| 摘要 |
Title cpds are of formula I: where R1 = an amine protecting gp., R2 = H or acyl; or R1 + R2 tog. = a bivalent amine protecting gp.; R3 = an opt. subst. hydrocarbon residue, or acyl; and R4 = OH or a carboxyl protecting gp I are prepd. by acylating the corresp. 7 beta-amines (I, R1 = R2 = H). |
