2-Hydroxybenzaldehydes 1a-e on reaction with malononitrile 2 in the presence
of iodine as catalyst give 3-cyanocoumarins 3a-e in one step under thermal
heating as well as microwave irradiations. The latter conditions are much
more efficient in terms of time (2-5 minutes) and yield as compared to
thermal conditions (2-2.5 hours). Following similar procedure,
3-cyano-4-methylcoumarins 3f-i have also been prepared by the reaction of
2-hydroxyacetophenones 1f-i with malononitrile 2.
2-Hydroxybenzaldehydes 1a-e 在碘作为催化剂的存在下与丙二腈 2 反应,在热作用下一步生成 3-Cyanocoumarins 3a-e
与丙二腈 2 反应时,在碘作为催化剂的存在下,一步即可得到 3-氰基香豆素 3a-e。
加热和微波辐照条件下,一步生成 3-氰基香豆素 3a-e。后一种条件
微波辐照在时间(2-5 分钟)和产量方面都比热条件(2-2.5 小时)更有效。
2-2.5小时)相比,后者在时间(2-5分钟)和产量方面都更为高效。按照类似的程序、
3-氰基-4-甲基香豆素 3f-i 也是通过以下反应制备的
2- 羟基苯乙酮 1f-i 与丙二腈 2 反应制备 3-氰基-4-甲基香豆素 3f-i。