Synthesis Of Phenylpropanoid Glycoside Luteoside A And Stereoselective Synthesis Of β-Lactams

The research in synthesizing biologically active compounds still constitutes active area in organicsynthesis. We, therefore, studied the synthesis of phenylpropanoid glycosides and thestereoselective synthesis ofβ-Lactams, and the details are summarized below.1. Phenylpropanoid glycosides are natural glycosides, many of which possessing potent biological activities such as antiviru, antitumor, antifugal activities and so on. In this dissertertation, we investigated the total synthesis of 2, 3-branched trisaccharide phenylpropanoid glycoside Luteoside A. we tried to synthesize trisaccharidel-O-(3, 4-dihydroxyphenyl)ethyl-(2, 3, 4-tri-O-acetyl-β-D-apiofuranos yl-(1→2)-(2, 3, 4-tri-O-acetyl-α-L-rhamnopyranosyl-(1→3)-4, 6-O-benzylidene-β-D-glucopyranoside from D-glucose as starting material. At first, we synthesized the segment 1-O-(4-benzylphenyl)-ethyl-(2, 3, 4-tri-O-acetyl-α-L-rhamnopyranosyl-(1→3)-4, 6-O-benzylidene-β-D-glucopyranoside(F) of Luteoside A analog 2.0. But the reaction of F and apiosyl trichloroacetimidates was unsuccessful. Then we investigated the related methodologies of 2, 3-branched trisaccharide and found that 2, 3-branched trisaccharide could be synthesized from benzoyl trichloroacetimidates reacting with 2-hydroxy of F if F had benzoyl protecting group in the 3-branch. Using this method, we successfully obtained 1-O-(4-benzyl phenyl)ethyl-(2, 3, 4, 6-terta-O-benzoyl-β-D-glucopyranosyl(1→2)-(2, 3, 4, 6-tetra-O-benzoyl-β-D-glucopryanosyl)-(1→3)-4, 6-O-benzylidene-β-D-glucopyranoside 2.47 and 1-O-(4-benzylphenyl)ethyl-(2, 3, 4, 6-terta-O-benzoyl-β-D-glucopyranosyl (1→2)-(2, 3, 4-tri-O-benzoyl-α-L-rhamnopyranosyl-(1→3)-4, 6-O-benzylidene-β-D-glucopyranoside 2.49, Moreover the synthesis of the F segment of Luteoside A1-O-(3, 4-dibenzylphenyl)ethyl-(2, 3, 4, 6-terta-O-benzoyl-β-D-(2, 3, 4-tri-O-acetyl-α-L-rhamnopyranosyl-(1→3)-4, 6-O-benzylidene-β-D-glucopyranoside 2.52 was unprepared. 2. Theβ-lactams are one of the best known and extensively investigated heterocyclic ring systems as a result of both their biological activity as antibiotic and their utility as synthetic intermediates. The chiral spiro[2H-1, 3-benzoxazine-2, 1'-cyclohexan]-4(3H)-one 3.18 is synthesized from salicylamide and L-menthone. Firstly the reaction of 3.18 with 2-bromo-alkanoyl bromide in the presence of pyridine gave the corresponding carboximides 3.16. The Reformatsky reaction of 3.16 with imines in the presence of zinc dust proceeded in THF under reflux conditions, and was completed to give the corresponding one isomer of transβ-lactams with a recycle of chiral auxiliary 3.18. The procedure furnished 16 transβ-lactams in good yields(65-85%), acceptable ee value(77-86%). An enolate-imine mechanism has been proposed to explain the stereoselective mechanism, which is validified by the intermediate tripped.