Clathria pyramida

Thio-D-mannose (638), the first example of a naturally occurring 5-thio-sugar has been isolated from Clathria pyramida [504] and was later synthesised in 12 steps from D-mannose [505]. 

Capon, R. J. and MacLeod, J. K., 5-Thio-D-mannose from sponge Clathria pyramida (Lendenfeld). First example of a naturally occurring 5-thiosugar., J. Chem. Soc., Chem. Commun., 1200, 1987. 

Thio-D-mannose 7, discovered as a metabolite of the marine sponge Clathria pyramida (Lendenfeld), is still unique as the only example of a 5-thioaldopyranose occurring in nature [45]. Shortly after its discovery, a synthesis from methyl 2,3 5,6-di-0-isopropylidene-a-D-mannofurano-side was reported [46], which essentially followed the principle of the approach depicted in Scheme 9.1. Earlier, 5-thio-D-mannose had been available by molybdate catalyzed epimerization [47,48] of 5-thio-D-glucose 10 [37]. 

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