Scheme 1From: Design, synthesis and biological evaluation of novel betulinic acid derivativesSynthetic route to BA derivatives. Reagents and conditions: (i) BrCH2CH2Br, BrCH2CH2CH2Br, or BrCH2(CH2)2CH2Br, K2CO3, DMF, r.t.; (ii) amine, K2CO3, DMF, r.t.Back to article page