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are of interest as intercalating and antibacterial agents [1][2][3] and also as photochromic materials [4,5]. However, the choice of suitable methods for preparing them is limited and includes thermolysis of imidoylketenes [6], condensation of thiophosgene with 2'-aminosalicylanilides [7], interaction of 2-azidomethylphenols with cyanogen bromide [8], and the reaction of tetrahydrocarbazoles with 2-chloromethylphenols [9]. OH R R NMe 2 O R N N Br R R 1 N H N Br R Br O R R N N Br R Br OH R R 1 1 DMF 1a-c 2a-e 2 2 1 2 -Me 2 NH -HBr 1a, 2a,d R = R 1 = H, 1b, 2b R = 1-Ad, R 1 = H, 1c, 2c,e R = H, R 1 = 4-MeOC 6 H 4 ; 2 a-c R 2 = Br, d,e R 2 = NO 2 We have shown that the new heterocyclic system of naphtho[1,2-e]pyrazolo[5,1-b][1,3]oxazines 2a-e are formed on the interaction of Mannich bases of the naphthalene series 1a-c with 3,4,5-tribromopyrazole or 3,5-dibromo-4-nitropyrazole in boiling DMF.

pyrazole.1,3-Benzoxazines fused to nitrogen heterocycles hold interest in light of their potential physiological activity. However, the number of available methods for the preparation of these compounds is very limited [1][2][3]. We propose a one-step method for the synthesis of pyrazolo[5,1-b][1,3]benzoxazines 1a,b involving heating 3,4,5-tribromopyrazole with salicyl alcohols in DMF at reflux in the presence of K 2 CO 3 . N H N Br Br Br K 2 CO 3 OH OH R N N Br Br Br O H R O N N Br Br R + 1a,b 2a,b a R = H, b R = Br DMF DMF Pyrazolylmethylphenols 2a,b are formed selectively in the absence of potassium carbonate. The active alkylating agents in these reactions are probably o-methylenequinones formed upon the dehydration of the salicyl alcohols.The IR spectra were taken on a Shimadzu FTIR-8400S spectrometer for KBr pellets. The 1 H NMR spectra were taken on a Bruker AM-400 spectrometer at 400 MHz in CDCl 3 (1a,b) and DMSO-d 6 (2a,b) with TMS as the internal standard. The mass spectra were taken on a Finnigan Trace DSQ mass spectrometer. The ionizing electron energy was 70 eV. The elemental analysis was carried out on a Eurovector EA-3000 automatic CHNS analyzer. 2,3-Dibromo-9H-pyrazolo[5,1-b][1,3]benzoxazine (1a).A mixture of 3,4,5-tribromopyrazole [4] (1 g, 3.3 mmol), salicyl alcohol (0.41 g, 3.3 mmol), and K 2 CO 3 (1.38 g, 10 mmol) in DMF (10 ml) was heated at reflux for 6 h with stirring. The mixture was cooled and poured into 50 ml water. The precipitate formed was

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The title compounds (III), representatives of a previously unknown heterocyclic system, are obtained by condensation of 1‐dimethylaminoethyl‐2‐naphthols (I) with bromopyrazoles (II).