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To search for an economical and convenient synthesis of sunitinib and its malate salt, optimization of a scalable synthetic route was explored by designing a standard experimental protocol on laboratory scale using commercially available materials including acetyl ethyl acetate, 4-fluoroaniline, and N 1 ,N 1 -diethylethane-1,2-diamine. The optimal conditions were established based on investigating the main reaction steps, including cyclization, hydrolysis, decarboxylation, formylation, and condensation, giving optimized yields for each step of 94.4, 97.6, 98.5, 97.1, 91.0, 86.3, 85.5, 88.2, 99.1, 97.3, and 58.7 %, respectively. The synthesis process of 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid as the important intermediate was significantly improved by using solvent-free decarboxylation instead of the traditional process in a high-boiling-point solvent. The subsequent formylation was conducted directly using the dichloromethane solution of the crude product from decarboxylation, leading to an almost quantitative combined yield of these two steps. The overall yields of sunitinib and its salt using the optimal synthesis process were 67.3 and 40.0 % based on acetyl ethyl acetate. The obtained data could be used as reference for future industrialization, especially for avoiding expensive solvents and reducing reaction time.Electronic supplementary material The online version of this article (

As an important newly Food and Drug Administration (FDA)-approved drug for treating diabetes, rosiglitazone (1) has received much attention from researchers in many areas. To search for an economical and convenient synthesis method for 1, we explored the reaction conditions and workup of a scalable five-step synthetic route by an orthogonal method to determine the best condition for each reaction step. The starting materials are commercially available, including 2-chloropyridine (2), N-methylethanolamine (3), 4-fluorobenzaldehyde (4a) or 4-hydroxybenzaldehyde (4b), and 1,3-thiazolidine-2,4-dione (5). The five sequential reaction steps are cyclization, alkylation, etherification, condensation, and reduction, having optimal yield of 90, 99, 59, 75, and 91 %, respectively. The best overall yield to synthesize rosiglitazone based on compound 2 was 40 %, being suitable for industrial purposes, using water as a green solvent and avoiding column chromatography during the last three reaction steps.

A series of 2,3‐substituted‐2‐iminothiazoline‐4‐ones derivatives have been synthesized via an improved method including an auto‐catalyzed reaction. This method avoided using any extra catalyst except for the reaction material. This method has been successful in both the aromatic substituted 2‐iminothiazolines and the alkyl substituted 2‐iminothiazolines. The special product with a hydroxyl group on the 2‐iminogroup of 1,3‐thiazoline‐4‐ones has also been obtained unexpectedly. The possible mechanism has been proposed for the special process of dealkylation and hydroxylation. This method offered a special way to afford the 2‐hydroxyimino‐substituted thiazoline‐4‐one derivatives in an efficient and eco‐friendly way. The mechanism of the transformation under acid condition has also been proposed.

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