International Society of Pteridinology Acta Medica Okayama 0933-4807 24 1 2013 First Synthesis of Asperopterin A, an Isoxanthopterin Glycoside from Aspergillus Oryzae 3 6 EN Tadashi Hanaya Hiroshi Yamamoto The 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 Pteridinology Acta Medica Okayama 0933-4807 19 3 2008 An Efficient Synthesis of 2'-O-(β-D-Ribofuranosyl)biopterin 72 78 EN Tadashi Hanaya Kiyoshi Torigoe Kazuyuki Soranaka Hiroshi Fujita Hiroshi Yamamoto Wolfgang Pfleiderer N(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-β 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-β-D ribofuranosyl)biopterin derivatives (6a, 42% and 6b, 60%) as major products. Removal of the protecting groups of 6b provided 2'-O-(β-D-ribofuranosyl)biopterin (1c, 87% overall yield) in 3 steps. No potential conflict of interest relevant to this article was reported.

International Society of Pteridinology Acta Medica Okayama 0933-4807 20 Special Issue 2009 First Synthesis of a Representative, Natural Pterin Glycoside: 2’-O-(α-D-Glucopyranosyl)biopterin 36 41 EN Tadashi Hanaya Hiroshi Yamamoto Wolfgang Pfleiderer Glycosylation of N(2)-(N,N-dimethylaminomethylene)-1’-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)-α-D-glucopyranosyl bromide (19) in the presence of silver triflate and tetramethylurea predominantly afforded the corresponding α-D-glucopyranoside (20a), from which 2’-O-(α-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 Pteridinology Acta Medica Okayama 0933-4807 21 3 2010 First Synthesis of a Natural Neopterin Glycoside: 3'-O-(β-D-Glucopyranosyluronic acid)neopterin 79 83 EN Tadashi Hanaya Takafumi Hattori Daisuke Takayama Hiroshi Yamamoto 1',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-α-D-glucopyranosyluronate bromide in the presence of silver triflate and tetramethylurea afforded the corresponding 3'-O-(methyl β-D-glucopyranosyluronate) neopterin derivative (2) in 64% yield. The first synthesis of 3'-O-(β-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.