150840-72-5 AIDS-033488 AIDS033488 Betulinic acid NH-PenCONH-PrCOOH deriv. Butanoic acid, 4-[[6-[[(3.beta.)-3-hydroxy-28-oxolup-20(29)-en-28-yl]amino]-1-oxohexyl]amino]- N'-[N-[3.beta.-Hydroxylup-20(29)-en-28-oyl]-6-aminohexanoyl]-4-aminobutyric acid