Reaction of 3-aminoquinoline-2,4-diones with isothiocyanic acid—an easy pathway to thioxo derivatives of imidazo[1,5-c]quinazolin-5-ones and imidazo[4,5-c]quinolin-4-ones
potassium thiocyanate in boiling acetic acid to give novel 2,3-dihydro-3-thioxoimidazo[1,5-c]quinazolin-5(6H)-ones in high yields. However, if the starting compounds are substituted with a benzyl group at position 3, a C-debenzylation proceeds to give 2,3-dihydro-2-thioxo-1H-imidazo[4,5-c]quinolin-4(5H)-ones. According to a proposed reaction mechanism, a molecular rearrangement of the primarily formed mono-substituted
3-Amino-1 H,3 H -quinoline-2,4-diones与硫脲或硫氰酸钾在沸腾的乙酸中反应,生成新的2,3-二氢-3-thioxoimidazo [1,5- c ] quinazolin -5(高产率的6 H)-一。但是,如果起始化合物在位置3处被苄基取代,则会进行C-脱苄基作用,得到2,3-二氢-2-硫代-1 H-咪唑并[4,5- c ]喹啉-4(5 H)-那些。根据提出的反应机理,发生了最初形成的单取代的硫脲的分子重排。所有化合物的特征在于1 H,13 C和15N NMR和IR光谱以及质谱法。
Unprecedented reactivity of 3-amino-1H,3H-quinoline-2,4-diones with urea: an efficient synthesis of 2,6-dihydro-imidazo[1,5-c]quinazoline-3,5-diones
Substituted 3-amino-1H,3H-quinoline-2,4-diones react with urea in acetic acid to, give novel 2,6-dihydro-imidazo[1,5-c]-quinazoline-3,5-diones in high yields. The same compounds were obtained, albeit with small yields, from 3-chloro-1H,3H-quinoline-2,4-diones and urea. In the proposed reaction mechanism, a molecular rearrangement of the primarily formed mono-substituted urea takes place. The prepared 2,6-dihydro-imidazo[1,5-c]-quinazoline-3,5-diones were characterized by their H-1, C-13, N-15 NMR and IR spectra and atmospheric pressure chemical ionisation mass spectra. (C) 2003 Elsevier Science Ltd. All rights reserved.