohalogenoalkenyls represented by the general formula () include 3-butenyl chloride, 3-butenyl bromide, 3-butenyl iodide, 4-pentenyl chloride, 4-pentenyl bromide, 4-pentenyl iodide, 5-
Hexenyl chloride, 5-hexenyl bromide, 5-hexenyl iodide, 6-heptenyl chloride, 6-heptenyl bromide, 6-heptenyl iodide, 7-octenyl chloride, 7
-octenyl bromide, 7-octenyl iodide, etc. Dehydrohalogenating agents include hexamethyltriamide phosphate, sodium amide-hexamethyltriamide phosphate, lithium dicyclohexylamide, dimethyl sulfoxide, sodium ethylate-dimethyl sulfoxide, 1,5-diazabicyclo[5,4, 0] undecene-5-dimethyl sulfoxide, but is not limited thereto. Among these, a particularly preferred dehydrohalogenating agent is hexamethyltriamide phosphate, which will be described in detail.

This reaction is preferably carried out under stirring in a nitrogen stream, but may also be carried out in air.

The reaction temperature is 50~250°, preferably 150°~
200°, reaction time is 5 minutes to 6 hours, preferably 10
It is from minutes to 1 hour. The amount of hexamethyltriamide phosphate used is preferably equimolar to the α,ω-dihalogeno hydrocarbon ().

Furthermore, in this reaction, the reaction product is distilled out during the reaction, so the target product can be fractionated with an extremely simple operation.

This reaction involves α,ω-dihalogeno hydrocarbons ()
is reacted with phosphoric acid hexamethyltriamide, generally under heating, to easily synthesize a dehydrohalogenated alkenyl halide (). The compound () thus obtained is a highly reactive compound, is used as a reagent, is useful as an intermediate for pharmaceutical synthesis, and facilitates its production method. The present invention will be explained below with reference to Examples, but is not limited thereto.

Example 1 Method for producing 5-hexenyl bromide A mixture of 13.6 g of 1,6-dibromohexane and 10 g of hexamethyltriamide phosphate was heated and stirred at 200° in a nitrogen stream, and the liquid immediately distilled was subjected to atmospheric distillation. 7.2 g (yield: 79.1%) of 5-hexenyl bromide was obtained as a colorless oil with a boiling point of 146-148° (760 mmHg).

NMR (CCl ₄ ) δ: 3.34 (2H, triplet, J=6
Hz, Br―C H ₂ -), 4.77~6.07 (3H, multiplet,
olefin proton).

Example 2 Process for producing 3-butenyl bromide A mixture of 10 g of 1,4-dibromobutane and 8.3 g of hexamethyltriamide phosphate was subjected to a similar reaction to produce 3-butenyl bromide as a colorless oil with a boiling point of 98-100° (760 mmHg). Butenyl bromide 5.1g (yield 81.6
%).

Reference Example 1 (When 2 mol of dehydrohalogenating agent is used based on the raw material) A mixture of 13.6 g of 1,6-dibromohexane and 20 g of hexamethyltriamide phosphate was heated and stirred at 200°C in a nitrogen stream. , the product was subjected to atmospheric distillation. Although 1,5-hexadiene was confirmed as a product, the desired 5-hexenyl bromide could not be isolated.

Claims (1)

[Claims _] 1 General formula ₍ ) The α,ω-dihalogeno hydrocarbons represented by include hexamethyltriamide phosphate, sodium amide-hexamethyltriamide phosphate, lithium dicyclohexylamide, dimethyl sulfoxide, sodium ethylate-dimethyl sulfoxide, and 1,5
-Diazabicyclo[5,4,0]undecene-5
- Dehydrohalogenation is carried out by using a dehydrohalogenating agent selected from the group consisting of dimethyl sulfoxide in an approximately equimolar amount to α,ω-dihalogeno hydrocarbons (). _A method for producing monoalkenyl halides _represented by _the general formula ()