# US 11,028,091 B2 · Method for producing 3, 6-disubstituted imidazo[1, 2-b]pyridazine derivative

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- Number: US 11,028,091 B2
- Document ID: US11028091B2
- Status: Granted
- Kind: B2
- Application number: 16/494,116
- Filed: 2018-03-13
- Published: 2020-02-27
- Granted: 2021-06-08
- Earliest claimed: 2017-03-14
- Assignees: Daiichi Sankyo Company, Limited
- Applicants: Daiichi Sankyo Company, Limited
- Inventors: Ryoji Koike; Yoshifumi Hachisu; Takafumi Kitawaki; Shohei Shiraishi
- Web page: https://patentgrep.com/patent/US11028091B2

## CPC

- C07D 487/04: Ortho-condensed systems
- C07C 55/14: Adipic acid
- A61K 31/5025: ortho- or peri-condensed with heterocyclic ring systems
- A61P 35/00: Antineoplastic agents
- C07B 61/00: Other general methods
- Y02P 20/55: Design of synthesis routes, e.g. reducing the use of auxiliary or protecting groups
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- C07B: GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR (preparation of carboxylic acid esters by telomerisation C07C67/47; telomerisation C08F)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Provided is a novel and industrially useful method for producing a 3, 6-disubstituted imidazo[1, 2-b]pyridazine derivative. The present invention provides a method for producing a 3, 6-disubstituted imidazo[1, 2-b]pyridazine derivative, which uses 6-fluoroimidazo[1, 2-b]pyridazine as a starting material, while using an aromatic substitution reaction that utilizes C—H activation by means of palladium.

## Claims

### Claim 1

A method for producing a compound represented by Formula (III) or a salt thereof:
wherein PG represents a protecting group for a nitrogen atom, the method comprising reacting a compound represented by Formula (I) or a salt thereof:
with a compound represented by Formula (II) or a salt thereof:
wherein each symbol is as defined above, in a solvent in the presence of a palladium catalyst and a base.

### Claim 2 (depends on 1)

The method according to claim 1, wherein in Formulae (II) and (III), PG is a tert-butoxycarbonyl group.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the palladium catalyst consists of palladium acetate and tris(2-methylphenyl)phosphine.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the base is potassium carbonate.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the solvent is diethylene glycol dimethyl ether.