Quinoxalines. XXVII. The cyanation of 2-substituted quinoxaline 4-oxides with trimethylsilyl cyanide.
作者:Chihoko IIJIMA、Akira MIYASHITA
DOI:10.1248/cpb.38.661
日期:——
The deoxy-cyanation of 2-substituted quinoxaline 4-oxides (Ia-k) with trimethylsilyl cyanide in the presence of 1, 8-diazabicyclo[5.4.0]undec-7-ene gave the corresponding 3-substituted 2-quinoxalinecarbonitriles (IIa-k). However, in the case of 2-(p-tolylsulfonyl)quinoxaline 4-oxide (II), the substitution with cyanide ion proceeded together with deoxy-cyanation to give 2, 3-quinoxalinedicarbonitrile (III).
Ever since the idea arose that melatonin might promote sleep and resynchronize circadian rhythms, many research groups have centered their efforts on obtaining new melatonin receptor ligands whose pharmacophores include an aliphatic chain of variable length united to an N-alkylamide and a methoxy group (or a bioisostere), linked to a central ring. Substitution of the indole ring found in melatonin with a naphthalene or quinoline ring leads to compounds of similar affinity. The next step in this structural approximation is to introduce a quinoxaline ring (a bioisostere of the quinoline and naphthalene rings) as the central nucleus of future melatoninergic ligands.