150840-59-8 AIDS-033500 AIDS033500 Betulinic acid NH-HepCO-Ser deriv. D-Serine, N-[8-[[(3.beta.)-3-hydroxy-28-oxolup-20(29)-en-28-yl]amino]-1-oxooctyl]- N'-[N-[3.beta.-Hydroxylup-20(29)-en-28-oyl]-8-aminooctanoyl]-D-serine