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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #62736

Title: CRYSTAL STRUCTURAL EQUIVALENCE OF METHYL 3,6-ANHYDROPYRANOSIDES

Author
item SCHAFER, STEVEN
item STEVENS, EUGENE
item Dowd, Michael

Submitted to: Carbohydrate Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/1994
Publication Date: N/A
Citation: N/A

Interpretive Summary: Based on modeling of optical properties it was proposed that a conformational difference existed between the solution and crystalline structures for 3,6-anhydro sugar rings. This phenomena was studied with three different computational techniques. All three yielded results in disagreement with the proposed shift. The discrepancy was traced to the lack of explicit parameters for some of the atom linkages in these compounds.

Technical Abstract: Previously published chiroptical modeling of the anhydrosugars indicated that a conformational shift occurs upon solution of the 3,6-anhydopyranosid dynamics and molecular mechanics methods. All of the various computational approaches as well as previously reported nmr data indicated that no significant conformational change occur between the crystalline and solution states for this class of strained rings. The difference has been traced to the lack of explicit ether C-O polarization parameters in the original molar rotation modeling.