Acetic Anhydride → Carbon Dioxide

2,6-Dichloropyridin-4-amine can be added in portions to concentrated sulfuric acid, followed by the addition of fuming nitric acid to provide 2,6-dichloro-3-nitropyridin-4-amine. The reaction is typically performed at reduced temperature before warming to ambient temperature. 2,6-Dichloro-3-nitropyridin-4-amine can be reacted with N-bromosuccinimide in acetic acid to provide 3-bromo-2,6-dichloro-5-nitropyridin-4-amine. The reaction is typically performed at elevated temperature. Reduction of -bromo-2,6-dichloro-5-nitropyridin-4-amine with Raney nickel and hydrogen gas can provide 5-bromo-2,6-dichloropyridine-3,4-diamine. The reaction may be performed at ambient temperature in a solvent such as but not limited to ethanol. 7-Bromo-4,6-dichloro-1H-imidazo[4,5-c]pyridine can be prepared by reacting 5-bromo-2,6-dichloropyridine-3,4-diamine with triethyl orthoformate and acetic anhydride. The reaction is typically performed at elevated temperature. N,N,N′,N′-Tetramethylethylenediamine can be added to 7-bromo-4,6-dichloro-1H-imidazo[4,5-c]pyridine followed by the addition of n-butyllithium and then dry carbon dioxide gas to provide 4,6-dichloro-1H-imidazo[4,5-c]pyridine-7-carboxylic acid. The reaction is typically performed at reduced temperature in a solvent such as but not limited to tetrahydrofuran, hexane, and the like, or mixtures thereof. A mixture of 4,6-dichloro-1H-imidazo[4,5-c]pyridine-7-carboxylic acid and thionyl chloride can be refluxed together and concentrated, followed by the addition of aqueous ammonia at reduced temperature in a solvent such as but not limited to tetrahydrofuran to provide 4,6-dichloro-1H-imidazo[4,5-c]pyridine-7-carboxamide. Phosphorus oxychloride can be reacted with 4,6-dichloro-1H-imidazo[4,5-c]pyridine-7-carboxamide at elevated temperature to provide 4,6-dichloro-1H-imidazol-[4,5-c]pyridine-7-carbonitrile. A base such as but not limited to triethylamine can be reacted with 4,6-dichloro-1H-imidazo[4,5-c]pyridine-7-carbonitrile, followed by the addition of 2-(trimethylsilyl)ethoxymethyl chloride to provide 4,6-dichloro-1-((2-(trimethylsilyl)ethoxy)methyl)-1H-imidazo[4,5-c]pyridine-7-carbonitrile. The reaction is typically performed at low temperature followed by warming to ambient temperature, in a solvent such as but not limited to tetrahydrofuran. Compounds of formula (12), can be prepared by reacting 4,6-dichloro-1-((2-(trimethylsilyl)ethoxy)methyl)-1H-imidazo[4,5-c]pyridine-7-carbonitrile with an organozinc compound of formula (2A), wherein Z, A, R1, and n are as described herein and XA is a halide. The reaction typically involves the use of heat and a nickel or palladium catalyst such as but not limited to bis(triphenylphosphine)palladium(II) dichloride or tetrakis(triphenylphosphine)palladium(0) in a solvent such as but not limited to N-methylpyrrolidone, tetrahydrofuran, or mixtures thereof. A compound of formula (IA) wherein B, R2, R3, and m are as described herein, can be reacted with compounds of formula (12) in the presence of a base such as but not limited to N,N-diisopropylethylamine or cesium carbonate to provide compounds of formula (13). The reaction typically requires the use of heat and a solvent such as but not limited to 1,4-dioxane or toluene. Compounds of formula (13) can be heated in a mixture of concentrated sulfuric acid and water to provide compounds of formula (14), which are representative of the compounds of Formula (I).

1. customThe reaction
2. custommay be performed at ambient temperature in a solvent

ORD record

ord-0a034186007249f2a4e96a0abd096de0

Source dataset

uspto-grants-2015_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09212192B2