1995 Fiscal Year Final Research Report Summary
Synthesis and Cleavage of the Cyclic Oxalates of 1,2-Glycols.
| Project/Area Number |
06672095
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Chemical pharmacy
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| Research Institution | Kanazawa University |
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Principal Investigator |
ITAYA Taisuke Kanazawa University, Faculty of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (20019657)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Oxalyl chloride / Cycloalkane-1,2-diol / Cyclic oxalate / Highly selective synthesis / Stereospecific cyclocondensation / Hydrolysis rate |
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| Research Abstract |
We have already disclosed that oxalyl chloride reacts with acyclic 1,2-glycols in tetrahydrofuran in the presence of triethylamine to afford a different type of compound as a major product, depending on the structure of the glycol : unsubstituted, monosubstituted, and erythro-disubstituted ethylene glycols provided the cyclic oxalates or polymeric oxalates, while the threoisomers and pinacol afforded the cyclic carbonates.
1.The only exception we found was trans-cyclohexane-1,2-diol, which exclusively afforded the cyclic oxalates. This reaction probably proceeded through the tetrahedral intermediate with a boat form, avoiding steric interference between the bridge-head hydrogen and carbonyl oxygen.
2.The dramatic reversal of the product ratio was realized in the reaction with pinacol or the threo-compounds by the use of pyridine instead of triethylamine to afford the cyclic oxalates. 1,1'-Oxalyldiimidazole was found to be a good choice for the exclusive formation of the cyclic oxalates. The formation of the polymeric oxalates from the erythro-compounds was completely suppressed by the use of 2,4,6-collidine.
3.The cyclic oxalates thus obtained underwent hydrolytic cleavage of the acyl-alkoxy linkage to afford the monoester of oxalic acid at pH 5 at the rate of 200-1000 times faster than the cyclic oxalate of pinacol. The three-dimensional structure elucidated by X-ray crystal analysis shows that the carbonyl carbons of the cyclic oxalate of pinacol are effectively blocked by two of the four methyl groups.
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Research Products
(2 results)
