Synthesis of pseudo-C-nucleosides

Area of Science:

• Carbohydrate Chemistry
• Organic Synthesis
• Medicinal Chemistry

Background:

• The Wittig reaction is a fundamental tool in organic synthesis for forming carbon-carbon double bonds.
• Maleimide derivatives, such as showdomycin, possess significant biological activities.
• Understanding the stereochemical control in Wittig reactions involving carbohydrate derivatives is crucial for synthesizing complex molecules.

Purpose of the Study:

• To investigate the reaction of specific hexulofuranuronamide derivatives with a Wittig reagent.
• To analyze the influence of stereochemistry and protecting groups on the reaction outcome.
• To synthesize novel maleimide compounds analogous to showdomycin.

Main Methods:

• Reaction of 1,2-O-isopropylidene-alpha-D-xylo-5-hexulofuranuronamide and 3-O-benzyl protected analogs with ethoxycarbonylmethylenetriphenylphosphorane.
• Purification and characterization of reaction products using chromatographic and spectroscopic techniques.
• Stereochemical analysis of the starting materials and resulting products.

Main Results:

• The reaction of 1,2-O-isopropylidene-alpha-D-xylo-5-hexulofuranuronamide yielded a mixture of a maleimide (2) and an enoate (3).
• 3-O-benzyl protected analogs selectively produced either the maleimide (5) or the enoate (7), depending on the configuration at C-3.
• Compounds 2 and 5 were identified as analogs of the biologically active compound showdomycin.

Conclusions:

• The formation of the maleimide ring is highly dependent on the orientation and substitution at the C-3 hydroxyl group of the hexulofuranuronamide.
• Stereochemical control is critical in directing the Wittig reaction towards maleimide or enoate products.
• The study successfully synthesized potential showdomycin analogs, offering new avenues for medicinal chemistry research.