5-[2(S)-[(1,1-Dimethylethyl)aminocarbonyl]-4-[(2-benzyloxy)ethyl]-1-piperazinyl]-4(S)-hydroxy-N-(2(R)-hydroxy-1(S)-indanyl)-2(R)-(phenylmethyl)pentanamide AIDS-033561 AIDS033561 L-735,524 analog