# US 4,391,806 A · Substituted tetrahydropyridazino-(1,6-A)benzimidazoles and use as bronchodilators

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- Number: US 4,391,806 A
- Document ID: US4391806A
- Status: Granted
- Kind: A
- Application number: 06/397,300
- Filed: 1982-07-12
- Granted: 1983-07-05
- Earliest claimed: 1982-07-12
- Assignees: The Dow Chemical Company
- Inventors: Catherine A. Alexander; Robert J. Cregge; Norton P. Peet
- Web page: https://patentgrep.com/patent/US4391806A

## CPC

- C07D 487/04: Ortho-condensed systems
- A61P 11/08: Bronchodilators
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS

## Abstract

Substituted tetrahydropyridazino[1,6-a]benzimidazole compounds such as 2-methylamino-6,7,8,9-tetrahydropyridazino[1,6-a]benzimidazole are prepared by reacting a 2-halo-6,7,8,9-tetrahydropyridazino[1,6-a]benzimidazole with an appropriate amine. The compounds are useful as bronchodilators.

## Claims

### Claim 1

A compound of the formula:
wherein --NRR' is (lower alkyl)amino, di(lower alkyl)amino, 1-pyrrolidinyl, 1-piperidinyl, methyl-1-piperidinyl, hexahydroazepin-1-yl, 4-methyl-1-piperazinyl, 4-methylhexahydro-1,4-diazepin-1-yl and 4-morpholinyl; and the pharmaceutically acceptable acid addition salts of

### Claim 2 (depends on 1)

A compound according to claim 1 which is

### Claim 3 (depends on 1)

A compound according to claim 1 which is 2-(4-methyl-1-piperidinyl)-6,7,8,9-tetrahydropyridazino[1,6-a]benzimidazol

### Claim 4 (depends on 1)

A compound according to claim 1 which is

### Claim 5

A method of producing bronchodilation which comprises administering to a mammal in need thereof an effective amount of a compound of the formula ##STR4## wherein --NRR' is (lower alkyl)amino, di(lower alkyl)amino, 1-pyrrolidinyl, 1-piperidinyl, methyl-1-piperidinyl, hexahydroazepin-1-yl, 4-methyl-1-piperazinyl, 4-methylhexahydro-1,4-diazepin-1-yl and 4-morpholinyl; and the pharmaceutically acceptable acid addition salts of said compound.