Cis-trans isomerisation of semicarbazone compounds

一种化合物、异构化的技术,应用在旋光化合物分离、有机化学、有机化学方法等方向,能够解决不具有E/Z比、低产率分离产物、结晶费时等问题

Active Publication Date: 2006-12-13
BASF SE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Second, the crystallization of the E-isomer I-E in the presence of the Z-isomer I-Z is time-consuming and difficult
Third, it is also time-consuming and difficult to recrystallize the isolated product I, which contains significant amounts of the undesired Z-isomer, to obtain the desired E / Z ratio
These situations involve the risk of isolating the product in low yield or not having the required E / Z ratio

Method used

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  • Cis-trans isomerisation of semicarbazone compounds
  • Cis-trans isomerisation of semicarbazone compounds
  • Cis-trans isomerisation of semicarbazone compounds

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] Conversion of the pure Z-form of compound I.1 into its E-form

[0050] A mixture of 2 g of the Z-isomer I.1-Z and 0.04 g of iodine was heated at 90° C. in a sealed tube. Liquid chromatography (see below) indicated that the product contained 97.8% of the E-isomer I.1-E and 2.2% of the Z-isomer I.1-Z (E / Z ratio 97.8:2.2). Iodine was then removed under vacuum at 90°C for 2 hours. The recovery yield was 100%. No other impurities were detected by liquid chromatography.

[0051] Liquid chromatography: column: reverse phase RP 8-column, Kromasil 100-3.5C8; unit: acetonitrile / (water+0.1% trifluoroacetic acid, pH 2.4) gradient; detection: UV 2235.4nm.

Embodiment 2

[0053] Treatment of crude reaction mixture containing 97.3% of compound I.1 with an E / Z ratio of about 4.9:1

[0054] 2 g of a solid containing about 97.3% of compound I.1 with an E / Z ratio of about 4.9:1 and 0.04 g of iodine were heated in a sealed tube at 90° C. for 2 hours. Iodine was then removed in vacuo by drying overnight at 90°C. The recovery yield was about 100%. No other impurities were detected. The product contained 95.9% by weight of the E-isomer I.1-E and 1.4% by weight of the Z-isomer I.1-Z, determined by liquid chromatography (E / Z ratio 68.5:1).

Embodiment 3

[0056] Conversion of pure Z-form compound I.1

[0057] 2 g of compound I.1-Z and 0.1 g of iodine were suspended in 8 g of chlorobenzene and the resulting slurry was heated at 60° C. for 6 hours. The reaction mixture was then cooled and 10 g of hexane was added. The reaction product was filtered and dried overnight in an oven at 70 °C. 1.8 g of product are thus obtained. The resulting E / Z ratio is about 12:1.

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Abstract

The present invention relates to the isomerisation of the Z-isomer I-Z of semicarbazone compounds of the general formula (I) into its E-isomer I-E, where the variables in formula (I) have meanings given in claim 1.

Description

Background technique [0001] The present invention relates to the isomerization of the Z-isomer I-Z of a semicarbazone compound of general formula I into its E-isomer I-E: [0002] [0003] Wherein the variable of formula I has following meaning: [0004] m, p and q are each independently an integer of 0, 1, 2, 3 or 4; [0005] R 1 , R 2 , R 3 Each independently is halogen; OH; CN; NO 2 ; [0006] C 1 -C 6 Alkyl, which is optionally replaced by C 1 -C 4 Alkoxy, C 1 -C 4 Haloalkoxy or C 3 -C 6 Cycloalkyl substitution; [0007] C 1 -C 6 Haloalkyl; [0008] C 3 -C 6 Cycloalkyl; [0009] C 1 -C 6 Alkoxy, which is optionally replaced by C 1 -C 4 Alkoxy or C 3 -C 6 Cycloalkyl substitution; [0010] C 1 -C 6 Haloalkoxy; [0011] C 1 -C 6 Alkylcarbonyl; [0012] C 3 -C 6 Cycloalkoxy; [0013] C 1 -C 6 alkoxycarbonyl or [0014] C 1 -C 6 Alkoxycarbonyloxy. [0015] Semicarbazone compounds of the general formula I are known from EP-A-462456 to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C281/14C07B57/00C07B61/00
CPCC07C281/14C07B57/00C07B61/00
Inventor 刘卫国P·哈林顿
Owner BASF SE
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