合成路线1

A new synthesis for tomoxetine hydrochloride has been reported: The reduction of benzoylacetic acid ethyl ester (I) with Baker's yeast and glucose in water, or the enzymatic hydrolysis of 3-acetoxy-3-phenylpropionic acid ethyl ester (II), gives (-)-3-hydroxy-3-phenylpropionic acid ethyl ester (III), which by reaction with methylamine yields the corresponding amide (IV). The reduction of (IV) with LiAlH4 in ether affords (-)-3-hydroxy-N-methyl-3-phenylpropylamine (V), which is protected with di-tert-butyldicarbonate to the amide (VI). The condensation of (VI) with o-cresol (VII) by means of triphenylphosphine and diethylazodicarboxylate (DEAD) in ether yields the protected final product (VIII), which is finally deprotected with dry HCl in methanol.

合成路线2

A new synthesis of tomoxetine has been described: The reduction of omega-chloropropiophenone (I) with NaBH4 in ethanol gives 3-chloro-1-phenyl-1-propanol (II), which is treated with butyric anhydride and pyridine in dichloromethane to yield the corresponding racemic ester (III). The optical resolution of (III) with immobilized lipase B from Candida antarctica (CALB) affords a mixture of unreacted (S)-ester and (R)-alcohol (IV) that are separated by column chromatography. Condensation of th (R)-alcohol (IV) with 2-methylphenol (V) by means of PPh3 and diethyl azodicarboxylate (DEAD) in THF gives the corresponding ether (VI), which is finally treated with methylamine in refluxing ethanol.

合成路线3

The reduction of 3-hydroxy-3-phenylpropionic acid ethyl ester (I) with LiAlH4 in THF gives 1-phenylpropane-1,3-diol (II), which is treated with Ts-Cl and TEA in dichloromethane to yield the monotosylate (III). The optical resolution of (III) by means of (Pd(OAc)2, (-)-sparteine and O2 in hot toluene yields a mixture of the desired (S)-1-phenyl-3-(tosyloxy)-1-propanol (IV) and the propiophenone (V) that is separated by column chromatography. The reaction of (IV) with methylamine in hot THF affords the chiral secondary amine (VI), which is finally condensed with 2-methylphenol (VII) by means of PPh3 and DEAD in ethyl ether to provide the target (R)-tomoxetine.

合成路线4

The asymmetric epoxidation of (E)-3-phenyl-2-propen-1-ol (I) by means of titanium tetraisopropoxide, (+)-diethyl tartrate (+)-(DET) and tBu-OOH in dichloromethane gives the chiral epoxide (II), which is opened by means of bis(2-methoxyethoxy)aluminum hydride (Red-Al) in DME to yield the chiral diol (III). The regioselective reaction of (III) with Ms-Cl and TEA in ethyl ether affords the primary mesylate (IV), which is condensed with 2-methylphenol (V) by means of PPh3 and DEAD in ethyl ether to provide the adduct (VI). Finally this compound is treated with methylamine in hot aq. THF to give rise to the target (R)-tomoxetine.

合成路线5

The 5-methylsalicylaldehyde (I) is prepared by a tin (IV) chloride-catalyzed formylation. Iodination of the aldehyde with ICl in glacial acetic acid gives good yield of 3-methyl-5-iodobenzylaldehyde (III). The iodinated salicylaldehyde is reductively aminated with N,N,N'-trimethylpropane-1,3-diamine and sodium borohydride to give N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3-propanediamine (HIPDM) (III) in excellent yield.

合成路线6