1 4UD (2s)-amino[(5s)-4,5-dihydro-1,2-oxazol-5-yl]acetic acid 1.000 2 AVN (2s)-amino[(5s)-3-chloro-4,5-dihydroisoxazol-5-yl]acetic acid 0.909 3 SJU (furan-2-yl)acetic acid 0.727