Substituent effects and structural limitations in the conversion of 3,3-diarylphthalides to 4,4-diaryl-3,4-dihydro-1(2H)-phthalazinones.
作者:MASAYUKI KUZUYA、TAMOTSU USUI、SEIJI ITO、FUMIO MIYAKE、SHIGENORI NOZAWA、TAKACHIYO OKUDA
DOI:10.1248/cpb.28.3561
日期:——
Heating of crystal violet lactone (CVL) (1a) and its analogs with hydrazine hydrate afforded a single product in each case, to which the 4, 4-diaryl-3, 4-dihydro-1 (2H)-phthalazinone structure (2) was assigned. Kinetic data showed that the introduction of a dimethylamino substituent in 3, 3-diarylphthalides (1) led to an increase in the rate of formation of the dihydrophthalazinone (2). Thus, the reaction seems to occur by a mechanism which involves a carbonium intermediate. Replacement of 3, 3-diaryl groups on the phthalide by a xanthyl group resulted in the formation of an N-aminophthalimidine derivative on similar treatment. The dihydrophthalazinone (2a) exhibited a greenish-blue color on exposure to a weak acid, indicative of heterolytic ring cleavage to form the dye cation, whereas treatment of 2a with a strong acid resulted in a facile conversion to the N-aminophthalimidine (6) and CVL (1a) in a ratio of ca. 2 : 1.
用水合肼加热结晶紫内酯(CVL)(1a)及其类似物,在每种情况下都能得到单一产物,并将其归类为 4,4-二芳基-3,4-二氢-1 (2H) -酞嗪酮结构(2)。动力学数据显示,在 3,3-二芳基酞(1)中引入二甲基氨基取代基会导致二氢酞嗪酮(2)的生成速率增加。因此,该反应似乎是通过一种涉及羰基中间体的机理发生的。用一个黄原基取代邻苯二甲酸酯上的 3,3-二芳基后,在类似的处理过程中形成了一种 N-氨基酞脒衍生物。二氢酞嗪酮(2a)在接触弱酸时呈现出绿蓝色,这表明染料阳离子发生了异溶解环裂解,而用强酸处理 2a 时,则很容易转化为 N-氨基酞酰亚胺(6)和 CVL(1a),二者的比例约为 2:1。