Comparison of N,N′-diaryisquaramides and N,N′-diarylureas as antagonists of the CXCR2 chemokine receptor

N,N'-diarylsquaramides were prepared and evaluated as antagonists of CXCR2. The compounds were found to be potent and selective antagonists of CXCR2. Significant differences in SAR was observed relative to the previously described N,N'-diarylurea series. As was the case in the N,N'-diarylurea series, placing sulfonamide substituent adjacent to the acidic phenol significantly reduced the clearance in rat pharmacokinetic studies. (c) 2007 Elsevier Ltd. All rights reserved.