Synthesis 2010(6): 1014-1022  
DOI: 10.1055/s-0029-1218639
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Hydrazinium Carbazate-H2O2: An Ideal Combination for Diimide Reduction of Base-Sensitive Unsaturated Peroxides [¹]

Chandan Singh*, Ajit Shankar Singh, Niraj Krishna Naikade, Ved Prakash Verma, Mohammad Hassam, Nitin Gupta, Shilpi Pandey
Division of Medicinal and Process Chemistry, Central Drug Research Institute, Lucknow 226001, India
Fax: +91(522)2623405; e-Mail: chandancdri@yahoo.com;
Further Information

Publication History

Received 9 September 2009
Publication Date:
08 January 2010 (online)

Abstract

The utility of a hydrazinium carbazate (N2H3COON2H5) and H2O2 combination for the double bond reduction of base-sensitive unsaturated 1,2,4-trioxanes, 1,2,4-trioxepanes, and their precursors β- and γ-hydroxyhydroperoxides is presented. The method is superior to the conventional diimide reduction using N2H4˙H2O-H2O2 and catalytic hydrogenation.

1

CDRI communication number: 7233.

1

CDRI communication number: 7233.

12

The progress of the reaction was monitored by TLC of the samples drawn at regular time intervals of 15 min. At no stage of the reaction was the required saturated trioxane observed.

15

The pH values of 1% aqueous solutions of N2H4˙H2O and N2H3COON2H5 at 25 ˚C (glass electrode) were found to be 9.79 and 7.51, respectively.

16

The stereochemistry assigned to the diastereomers is only relative and is based upon coupling constants and NOESY experiments.

18

Due to intramolecular hydrogen bonding in diols 11, 15, 19, and 23, ¹H NMR spectra of these compounds show complex multiplicity pattern. Conversion of these diols into the corresponding diacetates, on the other hand, provides clear multiplicity pattern in ¹H NMR spectra.

19

Diimide reduction of ascaridole using dipotassium azodicarboxylate is known to furnish dihydroascaridole in ∼40% yield: see reference 10a.

20

In our hands all these peroxides have behaved well, but the usual precautions for handling of peroxides are recommended.