合成路线1

The reaction of D-mannitol (I) with acetone and ZnCl2 gives the diacetonide (II), which is oxidized with Pb(OAc)4 to yield the acetonide of (R)-glyceraldehyde (III). The reduction of (III) with H2 over Pd/C affords the (S)-glycerin acetonide (IV), which is treated with TsCl in pyridine to provide the corresponding tosylate (V). The condensation of (V) with the urea derivative (VI) by means of KOH in DMSO gives the adduct (VII), which is deprotected with HCl in acetone to yield the diol (VIII). Monotosylation of (VIII) with TsCl in pyridine affords the primary tosylate (IX), which is treated with Na in methanol to provide the epoxide (X). Finally this compound is treated with tert-butylamine to furnish the target (R)-enantiomer.

合成路线2

The 3-(isopropylamino)propane-1,2(S)-diol (IV) intermediate has been obtained by two different methods: 1. The oxidation of 1,2,5,6-O-diisopropylidene-D-mannitol (I) with Pb(OAc)4 in THF gives (R)-2,3-O-isopropylideglyceraldehyde (II), which is reductocondensed with isopropylamine by means of H2 over Pd/C in methanol to yield (S)-3-(isopropylamino)-1,2-O-isopropylidenepropane-1,2-diol (III). The cleavage of the isopropylidene protecting group of (III) in hot 6N HCl affords the desired 3-(isopropylamino)propane-1,2-diol (IV) intermediate. 2. The reductocondensation of (R)-glyceraldehyde (V) with isopropylamine by means of H2 over Pd/C in methanol gives the desired 3-(isopropylamino)propane-1,2-diol (IV) intermediate. The cyclization of (IV) with benzaldehyde (VI) by heating at 150 C gives the oxazolidine (VII), which is treated with Ts-Cl and K2CO3 in pyridine to yield the tosylate (VIII). Finally, this compound is condensed with 4-[2-(cyclopropylmethoxy)ethyl]phenol (IX) by means of NaH in DMF and hydrolyzed with conc. aq. HCl to provide the target isopropanol derivative.

合成路线3

Diisopropylidene mannitol (I) was first converted into the dibutyltin derivative (II), which was subsequently mono-benzylated to (III). Acetylation of (III) with acetic anhydride in pyridine gave (IV). After acidic hydrolysis of the isopropylidene ketals of (IV), the resultant tetraol (V) was converted into tetramesylate (VI). Reductive elimination in (VI) with Zn and NaI produced diene (VII). The acetate group of (VII) was then hydrolyzed to (VIII) using NaOMe. Intermediate (VIII) was reacted with triethyl orthoacetate in the presence of propionic acid to generate the allyl vinyl ether (IX), which underwent a Claisen rearrangement to the diene-ester (X). Selective hydroboration-oxidation of the terminal double bond of (X) yielded the primary alcohol (XI). Subsequent benzyl group hydrogenolysis in (XI) furnished the target intermediate diol (XII).

合成路线4

Esterification of diisopropylidene mannitol (I) with benzoyl chloride in pyridine afforded dibenzoate (II). Hydrolysis of the isopropylidene ketals of (II) with aqueous HOAc gave tetraol (III), which was further converted to tetramesylate (IV) on treatment with methanesulfonyl chloride and pyridine. Reductive elimination of the mesylate groups of (IV) using Zn dust and NaI yielded diene (V). The benzoate esters of (V) were then removed by treatment with sodium methoxide. The resultant divinylglycol (VI) was reacted with dibutyltin oxide to produce the tin derivative (VII), which was converted to the target intermediate, themono-benzyl ether (VIII), by treatment with benzyl bromide in hot DMF.

合成路线5