Cyanic acid → 1-Benzylimidazolidine-2,4-dione
Reaction equation
[CH2:1]([NH:8][CH2:9][C:10]([OH:12])=O)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[N:13]#[C:14][OH:15]>>[CH2:1]([N:8]1[CH2:9][C:10](=[O:12])[NH:13][C:14]1=[O:15])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1Participants
Procedure
The starting material for the abovementioned synthetic route a), viz. N-benzyl-aminoacetonitrile, is prepared by reaction of benzylamine and formaldehyde with the extremely toxic hydrocyanic acid (see also Tetrahedron Letters [23], 27 (1982), 2741-4). The starting material for the synthetic route b), viz. N-benzylglycine, also firstly has to be prepared by reaction of glycine with benzyl chloride or of chloroacetic acid with benzylamine. The reaction of N-benzylaminoacetonitrile or N-benzylglycine as per a) or b) is carried out either by fusion with urea for a long time or by reaction with the toxic cyanic acid. Both methods give 1-benzyl-hydantoin in only low yields: thus, according to Huaxue Shiji 1993, 15(1) 15-16, the reaction of N-benzylglycine (obtained by reaction of benzylarnine with chloroacetic acid) with cyanic acid gives 1-benzylhydantoin in a yield of only 39.5% and the reaction of N-benzylglycine with urea gives 1-benzylhydantoin in a yield of only 45.6%. The subsequent bromination of the 1-benzylhydantoin and treatment with ethanol again proceeds in only a low yield of 42.7%.
Workup
- customin only low yields
Sources & evidence
- ORD record
- ord-8480039924e14c91b7c2428335c8431b
- Source dataset
- uspto-grants-2002_04
- Patent number
- US06365752B1
Reaction notes
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