One‐pot three‐component synthesis of dihydrobenzo‐ and naphtho[e]‐1,3‐oxazines in water

Abstract

A simple, green and efficient method has been developed for the synthesis of biologically and materially important dihydrobenzo/naphtho[e]-1,3-oxazines in good to excellent yields through a Mannichtype condensation cyclization reaction of aromatic alcohols with HCHO and primary amines in aqueous media at ambient temperature.

An eco-friendly synthesis and antimicrobial activities of dihydro-2H-benzo- and naphtho-1,3-oxazine derivatives

“…The typical synthetic procedure and characterization data of compounds (2i-j, 2n, 3b, 4b, and 4d-e) are presented in the Experimental Section. The physical data of all the known compounds (2a -h, 2k-m, 3a, 3c-d, 4a, 4c, 4f-j and 5) are in agreement with those of reported data [10][11][12][13][14].…”

“…Thus, the development of simple, efficient and green procedure for the synthesis of these molecules is highly desirable. In continuation of our efforts to develop a simple and economical methodology for the synthesis of target compounds of biological interests, we have successfully developed an efficient and eco-friendly synthetic strategy [14] for the construction of a series of 3,4-dihydro-2H-benzo [e][1,3]oxazines (2a-n), 1,2-bis [3,4-dihydrobenzo-[e][1,3]oxazin-3(4H)-yl]ethanes (3a-d), 2,3-dihydro-1H-naphtho-[1,2-e][1,3]oxazines (4a-j) and 3,4-dihydro-3-phenyl-2H-naphtho [2,1-e][1,3]oxazine (5) in good to excellent yields via Mannich type condensation-cyclization reaction of phenols or naphthols with HCHO and primary amines in water at ambient temperature (Scheme 1). The structures of all the synthesized molecules were confirmed by elemental analyses and spectral (IR, 1 H NMR, 13 C NMR, and mass) data.…”

Syntheses, transformations and applications of aminonaphthol derivatives prepared via modified Mannich reactions

“…28 With the aim of a better biological effect, the structure of 14 was extended with different dialkylaminoethoxy substituents at position-4 of the aryl group (15aef, Scheme 6). 29 The syntheses of naphth [2,1- 3]oxazines 17 from amine, 2 equiv of formalin and 1-or 2-naphthol with water as solvent were described by Nath et al 30 The same reaction was achieved by Shingare et al with KAl(-SO 4 ) 2 $12H 2 O as a reusable, non-toxic inexpensive catalyst. It should be mentioned that, in this case, water was applied as solvent (Scheme 7).…”

Novel and Efficient Microwave-Assisted Three Component Reaction for the Synthesis Ofoxazine Derivatives

“…A l t h o u g h s eve ra l m e t h o d s fo r t h e preparation of oxazine derivatives have been reported previously [22][23][24][25] . Some have been focused on the multicomponent reactions method.…”