4-Benzylcyclohexanone → 6-Benzyl-5,6,7,8-tetrahydroquinazoline-2,4-diamine
Reaction equation
[C:1]1([CH2:7][CH:8]2[CH2:13][CH2:12][C:11](=O)[CH2:10][CH2:9]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[C:15]([NH:17][C:18]([NH2:20])=[NH:19])#[N:16]>>[NH2:20][C:18]1[N:17]=[C:15]([NH2:16])[C:12]2[CH2:13][CH:8]([CH2:7][C:1]3[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=3)[CH2:9][CH2:10][C:11]=2[N:19]=1Participants
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-d1240be0c00b43de83f38b140f0f34da
- Source dataset
- uspto-grants-1998_01
- Patent number
- US05712281
Reaction notes
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