| 摘要 |
<p>Cpds. (I) and compsns. contg. (I) (where R1 is 1-6C alkyl or 3-6 C cycloalkyl; R2 is H, 1-6 C alkyl or Ph; R3 and R4 are 1-6 C alkyl and X is O or S). Insecticides, acaricides, nematocides and fungicides (esp. active against phytopathogenic mycetes). EXAMPLE 117 g. 1-isopropylsemicarbazide heated 3 hrs. at 130 degrees C with 300 ml. ethyl orthoformate with the evolution of 200 ml. ethanol, and the mixt. cooled gave 81 g. (II, R1 = iso Pr, R2 = H) m.pt. 124-4 degrees C (EtOAc). 5.5 g. (II) heated 1 hr. with 6 g. K2CO3 and 100 ml. MeCOEt, cooled, 8.2 g. (EtO)2PS.Cl added dropwise, the mixt. refluxed 2 hrs., stirred 5 hrs., kept overnight, filtered, the filtrate evapd. and purified over silica gel using acetone as eluant gave 6.5 g. (I, R1 = iso Pr, = H, R3 = R4 = Et) n20D = 1.4853.</p> |
