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

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

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

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

4-(3,5-dichlorobenzoyl)-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

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

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

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

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

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

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

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

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

8-ethyl-4-(naphthalene-2-carbonyl)-1-oxa-4,8-diazaspiro[4.5]decane-3-carboxylic acid