Patent GB-1298209-A (GB)
Title: Improvements in or relating to pyridazine derivatives
Inventor: ANDERSON PAUL LEROY
IPC: E04H1/14
Filed: 1969-12-19
Abstract: 1298209 Hydrazinopyridazines SANDOZ Ltd 19 Dec 1969 [30 Dec 1968 25 July 1969 4 Aug 1969] 62089/69 Heading C2C Novel hydrazinopyridazines of the general formula wherein R 1  is a hydrogen atom, a C 1-5  alkyl group, a C 3-5  alkenyl group, with the proviso that an ethylenic linkage is not adjacent the nitrogen atom, a C 2-4  hydroxyalkyl group (provided that the OH group is not in the α-position) or a phenyl group optionally monosubstituted by a fluorine or chlorine atom, or a C 1-5  alkyl, C 1-5  alkoxy or trifluoromethyl group and one of R 2  and R 3  is a hydrazino or -NH-N = CR 4 R 5  group, in which R 4  and R 5  are each a hydrogen atom or a C 1-5  alkyl, C 3-5  alkenyl, phenyl, styryl or phenyl-(CH 2 ) n - group, where n is 1, 2 or 3, and the other is a hydrogen, chlorine or bromine atom, with the provisos that when R 2  is a hydrazino group and R 3  is a chlorine atom, or when R 3  is a hydrazino group and R 2  is a chlorine atom, R 1  is other than a hydrogen atom or C 1-5  alkyl group, and when R 3  is a hydrazino group and R 2  is a hydrogen atom, R 1  is other than a hydrogen atom, and acid addition salts thereof are prepared (a) when one of R 2  and R 3  is a hydrazino group and the other is a chlorine or bromine atom, by reaction of an aminohalopyridazine of the general formula wherein X is a chlorine or bromine atom, with the proviso that when X is a chlorine atom, R 1  is not a hydrogen atom or C 1-5  alkyl group, with hydrazine; (b) when one of R 2  and R 3  is a hydrazino group and the other is a hydrogen atom, by reaction of an aminohalopyridazine of the general formula wherein one of Y 1  and Y 2  is a hydrogen atom and the other is a chlorine or bromine atom, with hydrazine; (c) when R 1  is other than a C 3-5  alkenyl group and one of R 2  and R 3  is a hydrazino group and the other is a hydrogen atom, by catalytic hydrogenation of the corresponding compound wherein one of R 2  and R 3  is a hydrazino group and the other is a chlorine or bromine atom, in the presence of an alkali metal base and an inert solvent; or (d) when one of R 2  and R 3  is a -NH-N = CR 4 R 5  group and the other is a hydrogen, chlorine or bromine atom, by reaction of the corresponding compound wherein one of R 2  and R 3  is a hydrazino group and the other is a hydrogen, chlorine or bromine atom with a carbonyl compound of the general formula R 4 R 5 CO; followed optionally by salification of the product. Aminohalopyridazines of the third general formula above are prepared by treatment of a hydrazinopyridazine of the first general formula above wherein one of R 2  and R 3  is a hydrazino group and the other is a chlorine or bromine atom, with copper sulphate at 50-100‹C. in an inert solvent. Pharmaceutical compositions having antihypertensive, and in some cases, anti-inflammatory and anorexic activity comprise, as active ingredient, a hydrazino-pyridazine of the first general formula above or a pharmaceutically acceptable acid addition salt thereof, in admixture with a diluent or carrier, and may be administered orally or parenterally.