8-Benzylidene-1,4-dioxaspiro[4.5]decane → 8-Benzyl-1,4-dioxaspiro[4.5]decane

HRID 1735271Notes

Reaction equation

HRID 1735271 reaction equation
[C:1]1([CH:7]=[C:8]2[CH2:17][CH2:16][C:11]3([O:15][CH2:14][CH2:13][O:12]3)[CH2:10][CH2:9]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[H][H]>[Pd]>[C:1]1([CH2:7][CH:8]2[CH2:17][CH2:16][C:11]3([O:12][CH2:13][CH2:14][O:15]3)[CH2:10][CH2:9]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1

Participants

4

Reactant 2

HCID 154177378-Benzylidene-1,4-dioxaspiro[4.5]decaneHCID 178418361HCID 178418361, compound

Product 1

HCID 107282938-Benzyl-1,4-dioxaspiro[4.5]decane

Reagents, catalysts & solvents 1

HCID 23938PalladiumCatalyst

Procedure

For example, when n is the bridging group --CH2--, an appropriately substituted or unsubstituted phenylmethyl bromide, for example, 2-chlorophenylmethyl bromide, is reacted with triphenylphosphine in toluene, affording the corresponding phenylmethyltriphenylphosphonium bromide. The so-prepared phosphonium bromide is then treated with n-butyllithium, and reacted with 1,4-cyclohexanedione mono-ethylene ketal, yielding the appropriate 8-phenylmethylene-1,4-dioxaspiro[4.5]-decane. The 8-phenylmethylene-1,4-dioxaspiro[4.5]decane is in turn reduced with hydrogen gas in the presence of 10% palladium on charcoal, giving the corresponding 8-phenylmethyl-1,4-dioxaspiro[4.5]-decane. The 1,4-dioxaspiro functional group is then cleaved from the so-prepared molecule with acetic acid and water, affording the corresponding 4-phenylmethylcyclohexanone. The 4-phenylmethylcyclohexanone is then reacted with cyanoguanidine, as previously described, yielding the targeted 2,4-diamino-6-phenylmethyl-5,6,7,8-tetrahydroquinazoline. Example 2 provides a detailed description of how this reaction is conducted.

Sources & evidence

ORD record
ord-617856ebeec5441096e01804592354dd
Source dataset
uspto-grants-1996_07
Patent number
US05536725

Reaction notes

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