| 摘要 |
The invention provides a process for synthesising a compound of formula (V) wherein: formula (z) or a physiologically acceptable salt, tautomer, stereoisomer or mixture of stereoisomers thereof. The process utilizes a /V-benzyl protected histidine rather than the unprotected form of histidine. The process of the invention comprises the steps of: (a) deprotecting a /V-benzyl protected histidine of formula 11 to form A/-benzyl histidine of formula 12; (b) converting compound 12 to (S)-3-(1 -benzyl-1 H-imidazol-4-yl)-2-(dimethylamino)propanoic acid of formula 13; (c) converting compound 13 to (2S)-N,N,N-2-trimethylethanaminium-3-(1 -benzyl- 1H-imidazol-4-yl)propanoic acid of formula 14; (d) brominating the imidazole ring of the compound of formula 14 to form 5-bromohercynine lactone (reactive intermediate); and (e) converting the 5-bromohercynine lactone of step (d) to (p-amino-p- carboxyethyl)ergothioneine sulfide of formula 15. The process optionally further includes one of steps (f) to (h): (f) converting the compound of formula 15 to a sulfoxide; (g) converting the compound of formula 15 to a sulfone; or (h) converting the compound of formula 15 to ergothioneine (ESH). |
