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was refluxed for 15 min. The precipitate that formed was
filtered off, washed with water (5×10 ml) and EtOH (3×5 ml),
and finally recrystallized from EtOH. The crystallized pure
compounds were then subjected for the synthesis of 6-cyano-
2-oxa-7-azabicyclo[4.1.0]hept-3-en-1-yl acetates.
Acknowledgement
We gratefully acknowledge the financialDsOuI:p1p0o.1r0t39f/rCo5mRAU24.G51.0CA.
and University of Calcutta. P. M. thanks U.G.C. New Delhi,
India for the grant of his Senior Research Fellowship.
Crystallography was performed at the DST-FIST, India-funded
Single Crystal Diffractometer Facility at the Department of
Chemistry, University of Calcutta.
General procedure for the synthesis of spiropyrans.
Triethylamine (1 drop) was added to a solution of ninhydrin (2
mmol), malononitrile (2 mmol), and 1,3-diketones (2 mmol) in
EtOH (5 ml) and the reaction mixture was refluxed for 15 min.
The precipitate that formed was filtered off, washed with
water (5×10 ml) and EtOH (3×5 ml), and finally recrystallized
from EtOH. The crystallized pure compounds were then
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for
the
synthesis
of
6-cyano-2-oxa-7-
azabicyclo[4.1.0]hept-3-en-1-yl acetates.
General procedure for the synthesis of 6-cyano-2-oxa-7-
azabicyclo[4.1.0]hept-3-en-1-yl acetate 2.
2
To a stirring suspension of 2-amino-3-cyano-4-H-pyrans (1
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Conclusion
In conclusion, 4-H-pyrans have been successfully hybridized
into novel 6-cyano-2-oxa-7-azabicyclo[4.1.0]hept-3-en-1-yl
acetate molecular scaffold. The methodology appeared to be
the first example of one step synthesis of pyran fused 2-
acetoxy-NH-aziridines from 4-H-pyrans and spiropyrans using
iodobenzene diacetate as the sole oxidant and involving no
other reagent or catalyst. The diastereoselective nature of this
reaction makes this protocol highly interesting from synthetic
chemistry aspect. The product of this reaction is well
fascinating as it is a pyran fused 2-acetoxy-NH-aziridine
molecular scaffold possessing high functionalization, and we
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