中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
3-甲基-5-苯基-1H-1,2,4-三唑 | 5-methyl-3-phenyl-1H-1,2,4-triazole | 3213-91-0 | C9H9N3 | 159.191 |
Unambiguous syntheses of four unreported monomethylated derivatives of 3-phenyldihydro-1,2,4-triazin-6(1H)-ones, namely, the 1-methyl (2), 2-methyl (3), 4-methyl (4) and the imidic O-methyl derivative (5), are described. Regioselectivity was achieved for the synthesis of (2) by addition of ethyl glycinate to the 1,3-dipolar nitrile imine derived from N- methylbenzohydrazonoyl bromide hydrobromide (8). The key step for the synthesis of (3) was addition of benzyl 3-methylcarbazate (14) to ethyl N-[ chloro (phenyl) methylene ] glycinate (15b). The 4-methyl compound (4) was prepared by cycloaddition of ethyl N-( thiobenzoyl ) sarcosinate (21) with hydrazine hydrate, and the O-methyl compound (5) was prepared by reaction of sodium methoxide with 6-chloro-3-phenyl-4,5-dihydro-1,2,4-triazine (23).