Synthesis structure and NMR spectroscopy of some deoxy carbohydrate polyol derivatives and their mono-O-butylidene acetals

Abstract

The reactions between some deoxy polyol derivatives and n-butyraldehyde have been studied in aqueous hydrochloric acid and the initial rate coefficients of the deoxy polyols determined. 1.2-Deoxy-D-arabino-hexitol yielded a 1,3-acetal as a kinetic phase and a 4,6-acetal as a thermodynamic phase. 2. 2-Deoxy-D-lyxo-hexitol yielded a 1,3-acetal as a kinetic phase. It also gave 4,5 and 4,acetals as a combined thermodynamic phase. 3. 2-Deoxy-D-erythro-pentitolyielded a 1,3-acetal asa kinetic phase and a 3,5-acetal as a thermodynamicphase. 4. 3-Deoxy-D-ribo-hexitol yielded a 2,4-acetal only. 5. 4-Deoxy-D-xylo-hexitol yielded diastereoisomeric 2,3-acetals as a kinetic phase with a 1,3-acetal as a thermodynamic phase. 6. 3-Deoxy-3-fluoro-D-glucitol yielded a 4,6-acetal as akinetic phase and a 2,4-acetal as a thermodynamic phase. 7. 6-Deoxy-6-fluoro-B-galactitol yielded diastereoisomeric 4,5-acetals, there was also evidence suggesting the presence of 1,3 and 2,3-acetals. A carbon-13 n.m.r. spectral analysis has been undertaken for some deoxy polyols and acetals derived there from. 1. The carbon-13 chemical shifts of the deoxy polyols were assigned by consideration of substituent effects upon the appropriate non deoxy polyols and deuteriumsubstitution. 2. The structures of the acetals of the deoxy polyols have been ascertained by consideration of carbon-13 chemical shift changes associated with acetalation. Proton n.m.r. spectroscopy has been used for further structural and conformational analysis of the acetals of the deoxy polyols. Fluorine-19 n.m.r. spectroscopy was used to investigate the conformation and structure of the deoxy fluoro polyols and their acetals.