NEW MATERIAL:The compound of formula (R1 is H, lower acyl, lower alkoxycarbonyl, etc.; R2 is H, lower alkyl or benzyl; R3 is H, lower acyl, tetrahydropyranyl, etc.).

EXAMPLE: Methyl 2-N-(t-butoxycarbonyl)-amino-3-hydroxy-4-pentenoate.

USE: Useful as a synthetic intermediate of detoxinine which is a constituent amino acid of detoxin D1 (a peptide antibiotic substance). Useful also as an agricultural chemical such as insecticide, and a drug for central nervous system.

PREPARATION: The compound of formula is produced by protecting the amino group of allylglycine (a known amino acid) with acyl, t-butoxy-carbonyl, etc., esterifying the carboxyl group with lower alkyl, benzyl, etc., and oxidizing the product with an oxidation agent (e.g. selenium dioxide).