Stannous Chloride → 5,6-Dichloropyridine-2,3-diamine

HRID 53590

Reaction equation

HRID 53590 reaction equation
[NH2:1][C:2]1[C:7]([N+:8]([O-])=O)=[CH:6][C:5]([Cl:11])=[CH:4][N:3]=1.[Cl:12][Sn]Cl>Cl>[NH2:1][C:2]1[C:7]([NH2:8])=[CH:6][C:5]([Cl:11])=[C:4]([Cl:12])[N:3]=1

Participants

4

Reactant 2

HCID 24479Stannous ChlorideHCID 2241682-Amino-5-chloro-3-nitropyridine

Product 1

HCID 134926415,6-Dichloropyridine-2,3-diamine

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent

Procedure

The compounds of the present invention may be prepared as follows. It has been reported that reduction of 2-amino-5-chloro-3-nitropyridine (2) by SnCl2 in concentrated HCl resulted in both reduction of the nitro group to an amino group as well as chlorination of the pyridine ring to give 2,3-diamino-5,6-dichloropyridine (4) as the only isolated product (Israel & Day, J. Org. Chem. 24:1455-1460 (1959)). We found that reduction of 2 under identical conditions as reported gave a mixture of 2,3-diamino-5-chloropyridine (3) and 2,3-diamino-5,6-dichloropyridine (4) in a ratio of 4:1. The mixture could not be separated by crystallization in water. It could be separated by preparative TLC and chromatography. Cyclization of 3 with oxalic acid gave 8-NQX 5 and cyclization of 4 with oxalic acid gave 8-NQX 6. 6,7-dichloro-8-NQX 6 was found to have a Ki of about 200 nM, which is similar to the corresponding 6,7-dichloro-QX. 6-Chloro-8-NQX 5 also was found to be about as active as the corresponding 6-chloro-QX. 6-Bromo-7-methyl-8-NQX (8) was found to have a Ki of about 200 nM. 6-NQX 11 and 6,8-diN-QX 13 also were found to be about as active as QX. ##STR8##

Workup

  1. customThe compounds of the present invention may be prepared
  2. customresulted in both reduction of the nitro group to an amino group as well as chlorination of the pyridine ring

Sources & evidence

ORD record
ord-db7b7438ec9b4d138b262aa4587c1145
Source dataset
uspto-grants-1997_04
Patent number
US05620978

Linked notes

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