FR2549055A1 - New amino derivatives of 1,4-benzoxazin-2-one, process for obtaining them and application to the frequency conversion of light and to the laser effect - Google Patents

Abstract

The invention relates to new amino derivatives of 1,4-benzoxazin-2-one, to the process for obtaining them and to their application to the frequency conversion of light and to the laser effect. The 1,4-benzoxazin-2-one derivatives have the formula: in which R1 and R2 are identical or different and are hydrogen, a methyl or ethyl group, or any group capable of being joined to the nitrogen atom and especially saturated rings; R3 is an aliphatic group, for example methyl, or an unsaturated ring, for example a phenyl, benzyl, styryl or formylstyryl group. They can be used in dye lasers.

Description

NOVEL AMINO DERIVATIVES OF BENZOXAZINE-1,4 ONE-2,
PROCESS FOR OBTAINING THEM AND APPLICATION TO CONVERSION
FREQUENCY OF LIGHT AND LASER EFFECT
The subject of the present invention is new derivatives of 1,4-benzoxazines-2-ones. It relates more particularly to such derivatives substituted in position 7 by an amino group.

 The invention also relates to a process for obtaining and preparing these novel derivatives, as well as the applications thereof.

dans laquelle R1 et R2 sont identiques ou différents et sont l'hydrogène, un groupe méthyle ou ethyle,ou tout groupement sus- ceptible d'être relie à l'atome d'azote et notamment des cycles saturés ; R3 est un groupe aliphatique, par exemple méthyle, ou un cycle insaturé, par exemple un groupe phényle, benzyle, styryle ou formylstyryle.The products according to the invention correspond to the formula

in which R 1 and R 2 are identical or different and are hydrogen, a methyl or ethyl group, or any group likely to be connected to the nitrogen atom and especially to saturated rings; R3 is an aliphatic group, for example methyl, or an unsaturated ring, for example a phenyl, benzyl, styryl or formylstyryl group.

Among the corresponding products 2 this formula can be mentioned in particular
7-amino-3-methyl-1,4-benzoxazinone-2
. 7-amino-3-phenylbenzoxazine-1,4-one-2
. 7-amino-3-benzyl-1,4-benzoxazin-2-one;
. 7-dimethylamino-3-methyl-1,4-benzoxazin-2-one;
. 7-dimethylaminophenyl-3-benzoxazin-1,4-one;
. 7-dimethylamino-3-benzyl-1,4-benzoxazin-2-one
. 7-dimethylamino-formylstyryl-3-benzoxazin-1,4-one
By way of example of compounds in which the substituents R 1 and R 2 form a saturated ring, mention may be made of a product of formula

 The characteristics and properties of these compounds will be described in more detail below, but it can already be said that they all exhibit intense fluorescence, in organic solvents, ranging from yellow to orange-red.

daris laquelle R1 et R2 sont identiques ou différents et sont l'hydrogène, un groupe méthyle ou éthyle,ou tout groupement susceptible d'être relié à l'atome d'azote et notamment des cycles saturés ; R3 est un groupe aliphatique, par exemple méthyle, ou un cycle insaturé, par exemple un groupe phényle, benzyle, ou formylstyryle, consiste à ajouter en proportions équimolaires à un dérivé du diamino 2,5 phénol de. formule

dans lequel R1 et R2 sont tels que définis précédemment, un com posé de formule R3COCOOR4 dans lequel R3 est tel qu'indiqué cidessus et R4 est l'hydrogène ou C2H5.The process for producing compounds of formula

in which R1 and R2 are identical or different and are hydrogen, a methyl or ethyl group, or any group likely to be connected to the nitrogen atom and in particular to saturated rings; R 3 is an aliphatic group, for example methyl, or an unsaturated ring, for example a phenyl, benzyl or formylstyryl group, is to add in equimolar proportions to a derivative of diamino 2,5 phenol of. formula

wherein R1 and R2 are as previously defined, a compound of formula R3COCOOR4 wherein R3 is as indicated above and R4 is hydrogen or C2H5.

 When R 1 and R 2 are hydrogen, the 2,5-diaminophenol may be prepared by catalytic reduction of the 5-aminophenol-5-amin.

 This catalytic reduction is preferably carried out by hydrogenation of 2-amino-5-nitro phenol dissolved in the presence of Raney nickel.

 When R 1 R 2 are identical and are a methyl group, 2-amino-5-dimethylaminophenol is prepared by the action of HNO 2 on dimethylamino-3-phenol, recovery of 2-nitrosodimethylamino-5 phenol obtained, and catalytic reduction of the latter compound.

The action of HNO2 can be carried out by addition to
cold of NaNO2 on dimethylamino-3-phenol dissolved in acid
hydrochloric,
Hard to manufacture the compound according to the invention in which
Rlet R2 are identical and are a methyl group and R3 is a group
formylstyryl, the product is first prepared according to the invention
in which R3 is a methyl group and then made to act pro
equimolar portion of terephthalaldehyde on said product
It can be specified that when the styrilic group fi
xed in position 3 on the cycle is substituted by another group than a
formyl, its synthesis can be carried out using aldehydes
very much as terephthalic aldehyde.

 In addition, it has been found that the products according to the invention are capable of giving rise to various applications related to their fluorescence and their ability to convert the frequency of light.

These applications are more precisely interesting because of the low overlap between the absorption spectrum and the
emission spectrum of these compounds.

 Indeed, it is known that the necessity of converting an incidental dilation into a light of longer wavelength appears in various fields. The fluorescence phenomenon can be used to achieve such a frequency conversion since the photons resulting from the fluorescence emission correspond to a domain of. wavelengths greater than those of absorption.Or, when guiding light in a doped transparent material, the main source of loss is the reabsorption of fluorescence photons due to the overlap between the spectrum of absorption and the emission spectrum.

In the compounds according to the invention, there exists within the molecules a conjugation between a carbonyl group and an amino group. The dipole moment being then higher in the excited state than in the ground state results in a great influence of the polarity of the medium which can be used to reduce the overlap between the absorption spectrum and the spectrum of Emission experiments carried out in solvents of various polarities have shown, in fact, a decrease in the recovery when the polari -te increases. The stability to light is also a criterion.
In this type of application, tests have proved that the stability of the new coloring products according to the invention is good or excellent in certain cases.

 In particular it is important to point out that the coppo- sives according to the invention also gave rise to laser effect which is an essential application.They can also be used in other applications where it is desired to convert the frequency of light .

 By way of example, it can be recalled that scintillators are often coupled to wavelength shifters. The light emitted by the scintillator excites the fluorescence of dissolved organic molecules in a polymer plate. Part of the fluorescence photons The same principle is used in fluorescent solar concentrators, the photovoltaic cells being located along one of the edges of the doped plate. wave, photocells collect photons whose energy is better adapted to their sensitivity. In the same way the efficiency of photosynthesis can be improved thanks to the conversion of sunlight into a light whose spectral range corresponds to the absorption domain of chlorophylls.

 The following examples are intended to illustrate the invention without in any way limiting its scope.

7-Amino-1,4-benzoxazines-2-ones were prepared by heterocyclization with an acid or an alpha-ester; ketone, diamino 5 phenol The reaction process was as follows

B (R4 = H or C2H5)
The 2,5-diaminophenol was prepared by catalytic reduction of 2-amino-5-nitro phenol: 4.6 g (3/100 mole) of 2-amino-5-nitro phenol are dissolved in 100 ml of absolute ethanol; about 4 g of wet Raney Ni are added to the yellow solution and hydrogenation is carried out with magnetic stirring. After absorption of 2 l of hydrogen, the colorless solution obtained is placed under nitrogen to avoid the oxidation of the diaminophenol B formed, and the appropriate heterocyclization reagent is then added.

EXAMPLE 1 AMINO-7-METHYL-3-BENZOXAZINE-1,4 N-2

 To the diaminophenol solution above, 3.5 g of ethyl pyruvate or 3.2 g of pyruvic acid are added and the mixture is kept under nitrogen and with good stirring for 2 hours (4 hours). pyruvic acid).

The yellow green fluorescence appears quickly. Filtration collected a mixture of nickel and yellow dye which was separated by extraction with 80 ml of warm pyridine. The pure dye was recovered by evaporating the pyridine in vacuo, yielding 3.7 g (70%) of yellow crystals giving yellow-green fluorescence in the solvents (ethanol, acetonitrile, pyridine, chloroform, benzene, DMF). Except in ethanol, where it deteriorates fairly rapidly, its solutions are stable -> 2700C-spectra: visible (EtOH) X m = 385 nm, X-ray fluorescence 515 nm; IR (KBr) (νcm-1): 3465, 3365, 3240 (NH2), 1710 (C = O) 1640, 1600 (NH2), 1550 (C = N);
NMR (pyridine D5 # ppm) 2.4 (s.CH3), 5.3 (broad signal NH2) 6.55 (d H8 J J6.8 = 3), 6.72 (q H6 - J5.6 8), 7.46 (d.5)

<tb> Analysis <SEP>: <SEP> calculated <SEP> for <SEP> C9H8O2N2: <SEP> C <SEP> 61.36 <SEP> H <SEP> 4.54 <SE> N <SEP> 15, 90
<tb><SEP> found <SEP> 61.26 <SEP> 4.57 <SEP> 15.98
<Tb>
EXAMPLE 2: AMINO-7 PHENYL-3-BENZOXAZINE-1,4-ONE -2

3
To the solution of 100 mol of diaminophenol kept under nitrogen was added 4.5 g of benzoylpyruvic acid dissolved in 18 ml of ethanol; the mixture is stirred for 2 hours and then left to rest for 48 hours, always keeping it under nitrogen. The yellow crystals of a yellow-green fluorescent dye are etched together with the nickel in the ethanol, pyridine and acetone, and blue green in benzene and chloroform. It is separated by dissolving in ethanol or toluene, filtering the nickel, and partially evaporating the filtrate, which is then cooled in ice. Benzoxazinone crystallizes in bright yellow platelets, yield: 5.3 g (75%) F 172 C-spectra: visible (EtOH! #M 425 nm, fluorescence #m 520 nm, infrared (KBr, # cm-1) 3480, 3380 (NH 2), 1702 (C = O), 1615 (NH 2);
NMR (DMSO D6 # ppm): 5.5 (broad signal NH2), 6.18 (q.H6), 6.36 (d H8), 6.83 (d H5), 7.35-8.03 ( m C6H5). The values of the couplings for all this series are identical to those of example 1.

Analysis: Calculated for C14H1002N2: C 70.59H 4.20 N 11.76
found 70.30 4.19 11.69
EXAMPLE 3: AMINO-7 BENZYL-3 BENZOXAZINE-1,4-ONE -2

To the solution of 3/100 moles of diaminophenol is added 5 g of freshly prepared phenylpyruvic acid, dissolved in 25 ml of ethanol, and the mixture is maintained under nitrogen and with magnetic stirring for 10 hours; the fluorescence begins to appear after 1 hour. The nickel is filtered and the filtrate is evaporated to dryness; the residue is taken up in a little absolute ethanol and filters the ocher crystals which are slowly deposited, (yield 5.5 g (72%), F 167 C). This fluorescent dye in green yellow in ethanol and pyridine, in green blue in acetone, in light blue in chloroform, in blue violet in benzene.Spectra: visible (EtOH) At m 394 nm, fluorescence Xm 514 nm; IR (KBr v cm -1): 3470, 3370 (NH 2), 1710 (C = O), 1610-1630 (NH 2), 1530 (C = N); NMR (pyridine D5, δ ppm): 4.12 (s CH2), 5.74 (massive
NH2), 6.55 (d H8), 6.76 (q H6), 6.94-7.62 (m H5 + C6H5).

Analysis: Calculated for C15H12O2N2: C 71.42 H 4.76 N 11.11
found 71.25 4.80 10.89
DIMETHYLAMINO-7-BENZOXAZINES-1,4 ONES-2 were prepared according to the following reaction scheme:

5-NITROSO-DIMETHYLAMINO-5-PHENOL C. A solution of 41.1 g of 3-dimethylaminophenol in 126 ml of HCl (d.118) is cooled to 5 ° C. in an ice-salt bath. It is added very slowly to t <50, in about 1 hour and stirring with stirring, that 21.75 g of Na NO 2 dissolved in 36 ml of water. The mixture is stirred for a further 3 hours and the light green hydrochloride precipitate is filtered off with 48 ml of HCl (50%) and then with 12 ml of ethanol. The precipitate is then suspended in 800 ml of saturated water. Acetate of sodium to form base D. After stirring for 2 hours, the reddish crystalline precipitate is filtered off and washed twice with stirring with 100 ml of methanol. There is thus obtained 2: 0 g (40%) of 2-nitroso-5-dimethylamino phenol (single isomer formed) in the form of a garnet powder, which is preserved after drying in colored flask, without further purification. Visible spectra (EtOh) 407 nm; infrared (RBr # cm-1) 3450 (broad band, intermolecular association), 1620 (CN = O) 1500 (NO), 1430 (OH), 1240 (NO); NMR (DMSO D6): 3.25 (s N (CH3) 2), 5.7 (d H6 J4.6 = 2), 6.84 (q.H4 J3.4 = 10), 7.26 ( H, 18.24 (OH with intramolecular linkage)
Analysis: Calculated for C 8 H 10 O 2 N 2 at C 57.83 H 6.02 N 16.87
found 57.93 6.24 17.01
PREPARATION OF AMINO-2 DIMETHYLAMINO-5-PHENOL (D)
5 g (3/100 mole) of 2-nitroso-5-dimethylaminophenol suspended in 150 ml of ethanol are reduced with hydrogen in the presence of 4 g of wet Raney nickel.

When the theoretical amount of hydrogen has been absorbed (approx.

1340 ml), a colorless solution of diaminophenol-highly oxidizable is obtained.

EXAMPLE 4: DIMETHYLAMINO-7-METHYL-3-BENZOXAZINE-1,4-ONE 2

 To the solution of D prepared above and kept under nitrogen and with magnetic stirring, 4 g of ethyl pyruvate are added and allowed to react under nitrogen for 2 hours at ordinary temperature and then for 1 hour in a boiling water bath. After cooling, the nickel is filtered, to which yellow dye crystals can be mixed (in this case, they are extracted with pyridine, cold and reprecipitated with water), the alcoholic filtrate is evaporated to dryness and the residue is taken up. by a little methanol and filtered. 5 g (83%) of bright yellow crystals whose fluorescence is yellow to dry and in ethanol, yellow green in acetone and pyridine, green blue in chloroform and blue in ben zene are isolated. F 124 C C.Spectra: visible (ethanol) #m 403 nm, fluorescence #m 541 nm; infra-red (KBr v cm -1), 2900 (N (CH 3) 2), 1716, 1706 (C = 0 double band) 1610 (C = N); NMR (pyridine D5 6 ppm): 2.47 (s CH3), 2.81 (s, N (CH3) 2), 6.42 (d H8 J6.8 = 3) 6.61 (g H6) J5 6 = 9), 7.57 (d, H5).

Analysis: Calculated for C11H12O2N2: C 64.70 H 5.88 N 13.72
found 64.76 6.11 13.65
EXAMPLE 5: DIMETHYLAMINO-7-PHENYL-3-BENZOXAZINE-1,4 ONE-2

To the solution of D kept under nitrogen and with magnetic stirring, add 5 g of benzoylformic acid dissolved in 30 ml of ethanol and bring 2 hours boiling waterbath. The nickel is filtered hot and the filtrate is evaporated under vacuum. A magma is obtained which is taken up by a little methanol; after filtration, 4.49 g (55%) of bright-orange crystals, with good fluorescence orange-dry, yellow in alcohols (but the solution deteriorates rather quickly in this solvent), acetone and pyridine, are recovered, and yellow green in chloroform and benzene. C. Spectra: Visible (EtOH) #m 443 nm; 548 nm AXm fluorescence; infra-red (KBr v cm1), 2900 cm-1 (N (CH3) 21, 1720 (C = O), 1605 (C = N);
NMR (pyridine D 5 6 ppm) 2.78 (s, N (CH 3) 2), 6.37 (d H 8), 6.59 (q H 6), 7.63 (d Hg), 7.25 -7.63 and 8.35-8.57 (multiplets respectively 3 and 2 protons of C6H5).

Analysis: Calculated for C16H14O2N2 C 72.18 H 5.26 N 10.53
found 72.02 5.40 10.49
EXAMPLE 6: DIMETHYLAMINO-7 BENZYL-3 BENZOXAZINE-1,4 ONE-2

 Under the same conditions as in Example 5; 5 g of freshly prepared phenylpyruvic acid, dissolved in 30 ml of ethanol, are added to the solution of D. Still under nitrogen, the mixture is heated for 3 hours in a boiling bath, the nickel is filtered, and the filtrate is evaporated to dryness. The residue is taken up in 100 ml of ether; the mixture is filtered, the filtrate is evaporated and the brownish resin obtained is taken up in 5 ml of methanol; after a few minutes the light tint crystals of the dye precipitate, yield 3.8 g (45%) .They fluoresce in dry orange, yellow in ethanol and pyridine, in yellow green in acetone and chloroform , blue in benzene. F 136 C. Spectra; visible (EtOH) #m 413 nm; fluorescence #m 544 nm; infra-red (KBr # cm-1) 2910 (N (CH 3) 2, 1732 (C = O), 1620 (C = N); NMR (pyridine D 5 6 ppm) 2.79 (s N (CH 3) 2) 4.27 (s CH2), 6.45 (d H8), 6.65 (q H6), 7.28-7.75 (m C6H5).

Analysis: Calculated for C17H16O2N2 C 72.86 H 5.71 N 10.00
found 72.84 5.86 9.99
Styryl derivatives of the dye obtained in Example 4 have now been prepared.

EXAMPLE 7: DIMETHYLAMINO-7 (eg FORMYLSTYRYL) -3-BENZOXAZINE-1,4
ONE-2

 1.2 g of 7-dimethylamino-3-methyl-benzoxazin-1,4-one-2 and 2 g of terephthalaldehyde are suspended in 4 ml of acetic anhydride and heated in an oil bath for 4 hours at 140 ° C. first observe the dissolution of the reagents; then, little by little, the setting in mass of the product of condensation. After cooling, it is taken up in 15 ml of acetone and maintained for 1 hour with magnetic stirring. The crystalline precipitate which recrystallizes into beautiful garnet needles in pyridine is filtered (yield 1.6 g (85%) .The fluorescence is yellow-orange in acetone and chloroform, yellow in benzene, orange-red in pyridine and dimethylformamide.F 235 C. Visible spectra (DMF) Am 491 nm, fluorescence (DMF) at 594 nm infra-red (KBr v cm -1) 3050 (CH = CH), 2900 (N (CH 3) 2) , 1720 (C = O lactone), 1687 (C = 0 conjugated aldehyde), 1625 (C = N) The very low solubility of this product makes its NMR spectrum difficult.

Analysis: Calculated for ClgH1O60N2: C 71.25 H 5.00 N 8.75
found 71.63 5.20 8.88
The products synthesized in Examples 1 to 7 have now been tested in a dye laser.

 The laser effect of the compounds described in this patent was obtained from the fluorescent state. This state.

fluorescent was created by means of a light pulse.

Two types of light pulse were used: 1) Ultra-short pulse: this pulse with a duration of 25
picoseconds and wavelength 5500 A or 3530 A,
was delivered by a YAG / Nd3 + mode-locked laser. This
pulse was focused, using a cylin lens
drique (f = 10 cm), on a cell containing the sample
lon. The laser effect was highlighted by the existence
of a light beam, intense and directive, emitted from
and other of the cell containing the sample. This ef
fet was observed with the compounds of Examples 1 to 7.

The solvent used was N, N dimethylformamide (DMF)
and the concentrations of 10-3 M / 1. No effect of con
centering on laser emission wavelengths did
been observed.

2) Brief impulse: this impulse, with a duration of 10 ns
and wavelength 3371 A, was delivered by a laser
nitrogen (N2) commercial. This impulse allowed
to pump a commercial dye laser equipped with a device
tif dispersive (network) to vary
continues the laser emission wavelength of the dye
used. The laser effect spectral domains of the compounds studied are described in the table below. The solvent used was ethanol jump for compound No. 7 where DMF was employed.

The following table shows the laser effect wavelengths obtained in each of the 2 experimental conditions described above and for each of the compounds of Examples 1 to 7.

<Tb>

<SEP> Number of <SEP> 1 <SEP> 2 <SEP> 3 <SEP> 4 <SEP> 5 <SEP> 6 <SEP> 7
<tb> composed
<tb> Length <SEP> wave
<tb> effect <SEP> laser <SEP> 5025 <SEQ> 5435 <SEQ> 5050 <SEQ> 5325 <SEQ> 5700 <SEQ> 5385 <SEQ> 6825
<tb> in <SEP><SEP> (1)
<tb> Spectral domain <SEP>
<tb> effect <SEP> laser <SEP> 5050- <SEP> 5300- <SEP> 5050- <SEQ> 5300- <SEP> 5350- <SEP> 6600
<tb> in <SEP><SEP> (2) <SEP> 5625 <SEQ> 5800 <SEQ> 5325 <SEQ> 5800 <SEQ> - <SEQ> 5850 <SEQ> 6775
<tb> (1) Laser effect wavelength obtained by pumping
ultra brief (25 ps). Solvent used: N, N dimethylformamide.

(2) Spectral domain of laser effect obtained by brief pumping
pulse of 10 ns delivered by a nitrogen laser
Repetition rate 10 Hz. Concentrations used vary
from 10-3 to 10-2 M / l according to the compounds.

The laser effect of some of these compounds was compared under the same experimental conditions to the laser effect of rhodamine B, a dye commonly used in dye lasers. Rhodamine
B is indeed a commercial compound having a good laser efficiency. In the case of the compound of Example No. 3, a ratio of 1.25 was measured between its laser effect efficiency and that of rhodamine B. The laser effect yield can thus be compared advantageously with the yield of commercial compound. known from the prior art.

 In addition, the high sensitivity of the compounds according to the invention to the polarity of the solvent may have made it possible to shift the fluorescence spectrally and thus to vary the spectral range of the laser effect.

 As already stated above, the invention can not be limited to the embodiments described here.

 In particular, the compounds of the invention may find other particular applications remaining within the scope thereof since the fluorescence effect of the compounds and light frequency conversion is used.

 Thus, it can be indicated in particular that the dye of Example 7 has characteristics of interest for use as a guanta counter.

Indeed, its absorption bands are wide and the absorption spectral range extends up to 600 nz Moreover, thanks to the weak overlap between absorption and emission spectra, the disturbance due to the reabsorption phenomenon is scaled down.

Claims (14)

 1. As new products, derived from 1,4-benzoxazine-2-one of the formula

 in which R1 and R2 are identical or different and are hydrogen, a methyl or ethyl group, or any group likely to be connected to the nitrogen atom and in particular saturated rings; R 3 is an aliphatic group, for example methyl, or an unsaturated ring, for example a phenyl, benzyl, styryl or formylstyryl group.  2. Product according to claim 1 characterized in that it meets the formula

 . 7-dimethylamino (formylstyryl) -3-benzoxazin-1,4-one.  . 7-dimethylaminobenzyl-benzoxazin-1,4-one-2;  . 7-dimethylaminophenyl-3-benzoxazin-1,4-one;  . 7-dimethylamino-3-methyl-1,4-benzoxazin-2-one;  . 7-amino-3-benzyl-1,4-benzoxazin-2-one;  . 7-amino-3-phenylbenzoxazne-1,4-one;  . 7-amino-3-methyl-1,4-benzoxazin-2-one;  3. Product according to claim 1 characterized in that it is about  4. Process for preparing a compound of formula

 in which R1 and R2 are identical or different and are hydrogen, a methyl or ethyl group, or any group likely to be connected to the nitrogen atom and in particular saturated cycles; R3 is an aliphatic group, for example methyl, or an unsaturated ring, for example a phenyl, benzyl, styryl or formylstyryl group, characterized in that it consists in adding to a derivative of diamino 2,5 phenol of formula

 wherein R1 and R2 are as defined above, a compound of formula R3COCOOR4 wherein R3 is as indicated above and R4 is hydrogen or C25.  5. Method according to claim 3 characterized in that R1 and R2 are identical and are hydrogen and in that the diamino-2,5 phenol is prepared by catalytic reduction of 2-amino-5-nitro phenol.  6. Method according to claim 4 characterized in that this catalytic reduction is carried out by hydrogenation of 2-amino-5-nitro phenol dissolved in the presence of Raney nickel.  7. Process according to Claim 4, characterized in that R1 and R2 are identical and are a methyl group and in that 2-amino-5-dimethylamino phenol is prepared by the action of HNO2 on 3-dimethylamino phenol, recovery of nitroso 2-dimethylamino-5-phenol obtained, then catalytic reduction of the latter compound.  8. Method according to claim 5 characterized in that the action of HNO2 is carried out by cold addition of NaNO2 on dimethylamino-3-phenol dissolved in hydrochloric acid.  9. Process according to claim 4, characterized in that R1 and R2 are identical and are a methyl group, R3 is a formylstyryl group and in that the compound is obtained by equimolar action of terephthalaldehyde on a compound of formula

 10. Application of a benzoxazin-1,4-one-2 derivative of the formula

 wherein R1 and R2 are the same or different and are either hydrogen or a methyl group R3 is a methyl, phenyl, benzyl, or formylstyryl group, at the frequency conversion of light.  11. Application according to claim 10 characterized in that said benzoxazin-1,4-one-2 derivative is the active medium of a dye laser.  12. Application according to claim 10, characterized in that said benzoxazin-1,4-one-2 derivative is used as a scintillator.  13. Application according to claim 10, characterized in that said 1,4-benzoxazin-1-one derivative is used in a fluorescent solar concentrator.  14. Application according to claim 10 characterized in that the drift used is dimethylamino-7 (p -formylstyryl) -3 benzoxazin-1,4-one-2 and is used as a quantum counter.