Patent GB-629177-A (GB)
Title: Manufacture of new hydrazine compounds and derivatives thereof
Filed: 1946-12-12
Abstract: Hydrazino derivatives of compounds containing a pyridazine ring are prepared by substituting a group in the ortho position to a nitrogen atom in the pyridazine ring by a hydrazino group.  The compounds containing a pyridazine ring may be pyridazine, pyridazines which are substituted with alkyl, aryl, aralkyl or substituted aromatic residues, or pyridazines having fused on aromatic or heterocyclic rings such as the phthalazines or pyrido-pyridazines.  As substituents in the ortho position which can be substituted by a hydrazine group there may be used a halogen atom, an esterified hydroxy group, or a phenoxy or thioether group.  Many examples of suitable starting materials are given.  The hydrazine may or may not be substituted and one of the nitrogen atoms may form part of a heterocyclic ring, e.g. the piperidine or morpholine ring.  The hydrazino derivatives formed may be converted into their salts, or they may be condensed with carbonyl compounds such as aldehydes or ketones.  The following examples are given: (1) 1 - chlorophthalazine or 1-phenoxyphthalazine is heated with hydrazine hydrate in alcohol to yield 1-hydrazinophthalazine; (2) 1 - hydrazino - 4 - methylphthalazine is made by heating 1-chloro-4-methyl-phthalazine with hydrazine hydrate in alcohol; (3) 3-chloro-6-phenyl-pyridazine is heated with hydrazine hydrate in alcohol to yield 3-hydrazino-6-phenyl-pyridazine; (4) 3-chloro - 6 - methyl - pyridazine is heated with hydrazine hydrate in alcohol to yield 3-hydrazino - 6 - methyl - pyridazine; (5) 1 - chloro - 4-(p - methoxyphenyl) - phthalazine is heated with hydrazine hydrate in alcohol to yield 1-hydrazino - 4 - (p - methoxyphenyl) - phthalazine; (6) 1 - chloro - 4 - (p - dimethylaminophenyl) - phthalazine is treated as in (5) to yield 1 - hydrazino - 4 - (p - dimethylaminophenyl) - phthalazine; (7) 1 - hydrazinophthalazine is condensed with acetone in 2 N-acetic acid to yield the corresponding phthalazinyl - hydrazone of acetone; (8) 1 - chloro-4-benzyl-phthalazine is heated with hydrazine hydrate in alcohol to yield 1-hydrazino-4-benzyl-phthalazine; (9) 1-chloro-4-methyl-phthalazine is heated with methyl hydrazine to yield 1 - methylhydrazino - 4 - methyl-phthalazine; (10) 1 - hydrazino - phthalazine is condensed with formaldehyde in methanol to yield the phthalazinyl-hydrazone of formaldehyde; (11) 1-hydrazino-phthalazine is condensed with pyroracemic acid in methanol to give a compound of the formula <FORM:0629177/IV (b)/1> (12) b -benzoyl-picolinic acid (obtained from quinolinic anhydride and benzene in presence of aluminium chloride) is heated with hydrazine hydrate in water to yield phenyl-pyrido-pyridazine which is converted to the chloro compound with phosphorous oxychloride and then reacted with hydrazine hydrate in alcohol to give 6-hydrazino-3-phenyl-pyrido-21,31,4,5-pyridazine <FORM:0629177/IV (b)/2> (13) 1-chloro-4-phenyl-phthalazine is heated with hydrazine hydrate in alcohol to give 1-hydrazino-4-phenyl-phthalazene.  The Specification as open to inspection under Sect. 91 comprises also the preparation of hydrazino derivatives of compounds containing a pyridazine ring by reducing a group, such as a nitroamino group, in the ortho position to a nitrogen atom in the pyridazine ring, and an example is given of the preparation of 1-hydrazino - 4 - methyl - phthalazine by reducing 1 - nitroamino 4 methyl - phthalazine (obtained by reacting 1-chloro-4-methyl-phthalazine with alcoholic ammonia and nitrating the product with fuming nitric acid in sulphuric acid) with zinc dust in caustic soda solution.  It comprises also the treatment of the hydrazino derivatives of compounds containing a pyridazine ring with formic acid or chlorides or anhydrides of organic acids, and includes examples of the treatment of 1-hydrazino-phthalazine with acetyl chloride, formic acid and benzoyl chloride to give, respectively, compounds of the formul   <FORM:0629177/IV (b)/3> This subject-matter does not appear in the Specification as accepted.