Pyrimidine Derivatives. XI. Facile Carbon-Carbon Bond-Cleavage Reaction of 6-Bromomethylpyrimidinediones and (2,4-Dioxo-1,2,3,4-tetrahydropyrimidin-6-yl)methyl Nitrate via 6-Formyl Derivatives.
作者:Toshio KINOSHITA、Hiroshi OHISHI、Youko TANIMOTO
DOI:10.1248/cpb.41.2073
日期:——
The reaction of 5-bromo-6-bromomethyl-1, 3-dimethyl- (1a) and 5-bromo-6-bromomethyl-1-(3-bromopropyl)-3-methyl-2, 4(1H, 3H)-pyrimidinedione (4a) with 1.0 and 2.0 eq of the sodium salt of 2-nitropropane yielded a mixture of 6-formyl (2 and 5a) and carbon-carbon bond-cleavage products (3 and 6a). When a large excess of the sodium salt of 2-nitropropane was used, 3 and 6a were obtained as sole products, respectively. The nitrates [(5-bromo-1, 3-dimethyl-2, 4-dioxo-1, 2, 3, 4-tetrahydropyrimidin-6-yl)methyl nitrate (1b) and the dinitrate of 5-bromo-6-hydroxymethyl-1-(3-hydroxypropyl)-3-methyl-2, 4(1H, 3H)-pyrimidinedione (4b)] were exclusively converted to 6-formylpyrimidines (2 and 5b) or 6-unsubstituted pyrimidinediones (3 and 6b) by reaction with 1.0 or 2.0 eq of sodium methoxide, respectively. The dinitrate of 5-bromo-1-(2-hydroxyethyl)-6-hydroxymethyl-3-methyl-2, 4(1H, 3H)-pyrimidinediones (7) was treated with sodium methoxide to yield 2-(5-bromo-6-formyl-3-methyl-2, 4-dioxo-1, 2, 3, 4-tetrahydropyrimidin-1-yl)ethyl nitrate (8), a 3, 4-dihydropyrimido[6, 1-c][1, 4]oxazine derivative (9) and 2-(5-bromo-3-methyl-2, 4-dioxo-1, 2, 3, 4-tetrahydropyrimidin-1-yl)ethyl nitrate (10). A plausible reaction mechanism is presented.
5-bromo-6-bromomethyl-1, 3-dimethyl- (1a)和 5-bromo-6-bromomethyl-1-(3-bromopropyl)-3-methyl-2, 4(1H, 3H)-primidinedione(4a)与 1.0 和 2.0 eq 的 2-硝基丙烷钠盐反应,生成 6-甲酰基(2 和 5a)和碳碳键裂解产物(3 和 6a)的混合物。当使用大量过量的 2-硝基丙烷钠盐时,3 和 6a 分别成为唯一的产物。硝酸盐[(5-溴-1,3-二甲基-2,4-二氧代-1,2,3,4-四氢嘧啶-6-基)硝酸甲酯(1b)和 5-溴-6-羟甲基-1-(3-羟基丙基)-3-甲基-2、4(1H,3H)-嘧啶二酮 (4b)]通过与 1.0 或 2.0 eq 的甲醇钠反应,分别转化为 6-甲酰基嘧啶(2 和 5b)或 6-未取代的嘧啶二酮(3 和 6b)。将 5-溴-1-(2-羟乙基)-6-羟甲基-3-甲基-2,4(1H,3H)-嘧啶二酮(7)的二硝酸盐用甲醇钠处理,得到 2-(5-溴-6-甲酰基-3-甲基-2,4-二氧代-1,2,3,4-四氢嘧啶)、4-四氢嘧啶-1-基)硝酸乙酯(8)、3,4-二氢嘧啶并[6,1-c][1,4]恶嗪衍生物(9)和 2-(5-溴-3-甲基-2,4-二氧代-1,2,3,4-四氢嘧啶-1-基)硝酸乙酯(10)。本文介绍了一种合理的反应机理。