Homo-C-nucleoside analogs IV. Synthesis of 4-(2,5-anhydro-D-altro-pentitol-1-yl)-2-phenyl-2H-1,2,3-triazole homo-C-nucleoside. CD assignment of the absolute configuration of the carbon bridge.
Dehydrative cyclization of 4-(D-altro-pentitol-1-yl)2-phenyl-2H-1,2,3-triazole in basic medium with one moler equivalent of p-toluene sulfonyl chloride in pyridine solution gave the homo-C-nucleoside 4-(2,5-anhydro-D-altro-1-yl)-2-phenyl-2H-1,2,3-triazole. The structure and anomeric configuration was determined by acylation, nuclear magnetic resonance (NMR), and mass spectroscopy. The stereochemistry at the carbon bridge of homo-C-nucleoside 2-phenyl-2H-1,2,3-triazoles was determined by circular dichroism (CD) spectroscopy.
Homo-C-Nucleoside Analogs† II. Synthesis and Anomeric Configuration of 4-(2,5-Anhydro-D-Gluco-PEntitol-1-YL)-2-Phenyl2H-1,2,3-Triazole††
Abstract Treatment of 4-(D-gluco-pentitol-l-y1)-2-pheny1–2H-1,2,3-triazole (1) with p-toluenesulfonyl chloride in pyridine solution, afforded the homo-C-nucleoside analog, 4-(2,5-anhydro-D-gluco-pentitol-1-yl)-2-phenyl-2H-1,2,3-triazole (2) as well as its partial p-toluenesulfonyl derivative (3). 4-(5-Chloro-5-deoxy-D-gluco-pentitol-1-yl)-2-phenyl-2H-1,2,3-triazole (8), was isolated as a byproduct from the reaction. The structure and anomeric configuration of 2 was determined by acylation, 1H, 13C NMR, and NOE, spectroscopy as well as mass spectrometry. For part I see ref. 1. For a preliminary report see ref. 2.
Cyclization of Pentitols in Pyridine Via Their O-Tosyl Derivatives
Abstract Heating of equimolar quantities of pentitols with p-toluenesulfonyl (tosyl) chloride in pyridine at 60 °C for 4 h afforded 1, 4- or 2, 5-mono-anhydropentitols, which retained configuration of the asymmetric carbon atoms 2 or 4, together with small amounts of products with altered configuration at these centers. Variation of the reaction conditions by using a triple-molar excess of tosyl chloride and elevation of the temperature up to 115 °C gave mainly 1, 4-anhydro-5-chloro-5-deoxy-pentitols and small amounts of 1, 4-anhydro-2, 5- and 3, 5-dichloro-2, 5- and 3, 5-dideoxy-pentitols. The stereochemistry of the molecule of D-arabinitol was shown to favor the formation of 1, 4: 2, 5-dianhydro-D-arabinitol, a compound with two tetrahydrofuran rings. All mixtures were separated by capillary GC, and their components were identified by co-injection of standards by GC-MS.