Synthesis of Stable Carotenoid Sulphates

Carotenoid sulphates that can be stored unchanged in methanol solution for at least 3 months at -10°C are considered as stable [11]. 

The first carotenoid sulphates to be prepared were zeaxanthin (119) disulphate and lycoxanthin (109) sulphate, in moderate yields [14]. Improved yields of zeaxanthin (119) disulphate and monosulphate were subsequently obtained [11] by using about a 20-fold excess of chlorosulphonic acid. In experiments on the mg scale the yields reported were zeaxanthin (119) disulphate ca. 70%, 119 monosulphate ca. 10%, alloxanthin (117) disulphate 12%, 117 monosulphate 39%, fucoxanthin (369) 3-sulphate 64%, peridinin (558) 3-sulphate 60%, capsorubin (413) disulphate 53%, 413 monosulphate 11%, astaxanthin (406) disulphate ca. 65% and 406 monosulphate ca. 4%. Astaxanthin (406) disulphate has also been prepared in the Roche laboratories (see IR spectrum, Vol. IB, p.l33). 

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