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).
本发明提供了一种合成式(V)化合物的方法,其中:公式(z)或其生理可接受的盐、变构体、立体异构体或立体异构体混合物。该方法使用/V-苄基保护组
氨酸代替未保护的组
氨酸。本发明的方法包括以下步骤:(a)去保护公式11的/V-苄基保护组
氨酸,形成公式12的A/-苄基组
氨酸;(b)将化合物12转化为公式13的(S)-3-(1-苄基-
1H-咪唑-4-基)-2-(
二甲氨基)
丙酸;(c)将化合物13转化为公式14的(2S)-N,N,N-2-三甲基乙酰胺-3-(1-苄基-
1H-咪唑-4-基)
丙酸;(d)
溴化公式14化合物中的
咪唑环,形成5-
溴赫尔岑酮(反应中间体);和(e)将步骤(d)中的5-
溴赫尔岑酮转化为公式15的(对
氨基-对羧乙基)麦角
硫氨酸
硫醚。该方法还可选地进一步包括步骤(f)至(h)中的一项:(f)将公式15的化合物转化为亚砜;(g)将公式15的化合物转化为磺酰;或(h)将公式15的化合物转化为麦角
硫氨酸(ESH)。