Background: A rapid, efficient, and environmentally benign procedure for the synthesis of novel furo [2,3-c]phenazine derivatives has been developed via reactions of 2-hydroxynaphthalene-1,4-dione, arylglyoxals, and indole in the presence of TiO₂-SO₃H-catalyst (TSAC) as a recyclable heterogeneous catalyst under solventfree conditions using microwave irradiation.

Introduction: This study describes a successful approach for the synthesis of 2-(4-bromophenyl)-1-(1H-indol-3- yl) benzo[a]furo[2,3-c] phenazine in the presence of TiO₂-SO₃H-catalyst using microwave irradiation.

Objectives: In this paper, we report an efficient and convenient method for the synthesis of phenazine derivatives from benzo[a]phenazin-5-ol, arylglyoxal derivatives, and indoles in the presence of TiO₂-SO₃H-catalyst under microwave irradiation.

Materials and Methods: All reagents and solvents were purchased from Merck and Aldrich and used without further purification. 1H NMR spectra (DMSO) were recorded on the Gemini-500 MHz spectrophotometer with TMS as an internal standard.

Results and Discussion: To investigate the reaction conditions for the synthesis of 2-(4-bromophenyl)-1-(1Hindol- 3-yl) benzo[a]furo [2, 3-c] phenazine derivatives, we performed a reaction between 2-hydroxynaphthalene- 1,4-dione (1 mmol) and aromatic 1,2-diamines (1 mmol) as a model.

Conclusion: We demonstrated a green and straightforward procedure for the efficient synthesis of novel benzo[ a]furo[2, 3-c] phenazine derivatives in high yields via a one-pot, four-component domino protocol by using TiO₂-SO₃H as a mild, effective, non-toxic, and inexpensive solid acid catalyst without the addition of an organic co-solvent.

背景：通过 2-羟基萘-1,4-二酮、芳基乙二醛和吲哚在TiO ₂ -SO ₃ H-催化剂（TSAC）在无溶剂条件下使用微波辐射作为可回收的多相催化剂。

简介：本研究描述了在 TiO ₂存在下合成 2-(4-溴苯基)-1-(1H-indol-3-yl) 苯并[a]呋喃[2,3-c]吩嗪的成功方法-SO ₃ H-催化剂使用微波辐射。

目的：在本文中，我们报告了一种在 TiO ₂ -SO ₃ H 催化剂存在下，在微波辐射下，从苯并[a]吩嗪-5-醇、芳基乙二醛衍生物和吲哚合成吩嗪衍生物的高效便捷方法.

材料和方法：所有试剂和溶剂均购自 Merck 和 Aldrich，无需进一步纯化即可使用。1H NMR 光谱 (DMSO) 在 Gemini-500 MHz 分光光度计上记录，TMS 作为内标。

结果与讨论：为了研究合成 2-(4-溴苯基)-1-(1Hindol-3-yl) 苯并[a]呋喃 [2, 3-c] 吩嗪衍生物的反应条件，我们在2-羟基萘-1,4-二酮（1 mmol）和芳香族1,2-二胺（1 mmol）作为模型。

结论：我们展示了一种使用 TiO ₂ -SO ₃通过一锅四组分多米诺骨牌协议以高产率高效合成新型苯并[a]呋喃 [2, 3-c] 吩嗪衍生物的绿色且直接的程序H 作为一种温和、有效、无毒、廉价的固体酸催化剂，无需添加有机助溶剂。