Diversity-Oriented Synthesis of Novel 2’-Aminospiro[11H-indeno[1,2- b]quinoxaline-11,4’-[4H]pyran] Derivatives via a One-Pot Four-Component Reaction by Alireza Hasaninejad* a ), Nooshin Golzar a ), Mohsen Shekouhy a ), and Abdolkarim Zare* b ) a )Department of Chemistry, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Iran (phone/fax: þ 98-771-4541494; e-mail: ahassaninejad@yahoo.com) b )Departmentof Chemistry, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran (phone/fax: þ 98-771-5559486; e-mail: abdolkarimzare@yahoo.com) A sequential one-pot four-component reaction for the efficient synthesis of novel 2’-aminospiro- [11H-indeno[1,2-b]quinoxaline-11,4’-[4H]pyran] derivatives 5 in the presence of AcONH 4 as a neutral, inexpensive, and dually activating catalyst is described ( Scheme 1). The syntheses are achieved by reacting ninhydrin (1) with benzene-1,2-diamines 2 to give indenoquinoxalines, which are trapped in situ by malono derivatives 2 and various a-methylenecarbonyl compounds 4 through cyclization, providing the multifunctionalized 2’-aminospiro[11H-indeno[1,2-b]quinoxaline-11,4’-[4H]pyran] analogs 5. This chemistry provides an efficient and promising synthetic way of proceeding for the diversity-oriented construction of the spiro[indenoquinoxalino-pyran] skeleton. Introduction. – Quinoxaline derivatives are an important group of aza-polycyclic compounds which have many biological and pharmaceutical applications such as antibacterial [1], antifungal [1], antidepressant [2], and antitumor agents [3]. On the other hand, pyrans and their derivatives are of considerable interest because of their wide range of biological properties [4] such as spasmolytic [5], diuretic [6], and anticancer activity [7]. The 4H-pyrans also constitute the structural framework of many natural products [8]. Moreover, spiro compounds represent an important class of naturally occurring substances characterized by highly pronounced biological proper- ties. The spiro functionality has been found to be present in phytochemicals such as alkaloids, lactones, or terpenoids [9]. The biological activities of spiro compounds containing pyran moieties have also been reported [10] . They also show good activity as hypertensive agents [11] and have been the subject of significant interest as potential novel analgesic agents [12]. In continuation of our research on the synthesis of quinoxalines [13] and the development of multicomponent reactions [14], we report herein a one-pot, four- component method for the diversity-oriented synthesis of novel 2’-aminospiro[11H- indeno[1,2-b]quinoxaline-11,4’-[4H]pyran] derivatives 5 from ninhydrin (¼ 2,2-dihy- droxy-1H-indene-1,3(2H)-dione; 1), benzene-1,2-diamines 2, malono derivatives 3, and a-methylenecarbonyl compounds 4 in the presence of ammonium acetate as a neutral, inexpensive, and dually activating catalyst ( Scheme 1). Results and Discussion. – Our initial efforts focused on the search for a suitable catalyst for the synthesis of 2’-aminospiro[11H-indeno[1,2-b]quinoxaline-11,4’- Helvetica Chimica Acta – Vol. 94 (2011) 2289  2011 Verlag Helvetica Chimica Acta AG, Zürich