Facile and convenient synthesis of 2,6-disubstituted 4<i>H</i>-1,3-oxazin-4-one derivatives
作者:Yasuo Morita、Masakazu Kaneko、Sumiko Matsuzawa、Yutaka Yamamoto
DOI:10.1002/jhet.5570340227
日期:1997.3
for the preparation of a variety of 2,6-disubstituted 4H-1,3-oxazin-4-ones 3 by three complementary methods are described. Treatment of the branched aliphatic imidate 2c,d with diketene 1 in the presence of a catalytic amount of acetic acid affords 2-substituted 6-methyl-1,3-oxazin-4-ones 3c,d, whereas the unbranched imidate 2b,e gave oxazines 3b,e and pyrimidines 4b,e (Method A). The reaction of acyl
描述了通过三种互补方法制备各种2,6-二取代的4 H -1,3-恶嗪-4-酮3的简便方法。在催化量的乙酸存在下用双烯酮1处理支链脂族亚氨酸酯2c,d,得到2-取代的6-甲基-1,3-恶嗪-4-酮3c,d,而未支链的亚氨酸酯2b,e得到恶嗪3b,e和嘧啶4b,e(方法A)。酰基麦德鲁姆酸5与亚氨酸酯2的反应得到2,6-二取代的恶嗪3,尽管烷基亚胺基丁酸酯与乙酰基麦德鲁姆的酸产生3和5-乙酰基-1,3-恶嗪-4,6-二酮8(方法B)。酰基乙酰基羧酰胺13的烷基脱水 用酸,例如70%高氯酸或氟磺酸,得到1,3-恶嗪3(方法C)。