申请人:University of Cape Town
                            
                            
                                公开号:US20170305865A1
                            
                            
                                公开(公告)日:2017-10-26
                            
                            The invention provides a process for synthesising a compound of formula V
wherein:
n is 0, 1 or 2; and
R is H or
or a physiologically acceptable salt, tautomer, stereoisomer or mixture of stereoisomers thereof. The process utilizes a N-benzyl protected histidine rather than the unprotected form of histidine. The process of the invention comprises the steps of: (a) deprotecting a N-benzyl protected histidine of formula 11 to form N-benzyl histidine of formula 12; (b) converting compound 12 to (S)-3-(1-benzyl-1H-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 (6-amino-6-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).