CC(C)(C)OC[C@H](NC(=O)OC(C)(C)C)c1nnc([C@H](CC(=O)OC(C)(C)C)NC(=O)C2CCN(C(=O)OC(C)(C)C)CC2)o1
Hydrogen bond acceptor: The atom, ion, or molecule component of a hydrogen bond which does not supply the bridging (shared) hydrogen atom. How many hydrogen bond acceptors does the molecule have?