Methyl D-arabino-hex-2-ulopyranosonate as a building block for spiro[1,4-benzoxazine-2,2'-pyrans]

Article abstract of DOI:10.1016/S0008-6215(99)00039-7

A novel glycosyl donor, methyl (3,4,5-tri-O-acetyl-β-D-arabino-hex-2-ulopyranosyl)onate bromide, obtained in two steps from methyl β-D-arabino-hex-2-ulopyranosonate, was converted into its α-nitrophenyl glycoside, which in turn was reductively cyclized to form acetylated benzoxazinoid spirans. Deprotection led to (2S)-3',4,4',5'-tetrahydroxy-D-arabino-2H-1,4-benzoxazin-2-spiro-2'-pyran-3(4H)-one and (2S)-3',4',5'-trihydroxy-D-arabino-2H-1,4-benzoxazin-2-spiro-2'-pyran-3(4H)-one. Analogous compounds are prepared from 5-methoxy-2-nitrophenol. The new class of spiro functionalized carbohydrates is structurally related to natural benzoxazinone acetal glucosides. The assignment of configuration and conformation of all products was based on ¹H NMR H,H coupling constants and optical rotation values. Copyright (C) 1999 Elsevier Science Ltd.