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Labelled organophosphorus pesticides. II. Synthesis of carbon‐14 labelled N‐sec‐butyl O‐ethyl O‐(5‐methyl–2‐nitrophenyl) phosphoramidothioate (cremart®)
Author(s) -
Yoshitake Akira,
Shono Fumiaki,
Kamada Takeshi,
Nakatsuka Iwao
Publication year - 1977
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580130306
Subject(s) - chemistry , potassium carbonate , acetic anhydride , benzene , methanol , medicinal chemistry , yield (engineering) , demethylation , organic chemistry , nuclear chemistry , catalysis , biochemistry , materials science , dna methylation , gene expression , metallurgy , gene
N‐sec‐Butyl O‐ethyl O‐(5‐methyl–2‐nitrophenyl) phosphoramidothioate (Cremart) (I), an organophosphorus herbicide, was labelled with carbon‐14 at the aryl methyl group for metabolic studies. The synthetic procedures are shown in Fig. 1. 1‐Methoxy‐3‐methyl‐ 14 C‐benzene was nitrated with fuming nitric acid‐acetic anhydride to give 2‐methoxy‐4‐methyl‐ 14 C‐1‐nitrobenzene which on O‐demethylation with boron tribromide gave 5‐methyl‐ 14 C‐2‐nitrophenol. Condensation of the latter with N‐sec‐butyl O‐ethyl phosphoramidochloridothioate in the presence of potassium carbonate afforded Cremart‐(aryl methyl‐ 14 C)(I) in the overall yield of 9.2% from methanol‐ 14 C, which had a specifie activity of 5.96 mCi/mmole.