Patent GB-711756-A (GB)
Title: Novel heterocyclic compounds and process for the manufacture thereof
IPC: C07D487/04
Filed: 1952-09-04
Abstract: The invention comprises compounds of the formula <FORM:0711756/IV (b)/1> wherein Y and Y1 both stand for hydrogen or halogen atoms or for alkoxy groups, R2 stands for a hydrogen atom and R3 stands for a heterocyclic radical or R2 and R3, together with the nitrogen atom to which they are attached, form a heterocyclic ring which, when Y and Y1 both stand for hydrogen, is other than a saturated six-membered ring, or, where the fragment -NH-N(R2)R3 contains the group <FORM:0711756/IV (b)/2> triazolo compounds derived therefrom by loss of the elements of water and having the group <FORM:0711756/IV (b)/3> Pyridine-4-carboxylic acids or derivatives thereof of the general formula <FORM:0711756/IV (b)/4> or salts thereof, wherein X stands for a hydroxy, an alkoxy, an amino or an azido group or for a halogen atom are reacted with hydrazine derivatives of the formula <FORM:0711756/IV (b)/5> or salts thereof, preferably in presence of a basic agent such as pyridine.  Pyridine carboxylic acid derivatives containing the following radicals are specified as starting materials: pyridyl-(4)-, 2,6 - dichloro - pyridyl - (4) -, 2,6 - diethoxy - pyridyl-(4)- and 2,6-dibutyloxy-pyridyl-(4)-.  Acid halides are especially suitable derivatives, particularly the acid chlorides which may be employed in the form of the hydrochloride salts. Specified hydrazine derivatives are: pyridyl-(2, 3, or 4)-hydrazine, 5-nitro-2-hydrazinopyridine, 5 - amino - 2 - hydrazino - pyridine, 2 - hydrazino - thiazole, 2 - hydrazino - benzthiazole, 6 - chloro - 3 - hydrazino - pyridiazine, 6 - methyl - 3 - hydrazino - pyridazine, 1 - hydrazino - phthalazine, 2,4 - dimethyl - 6 - hydrazino-pyrimidine, 2-hydrazino-pyrazines and 2 - hydrazino - quinoxalines. Alternatively pyridine-(4)-carboxylic acid hydrazides are reacted with the appropriate heterocyclic halogen compounds. Products in which Y and Y1 are chlorine atoms may be subsequently reduced to give compounds in which Y and Y1 are hydrogen atoms.  The examples describe the preparation of N1-[isonicotinoyl]-N2-[5-nitro - pyridyl - (2)] - hydrazine; N1 - [isonicotinoyl] - N2 - (5 - amino - pyridyl - (2)] - hydrazine; N - [morpholinyl - (41)] - 2,6 - dichloro-isonicotinic acid amide; N-[piperidyl-(11)]-2,6-dichloro-isonicotinic acid amide; N1-[2,6 - dichloro - isonicotinoyl] - N2 - [61 - chloro - pyridazinyl - (31)] - hydrazine; N1 - [2,6-dichloro - isonicotinoyl] - N2 - [31 - methyl - pyridazinyl - (61)] - hydrazine; N1 - [2,6 - dichloro - isonicotinoyl] - N2 - [benzthiazolyl - (21)]-hydrazine; 2,6-diethoxy-isonicotinic acid N - (morpholino) - amide; 2,6 - diethoxy - isonicotinic acid N-(piperidino)-amide; N1-[2,6-diethoxy - isonicotinoyl] - N2 - (21,41 - dimethyl - pyrimidyl - (61)] - hydrazine; 3 - [21,61 - di ethoxy - pyridyl - (41)] - triazolophthalazine; and 3 - [21,61 - dichloro - pyridyl - (41)] - triazolophthalazine.  3 - Hydrazino - 6 - chloro - pyridazine is prepared by boiling 3,6-dichloro-pyridazine with hydrazine hydrate in alcoholic solution.  2,6-Diethoxy-isonicotinic acid chloride is prepared by refluxing 2,6-diethoxy-isonicotinic acid with phosphorus pentachloride in absolute benzene.  2,6-Diethoxy-isonicotinic acid is prepared by heating 2,6-dichloro-isonicotinic acid with sodium ethoxide and treating the resulting sodium salt with hydrochloric acid.