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

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

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

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

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

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

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

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

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