Patent ID: 7098341

Claim:
A process for preparing haptens for immunoassay of organophosporous phosphorothioate pesticides, which comprises the steps of: (i) reacting a compound (10) with a phenolic compound (11) and K 2 CO 3 in acetonitrile at 4° C. for 30 to 90 min to obtain a compound (12); and, (ii) reacting the compound (12) with a compound (13) and KOH in methanol at 4° C. for 3 to 5 min to obtain a compound (14) wherein, R 1 is methyl or ethyl group; R 2 is an optionally substituted pyridyl or pyrimidinyl group; R 3 is hydrogen or alkyl group; and, R 4 is polymethylene or substituted polymethylene group.