4-(4-tert-butylbenzoyl)-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

4-(3-methoxybenzoyl)-8-methyl-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

4-(3-chlorobenzoyl)-8-methyl-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

4-(3,4-difluorobenzoyl)-8-methyl-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

4-(2-chlorobenzoyl)-8-methyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-(2,4-dichlorobenzoyl)-8-methyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-(3,4-dichlorobenzoyl)-8-methyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-(2-Fluorobenzoyl)-8-methyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-(4-chloro-3-nitrobenzoyl)-8-methyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

4-(2-methoxybenzoyl)-8-methyl-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid

8-methyl-4-[2-(trifluoromethyl)benzoyl]-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid