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

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##

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

ORDレコード

ord-db7b7438ec9b4d138b262aa4587c1145

出典データセット

uspto-grants-1997_04

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US05620978