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Preparation method of cyclopentadiene

A technology for cyclopentadiene and dichloromethane, which is applied in the field of intermolecular one-step synthesis of polysubstituted cyclopentadiene, and achieves the effects of mild conditions, simple operation, and easy availability of raw materials and reagents

Inactive Publication Date: 2014-01-08
NORTHEAST NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] So far, the preparation of highly functionalized cyclopentadienes from functionalized dithioketenes and propargyl alcohols under Lewis acid catalysis has not been reported in the literature.

Method used

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  • Preparation method of cyclopentadiene
  • Preparation method of cyclopentadiene
  • Preparation method of cyclopentadiene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] 1) propargyl alcohol compounds 2a Preparation

[0024]

[0025] Anhydrous tetrahydrofuran (THF) (100 mL) and phenylacetylene (0.190g, 10 mmol) were added to a 25 mL round bottom flask equipped with a magnetic stirring device, and then n-butyllithium (4.0ml, 9.5 mmol) was slowly added dropwise. , React for ten minutes, slowly add acetophenone (1.17ml, 10 mmol) dropwise. The reaction has been under an ice bath, anhydrous and oxygen-free conditions, and under agitation. TLC detects the disappearance of the substrate and the reaction ends. Pour the reaction solution into saturated sodium chloride aqueous solution (10 mL), extract with dichloromethane (3×10 mL), combine the organic phases, dry with anhydrous calcium chloride, filter, and then distill under reduced pressure to remove the organic solvent. A solid mixture was obtained, which was subjected to silica gel column chromatography (the eluent was V Petroleum ether : V Ethyl acetate = 20: 1) Obtained 2.00g of white sol...

Embodiment 2

[0032] Dithioketal 1b Instead of in "Example 1" 1a , The temperature is 80 ℃, other conditions are the same as "Example 1", the experimental results are shown in Table 1.

[0033]

[0034] Spectral analysis data 3b :

[0035] 1 H-NMR (500 MHz, CDCl 3 ) δ 7.34 (t, J = 7.5 Hz, 4H), 7.30-7.24 (m, 6H), 4.06-4.03 (m, 2H), 2.61 (q, J = 12.0, 7.5 Hz, 1H), 2.44 (q, J = 12.0, 7.5 Hz, 1H), 1.90 (q, J = 15.0, 7.5 Hz, 2H), 1.79 (s, 3H), 1.00 (t, J = 7.5 Hz, 3H), 0.94 (t, J = 7.5 Hz, 3H), 0.73 (t, J = 7.5 Hz, 3H); 13 C-NMR (CDCl 3 , 125 MHz) δ 165.0, 158.6, 145.7, 143.7, 138.2, 135.5, 134.5, 129.3, 128.7, 128.4, 127.8, 127.7, 127.2, 127.1, 126.5, 65.9, 60.5, 27.7, 26.9, 21.0, 14.5, 14.2, 13.6 ; HRMS (ESI) m / z calculated for C25H29O2S2 [M+H] + : 425.1609, found 425.1612.

Embodiment 3

[0037] Dithioketal with amide group 1c Instead of in "Example 1" 1a , Has been a solvent, and the temperature is 15°C. Other conditions are the same as "Example 1". The experimental results are shown in Table 1.

[0038]

[0039] Spectral analysis data 3c :

[0040] 1 H-NMR (500 MHz, CDCl 3 ) δ 7.43 (d, J = 7.0 Hz, 2H), 7.36 (t, J = 7.5 Hz, 2H), 7.32-7.23 (m, 6H), 6.34 (s, 1H), 5.81 (s, 1H), 2.55 (q, J = 12.5, 7.5 Hz, 1H), 2.46 (q, J = 12.5, 7.5 Hz, 1H), 1.97-1.93 (m, 2H), 1.75 (s, 3H), 0.98 (t, J = 7.5 Hz, 3H), 0.74 (t, J = 7.5 Hz, 3H); 13 C-NMR (CDCl 3 , 125 MHz) δ167.0, 153.5, 146.9, 142.8, 138.7, 137.9, 134.5, 128.7, 128.3, 128.0, 127.6, 127.1, 126.3, 61.4, 27.8, 0 27.3, 20.8, 14.45, 14.4; HRMS (ESI) m / z calculated for C 23 H 26 NOS 2 [M+H] + : 396.1456, found 396.1457.

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Abstract

The invention relates to a preparation method for intermolecular one-step synthesis of polysubstituted cyclopentadiene under the catalysis of Lewis acid, characterized by under the catalysis of Lewis acid, firstly coupling functionalized ketene dithioacetal to propargyl alcohol, carrying out intramolecular cyclization reaction on alkenyl allene intermediate substituted by di-alkylthio, then allowing alkylthio to conduct tetra-sites diffusion to cyclopentadiene, and conducting a series of tandem reaction to realize the one-step synthesis of high functionalized cyclopentadiene, wherein R1 represents aryl, alkyl and amino, R2 and R3 represents aryl and alkyl, R' represents alkyl, and R3 represents aryl. According to the invention, high purity cyclopentadiene derivatives can be effectively obtained.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis chemistry, and relates to a Lewis acid-catalyzed intermolecular one-step preparation method for synthesizing multi-substituted cyclopentadiene. Background technique [0002] Cyclopentadiene is a very important class of carbocyclic compounds. It is not only the key structural unit of many biologically active natural products, drugs, and organic conductive materials, but also a versatile organic synthon. Therefore, the development of cyclopentadiene synthesis The method has always been one of the important research directions of organic synthetic chemistry ( J. Am. Chem. Soc, 2005, 127 , 11606-11607.; Chem. Commun., 2010 , 46, 2247–2249.; Org. Lett., 2009 , 11, 4458-4461.). The methods that have been developed so far include: Nazarov cycling synthesis reaction, intramolecular synthesis reaction, multi-component coupling methodology and other multi-step operation reactions. Amo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C323/22C07C323/61C07C319/20
Inventor 毕锡和房忠雪宋金娜
Owner NORTHEAST NORMAL UNIVERSITY