Iodine → 4-Chlorofuro[3,2-c]pyridine

For example, in making a compound of formula I in which Y is oxygen, Scheme A can be followed. Briefly, 2-furfural (1) is converted under heating into 3-furan-2-yl-acrylic acid (2) using malonic acid and a suitable base such as piperidine. 3-(Furan-2-yl)-acrylic acid (2) is converted into 3-(furan-2-yl)-acryloyl azide (3) using DPPA and a suitable base such as triethylamine. The azide (3) was cyclized to afford 5H-furo[3,2-c]pyridin-4-one (4) upon heating and a catalytic amount of iodine. 5H-furo[3,2-c]pyridin-4-one is chlorinated on the 4th position with POCl3 to afford 4-chloro-furo[3,2-c]pyridine (5). 4-Chloro-furo[3,2-c]pyridine is treated with bromine, and subsequently with DBU to afford compound (6). The chlorine atom of compound (6) is replaced with an amino group by the action of aqueous ammonia to afford compound (7). Compound (7) is subsequently subjected to Pd(PPh3)4, sodium carbonate, R—B(OH)2 or a compound of formula R—B(OR′)2, in which the radical —B(OR′)2 can be represented as

1. temperatureupon heating

ORDレコード

ord-6d941b75fbdb4f41b4fdf168b231c8ff

出典データセット

uspto-grants-2009_09

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US07592352B2