PROCESS FOR PREPARING TRIAZOLE COMPOUNDS

Abstract: Process for the preparation of a compound of formula (VIII) wherein R1 is Cl, F or CF3; R2 is H, Cl, F or CF3; and R3 is C1-4 alkyl; characterized in that a triol of formula II is treated with a ketone or an aldehyde to give a dioxolane of formula III which by treatment with an aryl-methyl halide gives the compound of formula IV which is hydrolyzed to give a compound of formula V which is functionalized on the primary hydroxy group by a leaving group Lg and treated with a salt of 1,2,4-triazole. The compounds (VIII) is useful for preparing azole derivatives active as antifungal agent.

Description: PROCESS FOR PREPARING TRIAZOLE COMPOUNDS ********************************* The present invention refers to a process for the preparation of azole compounds endowed with antimycotic activity. The compounds of formula I wherein Ri is chlorine, fluorine or trifluoromethyl; R 2 is hydrogen, chlorine, fluorine or trifluoromethyl; R is C alkyl; and R4 is a Ci_ 5 polyfluoroalkyl group containing at least two fluorine atoms and optionally other halogen atoms selected from chlorine and bromine; and their salts with pharmaceutically acceptable acids, are known as antimycotic and antifun- gal agents. The patent application WO 97/31903 (in the Applicant's name) shows a class of compounds which those of formula I above fall within, as broad spectrum antimycotics against human and animal pathogenic fungi. Such compounds are obtained from the intermediate of formula VIII wherein Rj, R 2 .and R 3 are as defined above, which reacted with the suitable polyfluoroalkyl derivative provides the desired compound of formula I. It has been now found a new method for preparing the compounds of formula VIII constituting an alternative to the synthetic routes described in the above cited prior art. Therefore the present invention refers to a method for preparing compounds of formula VIII as illustrated hereinbelow. The synthesis of the compounds of formula VIII according to the present invention starts from the triol of formula II wherein R_, R 2 .and R 3 are as defined above. This is treated with a suitable ketone or aldehyde in acidic medium, for example in p-toluensulfonic acid, to selectively protect the two OH groups in α-position each other. For avoiding the formation of a further stereogenic centre it is preferred to use a symmetric ketone such as, for example, acetone or cyclohexanone. It is thus obtained the dioxolane of formula III wherein Ri, R 2 .and R 3 are as defined above, and R 1 and R π are depending on the aldehyde or ketone employed, which is duly protected on the free hydroxy moiety with an easily removable group, whereas resistant in acidic or weakly basic medium. Preferred examples of such groups are aryl-methyl such as benzyl or furfuryl-methyl optionally substituted which may be removed by hydrogenation. The protection reaction is effected, for example with an arylmethyl haliαe in the presence of .an alkali metal hydride, for example sodium hydride, and provides the compound of formula IV wherein R ls R 2 , R 3 , R 1 and R π are as defined above, and Ar is an optionally substituted aryl group. This is hydrolysed in strong acidic medium according to common methods, preferably in alcohol, for example ethanol, to give the compound of formula V wherein Ri, R 2 , R 3 and Ar are as defined above, which is functionalized on the primary hydroxy group by a leaving group Lg through reaction with a sulfonic acid chloride, such as meth- ansulfonyl-chloride or tosyl chloride, or with a halogenating agent such as, for example, phosphorous tribromide, thionyl chloride or phosphorous pentachloride, thus obtaining the compound of formula VI wherein R ]; R 2 , R 3 and Ar are as defined above, Lg is halogen or a OS0 2 R IV group wherein R IV is a (Cι^)alkyl or an optionally methyl-substituted phenyl group. The compound of formula VI is treated with a salt of 1,2,4-triazole prepared previously or in situ, for example, with 1,2,4-triazole in the presence of sodium hydride and gives the compound of formula VII wherein Ri, R 2 , R 3 and Ar are as defined above. Then the clearing of the protected hydroxy group is effected by common techniques (see, for example, T.W. Greene and P.G.M. Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, New York), thus yielding the desired compound of formula VUJ. The intermediates V and VI are known (patent application EP 667346 in the name of Eisai). In particular, intermediate V is said to be obtained from one of the following compounds wherein Xs are halogen atoms, Pr is a protecting group, R is a lower alkyl group, R 3 is methyl or a lower alkoxy group and R 2 is a lower alkyl group. The intermediate of formula VI is obtained from the intermediate of formula V. The substrate of formula II is known too and may be obtained both via literature methods and using a synthetic route claimed in a co-pending patent application filed in the same date of the present one by the Applicant, starting from a new compound claimed in another co-pending patent application filed in the same date of the present one by the Applicant. Hereinbelow fulfilment examples of the present invention are provided. Example 1 Synthesis of (2S.4R)-2.2-dimethyl-4-(2.4-dichloroDhenvn-4-(2-methyl-3-hvdroxyproDvn-1.3- dioxolane A solution of (2R,3S)-2-(2,4-dichlorophenyl)-3-methyl-l,2,4-trihydroxy-butane (2.65 g; 10 mmoles; enantiomeric excess: 97.8%) and p-toluensolfonic acid monohydrate (0.19 g; 1 mmole) in acetone (25 ml) was refluxed for 60 minutes, then cooled to 20°C, poured into water (100 ml) and extracted with toluene (25 ml x 3). The joined organic phases were washed with water (50 ml), anhydrified on dry Na 2 S0 4 , dried. 3.05 g Of (2S,4R)-2,2-dimethyl-4-(2,4- dichlorophenyl)-4-(2-methyl-3-hydroxypropyl)-l,3-dioxolane were obtained as a viscous oil. 'H-NMR (300MHz, DMSO, δ=ppm, J=Hz): 0.55 (d, 3H, J=6.90); 1.10 (s, 3H); 1.40 (s, 3H); 2.23 (ddq, IH, J=8.30, J=6.90, J=3.95); 3.17 (ddt, IH, J=11.20, J=8.30, J=5.30); 3.77 (ddt, IH, J=11.20, J=3.95, J=5.30); 4.06 (d, IH, J=9.29); 4.50 (t, IH, J=5.30); 4.72 (d, IH, J=9.20); 7.43 (dd, IH, J=8.50, J=2.16); 7.59 (d, IH, J=2.16); 7.63 (d, IH, J=8.50). Example 2 Svnthesis of (2S.4R)-2.2-dimethyl-4-(2.4-dichlorophenyl)-4-(2-methyl-3-phenylmethoxy)-pro- pyl- 1.3 -dioxolane A solution of crude (2S,4R)-2,2-dimethyl-4-(2,4-dichlorophenyl)-4-(2-methyl-3-hydroxypro- pyl)- 1,3 -dioxolane obtained in example 1 (3.05 g; 10 mmoles) in DMF (20 ml) cooled to 15°C under nitrogen was portionwise added with 60% NaH (0.5 g; 12.5 mmoles). The suspension was stirred for 30 minutes, then slowly added, in about 1 hour, with benzyl chloride (1.58 g; 12.5 mmoles) diluted in DMF (5 ml) and the mixture was kept under stirring at 15°C under nitrogen for further 20 hours, then poured into water (150 ml) and extracted with toluene (30 ml x 3). The organic phases were washed with water (50 ml), anhydrified over dry Na 2 S0 4 , dried. The crude was purified by flash chromatography (Si0 ; n-heptane/ethyl acetate 90/10) to give 3.82 g of (2S,4R)-2,2-dimethyl-4-(2,4-dichlorophenyl)-4-(2-methyl-3-phenylmethoxy)- propyl- 1,3 -dioxolane (yield 97%) as a colourless oil. 'H-NMR (300 MHz, DMSO, δ=ppm, J=Hz): 0.59(d,3H, J=6.85); 1.05(s,3H); 1.41(s,3H); 2.55(ddq,lH, J=7.60, J=4J0, J=6.85); 3.26(dd,lH, J=9.50, j=7.60); 3J6(dd,lH, J=9.50, J=4J0); 4.05(d,lH, J=9.20); 4.46(d,lH, J=11.90); 4.52(d,lH, j=11.90); 4J5(d, IH, J=9.20); 7.25-7.40(m, 5H); 7.44(dd, IH, J-8.50, J=2.20); 7.62(d, IH, J=2.20); 7.64(d, IH, j=8.50). Example 3 Synthesis of (2R3S)-l-(2.4-dichlorophenyl)-l-r(2-phenylmethoxy-l-methyl)-ethvn-ethandiol A solution of (2S,4R)-2,2-dimethyl-4-(2,4-dichlorophenyl)-4-(2-methyl-3-phenylmethoxy)- propyl-l,3-dioxolane obtained in example 2 (3.75 g; 9.5 mmoles), 37% HC1 (3J5 ml) .and water (3J5 ml) in ethanol (37.5 ml) was refluxed for 24 hours, then cooled to room temperature, poured into water (150 ml) and extracted with toluene (30 ml x 3). The organic phases were washed with water (50 ml), anhydrified over dry Na 2 S0 4 , dried. The crude was purified by flash chromatography (Si0 2 ; n-heptane/ethyl acetate 75/25) to give 2.32 g of (2R,3S)-1- (2,4-dichlorophenyl)-l-[(2-phenylmethoxy-l-methyl)-ethyl]-ethandiol (yield 73%) as a colourless oil. ! H-NMR (300MHz, DMSO, δ=ppm, J=Hz): 0.58 (d, 3H, j=7.00); 2.65 (ddq, IH, j=6.90, j =5.20, j =7.00); 3.32 (dd, IH, J=9J0, j=6.90); 3.76 (dd, IH, J=9J0, j=5.20); 3.80 (dd, IH, j =11.80, j =5.13); 4.25 (dd, IH, j=11.80, j=5.50); 4.47 (t, 2H, J=14.10); 4.52 (dd, IH, J=5.49, J=5.10); 5.00 (s, IH); 7.25-7.5 (m, 7H); 7.76 (d, IH, J=8.70). Example 4 Synthesis of (2R.3 S)- 1 -(2.4-dichlorophenyl)-r(2-Dhenylmethoxy- 1 -methvn-ethyll-ethandiol-2- p-toluensulfonate A solution of (2R,3S)-l-(2,4-dichlorophenyl)-l-[(2-phenylmethoxy-l-methyl)-ethyl]-ethandiol obtained in example 3 (2.15 g; 6.05 mmoles) in pyridine (15 ml) cooled to 15-17°C under nitrogen was portionwise added in about 30 minutes with p-toluensulfonyl chloride (1.32 g; 6.9 mmoles) and the solution was stirred at 15°C under nitrogen for further 16 hours, then poured into water (100 ml), acidified to pH<2 with 50% H 2 S0 4 and extracted with toluene (30 ml x 3). The joined organic phases were washed with water (50 ml), anhydrified over dry Na 2 S0 , dried. The crude was purified by flash chromatography (Si0 2 ; n-heptane/ethyl acetate 85/15) to give 2.80 g of (2R,3S)-l-(2,4-dichlorophenyl)-[(2-phenylmethoxy-l-methyl)-ethyl]-ethan- diol-2-p-toluensulfonate (yield 91%). *H-NMR (300MHZ, DMSO, δ=ppm, J=Hz): 0.45(d, 3H, J=7.00); 2.40(s, 3H); 2.67(ddq, IH, J=9.50, J=4.10, J=7.00); 3.26(dd, IH, J=9.90, J=4.10); 3J2(dd, IH, J=9.90, J=9.50); 4.42(s, 2H); 4.44(d, IH, j=10.50); 4.85 (d, IH, j=10.50); 5.85 (bs, IH); 7.20-7.70 (m, 12H). Example 5 Synthesis of f2R-3S)-2-(2.4-dichlorophenyl)-2-hvdroxy-3-methyl- 1 -( 1.2.4-triazol- 1 -yl)-4-ben- zyloxy-butane A solution of 1,2,4-triazole (0.56 g; 8.1 mmoles) in DMF (6 ml) cooled to 16°C was portion- wise added, under nitrogen, with 60% NaH (0.32 g; 8 mmoles) keeping the temperature at 15- 20°C. The mixture was stirred at room temperature until the end of the gas generation, then heated to 125°C, slowly added in 30 minutes with a solution of (2R,3S)-l-(2,4-dichlorophen- yl)-[(2-phenylmethoxy-l-methyl)-ethyl]-ethandiol-2-p-toluensulfonate obtained in example 4 (1.02 g; 2 mmoles) in DMF (2 ml), then kept under stirring at 125°C for further 90 minutes. The mixture was then poured into water (40 ml) and extracted with methylene chloride (20 ml x 3). The joined organic phases were washed with water (50 ml), anhydrified over dry Na 2 S0 , dried. The crude was purified by flash chromatography (Si0 2 ; hexane/ethyl aceta- te/methanol 80/20/5) to give 0.66 g of (2R,3S)-2-(2,4-dichlorophenyl)-2-hydroxy-3-methyl-l- (l,2,4-triazol-l-yl)-4-benzyloxy-butane (yield 82%). 1H-NMR (300MHz, DMSO, δ=ppm, J=Hz): 0.69 (d, 3H, J=7.00); 3.07 (ddq, IH, J=6.60, J=5.50, J=7.00); 3.45 (dd, IH, J=9.50, J=5.50); 3.90 (dd, IH, J=9.50, J=6.60); 4.53 (d, IH, J=12.00); 4.60 (d, IH, J=12.00); 4.74 (d, IH, J=14.60); 5.18 (d, IH, J=14.60); 5.65 (s, IH); 7.18-7.50 (m, 9H); 7.60 (s, IH); 8.22 (s, IH). Example 6 Synthesis of (2R.3 S)-2-(2.4-dichlorophenyl)-3-methyl- 1 -( IH- 1.2.4-triazol- 1 -vn-2.4-butan- diol A solution of (2R,3S)-2-(2,4-dichlorophenyl)-2-hydroxy-3-methyl-l-(l,2,4-triazol-l-yl)-4- benzyloxy-butane obtained in example 5 (0.66 g; 1.64 mmoles) in 37% HC1 (10 ml) was heated to 125°C for 30 minutes. After cooling to room temperature, the mixture was poured into ice (20 g), alkalinized to pH>10 by 30% NaOH and extracted with methylene chloride (15 ml x 3). The joined organic phases were washed with water (50 ml), anhydrified over dry Na 2 S0 , dried. The crude was purified by flash chromatography (Si0 2; hexane/ethyl acetate/ methanol 70/30/10) to give 0.44 g of (2R,3S)-2-(2,4-dichlorophenyl)-3-methyl-l-(lH-l,2,4- triazol-l-yl)-2,4-butandiol (yield 86%; enantiomeric excess: 97%). 1H-NMR (300MHz, DMSO, δ=ppm, J=Hz): 0.56(d, 3H, J=7.00); 2.86(ddq, IH, J=5.60, J=5.30, J=7.00); 3.58(ddd, IH, J=11.00, J=5.30, J=5.00); 3.83(ddd, IH, J=11.00, J=5.60, J=5.00); 4J8(d, IH, j=4.60); 5.05(t, IH, J=5.00); 5.2(d, IH, J=4.60); 5.63 (s, IH); 7.20 (dd, IH, j=8.60, j=2.20); 7.36 (d, IH, j=8.60); 7.47 (d, IH, J=2.20); 7.70 (s, IH); 8.25 s, IH).

Claims: Claims 1. Process for the preparation of a compound of formula Vffl wherein R is chlorine, fluorine or trifluoromethyl; R 2 is hydrogen, chlorine, fluorine or trifluoromethyl; and R 3 is C. alkyl; which comprises the treatment of a triol of formula II wherein Ri, R 2 and R 3 are as defined above, with a ketone or an aldehyde in strong acid to give the dioxolane of formula III wherein Ri, R 2 and R 3 are as defined above, and R 1 and R π are depending on the aldehyde or ketone employed, which by treatment with an aryl-methyl halide optionally substituted on the aromatic ring and in the presence of an alkali metal hydride gives the compound of formula IV wherein R u R 2 , R 3 , R 1 .and R π are as defined above, and Ar is optionally substituted aryl, which is hydrolyzed in acidic medium to give the compound of formula V wherein R], R 2 , R 3 .and Ar are as defined above, which is functionalized on the primary hydroxy group by a leaving group Lg through a reaction with a sulfonic acid halide or a halo- genating agent, thus yielding the compound of formula VI wherein Ri, R 2 , R .and Ar are as defined above, and Lg is halogen or a OS0 2 R IV group wherein R IV is a (Cι^)alkyl or an optionally methyl-substituted phenyl group, which treated with a salt of 1,2,4-triazole prepared previously or in situ, yields the compound of formula wherein R R 2 , R 3 and Ar are as defined above; then the clearing of the protected hydroxy group is effected. 2. Process for the preparation of a compound of formula I wherein Ri is chlorine, fluorine or trifluoromethyl; R 2 is hydrogen, chlorine, fluorine or trifluoromethyl; R 3 is C M alkyl; and R, is a C 1 . 5 polyfluoroalkyl group containing at least two fluorine atoms and optionally other halogen atoms selected from chlorine and bromine; and their salts with pharmaceutically acceptable acids, which comprises the treatment of a triol of formula II wherein Ri, R 2 and R 3 are as defined above, with a ketone or an aldehyde in strong acid to give the dioxolane of formula III wherein R h R 2 and R 3 are as defined above, and R 1 and R π are depending on the aldehyde or ketone used, which by treatment with an aryl-methyl halide optionally substituted on the aromatic ring and in the presence of an alkali metal hydride gives the compound of formula wherein R l5 R 2 , R 3 , R 1 and R π are as defined above, and Ar is optionally substituted aryl, which is hydrolyzed in acidic medium to give the compound of formula V wherein R R 2 , R 3 and Ar are as defined above, which is functionalized on the primary hydroxy group by a leaving group Lg through a reaction with a sulfonic acid halide or a halo- genating agent, thus yielding the compound of formula VI wherein Ri, R 2 , R 3 .and Ar are as defined above, and Lg is halogen or a OS0 2 R IV group wherein R IV is a (C w )alkyl or an optionally methyl-substituted phenyl group, which treated with a salt of 1,2,4-triazole prepared previously or in situ, yields the compound of formula VII wherein R R 2 , R 3 .and Ar are as defined above; then the clearing of the protected hydroxy group is effected thus giving a compound of formula VIII wherein R_, R 2 and R 3 are as defined above, which is reacted with the suitable polyfluoroalkyl derivative. 3. Process for the preparation of a compound of formula VIII according to claim 1, which comprises the treatment of a triol of formula II wherein R R 2 and R 3 are as defined in claim 1, with a ketone or an aldehyde in strong acid to give the dioxolane of formula III wherein Ri, R 2 .and R 3 are as defined in claim 1, and R 1 and R π are depending on the aldehyde or ketone used, which by treatment with an aryl-methyl halide optionally substituted on the aromatic ring and in the presence of an alkali metal hydride gives the compound of formula IV wherein Ri, R 2 , R 3 , R 1 .and R π are as defined in claim 1, and Ar is optionally substituted aryl, which is hydrolyzed in acidic medium to give the compound of formula V wherein Ri, R 2 , R 3 .and Ar aio as defined in claim 1. 4. Process for the preparation of a compound of formula VIII according to claim 1, which comprises the treatment of a triol of formula II wherein R., R 2 .and R 3 are as defined in claim 1, with a ketone or an aldehyde in strong acid to give the dioxolane of formula III wherein R b R 2 .and R 3 are as defined in claim 1, and R 1 and R π are depending on the aldehyde or ketone used, which by treatment with an aryl-methyl halide optionally substituted on the aromatic ring and in the presence of an alkali metal hydride gives the compound of formula IV wherein Ri, R 2 , R 3 , R ! , R I! and Ar are as defined in claim 1, which is hydrolyzed in acidic medium to give the compound of formula V wherein Ri, R 2 , R 3 .and Ar are as defined in claim 1, which is functionalized on the primary hydroxy group by a leaving group Lg through a reaction with a sulfoiύc acid halide or a halogenating agent, thus yielding the compound of formula VI wherein Ri, R 2 , R 3 , Lg .and Ar are as defined in claim 1. A process for the preparation of a compound of formula VHI according to claim 1, which comprises the treatment of the compound of formula VI wherein R R 2 , R 3 , Ar and Lg are as defined in claim 1, with a salt of 1,2,4-triazole prepared previously or in situ, to yield the compound of formula VII wherein Rj, R 2 , R 3 and Ar are as defined in claim 1; then the clearing of the protected hydroxy group.

Inventors: BELLI ALDO, PONZINI FRANCESCO, VILLA MARCO, BELLI, ALDO, PONZINI, FRANCESCO, VILLA, MARCO
Applicants: BELLI ALDO, PONZINI FRANCESCO, VILLA MARCO, ZAMBON SPA, BELLI, ALDO, PONZINI, FRANCESCO, VILLA, MARCO, ZAMBON GROUP S.P.A.
Application year: 1998
Main classification: C07D249
IPC codes: C07D249, C07D521