International Society of PteridinologyActa Medica Okayama0933-48072412013First Synthesis of Asperopterin A, an Isoxanthopterin Glycoside from Aspergillus Oryzae36ENTadashiHanayaHiroshiYamamotoThe key precursor, N-2-(N,N -dimethylaminomethylene)-6-hydroxymethyl-8-methyl-3-[2-(4-nitrophenyl)ethyl]-7-xanthopterin (16) was efficiently prepared from 2,5-diamino-6-methylamino-3H-pyrimidin-4-one (5) and ethyl 3-(tert-butyldimethylsilyloxy)-2-oxopropionate (12), followed by the protection of the pteridine ring. Glycosylation of 16 with 1-O-acetyl-2,3,5-tri-O-benzoyl-beta-D-ribofuranose (18) in the presence of tin(IV) chloride yielded the corresponding beta-D-ribofuranoside. Successive removal of the protecting groups of the resulting D-ribofuranoside provided asperopterin A (4b).No potential conflict of interest relevant to this article was reported.International Society of PteridinologyActa Medica Okayama0933-48072132010First Synthesis of a Natural Neopterin Glycoside: 3'-O-(-D-Glucopyranosyluronic acid)neopterin7983ENTadashiHanayaTakafumiHattoriDaisukeTakayamaHiroshiYamamoto1',2'-Di-O-acetyl-N2-(N,N-dimethylaminomethylene)-3-[2-(4-nitrophenyl)ethyl]neopterin (1) was prepared from neopterin in 5 steps. Glycosylation of 1 with methyl 2,3,4-tri-O-benzoyl--D-glucopyranosyluronate bromide in the presence of silver triflate and tetramethylurea afforded the corresponding 3'-O-(methyl -D-glucopyranosyluronate) neopterin derivative (2) in 64% yield. The first synthesis of 3'-O-(-D-glucopyranosyluronic acid)neopterin was achieved by successive removal (4 steps) of the protecting groups of 2.No potential conflict of interest relevant to this article was reported.International Society of PteridinologyActa Medica Okayama0933-480720Special Issue2009First Synthesis of a Representative, Natural Pterin Glycoside: 2f-O-(-D-Glucopyranosyl)biopterin3641ENTadashiHanayaHiroshiYamamotoWolfgangPfleidererGlycosylation of N(2)-(N,N-dimethylaminomethylene)-1f-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl) ethyl]biopterin (14) with the novel donor 4,6-di-O-acetyl-2,3-di-O-(4-methoxybenzyl)--D-glucopyranosyl bromide (19) in the presence of silver triflate and tetramethylurea predominantly afforded the corresponding -D-glucopyranoside (20a), from which 2f-O-(-D-glucopyranosyl)biopterin (1) was obtained by the successive removal of the protecting groups.No potential conflict of interest relevant to this article was reported.International Society of PteridinologyActa Medica Okayama0933-48071932008An Efficient Synthesis of 2'-O-(-D-Ribofuranosyl)biopterin7278ENTadashiHanayaKiyoshiTorigoeKazuyukiSoranakaHiroshiFujitaHiroshiYamamotoWolfgangPfleidererN(2)-(N,N-Dimethylaminomethylene)-3-[2-(4-nitrophenyl)ethyl]-1',2'-di-O (trimethylsilyl)biopterin (4) was prepared
from biopterin (1a, 86% overall yield) in 5 steps. Glycosylation of 4 with 1,2,3,5-tetra-O-acetyl- D-ribofuranose (5a) and its 2,3,5-tri-O-benzoyl analog (5b) respectively afforded the corresponding 2'-O-(2,3,5-tri-Oacetyl-
and 2,3,5-tri-O-benzoyl--D ribofuranosyl)biopterin derivatives (6a, 42% and 6b, 60%) as major products. Removal of the protecting groups of 6b provided 2'-O-(-D-ribofuranosyl)biopterin (1c, 87% overall yield) in 3 steps.No potential conflict of interest relevant to this article was reported.