One-Pot Synthesis of Benzotriazoles and Benzotriazole 1-Oxides by Reductive Cyclization of o-Nitrophenylazo Compounds with Benzyl Alcohol
摘要:
Reductive cyclization of 2-[(nitrophenyl)azophenols 1 with benzyl alcohol and sodium hydroxide afforded 2-(2H-benzotriazol-2-yl)phenols 3 and their 1-oxide 2 in good to excellent yields.
A process for the preparation of compounds of formula (I): wherein the general symbols are as defined in claim 1, which comprises reacting a compound of formula (V): wherein R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
, R
9
and R
18
are as defined in claim 1, and R
18
is especially nitro, chlorine or bromine, with an azide compound of formula (IX): wherein M and n are as defined in claim 1, especially with sodium azide.
During the diazo-coupling reaction, nucleophilicdisplacement of a nitro group was also observed. This was the main reaction (1→7) when the starting amine bore either a chlorine or methoxy group at the para position (1b–c). The newly prepared compounds (7) might serve as convenient building blocks in synthesis of some heterocycles.