91872-02-5

Basic information

• Product Name: 4-Amino-3,5-dichloropyridine N-oxide
• Synonyms: 4-Amino-3,5-dichloropyridine N-oxide;Roflumilast Impurity 17
• CAS NO: 91872-02-5
• Molecular Formula: C₅H₄Cl₂N₂O
• Molecular Weight: 179
• Product Categories: pharmacetical
• Mol File: 91872-02-5.mol

Chemical Properties

• Boiling Point: °Cat760mmHg
• Flash Point: °C
• Appearance: /
• Density: g/cm³
• CAS DataBase Reference: 4-Amino-3,5-dichloropyridine N-oxide(CAS DataBase Reference)
• NIST Chemistry Reference: 4-Amino-3,5-dichloropyridine N-oxide(91872-02-5)
• EPA Substance Registry System: 4-Amino-3,5-dichloropyridine N-oxide(91872-02-5)

Safety Data

• Hazardous Substances Data: 91872-02-5(Hazardous Substances Data)

Usage

Uses

Used in Pharmaceutical Industry:
4-Amino-3,5-dichloropyridine N-oxide is used as an impurity in the manufacturing process of Roflumilast (R639700), a selective PDE4 inhibitor and anti-asthmatic medication. Its presence, although as an impurity, is significant in the synthesis and production of this drug, which is utilized for the treatment of asthma and chronic obstructive pulmonary disease (COPD).

Preparation

4-amino-3,5-dichloropyridine-N-oxide is prepared by the following steps:A sealed Carius tube containing 4-nitro-3,5-dichloropyridine-N-oxide (36) (0.4 ?g, 1.9 mmol), aqueous ammonia (1 cm3 of 0.88 gi-l solution) and acetonitrile (1 cm3) ?was heated in a rotating oil bath at 70 OC for 3 h. The mixture was filtered giving a solid ?(0.1 g) and a filtrate, which was extracted into DCM, dried (MgS04) and evaporated ?giving a residue (0.0 g). The solid obtained from the filtration was recrystallised from hot ?methanol giving 4-amino-3,5-dichloropyridine-N-oxide (0.1 g, 30%), m.p. 210 oC from ?MeOH) (M+ found 177.9701. C5H4Cl2N20 requires M+ 177.9701); IR spectra no. 30; ?mass spectra no. 37; nmr spectrum no. 45.

InChI:InChI=1/C5H5Cl2N2O/c6-3-1-9(10)2-4(7)5(3)8/h1-2,10H,8H2

Upstream product

• 22889-78-7 3,5-dichloro-4-aminopyridine 
• 2457-47-8 3,5-dichloropyridine 
• 15177-57-8 3,5-dicholoropyridine N-oxide 
• 18344-58-6 3,5-dichloro-4-nitropyridine N-oxide 

Downstream Products

• 444659-43-2 N-(3,5-dichloro-1-oxido-4-pyridinyl)-8-methoxy-2-(trifluoromethyl)quinoline-5-carboxamide 
• 201285-35-0 1-Cyclohexylmethyl-3-methyl-1H-indole-6-carboxylic acid (3,5-dichloro-1-oxy-pyridin-4-yl)-amide 

Relevant articles and documents

NOVEL HETEROCYCLIC COMPOUNDS USEFUL FOR THE TREATMENT OF INFLAMMATORY AND ALLERGIC DISORDERS: PROCESS FOR THEIR PREPARATION AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM

The present invention relates to novel Phosphodiesterase type 4 (PDE4) inhibitors of the formula (1) and analogs, tautomers, enantiomers, a diasteromers, regioisomers, stereoisomers, polymorphs, pharmaceutically acceptable salts, appropriate N-oxides, pharmaceutically acceptable solvates thereof and the pharmaceutical compositions containing them which are useful in the treatment of allergic and inflammatory diseases including asthma, chronic bronchitis, atopic dermatitis, urticaria, allergic rhinitis, allergic conjunctivitis, vernal conjunctivitis, eosinophilic granuloma, psoriasis, rheumatoid arthritis, septic shock, ulcerative colitis, Crohn's disease, reperfusion injury of the myocardium and reperfusion injury of the brain, chronic glomerulonephritis, endotoxic shock and adult respiratory distress syndrome.

NOVEL HETEROCYCLIC COMPOUNDS USEFUL FOR THE TREATMENT OF INFLAMMATORY AND ALLERGIC DISORDERS

The present invention relates to novel Phosphodiesterase type 4 (PDE4) inhibitors of the formula (1) and analogs, tautomers, enantiomers, diasteromers, regioisomers, stereoisomers, polymorphs, pharmaceutically acceptable salts, appropriate N-oxides, pharm

SYNTHESIS OF QUINOLINE 5-CARBOXAMIDES USEFUL FOR THE PREPARATION OF PDE IV INHIBITORS

In one embodiment, the present application discloses a process for making the compound of the formula:

Polyhalogenated heterocyclic compounds. Part 42. Fluorinated nitrogen heterocycles with unusual substitution patterns

Reductive replacement of fluorine in 3,5-dichloro-2,4,6-trifluoropyridine 2a and pentafluoropyridine 2 using DIBAL and LAH leads to useful syntheses of fluoro and chlorofluoro pyridine derivatives. Replacement of fluorine by bromine using a mixture of HBr and AlBr3 is extremely efficient, giving excellent routes to 2,4,6-tribromo-3,5-difluoropyridine 3. Bromofluoro-pyrimidine and -quinoxaline derivatives have also been efficiently synthesised from perfluorinated precursors. Catalytic hydrogenation of bromofluoro heterocycles gives high yields of the corresponding fluorinated heterocycles. Reactions of nucleophiles with 3 gives surprising results. Soft nucleophiles, e.g. PhSNa displace bromine whereas hard nucleophiles, e.g. MeONa, displace fluorine. British Crown Copyright 1998, Defence Evaluation and Research Agency. Published by the Royal Society of Chemistry with the permission of the controller of Her Britannic Majesty's Stationery Office.