(1R,2R,3S,4R)-1-(Acetylamino)-2,4,5-tris(acetyloxy)-1-((2S)-4-(benzyloxy)-5-oxo-2,5-dihydrofuran-2-yl)pentan-3-yl Acetate

Round 1

Reviewer 1 Report

In this manuscript, the authors describe the synthesis of the peracetylated benzyl ester of Neu5Ac from N-Acetylneuraminic acid. The paper is a small advance as a synthesis of the benzyl ester of Neu5Ac (not peracetyled) has been previously reported (author reference 6) acetylation from this step would be trivial. In fact, the same reference describes the structure of the methyl ester of Neu5Ac. That said, I recommend this paper be accepted after minor revision to address any advantages of this method over the previously reported methods and address the following purity concerns: There are peaks in the 1H NMR that are unassigned (ca 3.5 ppm and ca 1.6 ppm), these peaks should be identified before publication for full characterization to be considered to have been taken place. These may be impurities as the LC trace also has unannotated peaks at rt = 3.6 to 4.4. 

Author Response

The advantage of using this methodology has been added to the introduction (Use of non-nucleophilic base). The compound has been further purified removing signals at 3.5 ppm and 1.6 ppm. The supporting material and experimental procedure has been updated to reflect this.

Reviewer 2 Report

The molecule reported by Fitzgerald et al. named (1R,2R,3S,4R)-1-(Acetylamino)-2,4,5-tris(acetyloxy)-1-((2S)-4-(benzyloxy)-5-oxo-2,5-dihydrofuran-2-yl)pentan-3-yl acetate have been well characterized by SCXRD, FT-IR, NMR, and HRMS. 

I recommend publishing the manuscript after some minor revisions that can be found in the PDF file attached.

Comments for author File: Comments.pdf

Author Response

The recommended revisions have been applied to the manuscript.