Development of an Optimized Process for the Preparation of 1-Benzylazetidin-3-ol: An Industrially Important Intermediate for Substituted Azetidine

Ring-Expansion Reactions of Epoxy Amides and Enamides: Functionalized Azetidines, Dihydrofurans, Diazocanes, or Dioxa-3-azabicyclonon-4-enes?

Functionalized azetidines, 2,3-dihydrofurans, or the unorthodox dioxa-3-azabicyclonone-4-ene motifs are the products from transition metal-free reaction between N-oxiranylmethyl benzenesulfonamide and β-chloro-cinnamaldehyde, depending on whether one uses either NaI/K₂CO₃ or LiBr/K₂CO₃. These ring expansion reactions involve enamide (X-ray evidence) derived from N-oxiranylmethyl benzenesulfonamide and β-chloro-cinnamaldehyde as an intermediate. The N-oxiranylmethyl benzenesulfonamide itself upon heating gives readily separable and crystalline isomeric diazocanes that can be characterized by X-ray crystallography.

Switchable synthesis of cyclic carbamates by carbon dioxide fixation at atmospheric pressure

The base-promoted switchable synthesis of five- and six-membered cyclic carbamates using atmospheric pressure carbon dioxide as the C1 source was developed. The chemoselectivity of products was simply controlled by changing bases and solvents. The reaction proceeds effectively under mild conditions, affording valuable cyclic carbamates. Experimental results and DFT studies revealed the reaction mechanism.

A green and facile synthesis of an industrially important quaternary heterocyclic intermediates for baricitinib

Background

Baricitinib, with a 2-(1-(ethylsulfonyl)azetidin-3-yl)acetonitrile moiety at N-2 position of the pyrazol skeleton, is an oral and selective reversible inhibitor of the JAK1 and JAK2 and displays potent anti-inflammatory activity. Several research-scale synthetic methods have been reported for the preparation of key quaternary heterocyclic intermediates of baricitinib. However, they were all associated with several drawbacks, such as the expensive materials, usage of pollutional reagents, and poor yields.

Results

In this manuscript, we established a green and cost-effective synthesis of 2-(1-(ethylsulfonyl)azetidin-3-ylidene)acetonitrile and tert-butyl 3-(cyanomethylene)azetidine-1-carboxylate for further scale-up production of baricitinib. This synthetic method employs commercially available and low-cost starting material benzylamine and an industry-oriented reaction of green oxidation reaction in microchannel reactor to yield important quaternary heterocyclic intermediates.

Conclusion

Generally, this procedure is reasonable, green and suitable for industrial production.