174740-48-8 AIDS-033499 AIDS033499 Betulinic acid NH-HepCO-Ser deriv. L-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]-L-serine