The information on the synthesis of substituted esters of oxepinecarboxylic acids is scanty. For instance, methyl esters of substituted oxepinecarboxylic acids are metabolites of the enzymatic epoxidation of substituted methyl benzoates [1-3], a substituted ethyl 2-oxo-2,5-dihydrobenzo[b]oxepine-3-carboxylate is obtained alongside the other products in reaction of diazoacetaldehyde dimethyl acetal with ethyl coumarin-3-carboxylate [4].We prepared alkyl-1,3-dihydro-3-oxobenzo[c]-oxepine-4-carboxylates along the following procedure. The bromination of dimethyl 2-(2-methylbenzylidene)malonate (Ia) with N-bromosuccinimide (NBS) led to the formation of dimethyl 2-(2-bromomethylbenzylidene)malonate (IIa). At heating compound IIa for 1 h at 190°C bromomethane liberated, and a cyclization occurred providing methyl 1,3-dihydro-3-oxobenzo-[c]oxepine-4-carboxylate (IIIa). The other esters IIIbIIIf were obtained without isolation of intermediate products IIb-IIf (see the scheme). The temperature of the reaction mixture and heating time were adjusted according the liberation of the corresponding alkyl bromide.The composition and structure of compounds IIa, IIIa-IIIf were confirmed by elemental analyses, IR and 1 H NMR spectra. The IR spectra of compounds IIIaIIIf contain characteristic absorption bands of carbonyl groups of ester fragments at 1705-1715 cm -1 and lactone fragments in the region 1730-1745 cm -1 , and also bands of C=C bonds in the region 1660-1680 cm -1 . In the 1 H NMR spectra characteristic singlets from vinyl protons =C=CH-and of protons of the methylene groups attached to the benzene ring appear at δ 7.96-8.11 and 4.99-5.07 ppm respectively. EXPERIMENTAL IR spectra of compounds IIa, IIIa-IIIf were recorded on a spectrophotometer Specord 75IR from mulls in mineral oil. 1 H NMR spectra were registered from solutions in CDCl 3 on spectrometers Tesla BS-576A (operating frequency 100 MHz) (compounds IIa, IIIa, IIIb, IIId) and Mercury Plus-300 (operating frequency 300 MHz) (compounds IIIc, IIIe, IIIf), internal reference HMDS (δ 0.05 ppm).Abstract-Alkyl-1,3-dihydro-3-oxobenzo[c]oxepine-4-carboxylates were obtained by bromination of dialkyl-2-(2-methylbenzylidene)malonates with N-bromosuccinimide followed by the cyclization of dialkyl-2-(2-bromomethylbenzylidene)malonates.

A series of 4-aroyl-1H-benzo[c]oxepin-4-ones have been prepared by heating ethyl 2-aroyl-3-(2-bromophenyl)propenoates. The synthesized compounds possess higher analgesic activity than the reference drug (analgin) and exhibit low toxicity.

Synthesis of Alkyl-1,3-dihydro-3-oxobenzo[c]oxepine-4-carboxylates (III). -(GLUKHOV, A. A.; KIRILLOV*, N. F.; Russ.

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