The reaction of 3-cyclopentyloxy-4-methoxybenzaldehyde (I) with LiBr, trimethylsilyl chloride (TMS-Cl) and 1,1,3,3-tetramethyldisiloxane in acetonitrile gives the corresponding benzyl bromide (II), which by reaction with NaCN in DMF affords 2-(3-cyclopentyloxy-4-methoxyphenyl)acetonitrile (III). The condensation of (III) with methyl acrylate (IV) by means of Triton B in refluxing acetonitrile yields the 4-cyanopimelate (V), which is cyclized by means of NaH in refluxing DME, giving the 2-oxocyclohexanecarboxylic ester (VI). The decarboxylation of (VI) by means of NaCl in DMSO/water at 150 C yields the cyclohexanone (VII), which is condensed with 2-(trimethylsilyl)-1,3-dithiane (VIII) by means of BuLi in THF, affording the cyclohexylidene-dithiane (IX). The methanolysis of (IX) catalyzed by HgCl2 and HClO4 in refluxing methanol gives a mixture of the cis- and trans-4-cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)cyclohexanecarboxylic acid methyl ester which is submitted to flash chromatography to obtain the cis-isomer (XII). Finally, this compound is hydrolyzed with KOH in methanol/THF/water.

The reaction of 3-cyclopentyloxy-4-methoxybenzaldehyde (I) with LiBr, trimethylsilyl chloride (TMS-Cl) and 1,1,3,3-tetramethyldisiloxane in acetonitrile gives the corresponding benzyl bromide (II), which by reaction with NaCN in DMF affords 2-(3-cyclopentyloxy-4-methoxyphenyl)acetonitrile (III). The condensation of (III) with methyl acrylate (IV) by means of Triton B in refluxing acetonitrile yields the 4-cyanopimelate (V), which is cyclized by means of NaH in refluxing DME, giving the 2-oxocyclohexanecarboxylic ester (VI). The decarboxylation of (VI) by means of NaCl in DMSO/water at 150 C yields the cyclohexanone (VII), which is condensed with 2-(trimethylsilyl)-1,3-dithiane (VIII) by means of BuLi in THF, affording the cyclohexylidene-dithiane (IX). The methanolysis of (IX) catalyzed by HgCl2 and HClO4 in refluxing methanol gives a mixture of the cis- and trans-4-cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)cyclohexanecarboxylic acid methyl ester which is submitted to flash chromatography to obtain the cis-isomer (XII). Finally, this compound is hydrolyzed with KOH in methanol/THF/water.

The reaction of 3-cyclopentyloxy-4-methoxybenzaldehyde (I) with LiBr, trimethylsilyl chloride (TMS-Cl) and 1,1,3,3-tetramethyldisiloxane in acetonitrile gives the corresponding benzyl bromide (II), which by reaction with NaCN in DMF affords 2-(3-cyclopentyloxy-4-methoxyphenyl)acetonitrile (III). The condensation of (III) with methyl acrylate (IV) by means of Triton B in refluxing acetonitrile yields the 4-cyanopimelate (V), which is cyclized by means of NaH in refluxing DME, giving the 2-oxocyclohexanecarboxylic ester (VI). The decarboxylation of (VI) by means of NaCl in DMSO/water at 150 C yields the cyclohexanone (VII), which is condensed with 2-(trimethylsilyl)-1,3-dithiane (VIII) by means of BuLi in THF, affording the cyclohexylidene-dithiane (IX). The methanolysis of (IX) catalyzed by HgCl2 and HClO4 in refluxing methanol gives a mixture of the cis- and trans-4-cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)cyclohexanecarboxylic acid methyl ester which is submitted to flash chromatography to obtain the cis-isomer (XII). Finally, this compound is hydrolyzed with KOH in methanol/THF/water.

The reaction of 3-cyclopentyloxy-4-methoxybenzaldehyde (I) with LiBr, trimethylsilyl chloride (TMS-Cl) and 1,1,3,3-tetramethyldisiloxane in acetonitrile gives the corresponding benzyl bromide (II), which by reaction with NaCN in DMF affords 2-(3-cyclopentyloxy-4-methoxyphenyl)acetonitrile (III). The condensation of (III) with methyl acrylate (IV) by means of Triton B in refluxing acetonitrile yields the 4-cyanopimelate (V), which is cyclized by means of NaH in refluxing DME, giving the 2-oxocyclohexanecarboxylic ester (VI). The decarboxylation of (VI) by means of NaCl in DMSO/water at 150 C yields the cyclohexanone (VII), which is condensed with 2-(trimethylsilyl)-1,3-dithiane (VIII) by means of BuLi in THF, affording the cyclohexylidene-dithiane (IX). The methanolysis of (IX) catalyzed by HgCl2 and HClO4 in refluxing methanol gives a mixture of the cis- and trans-4-cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)cyclohexanecarboxylic acid methyl ester which is submitted to flash chromatography to obtain the cis-isomer (XII). Finally, this compound is hydrolyzed with KOH in methanol/THF/water.

The reaction of cyclohexanone (I) with chloroacetonitrile, KOH and benzyltriethylammonium chloride in THF gives the cyanoepoxide (II), which is treated with LiBr and LiOH in DMF/acetonitrile/water to yield the lithium salt (III) of the title product. Finally, this salt is treated with HCl in ethyl acetate to afford the target Cilomilast.