SU910627A1 - Process for producing 2-pheancylidene-5,5-dihydro-1,4-oxazine-3-ons - Google Patents

Description

The invention relates to a new process for the preparation of previously unknown 1,4-oxazin-3-ones derivatives of the general formula

R

ft °

(I)

CH-CO

where R is a hydrogen atom or halogen, which can be used as starting materials for the synthesis of biologically active compounds.

A known method for the preparation of 3-phenacylidene-5, 6-digidao-1,4-oxaet1-2-one, which concludes that aroyl pyruvic acid is reacted with ethanolamine in dry dioxane at the boiling point of the reaction mixture for 11, 5 h 1.

However, it is not possible to obtain compounds of formula 1 in this way, where the keto group is in position 3.

The aim of the invention is to obtain novel 1,4-oxazium-3-ones derivatives, which can be used in the synthesis of biologically active substances.

A method is proposed for the preparation of compounds of formula I, which is concluded in that aroyl pyruvic acid of the general formula

ten

COCH, dOtiOOH

where and has the indicated values is reacted with ethanol 15 amine in absolute alcohol at the boiling point of the reaction mixture.

In the IR spectra of the synthesized compounds, the absorption bands of 3340-3200 cm are present (stretching vibrations of N-H bond), 1655-1645 cm (stretching vibrations of amide carbonyl), 1610-1600 cm- (stretching vibrations of ketone carbonyl).

25

In the UV region, the long-wavelength absorption maximum of the compounds is around 330–340 nm (Ed 4,274, 29), which is close to the maximal position of the arochylpyruvine

Claims (1)

30 acids (335-340 nm). in the spectrum of ITMP 2 -, (p-methylfenacyl den) -5, b-dihydro-1,4-oxazin-3-one is cleared in deuterosulfoxide, there is a singlet of three protons of the methyl group at 3.61 MD, doublet of two protons of the CH 0 group of the 1,4-oxazine cycle with a center at 6.18 ppm, the singlet of the proton of the methine group at 6.95 ppm, a multiple of four aromatic protons with a center at 7.68 ppm The same signal is present in the spectrum of the proton of the NH group at 11.01 ppm. In addition, 2-phenacylidene-5,6-dihydro-1, 4-oxazin-3-ones do not give a color reaction with the alcohol plant “ferric chloride,” which also confirms their cyclic structure. Example 1. 2-phenacylidene-5, dihydro-1,4-oxazin-Z-one. A mixture of 1.7 g (0.009 mol of benzoyl pyruvic acid and 0.55 g (0.009 mol) of ethanolamine in 15 ml of absolute alcohol was boiled for 1 h. Divide 0.85 g (81%) of crystalline product, t. mp 139-140C (from ± oluol). Found,%: to 6.35. c-iaHi-iNOj. Calculated,% t N 6.45. Example 2. 2- (p-Bromfenacil den) -5.6 -dihydro-i, 4-oxazin-3-one. Oiecb 1.35 g (0.005 mol) of P-bromo benzoyl pyruvic acid and 0.3 g (0.005 mol) of ethanolamine in 25 ml of absolute alcohol boiled g (68%) crystalline hours; 1,170-171 o of a solid product, m.p. (from alcohol), 4.92; Br 25.17. Found,% {N CcNcs Crr. Calculated,% 4.72; Br 25.41. Example 3. 2- (p-fluorofenacilide n) -5,6-D1Pgidro-1,4-oxazin-3-one a mixture of 2.1 g (0.01 mol) of p-fluorobenzoyl pyruvic acid and 0.61 g (0.01 mol) of ethanolamine in 30 ml of absolute the alcohol is boiled for 1.5 hours. 2.2 g (87%) of the crystalline product are recovered, mp 152-153 s (from alcohol). Found,%; N 5.92. C, H, NOjF Calculated ,% 1 N 5.95. Claim of Invention The method of producing 2-phenicylidene5, 6-dihydro-1,4-oxazin-3-ones of the total phot alula where R is a hydrogen or halogen atom, characterized in that aroyl pyruvic acid of general formula dodH .dodooH Where R has the indicated meanings, is reacted with ethanolamine e abs medium of the crude spitra at the boiling point of the reactionary reactionion. Sources of information taken into account in the examination 1. USSR author's certificate 621676, cl. C O-D 265/32, 1976.