CH639074A5 - Process for the preparation of 4-substituted 1,2-diphenyl- 3,5-dioxopyrazolidines - Google Patents

Description

The invention relates to a new process for the preparation of 4-substituted 1,2-diphenyl-3,5-dioxopyrazolidines of the formula I.

be used.

The compounds of the formula III can also be purple in situ from the corresponding saturated phosphonium salt of the formula

CH

CH2 - CH

CO-

-O-

"CO

_N - /%

in which R and R ', which are the same or different, represent a hydrogen atom, a lower alkyl group, a phenyl group or the radical -COOR "in which R" represents hydrogen or a lower alkyl group and A represents a hydrogen atom or a hydroxyl group. Compounds of the formula I exist in the so-called Z and in the isomeric E form, both of which (as well as mixtures thereof) come under the above-mentioned formula.

From GB-PS 1 301 857 it is already known that i.a. Compounds of the formula I are valuable antiphlogistic compounds which are superior to structurally similar butazolidine in terms of main action and freedom from side effects. Several processes for the preparation of these compounds are also described there.

It has now been found that compounds of the formula I can also be prepared by preparing a cyclohemiacetal of the formula II

HIGH'

V

Orto

• C - CO - N

rO - O

A '

(II),

wherein A 'is hydrogen or an etherified hydroxyl group, preferably the / 3-methoxyethoxymethoxy - (= MEM) group, with a triarylphosphorane derivative of the formula III

R '

C = P-

Ar Ar ■ Ar

(Iii),

in which R and R 'have the meaning given above, and Ar is an optionally with an inert radical, e.g. Means methyl, methoxy or phenyl, substituted phenyl group, reacted and then exposed any etherified hydroxyl group present using a mild Lewis acid. Suitable Lewis acids include in particular TiCLt and ZnBr2, but e.g. ZnCl2, ZnJ2, SnCLt, SnBr4, MgCl2, MgBr2 and similar metal halides are also considered.

The reaction of compounds II and III can be carried out in an aprotic solvent such as e.g. Dimethylformamide or preferably dimethyl sulfoxide take place under anhydrous conditions.

Instead of the cyclohemiacetals of the formula II, the reaction where A is hydrogen can also be carried out directly using the aldehyde of the formula IIa on which they are based

(purple),

wherein R, R 'and Ar are as defined above and X (-) is a halogen ion by elimination of hydrogen halide using a suitable metal reagent such as e.g. Na-15 triumhydride, sodium amide, butyllithium or phenyllithium.

The implementation of the method can e.g. in such a way that, after stirring at room temperature, the reaction mixture is heated at a temperature between 30 to 100 ° C., preferably 20 50 to 70 ° C., allowed to cool and stirred at room temperature.

Refurbishment after completion of the implementation can e.g. by pouring the reaction mixture onto ice, pulling out with a suitable organic solvent such as ethyl acetate, or dichloromethane and column chromatography or re-extraction of the organic solvent with a basic aqueous medium. In the latter case, the product is only obtained after acidification with a mineral acid (e.g. hydrochloric acid) and extraction with a suitable solvent. Additional purification and also the separation of the geometric (E, Z) isomers can be achieved by column chromatography.

If A in the starting compounds denotes an etherified hydroxyl group, this OH group, which is protected during the reaction, must subsequently be exposed in order to obtain compounds of the formula I with A = OH. This happens so that the etherified, e.g. after the reaction of the etherified cyclohemiacetal II with "the triphenylphosphorane derivative of the formula III with mild Lewis acids (e.g. TiCL" in dichloromethane), the OH group cleaved into the / 3-methoxy-ethoxymethyl (= MEM) ether after the reaction of the etherified cyclohemiacetal II has ended.

Such "compounds of formula I in which R = CH3 and R '= COOH are obtained, for example, by mildly alkaline saponification of the corresponding esters (R = CH3, R' = COOR").

The compounds of formula II can be easily obtained by rearrangement of the corresponding cyclic acetals of formula IV

50 CHg

CH,

\

y

CH - C11, - CH

/

i

\

CO-

rO-

(IV),

5J where A 'has the meaning given above. This rearrangement can e.g. by simply heating in aqueous ethanol.

The compounds of the formula IV can in turn be obtained by reaction of diethyl 2- (2-ethylenedioxyethyl) malonate of the formula 0 mei V

CH,

NNSN "C - CH, -

\

Ui

Oik - CH (

(IIa) 65 CH

, C00C2H5

"COOCgHj

(V)

with hydrazobenzene or etherified p-hydroxyhydrazobenzene / 3-methoxyethoxymethyl (= MEM) ether, in the presence of a

639 074

4th

ner solution of sodium in anhydrous ethanol can be obtained.

The compound of formula V can be obtained by measures known per se, for example by condensation of 2-ethylenedioxyethyl bromide with diethyl malonate in benzene / dimethylformamide in the presence of sodium hydride.

The aldehydes of the formula IIa can be obtained by decetalation of the compound of the formula IV with A '= hydrogen; which e.g. can be carried out in anhydrous dichloromethane with boron tri-bromide.

The process according to the invention proceeds smoothly and in high yields without substantial by-products, since the double bond can be introduced at the intended site and the formation of disubstituted products at C-4 of the pyrazolidine ring is avoided.

The following examples illustrate the invention.

example 1

p-hydroxyazobenzene-ß-methoxyethoxymethyl ether (MEM)

A solution of p-hydroxy-azobenzene (191 g, 0.963 mol) in 810 ml was added dropwise to a stirred suspension of 66.14 g (1.516 mol) of sodium hydride (55% dispersion in mineral oil) in tetrahydrofuran (400 ml) Tetrahydrofuran added. After stirring for 15 minutes, the solution was cooled and then MEM chloride, [E.J. Corey, J.L. Gras and P. Ulrich, Tetrahedron Lett., 809 (1976)] (144 g, 1.156 mol) were added dropwise and the mixture was stirred at this temperature for 30 minutes. The mixture was then stirred at room temperature for an hour, then the excess sodium hydride was destroyed by the addition of water and the mixture was concentrated in vacuo. The rest was taken up in ether and washed successively with water, 5% sodium hydroxide and water until it remained neutral. The ether extract was dried and concentrated under reduced pressure. The title compound formed as a thick reddish oil (271.44 g, 98%), which was used without further purification.

Example 2 p-Hydroxyhydrazobenzoläther MEM

A solution of p-hydroxyazobenzene-MEM ether (220 g, 0.768 mol) in 1300 ml of ethanol was hydrogenated in the presence of 2.2 g of Pd / C at room temperature and atmospheric pressure. After the calculated amount of hydrogen had been absorbed, the solution was filtered and evaporated to leave 220 g (99%) of a thick, yellow oil which, because of its easy oxidizability, was immediately used in the next step.

Example 3

Diethyl 2- (2-ethylenedioxyethyl) malonate

Diethyl malonate (471.8 g, 2.94 mol) was added to a stirred suspension of 141.38 g (3.24 mol) of sodium hydride (55% dispersion in mineral oil) in dimethylformamide (1300 ml) and benzene (500 ml). added dropwise. After stirring at room temperature until development was complete, 2-ethylenedioxyethyl bromide (492 g, 2.94 mol) in 500 ml of benzene was added and the solution was stirred at 80 ° C for 16 hours. The mixture was then cooled, poured into excess ice water and the product isolated with ether. After evaporating the dried extract, 2- (2-ethylenedioxyethyl) malonate was obtained.

Boiling point 105 to 108 ° C (0.5 mm).

Analysis for Cu Hi8H6:

found: C 53.42 H 7.42

calculated: C 53.65 H 7.37

Example 4

4- (2-ethylenedioxyethyl) -1, 2-diphenyl-3,5-dioxopyrazolidine

Hydrazobenzene (58.4 g, 0.317 mol) was added with stirring a sodium solution (8.02 g, 0.348 mol) in 480 ml of anhydrous ethanol and then diethyl 2- (2-ethylenedioxyethyl) malonate (78.05 g, 0.317 mol) was added dropwise over 2 hours at the reflux temperature. The mixture was additionally refluxed for one hour, the solvent was gradually evaporated to dryness, and the residue was heated at 130 to 140 ° C under reduced pressure (15 mm) for one hour. The reaction product was cooled, taken up in water, washed with ether and then filtered with activated carbon. The solution was acidified with cooling to give a white solid (72.95 g, 68%) which was dried in vacuo over phosphorus pentoxide and used in the next step without further purification.

Melting point: 150 ° C.

Analysis for Ci9Hi8N204:

found: C 67.71 H 5.33 N 8.23 calculated: C 67.44 H 5.36 N 8.28

Example 5

4- (2-ethylenedioxyethyl) -l- (p-MEM-oxyphenyl-3,5-dioxopyrazolidine p-hydroxyhydrazobenzene-MEM ether (137 g, 0.475 mol) in 140 ml of anhydrous ethanol was stirred with a solution of sodium (1092 g, 0.475 mol) in ethanol (330 ml) was added and then diethyl 2- (2-ethylenedioxyethyl) -ma-ionate (117 g, 0.475 mol) in 120 ml of ethanol was added dropwise over 2 hours at reflux temperature was refluxed for an additional hour, the solvent was gradually evaporated to dryness and the residue was heated under reduced pressure for one hour at 130 to 140 ° C. The reaction product was cooled, taken up in water, washed with ether and then filtered over activated carbon The solution was acidified to pH 4 with 10% hydrochloric acid and the oil which separated off was extracted with ethyl acetate, and the dried extract, which was evaporated to dryness, left an oily residue which was present in a saturated solution of piperazine in acetone was dissolved. The crystalline piperazine salt of 4- (2-ethylenedioxy-ethyl) -l- (p-MEM-oxyphenyl) -3,5-dioxopyrazolidine, which separated on standing, was filtered and then dissolved in water. After acidification with glacial acetic acid, the product was isolated with ether. Evaporation of the dried extract gave the desired pyrazolidine as a pale yellow oil (105 g, 50%), which was pure enough to be dissolved in 1,2,4,5-tetrahydro-l - (p - MEM-oxyphenyl) -2- phenyl-3 H-5-hydroxy-furo [2,3-c] pyrazol - 3-one to be converted.

Example 6

1,2,4,5-tetrahydro-1,2-diphenyl-3H-5-hydroxy-fuross, 3-cJ-pyrazol-3-one

A solution of 4- (2-ethylenedioxyethyl) -1, 2-diphenyl-3,5-dioxopyrazolidine (51.36 g, 0.152 mol) in 510 ml of 50% aqueous ethanol was refluxed for 3 hours. The solid which crystallized from the still hot solution was collected by filtering and dried in vacuo. 36.66 g (82%) of the 1,2,4,5-tetrahydro-1,2-diphenyl-3H-5-hydroxy-furo [2,3-c] pyrazol-3-one was obtained.

Melting point: 267 ° C dec.

Analysis for C17H14N2O3:

found: C 69.18 H 4.75 N 9.63. Calculated: C 69.37 H 4.80 N 9.52

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639 074

Example 7

l, 2,4,5-tetrahydro-1- (p-MEM-oxyphenyl) -2-phenyl-3H-5-- hydroxy-fuross, 3-c] pyrazole-3-site

A solution of 4- (2-ethylenedioxyethyl) -l- (p-MEM-oxy-phenyl) -2-phenyl-3,5-dioxopyrazolidine (130 g, 0.94 mol) in 1200 ml of 75% ethanol was 6 Boiled for hours at reflux and then concentrated to dryness. The residue obtained was recrystallized from ethyl acetate and gave 66 g (56%) of 1,2,4,5-tetrahydro-1- (p-MEM-oxyphenyl) -2-phenyl-3H-5-hydroxy-furo [2 , 3-c] pyrazol-3-ones as colorless crystals. Melting point: 203 ° C decomposition.

Analysis for C21H22N2O6:

found: C 62.99 H 5.49 N 6.95. Calculated: C 63.31 H 5.57 N 7.03

Example 8

4- (2-formylmethyl) -1, 2-diphenyl-2,5-dioxopyrazolidine

To a solution of 4- (2-ethylenedioxyethyl) -1, 2-diphenyl-3,5-dioxopyrazolidine (2.54 g, 7.5 mmol) in 400 ml dichloromethane, a solution of boron tribromide (18.79 g, 75 mmol) in 50 ml dichloromethane was added dropwise at -70 ° C with stirring. At this temperature, stirring was continued for 24 hours. Then the temperature was raised to room temperature and then the mixture was poured into excess ice water.

The organic layer was separated and washed (NaHCO 3 solution) until neutral, dried (Mg SO 4) and evaporated to dryness.

The viscous residue was crystallized from ethyl ether-dichloromethane (8: 2) and gave 0.7 g (31.7%) of the desired pyrazolidine as a colorless solid.

Melting point: 240 to 242 ° C.

Analysis for C17H14N2O3:

found: C 69.54 H 4.92 N 9.44. Calculated: C 69.37 H 4.80 N 9.52

Example 9

4- (3-methyl-2-butenyl) -1, 2-diphenyl-2,5-dioxopyrazolidine

A solution of isopropyl triphenylphosphonium iodide (45.24 g, 0.1 mol) [G. Wittig and D. Wittenberg, Ann., 606, 1 (1957)] in 180 ml of dimethyl sulfoxide was added dropwise to a stirred suspension of sodium methylsulfinyl methide at 20 to 25 ° C. [R. Greenwald, M. Chaykovsky, and E.J. Corey, J. Org. Chem., 28, 1128 (1963)], which was prepared in situ from 4.15 g (0.095 mol) from a 55% dispersion of sodium hydride in mineral oil and 120 ml of dimethyl sulfoxide. The mixture was stirred at room temperature for 30 minutes and then 1,2,4,5-tetrahydro-1,2-diphenyl-3H-5-hydro-xy-furo [2,3-c] pyrazol-3-one (14 g, 0.047 mol) was added in portions. The mixture was stirred at room temperature for 2 hours and then heated at 70 ° C for an additional hour.

After stirring at room temperature for 16 hours, the reaction mixture was poured into excess water and extracted with dichloromethane. The organic phase was separated, washed (H2O), dried (MgSQ »), and then evaporated to dryness. The residue obtained was dissolved in benzene and adsorbed on a silica gel column. Elution with 10% acetone in benzene gave 8.79 g (58.4%) of the desired pyrazolidine as a colorless solid.

Melting point: 155 to 157 ° C.

Analysis for C20H20N2O2:

found: C 75.20 H 6.23 N 8.64. Calculated: C 74.98 H 6.29 N 8.74

Example 10

4- (2-propenyl) -1, 2-diphenyl-3,5-dioxopyrazolidine

This compound was prepared in a manner similar to that described in Example 9, using 1,2,4,5-tetrahydro-1,2-diphenyl-3H-5-hydroxy-furo [2,3-c] pyrazole-3 -one (5.88 g, 0.02 mol) and methyltriphenylphosphonium iodide [CH Collins and G.S. Hammond, J. Org. Chem., 25, 1434 (I960)] (17.78 g, 0.044 mol) and used sodium methylsulfinyl methide (0.04 mol) in dimethyl sulfoxide (prepared as described above). The title compound was obtained as a colorless solid (64.5%) after column chromatography on silica gel (10% acetone in benzene).

Melting point: 133 to 135 ° C (EtOH 95%).

Analysis for Ci8Hi6N202:

found: C 74.12 H 5.63 N 9.37 calculated: C 73.95 H 5.52 N 9.58

Example 11

(E, Z) -4- (2-butenyl) -1, 2-diphenyl-3,5-dioxopyrazolidine

This compound was prepared as described in Example 9 by using 1,2,4,5-tetrahydro-1,2-diphenyl-3H-5-hydroxy-furo [2,3-c] pyrazol-3-one ( 5.88 g, 0.02 mol) and ethyl triphenylphosphonobromide (16.33 g, 0.044 mol) [G. Wittig and D. Wittenberg, Ann., 606, 1 (1957)] using sodium methylsulfinyl methide (0.04 mol) in dimethyl sulfoxide prepared as described above. The compound was obtained after column chromatography on silica gel (10% acetone in benzene) as a mixture of the E and Z forms, in which the Z isomer predominated (60%).

Melting point: 167 ° C (Et0H / H20 1: 1), literature melting point: 128 ° C for the compound which was obtained by the usual malonate hydrazobenzene route.

Analysis for C19H18N2O2:

found: C 74.32 H 5.87 N 9.22 calculated: C 74.49 H 5.92 N 9.15

Example 12

(E, Z) -4- (3-phenyl-2-propenyl) -1, 2-diphenyl-3,5-dioxopyrazolidine

This compound was prepared as described in Example 9, using 1,2,4,5-tetrahydro-1,2-diphenyl-3H-5-hydroxy-furo [2,3-c] pyrazol-3-one ( 5.88 g, 0.02 mol) and benzyltriphenylphosphonchloride (17.11 g, 0.044 mol) [G. Wittig and M. Schöllkopf, Chem. Ber. 87, 1318 (1954)] and sodium methylsulfinyl methide (0.04 mol) in dimethyl sulfoxide, prepared as described above, was used. The compound was obtained as a raw material in 64% yield.

The Z and E forms could be separated by column chromatography on silica gel (10% acetone in benzene). (Z) -isomer: melting point: 124 ° C (EtOH 95 °).

Analysis for C24H20N2O2:

found: C 78.29 H 5.31 N 7.48 calculated: C 78.23 H 5.47 N 7.60 (E) isomer: melting point: 133 ° C (EtOH 95 °)

C24H20N2O2:

found: C 78.42 H 5.54 N 7.46 calculated: C 78.23 H 5.47 N 7.60

Example 13

(E, Z) -4- (3-carbethoxy-2-butenyl) -1, 2-diphenyl-3,5-dioxopyrazolidine

A mixture of a-carbäthoxyäthyliden-triphenylphos-phoran [O. Isler, Helv. Chim. Acta, 40, 1242 (1957)] (63.53 g,

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639 074

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0.175 mol) and 1,2,4,5-tetrahydro-1,2-diphenyl-3H-5-hydroxy-furo [2,3-c] pyrazol-3-one (26 g, 0.088 mol) in 400 ml of anhydrous dimethyl sulfoxide was stirred at room temperature for one hour and heated at 60 ° C. for another hour. After the reaction mixture was stirred at room temperature for 15 hours, it was poured into excess water and extracted with ethyl acetate. The organic phase was separated and extracted several times with an aqueous 5% piperazine solution. The combined aqueous extracts were acidified to pH 8 with 10% hydrochloric acid and the waxy solid that separated was filtered off and discarded. The filtered solution was treated with activated carbon, then acidified to pH 5.5 and extracted with ethyl acetate. After evaporation of the dried extract, the crude isomeric mixture of the (E) - and (Z) -4- (3-carbethoxy-2-butenyl) -l, 2-diphenyl-3,5-dioxopyrazolidine became a brown, thick Obtained oil, which was dissolved in acetone and purified by its 2-amino-2-thiazoline salt. Working up of this salt as described in Example 5 gave, after extraction with ethyl acetate and evaporation of the dried extract, 19.5 g of an oily mixture of the desired pyrazo-lidin, the (E) form predominating. This mixture was dissolved in benzene and adsorbed on a silica gel column. Elution with 10% ethyl acetate in benzene gave 1.36 g (4%) of the (Z) form as a colorless solid.

Melting point: 151 ° C.

Analysis for C22H22N2O4:

found: C 69.59 H 5.97 N 17.02 calculated: C 69.82 H 5.86 N 16.91

Further elution with the same agent gave an intermediate fraction consisting of a mixture of 2 isomers and then a fraction of 14 g (42%) of the (E) form as a colorless solid which was recrystallized from cyclohexane. Melting point: 93 ° C.

Analysis for C22H22N2O4:

found: C 69.87 H 5.81 N 16.80. Calculated: C 69.82 H 5.86 N 16.91

Example 14

(E, Z) -4- (3-carbethoxy-2-butenyl) -1, 2-diphenyl-3,5-dioxopyrazolidine

This compound was prepared as described in Example 13 using a-carbäthoxyethylidene triphenylphosphorane (1.46 g, 4 mmol) and 4- (2-formylmethyl) -l, 2-diphenyl-3,5-di-oxopyrazolidine (0.59 g, 2 mmol) in 12 ml of dimethyl sulfoxide to give 0.24 g (31.7%) of the title compound.

The physico-chemical and analytical data and also the E / Z isomer ratio were almost identical to the data obtained in the previous example.

Example 15

(E, Z) -4- (3-carbethoxy-2-butenyl) -l- (p-MEM-oxyphenyl -2-phenyl-3,5-dioxopyrazolidine

A mixture of a-carbäthoxyäthylidentriphenylphos-phoran (14.49 g, 0.04 mol) and l, 2,4,5-tetrahydro-l- (p-MEM - oxyphenyl) -2-phenyl-3H-5-hydroxy -furo] 2,3-c] pyrazol-3-one (15.96 g, 0.04 mol) in 90 ml of anhydrous dimethyl sulfoxide was reacted as described in Example 13. Then the reaction mixture was poured into excess water, extracted with ethyl acetate and extracted again with 5% aqueous piperazine solution. After acidifying the aqueous phase to pH 6, the product was isolated with ether and, after evaporating the dried extract, gave 10.2 g of an oily mixture of the desired pyrazolidine, in which the (E) form predominated. The mixture was dissolved in benzene and adsorbed on a silica gel column. Elution with dichloromethane gave 0.58 g (3%) of the (Z) form as a yellow oil. Further elution gave, after a fraction consisting of a mixture of 2 isomers, a fraction of 6.05 g (31%) of the (E) -isomer as a yellow oil.

Example 16

(E) -4- (3-carbethoxy-2-butenyl) -1- (p-hydroxyphenyl) -2-phenyl-3,5-dioxopyrazolidine

A solution of (E) -4- (3-carbäthoxy-2-butenyl) -l- (p-MEM-oxyphe) was added to a stirred solution of titanium tetrachloride (77.26 g, 0.407 mol) in 750 ml of dichloromethane at 0 ° C -nyl) -2-phenyl-3,5-dioxopyrazolidine, prepared as in Example 15, (39.3 g, 0.081 mol) in 400 ml of dichloromethane added dropwise. The stirring was continued for an hour and the mixture was poured into an excess of ice water. The organic phase was separated, dried and evaporated to give an oily residue which was dissolved in dichloromethane and adsorbed on a silica gel column. Elution in 10% methanol in dichloromethane gave 25.4 g (79%) of the title compound as a colorless solid. Melting point: 70 to 74 ° C.

Analysis for C22H22N2O5:

found: C 66.84 H 5.51 N 6.92. Calculated: C 66.99 H 5.62 N 7.10

Example 17

(E) -4- (3-Carboxy-2-butenyl) -1, 2-diphenyl-3,5-dioxopyrazolidine

A solution of (E) -4- (3-carbethoxy-2-butenyl) -1, 2-diphenyl-3,5-dioxopyrazolidine, prepared as described in Example 13, (2.25 g, 5.28 mol ) in 10 ml of 10% sodium hydroxide was stirred for 30 minutes at room temperature and then acidified with 10% hydrochloric acid. The precipitated product was isolated with dichloromethane and, after evaporating the dried extract, gave a gummy residue which was crystallized from ethyl ether (1.05 g, 56.75%).

Melting point: 141 ° C.

Analysis for C20H18N2O4:

found: C 68.28 H 5.19 N 7.97 calculated: C 68.56 H 5.18 N 8.00

Example 18

(Z) -4- (3-Carboxy-2-bu tenyl) -1, 2-dipheny 1-3,5-dioxopyrazolidine

This compound was prepared as described in Example 17 by hydrolysis of the (Z) -4- (3-carbethoxy-2-butenyl) -1, 2-diphenyl-3,5-dioxopyrazolidine as prepared in Example 13, (1 g, 2.6 mmol) with 10% sodium hydroxide (20 ml). After the usual work-up, the compound was crystallized from ethyl ether and this gave 0.6 g (61%) of the desired pyrazolidine as colorless crystals.

Melting point: 65 ° C.

Analysis for C20H18N2O4:

found: C 68.37 H 5.28 N 7.88. Calculated: C 68.56 H 5.28 N 7.88

Example 19

(E) -4- (3-Carboxy-2-butenyl) -1- (p-hydroxyphenyl) -2-phenyl-3,5-dioxopyrazolidine

This compound was similarly synthesized by hydrolysis of the (E) -4- (3-carbethoxy-2-butenyl) -l- (p-hydroxyphenyl) -2-

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-phenyl-3,5-dioxopyrazolidine prepared, which was prepared as described in Example 16 (10 g, 25 mmol) with 10% sodium hydroxide (200 ml). The compound obtained was recrystallized from acetonitrile. This gave 2.15 g (23.2%) of the title compound as colorless crystals. s

Melting point: 170 ° C.

Analysis for C20H18N2O5:

found: C 65.30 H 5.01 N 7.61. Calculated: C 65.56 H 4.95 N 7.66

Claims (11)

639 074 2nd PATENT CLAIMS 1. Process for the preparation of substituted 1,2-diphenyl-3,5-dioxopyrazoidines of the formula I \ C - CH - CH2 - CH / \ CO N / \ - A 5 (I), CO N /% in the R and R ', which are the same or different, represent a hydrogen atom, a lower alkyl group, a phenyl group or the radical -COOR ", in which R" is hydrogen or a lower alkyl group and A represents a hydrogen atom or a hydroxyl group, characterized in that compounds of the formula II 6. The method according to any one of claims 1 to 3, characterized in that the reaction takes place at 50 to 70 ° C. 7. The method according to claim 1, characterized in that one carries out the possible splitting of the ether group A 'to the OH group in a suitable organic solvent. 8. The method according to claim 7, characterized in that anhydrous dichloromethane is used as the solvent. 9. Process for the preparation of substituted 1,2-diphenyl-3,5-ioxopyrazolidines of the formula I. CH CH2 - CH / \ .CO- / ^ CO- ^ 3 (I), HIGH in the o (II), A 'is hydrogen or an etherified hydroxyl group, with compounds of the formula III in the R and R ', which are the same or different, represent a hydrogen atom, a lower alkyl group, a phenyl group or the radical -COOR ", in which R" represents hydrogen or a lower alkyl group and A represents a hydrogen atom, characterized in that the free aldehyde of the formula IIa C = P cc- 30th (HI), C - CH2 - CH CO- ■ o o (IIa) 35 " in the R and R 'have the meanings given above and Ar denotes a phenyl group which is optionally substituted by an inert radical, and that in ether compounds obtained in which A 'denotes an etherified hydroxyl group, the ether group is cleaved by means of mild Lewis acids. 2. The method according to claim 1, characterized in that that A 'in formula II means the β-methoxyethoxymethoxy group. 3. The method according to claim 1 or 2, characterized in that the compounds of the formula III are in situ by splitting off hydrogen halide from compounds of the formula purple with compounds of the formula III R Ar C = P Ar Ar (in), 50 R ' in the R and R 'have the meanings given above and Ar represents a phenyl group which is optionally substituted by an inert radical. 10. The method according spoke 9, characterized in that the reaction takes place at 50 to 70 ° C. 11. Compounds of formula II (purple), HO - CH 55 \ / CH0 C " / \ - A ' CO - N / \ (II), where what R, R 'and Ar have the meaning given in claim 1 and «o X <- * means a halogen ion. 4. The method according to claim 1 or 2, characterized in that one carries out the reaction of the compounds of formula II with compounds of formula III in an aprotic solvent. 65 5. The method according to claim 4, characterized in that dimethyl sulfoxide is used as the aprotic solvent. A 'is hydrogen or an etherified hydroxyl group for carrying out the process according to claim 1. 12. Compounds of the formula IIa C - CH, CH V (IIa) co- - /% to carry out the method according to claim 9. 3rd 639 074