# US 5,707,997 A · Pyrazolo›1,5-a!pyrimidine derivative

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- Number: US 5,707,997 A
- Document ID: US5707997A
- Status: Granted
- Kind: A
- Application number: 08/602,824
- Filed: 1996-02-21
- Granted: 1998-01-13
- Earliest claimed: 1994-06-21
- Assignees: Otsuka Pharmaceutical Factory, Inc.
- Inventors: Yasuo Shoji; Makoto Inoue; Takashi Okamura; Kinji Hashimoto; Masayuki Ohara; Tsuneo Yasuda
- Web page: https://patentgrep.com/patent/US5707997A

## CPC

- C07D 487/04: Ortho-condensed systems
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

The invention provides a pyrazolo›1,5-a!pyrimidine derivative of the following formula (1): ##STR1## wherein R.sup.1, R.sup.3, R.sup.4, R.sup.5, R.sup.6, Q, A and n are defined in the description; and R.sup.2 is naphthyl, cycloalkyl, furyl, thienyl, optionally halogen-substituted pyridyl, optionally halogen-substituted phenoxy, or phenyl which may have 1 to 3 substituents selected from the group consisting of lower alkyl, lower alkoxy, halogen, nitro, halogen-substituted lower alkyl, halogen-substituted lower alkoxy, lower alkoxycarbonyl, hydroxyl, phenyl(lower)alkoxy, amino, cyano, lower alkanoyloxy, phenyl and di(lower)alkoxyphos-phoryl(lower)alkyl. This derivative is useful as a potent analgesic.

## Claims

### Claim 1

A pyrazolo›1,5-a!pyrimidine derivative of the following formula (1): ##STR199## wherein R.sup.1 is hydrogen, lower alkyl which may have thienyl, lower alkoxy, lower alkylthio, oxo or hydroxyl as a substituent, cycloalkyl, thienyl, furyl, lower alkenyl, or R.sup.1 phenyl, said R.sup.1 phenyl having 1 to 3 substituents selected from the group consisting of lower alkyl, lower alkoxy, phenylthio and halogen; R.sup.2 is naphthyl, cycloalkyl, furyl, thienyl, pyridyl, halogen-substituted pyridyl, phenoxy, halogen-substituted phenoxy, or phenyl which may have 1 to 3 substituents selected from the group consisting of lower alkyl, lower alkoxy, halogen, nitro, halogen-substituted lower alkyl, halogen-substituted lower alkoxy, lower alkoxycarbonyl, hydroxyl, phenyl(lower)alkoxy, amino, cyano, lower alkanoyloxy, phenyl and di(lower)alkoxyphosphoryl(lower)alkyl; R.sup.3 is hydrogen, phenyl or lower alkyl; R.sup.4 is hydrogen, lower alkyl, lower alkoxycarbonyl, phenyl(lower)alkyl, phenyl, phenylthio-substituted phenyl, or halogen; R.sup.5 is hydrogen or lower alkyl; R.sup.6 is hydrogen, lower alkyl, phenyl(lower)alkyl, or an R.sup.6 benzoyl, said R.sup.6 benzoyl having 1 to 3 substituents selected from the group consisting of lower alkoxy, halogen-substituted lower alkyl and halogen; R.sup.1 and R.sup.5 may conjointly form lower alkylene; Q is carbonyl or sulfonyl; A is a single bond, lower alkylene or lower alkenylene; and n is 0 or 1.

### Claim 2 (depends on 1)

A pyrazolo›1,5-a!pyrimidine derivative according to claim 1 which is selected from the group consisting of compounds of formula (1) wherein Q is carbonyl and n is 0, compounds wherein Q is carbonyl, n is 1, R.sup.1 is lower alkyl or phenyl, R.sup.2 is phenyl having 1 to 3 substituents selected from the group consisting of lower alkoxy and halogen-substituted lower alkyl, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each hydrogen, and A is a single bond; and compounds wherein Q is sulfonyl, n is 0, R.sup.1 is lower alkyl, R.sup.2 is phenyl which may have 1 to 3 halogens, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each hydrogen, and A is a single bond.

### Claim 3 (depends on 2)

A pyrazolo›1,5-a!pyrimidine derivative according to claim 2 wherein R.sup.1 is optionally lower alkylthio-substituted lower alkyl or optionally phenylthio-substituted phenyl, R.sup.2 is phenyl having 1 to 3 substituents selected from the group consisting of lower alkoxy, halogen and halogen-substituted lower alkyl, R.sup.3 is hydrogen or phenyl, R.sup.4 is hydrogen, halogen or phenyl; R.sup.5 is hydrogen; R.sup.6 is hydrogen or benzoyl having halogen-substituted lower alkyl as a substituent, Q is carbonyl and A is a single bond.

### Claim 4 (depends on 3)

A pyrazolo›1,5-a!pyrimidine derivative according to claim 3 wherein R.sup.3, R.sup.4 and R.sup.6 are each hydrogen, n is 0, R.sup.1 is n-butyl and R.sup.2 is phenyl having either 2 to 3 lower alkoxy groups or 1 to 2 halogen-substituted lower alkyl groups, or R.sup.1 is phenyl and R.sup.2 is phenyl having 3 lower alkoxy groups.

### Claim 5 (depends on 4)

A pyrazolo›1,5-a!pyrimidine derivative according to claim 4 wherein R.sup.2 is 2,4-dimethoxyphenyl, 3,4,5-trimethoxyphenyl, 2-trifluoromethylphenyl or 2,5-bis(trifluoromethyl)phenyl.

### Claim 6 (depends on 5)

A pyrazolo›1,5-a!pyrimidine derivative according to claim 5 which is selected from 5-n-butyl-7-(3,4,5-trimethoxybenzoylamino)pyrazolo›1,5-a!pyrimidine and 5-n-butyl-7-(2-trifluoromethylbenzoyl-amino) pyrazolo›1,5-a!pyrimidine.

### Claim 7 (depends on 6)

A pyrazolo›1,5-a!pyrimidine derivative according to claim 6 which is 5-n-butyl-7-(3,4,5-trimethoxybenzoylamino)pyrazolo›1,5-a!pyrimidine.

### Claim 8

An analgesic composition which comprises an effective amount of a pyrazolo›1,5-a!pyrimidine derivative defined in one of claims, 2-7 and 1 and a pharmaceutically acceptable carrier.

### Claim 9

An analgesic composition which comprises an effective amount of 5-n-butyl-7-(3,4,5-trimethoxybenzoylamino)-pyrazolo›1,5-a!pyrimidine as an active ingredient and a pharmaceutically acceptable carrier.

### Claim 10 (depends on 1)

A method for relieving pain, which comprises administering to a patient an effective amount of the pyrazolo›1,5-a!pyrimidine derivative defined in claim 1.