337975-22-1Relevant academic research and scientific papers
Synthesis of espicufolin based on 6-endo ring closure of o-alkynoylnaphthols
Uno, Hidemitsu,Sakamoto, Katsuji,Honda, Erina,Fukuhara, Kaori,Ono, Noboru,Tanaka, Junya,Sakanaka, Masahiro
, p. 229 - 238 (2007/10/03)
Regioselective halogenation of 3-acetoxymethyl-7-chloro-5,8-dimethoxy-1-naphthol 5 was achieved by DBH or I2/N-methylmorpholine to give the corresponding 2-halogeno-1-naphthols 8 and 11, which were converted to 1-methoxymethoxy-3-(alk-2-ynoyloxymethyl)-2-halogenonaphthalenes 17 and 18 in good yields. An intramolecular acyl-transfer reaction of the 2-halogenonaphthalenes triggered by halogen-lithium exchange with BuLl at -78 °C gave 1-methoxymethoxy-2-alkynoyl-3-(hydroxymethyl)naphthalenes 21 in high yields. After protection of the hydroxymethyl group as a benzoate, formation of a γ-pyrone ring was easily achieved by deprotection of the methoxymethyl group followed by spontaneous 6-endo ring closure under mildly acidic conditions. The pyrone derivative having a 1-methylpropyl group was successfully converted to espicufolin 1.
A novel synthetic approach to benzo[h]chromones via sequential intramolecular alkynoyl transfer followed by 6-endo ring closure
Sakamoto, Katsuji,Honda, Erina,Ono, Noboru,Uno, Hidemitsu
, p. 1819 - 1823 (2007/10/03)
An intramolecular acyl transfer reaction took place on treatment of 1- methoxymethoxy-3-(2-alkynoyloxy)methyl-2-iodonaphthalenes with n-BuLi at - 78°C to give 1-methoxymethoxy-2-alkynoyl-3-hydroxymethylnaphthalenes in high yields. After protection of the hydroxymethyl group as benzoates, formation of a γ-pyrone ring was easily achieved by deprotection of the MOM group followed by spontaneous 6-endo-digonal ring closure under mild acidic conditions. (C) 2000 Elsevier Science Ltd.
