Novel drug delivery conjugated moiety for oral administration of drug unsuitable for oral administration and preparation method thereof

A method for preparing a drug delivery conjugated moiety-low molecular weight heparin (LMWH) complex, comprising:

• (S1) preparing a compound of Formula 1 and a compound of Formula 2 from lysine;
• (S2) preparing a compound of Formula 3 by a reaction of the compound of Formula 1 with the compound of Formula 2;
• (S3) preparing a compound of Formula 4 by a deprotection of amine protecting groups of the compound of Formula 3;
• (S4) preparing a compound of Formula 5 by a reaction of the compound of Formula 4 with bile acids;
• (S5) preparing a compound of formula I by connecting a linker to the compound of Formula 5;
• and
• (S6) preparing the complex by reductive amination of the compound of Formula I and an end site of LMWH:
• wherein B is a bile acid residue;
• wherein L is a linker;
• wherein P1 is a carboxyl protecting group;
• and
• wherein P2 is an amine protecting group.