Synthesis of α-Hydroxyisovaleric acid (Hiv) and α-Acetyloxyisovaleric Acid (Ac-Hiv), Precursors of Aureobasidin B, with Improved Yield

Rani Maharani (Department of Chemistry, Universitas Padjadjaran)
Andi Rahim (Department of Chemistry, Universitas Padjadjaran)
Herdanu Rizqullah (Department of Chemistry, Universitas Padjadjaran)
Nur Muhammad Miftah (Department of Chemistry, Universitas Padjadjaran)
Ace Tatang Hidayat (Department of Chemistry, Universitas Padjadjaran)
Achmad Zainuddin (Department of Chemistry, Universitas Padjadjaran)
Nurlelasari Nurlelasari (Department of Chemistry, Universitas Padjadjaran)
Desi Harneti (Department of Chemistry, Universitas Padjadjaran)
Unang Supratman (Department of Chemistry, Universitas Padjadjaran)

Chimica et Natura Acta
Vol 6, No 3 (2018)

α-Hydroxyisovaleric acid (Ac-Hiv) and α-acetyloxyisovaleric acid (Ac-Hiv) have been successfully synthesized through a diazotisation of amino acid using sodium nitrite with the catalyst of sulfuric acid and acetic acid, respectively. In the synthesis of Hiv, Zubia et al. (2005) mentioned that 3 equivalents of sodium nitrite for the reaction gave the hydroxy acid with a good yield. However, Cohen-Arazi et al. (2008) described that 6 equivalents of sodium nitrite resulted the highest yield. In present study, a variation of equivalents of sodium nitrite (3, 4, 5, 6 eq.) were trialed for the same method of synthesis. Through several experiments, we found that 6 equivalents of sodium nitrite were the best portion among all. This finding was applied into the synthesis of protected Hiv (Ac-Hiv) that was previously reported by Maharani et al. (2017) giving 63% yield when 3 equivalent of sodium nitrite was employed. By increasing the equivalent of sodium nitrite into 6 equivalents, the Ac-Hiv can be synthesized with an improved yield (71%).