A new and convenient synthetic method for 1,2,3,5,6,11b-hexahydroimidazo [1,2-d][1,4]benzoxazepine and its derivatives

Abstract

A convenient approach is described for the general synthesis of novel tricyclic scaffolds incorporating an imidazolidine ring and medium sized rings, such as a benzoxazepine ring, through condensation of either aliphatic or aromatic 1,2-diamines with a 2-(2-bromoethoxy)benzaldehyde. The operational simplicity and the availability of the substrate make the process cost effective and practical.

A new and efficient synthesis of unsaturated benzoxazepines using sodium metabisulfite and potassium permanganate as oxidative reagents

“…It starts from the condensation of 2-(2-bromoethoxy)benzaldehydes 6-12 with ethylene diamine in the presence of anhydrous K 2 CO 3 and acetonitrile at reflux temperature to give the corresponding saturated oxazepines 13-19. 22,23 In addition to its 1 H, 13 C NMR and mass spectra, the structure of compound 16 was confirmed by X-ray analysis as shown in Figure 3. Oxidation of 13-19 with potassium permanganate in DMF at room temperature produced the targeted unsaturated benzoxazepines 20-26 in addition to the partially unsaturated benzoxazepines 27-33 in very good yields.…”

“…Recently, we reported new and a convenient synthetic methods for synthesis of [1,4]benzoxazepines. 22,23 In continuation of our research program regarding the synthesis of biologically active nitrogen heterocycles, herein we describe development of new and straightforward approaches for preparation of 5,6dihydroimidazobenzoxazepines 20-26 and 6,7-dihydrobenzo[f]benzimidazoloxazepines 35-39, in good yields (Figure 2). The synthetic pathway for preparation of targeted compounds 20-26, is shown in Scheme 1.…”

“…2-(2-Bromoethoxy)benzaldehydes 6-12 and benzoxazepines 13, 18, 19 were prepared according to the literature. 22,23 Benzoxazepines 14-17 were prepared as 13, 18 and 19. 22 Their physical properties and spectroscopic analyses were as follows:…”

A new, simple and efficient method for the synthesis of tricyclic [1,3]oxazolo[3,2-d][1,4]benzoxazepine, [1,3]oxazino[3,2-d][1,4]benzoxazepine, pyrimido[1,2-d][1,4]benzoxazepine and their derivatives

“…In 2011, we reported a new, straightforward, high-yielding and convenient synthetic method for 1,2,3,5,6,11bhexahydroimidazo [1,2-d] [1,4]benzoxazepines through a condensation of either aliphatic or aromatic 1,2diamines with 2-(2-bromoethoxy)benzaldehydes. 20 In continuation of our research program regarding generalization of this reaction as a useful method for the preparation of other [1,4]benzooxazepines, a new series of [1,4]benzoxazepines (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) have been prepared in high yield as shown in Scheme 1. They were obtained by the condensation of 2-aminoethanol, 3amino-1-propanol or 1,3-diaminopropane with 2-(2-bromoethoxy)benzaldehydes (1)(2)(3)(4)(5)(6) in presence of potassium carbonate in acetonitrile at reflux temperature.…”

“…2-(2-Bromoethoxy)benzaldehydes 1 and 6 were prepared according to the literature. 20 General procedure for the preparation of [1,4]benzoxazepines 7-25. In a 100 mL two-necked round bottom flask equipped with a magnetic stirrer bar, a reflux condenser and a gas line to maintain a nitrogen atmosphere, 2-(2-bromoethoxy)benzaldehyde (2 mmol) and anhydrous K2CO3 (0.55 g, 4 mmol) were suspended in anhydrous CH3CN (100 mL).…”