Figure 5

Synthesis of compounds 19 and 20. (a) i. 20% aq. sol. Cs2CO3, THF, H2O, ii. BrCH2CH2CH2COOEt, DMF, reflux overnight; (b) Dess-Martin periodinane reagent, dry CH2Cl2; (c) 50% CF3COOH in CH2Cl2.
Synthesis of compounds 19 and 20. (a) i. 20% aq. sol. Cs2CO3, THF, H2O, ii. BrCH2CH2CH2COOEt, DMF, reflux overnight; (b) Dess-Martin periodinane reagent, dry CH2Cl2; (c) 50% CF3COOH in CH2Cl2.