Liu Z, Hu BH, Messersmith PB. Acetonide Protection of Dopamine for the Synthesis of Highly Pure N-docosahexaenoyldopamine.
Tetrahedron Lett 2010;
51:2403-2405. [PMID:
20543896 PMCID:
PMC2882309 DOI:
10.1016/j.tetlet.2010.02.089]
[Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Direct acetonide protection of the catechol of dopamine has proven to be problematic due to formation of Pictet-Spengler isoquinolines. Here we report an efficient method for acetonide protection of dopamine, allowing preparation of a dopamine prodrug without complications from the Pictet-Spengler reaction. Acetonide-protected dopamine was first synthesized by pre-protecting the amino group with phthaloyl followed by refluxing with 2,2-dimethoxypropane in the presence of TsOH. Further work demonstrated that Fmoc or trifluoroacetyl were also suitable N-protective groups, while Boc-protected dopamine gave an isoquinoline product. Acetonide-protected dopamine was coupled to DHA (all cis-4,7,10,13,16,19-docosahexaenoic acid) to produce the N-DHA-dopamine prodrug in high purity.
Collapse