An alternative synthesis of pyrimido[4,5-b]quinoline-4-ones via metal-free amination in water and Vilsmeier-Haack cyclization

作者：Singh Radhey M^*; Sharma Neha; Kumar Ritush; Asthana Mrityunjaya; Upadhyay Shraddha

来源：Tetrahedron, 2012, 68(50): 10318-10325.

DOI：10.1016/j.tet.2012.10.004

• 2-Chloroquinoline-3-carbonitrile
• Amination
• Aqueous media
• Vilsmeier-Haack reaction
• Pyrimido[4,5-b]quinoline-4-one

Two-step synthesis of pyrimido[4,5-b]quinoline-4-ones is described from 2-chloroquinoline-3-carbonitries via amination and cyclization reactions, respectively. The amination reactions proceeded much faster in water via simple SNAr displacement reactions of chlorine. The cyclization reactions using Vilsmeier reagent at 60 degrees C gave the best yield of the products. The isolation of starting compound from the reaction of cyclized product with I-2/K2CO3 provided further chemical proof of the structure of the cyclized product. Plausible mechanism for cyclization is proposed.

• 出版日期2012-12-16