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

4-(2,5-difluorobenzoyl)-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

4-(2-ethoxybenzoyl)-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

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

8-methyl-4-(3,4,5-trimethoxybenzoyl)-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

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

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

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

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

4-(2-chloro-5-nitrobenzoyl)-8-methyl-1-oxa-4-azaspiro[4.5]decane-3-carboxylic acid

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