Nucleophilic ring opening of diepoxide (I) with sodium phenolate gave diol (II), which was converted to diazide (III) by treatment with diphenylphosphorazidate under Mitsunobu conditions. After acid hydrolysis of the acetonide group of (III), the resultant diol (IV) was further protected as the bis(methoxymethyl) ether (V). Subsequent reduction of the azido groups of (V) by hydrogenation over Pd/C furnished diamine (VI). This was then cyclized to thiadiazepine (VII) upon heating with sulfamide in refluxing pyridine. N-Alkylation of sulfonamide (VII) with methyl 4-(bromomethyl)benzoate (VIII) in the presence of NaH in DMF provided adduct (IX). The ester functions of (IX) were then reduced with LiBH4 to afford the bis-hydroxymethyl derivative (X). Finally, deprotection of the methoxymethyl groups of (X) was achieved by treatment with HCl in MeOH-Et2O.