Imidazo[1,2-b]Pyridazines. XVIII. Syntheses and Central Nervous System Activities of Some 6-, 7- and 8-(Chloro and methoxy)imidazo[1,2-a]pyridine Analogs

1995 ◽  
Vol 48 (5) ◽  
pp. 1031 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
PW Harrison

Syntheses are reported for some 2-aryl-3-(benzamidomethyl and methoxy)-6(7 and 8)-chloro- and 6(and 8)-methoxy-imidazo[1,2-a]pyridines. In tests of the ability of these compounds to displace [3H]diazepam from rat brain membrane, those with 6-chloro and 6-methoxy groups bound most strongly, and relatively small differences only were observed between corresponding imidazo[1,2-a]pyridines and imidazo[1,2-b]pyridazines.

1992 ◽  
Vol 45 (5) ◽  
pp. 877 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
SJ Ireland ◽  
MML Ngu ◽  
JK Zhang

Syntheses are reported for some 6-chloro(alkoxy,alkylthio and pheny1thio)-3-benzamidomethyl-(acetamidomethyl and methoxy)-2-arylimidazo[1,2-apyridines and some corresponding imidazo- [1,2- b]pyridazines, imidazo[1,2-a[pyrimidines and imidazo[l,2-a]pyrazines. IC50 values (or percentage displacement) are reported and discussed for the displacement of [3H]diazepam from rat brain membrane by each of these compounds. The imidazo[l,2-a[pyridines were generally slightly less potent than the imidazo[l,2- b]pyridazines but considerably more potent than the corresponding imidazo[1,2-a]pyrimidines or imidazo[1,2- a[pyrazines. Substitution of a 2-aryl group by a 2-alkyl group in imidazo[l,2- b]pyridazines led to a significant loss of activity.


1992 ◽  
Vol 45 (8) ◽  
pp. 1281 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
SJ Ireland ◽  
JK Zhang

6-(Variously substituted)-3-methoxy(unsubstituted, dimethylaminomethyl, acetamidomethyl and benzamidomethy1)-2-benzyl(phenethyl, biphenyl-4'-yl, 6'-methylnaphthalen-2'-yl, t-butyl and cyclohexyl)imidazo[1,2-b] pyridazines have been prepared and examined for activity in the central nervous system. Of these, 2-benzyl-3-methoxy-6-(3'-methoxybenzylamino) imidazo[1,2-b]pyridazine (IC50 88nM) bound most strongly to rat brain membrane. In general, the order of activity for groups at the 2-position was Ph > PhCH2 > PhCH2CH2 > C6H4Ph-p, 6'-methylnaphthalen-2'-yl, c-C6H11 or But.


1992 ◽  
Vol 45 (4) ◽  
pp. 751 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
SJ Ireland ◽  
JK Zhang

Syntheses are reported for 196-(N-benzyl-N-methylamino )-3-methoxy-2-phenyl(and substituted phenyl or pyridinyl ) imidazo [1,2-b] pyridazines from 6-(N-benzyl-N-methylamino)pyridazin-3- amine 2-oxide. The ability of each of these compounds to displace [3H]diazepam from rat brain membrane preparations was measured and the IC50 values (or percentage displacements) are reported and discussed. 6-(N-Benzyl-N-methylamino )-3-methoxy-2-phenylimido[1,2-b]pyridine was about half as active as its 6-bemylamino analogue, and the most active compound was 6-(N-benzyl-N-methylamino )-2-(2'-fluorophenyl)-3-methoxyimido[1,2-b] pyridazine with IC50 9.8 nM.


1990 ◽  
Vol 43 (3) ◽  
pp. 503 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
SJ Ireland ◽  
CLY Khoo ◽  
TMT Nguyen

Syntheses are reported for a series of 6-(o-methoxy -, o-ethoxy -, o-methylthio - and o-fluoro-phenoxy )-3-( methoxy and ethoxy )-2- phenyl(substituted phenyl and pyridin-3″-yl) imidazo [1,2-b] pyridazines . IC50 values are reported for the displacement of 3H-diazepam from rat brain membrane by each of these compounds. The most active compounds were found to be 3-ethoxy-2-(p- fluorophenyl )-6-(o- methoxyphenoxy )-, 3-methoxy-6-(o- methoxyphenoxy )-2-(m-nitrophenyl )- and 3-methoxy-6-(o- methoxyphenoxy )-2-(3″,4″-methylenedioxy ) imidazo [1,2-b] pyridazines with IC5O values of 15, 18 and 19 nM respectively.


1992 ◽  
Vol 45 (4) ◽  
pp. 731 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
SJ Ireland ◽  
MML Ngu ◽  
JK Zhang

Syntheses of some 3-( acetamido, benzamido , substituted benzamido or dimethylamino)methyl-2-(phenyl or substituted phenyl)-6( halogeno, alkylthio, alkoxy, phenylthio, phenoxy , benzylthio or benzyloxy ) imidazo [1,2-b] pyridazines from the 3-unsubstituted analogues are described. The IC50 values (or percentage displacements) are reported and discussed for the displacement of [3H]diazepam from rat brain membrane by each of these compounds. .The 3-benzamidomethyl compounds were generally the most active; of these, 3-benzamidomethyl-2-(3',4'-methylenedioxyphenyl)-6-methylthioimido[1,2-b] pyridazine showed outstanding activity with IC50 2 nM .


1993 ◽  
Vol 46 (3) ◽  
pp. 353 ◽  
Author(s):  
GB Barlin ◽  
LP Davies ◽  
SJ Ireland ◽  
JK Zhang

Syntheses are reported for 28 new 3-alkoxy-6-(3′-methoxy-,3′,4′-dimethoxy, 3′,4′-methylene-dioxy-, 2′- and 4′-chloro- and 4′-fluoro-benzylamino)-2-phenyl(and substituted phenyl) imidazo -[1,2-b] pyridazines from the corresponding 6-substituted pyridazin-3-amine 2-oxides with α- bromoacetophenones, followed by alkylation of the intermediate 3-hydroxyimidazo[1,2-b] pyridazines. In tests of the ability of these compounds to displace [3H]diazepam from rat brain membrane, 3-(2′-ethoxyethoxy)-6(3′-methoxybenzylamino)-2-phenyl- and 6(3′,4′-methylenedioxybenzylamino )-2-(3″,4″-methylenedioxyphenyl)-3-methoxy-imidazo[1,2-b] pyridazine bound most strongly, with IC50 values of 1nM.


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