2,5-Anhydro sugar diacid and 2,5-anhydro sugar diamine based C 2 symmetric peptidomimetics as potential HIV-1 protease inhibitors

Production of Hexaric Acids from Biomass

Sugar acids obtained by aldohexose oxidation of both the terminal aldehyde group and the hydroxy group at the other end to carboxyl groups are called hexaric acids (i.e., six-carbon aldaric acids). Because hexaric acids have four secondary hydroxy groups that are stereochemically diverse and two carboxyl groups, various applications of these acids have been studied. Conventionally, hexaric acids have been produced mainly by nitric acid oxidation of aldohexose, but full-scale commercialization has not been realized; there are many problems regarding yield, safety, environmental burden, etc. In recent years, therefore, improvements in hexaric acid production by nitric acid oxidation have been made, while new production methods, including biocatalytic methods, are actively being studied. In this paper, we summarize these production methods in addition to research on the application of hexaric acids.

Diversity-Oriented Synthesis of Diol-Based Peptidomimetics as Potential HIV Protease Inhibitors and Antitumor Agents

Peptidomimetic HIV protease inhibitors are an important class of drugs used in the treatment of AIDS. The synthesis of a new type of diol-based peptidomimetics is described. Our route is flexible, uses d-glucal as an inexpensive starting material, and makes minimal use of protection/deprotection cycles. Binding affinities from molecular docking simulations suggest that these compounds are potential inhibitors of HIV protease. Moreover, the antiproliferative activities of compounds 33 a, 35 a, and 35 b on HT-29, M21, and MCF7 cancer cell lines are in the low micromolar range. The results provide a platform that could facilitate the development of medically relevant asymmetrical diol-based peptidomimetics.

Stereoselective total synthesis of (+)-varitriol, (-)-varitriol, 5'-epi-(+)-varitriol, and 4'-epi-(-)-varitriol from D-mannitol

Stereoselective total syntheses of natural (+)-varitriol (1), (-)-varitriol (2), 5'-epi-(+)-varitriol (3), and 4'-epi-(-)-varitriol (4) have been accomplished with use of D-mannitol as a chiral pool material. The Heck reaction was used to assemble the olefinic sugar moiety and the aromatic triflate moiety.

Sugar amino acids in designing new molecules

Emulating the basic principles followed by nature to build its vast repertoire of biomolecules, organic chemists are developing many novel multifunctional building blocks and using them to create 'nature-like' and yet unnatural organic molecules. Sugar amino acids constitute an important class of such polyfunctional scaffolds where the carboxyl, amino and hydroxyl termini provide an excellent opportunity to organic chemists to create structural diversities akin to Nature's molecular arsenal. This article describes some of our works on various sugar amino acids and many other related building blocks, like furan amino acids, pyrrole amino acids etc. used in wide-ranging peptidomimetic studies.

Conformational studies of peptides containing cis-3-hydroxy-D-proline

Conformational analysis of peptides containing cis-3-hydroxy-d-proline (d-cis-3-Hyp) by NMR studies revealed that the 3-hydroxyl group in this amino acid plays a significant role in the overall three-dimensional structures of the peptides. When the d-cis-3-Hyp had its 3-hydroxyl group protected as the benzyl (Bn) ether, the peptide displayed a beta-hairpin structure in both CDCl(3) and DMSO-d(6). Even after the removal of the Bn group, the resulting deprotected compound retained the same structure as in the protected version in CDCl(3). However, in polar solvent DMSO-d(6), the C-terminal strand of the hydroxyl-deprotected peptide flipped to the side of the hydroxyl group, breaking the hairpin to form a pseudo beta-turn-like nine-membered ring structure involving an intramolecular hydrogen bond between LeuNH --> HypC3-OH.

1,2,5,6-Tetra- O -benzyl- d -mannitol derivatives as novel HIV protease inhibitors

The synthesis and structure-activity relationships of HIV protease inhibitors derived from carbohydrate alditols are discussed. We disclose a new series of 1,2,5,6-tetra-O-alkyl-D-mannitol exhibiting sub-micromolar activity against HIV-protease. This series of inhibitors are non-nitrogen containing HIV-protease inhibitors and they are readily prepared in a few chemical steps from inexpensive commercially available starting materials.

A facile synthesis of C(2)-symmetric 17 beta-estradiol dimers

A rapid and efficient synthesis of a series of C(2)-symmetric 17 beta-estradiol dimers is described. The new molecules are linked at position 17 alpha of the steroid nucleus with either an alkyl chain or a polyethylene glycol chain. They are made from estrone in five chemical steps with an overall yield exceeding 30%. The biological activity of these compounds was evaluated in vitro on estrogen dependent and independent (ER(+) and ER(-)) human breast tumor cell lines: MCF-7 and MDA-MB-231. Some of the dimers present selective cytotoxic activity against the ER(+) cell line.

Structure-based design and synthesis of HIV-1 protease inhibitors employing beta-D-mannopyranoside scaffolds

A preliminary account on the structure-based design, synthesis and evaluation of peptidomimetic inhibitors of HIV-1 protease containing beta-D-mannopyranoside scaffolds is given. The compounds prepared had IC(50) values in the micromolar range. The results provide a platform for the development of more potent carbohydrate-based inhibitors of HIV-1 and other aspartic proteases.