Microwave-assisted synthesis of naphthyridinoylpyrazolidinones (7a-7j) has been achieved rapidly via the
reaction of naphthyridine hydrazide (4) with different β-keto esters and ethoxymethylenemalonic ester (EMME) (5a-5e).
Initially, the reaction of naphthyridine hydrazide (4) with various β-keto esters under microwave irradiation for 5 mins at
130oC results in the formation of condensed products 6a-6j. This condensation was followed by cyclization, also, in
diphenyl ether under microwave irradiation for 10 mins at 230-250oC, yielding the corresponding cyclized products 7a-7j.
Alternatively, both reactants 4 and each of the β -keto esters/EMME (5a-5e) were treated in diphenyl ether under
microwave irradiation for 15 mins at 230-250oC giving the target molecules 7a-7j as one-pot reaction in good yields.
微波辅助合成
萘啶酰基
吡唑烷酮 (7a-7j) 已通过以下方法快速实现
萘啶酰
肼(4)与不同的β-
酮酯和乙氧基亚
甲基丙二酸酯(
EMME)的反应(5a-5e)。
首先,
萘啶酰
肼(4)与各种β-
酮酯在微波照射下在50℃下反应5分钟。
130℃导致形成缩合产物6a-6j。该缩合之后还进行环化,
将
二苯醚在230-250℃下微波照射10分钟,得到相应的环化产物7a-7j。
或者,将两种反应物4和每种β-
酮酯/
EMME(5a-5e)在
二苯醚中在
在 230-250oC 下微波辐射 15 分钟,一锅反应即可得到目标分子 7a-7j,收率良好。