# US 7,465,802 B2 · Facile synthesis of a series of liquid crystalline 2-(4′-alkylphenyl)-5-cyanopyridines

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- Number: US 7,465,802 B2
- Document ID: US7465802B2
- Status: Granted
- Kind: B2
- Application number: 11/609,910
- Filed: 2006-12-13
- Published: 2008-06-19
- Granted: 2008-12-16
- Earliest claimed: 2006-12-13
- Assignees: Fu Jen Catholic University
- Inventors: Win-Long Chia; Ru-Sung Lu
- Web page: https://patentgrep.com/patent/US7465802B2

## CPC

- C07D 213/85: in position 3
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

The invention relates to a facile synthesis of a series of 2-(4′-alkylphenyl)-5-cyanopyridine liquid crystal compounds which are represented by the following formula (I): wherein Cn is a linear alkyl having 1-12 carbon atoms. The synthesis of the liquid crystalline 2-(4′-alkylphenyl)-5-cyanopyridine is completed in a two-step reaction. First, a Grignard reagent (such as 4-alkylphenylmagnesium bromide) is added to a 3-cyanopyridinium salt (such as N-phenyloxycarbonyl-3-cyanopyridinium chloride) to get a 1,2-dihydropyridine. Then the 1,2-dihydropyridine is oxidized with o-chloronil to obtain the 2-(4′-alkylphenyl)-5-cyanopyridine.

## Claims

### Claim 1

A facile synthetic method for synthesizing a series of 2-(4′-alkylphenyl)-5-cyanopyridine liquid crystal compounds having the following formula (I),
wherein Cn is a linear alkyl group, n=1˜12,
said synthetic method comprising the following steps:
(1) reacting a Grignard reagent with N-phenyloxycarbonyl-3-cyanopyridinium chloride in a nucleophilic reaction to obtain a 1,2-dihydropyridine intermediate; and
(2) oxidizing the 1,2-dihydropyridine intermediate with an oxidant to obtain 2-(4′-alkylphenyl)-5-cyanopyridine liquid crystal compounds.

### Claim 2 (depends on 1)

The facile synthetic method for synthesizing a series of 2-(4′-alkylphenyl)-5-cyanopyridine liquid crystal compounds of claim 1, wherein said Grignard reagent is produced by adding magnesium to 4-bromoalklybenzene.

### Claim 3 (depends on 1)

The facile synthetic method for synthesizing a series of 2-(4′-alkylphenyl)-5-cyanopyridine liquid crystal compounds of claim 1, wherein said N-phenyloxycarbonyl-3-cyanopyridinium chloride is formed by adding phenyl chloroformate to 3-cyanopyridine.

### Claim 4 (depends on 1)

The facile synthetic method for synthesizing a series of 2-(4′-alkylphenyl)-5-cyanopyridine liquid crystal compounds of claim 1, wherein said oxidant is o-chloronil.