# US 4,395,547 A · Process for preparing 1-substituted-6-n-propyl-8-methylimidazo[1,5-d]-as-triazin-4(3H)-ones

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- Number: US 4,395,547 A
- Document ID: US4395547A
- Status: Granted
- Kind: A
- Application number: 06/347,653
- Filed: 1982-02-10
- Granted: 1983-07-26
- Earliest claimed: 1982-02-10
- Assignees: American Cyanamid Company
- Inventors: Sivaraman Raghu; James S. Farina; Steven L. Peake
- Web page: https://patentgrep.com/patent/US4395547A

## CPC

- C07D 233/64: with substituted hydrocarbon radicals attached to ring carbon atoms, e.g. histidine
- A61P 11/00: Drugs for disorders of the respiratory system
- A61P 43/00: Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
- C07D 487/04: Ortho-condensed systems
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS

## Abstract

This disclosure describes a novel process for the preparation of 1-(lower alkyl)substituted derivatives of 6-n-propyl-8-alkylimidazo[1,5-d]-as-triazin-4(3H)-ones which are useful as anti-asthmatic agents.

## Claims

### Claim 1

The process of preparing compounds of the formula: ##STR3## wherein R is methyl, ethyl or n-propyl, R' is methyl, ethyl or phenyl, R" is alkyl, aromatic or heterocyclic which comprises condensing a ketone of the formula: ##STR4## wherein R, R' and R" are as hereinabove defined with a lower alkyl carbazate ester in an inert solvent at 80.degree.-135.degree. for several hours whereby a lower alkyl 3-[1-(2-n-propyl-4-methyl-5-imidazolyl)alkylidene]carbazate of the formula: ##STR5## is obtained; and cyclizing the so obtained imidazolylalkylidene carbazate ester in diphenyl ether at 150.degree.-250.degree. C. for 15-45 minutes.