Date of Award


Document Type

Senior Scholars Paper (Colby Access Only)


Colby College. Biology Dept.


Evans B. Reid


Attempted Synthesis of 2,4 dichlorophenyl Analogue to Auxin-b Since 1935, possible routes to the final synthesis of auxin-b were investigated. At Johns Hopkins University, the possibility of the condensation of 3,5 di-S-butyl-I-cyclopentenealdehyde with γ-bromo-β-ethoxycrotonate by means of the Reformatsky reaction was thought to be the most promising. Out of these investigations, the possible route to the synthesis of the phenyl analogue and the substituted phenyl analogue to auxin-b was visualized. This route consisted of: reacting acetoacetic ester with ethyl-orthoformate (concentrated sulfuric acid as a catalyst) to obtain β-ethoxycrotonate. This molecule is brominated on the γ position to yield γ-bromo-β-ethoxycrotonate. The latter is reacted with an aldehyde (in my case 2,4 dichlorobenzaldehyde) in the Reformatsky reaction to give a condensation product. Conclusions 1) The Reformatsky condensation between γ-bromo-β-ethoxycrotonate and 2,4 dichlorobenzaldehyde apparently involves a deep-seated reaction between one or both of the reactants resulting in a red oil and a small percentage of unknown solid. 2) The synthesis of the 2,4 dichlorophyenyl analogue to auxin-b by the condensation of 2,4 dichlorobenzaldehyde and γ-bromo-β-ethoxycrotonate is improbable. 3) The possible route to the 4-chlorophenyl analogue to auxin-b by the Reformatsky reaction appears to be more favorable.


Reformatsky condensation, synthesis, auxin


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