| 摘要 |
New herbicidal substd. bicycloheptandione derivs. of formula (I) are prepd. by ring-closure reaction of cpds. (II) in the presence of a base. R1 = lower alkyl, opt. substd. phenyl, opt. substd. aralkyl or opt. substd. heterocyclic; R2 = halo, alkoxy, alkylthio, alkylsulphonyl, alkyl, alkoxyalkyl or alkoxycarbonyl; n = 0-4; R3 and R4 = H or lower alkyl; and Q = a leaving gp. Pref. cpd. (II), (where Q = halo, alkylsulphonate or phenylsulphonate), is treated with 2 moles (or excess) base at pref. 0-50 deg.C for 0.5-10h in a solvent (e.g. water, an alcohol, CH2Cl2, benzene, toluene, EtOAc, DMF, THF, CH3CN etc). The base is e.g. an alkali or alkaline earth hydroxide, a trialkylamine, pyridine, DBU, t-BuOK etc. |
