Azinphosmethyl is an insecticide and acaricide used on citrus, cotton, grapes, rice, and vegetables. It is sold under the trade names Guthion and Gusathion. Azinphosmethyl is a benzotriazine phosphoro dithioate synthesized by reacting benzazimide, formaldehyde, and thionyl chloride to form an intermediate that is then reacted with dimethyl phosphoramidic acid or diethyl phosphoramidic acid to yield azinphosmethyl or azinphosethyl respectively.

1. 668 Pesticides Synthesis Handbook
Azinphosmethyl
Azinphosethyl
Uses: insecticide, acaricide, citrus, cotton, grapes, rice, vegetables
Trade names: Guthion, Gusathion (Bayer)
Type: benzotriazine, phosphoro dithioate
Synthesis :
~ CN_
N~
+ C,,O )
/
O
II
C
N~
I
N-c-OH
I !
N
benzazimide formaldehyde
thionyl
S~ chloride
0
II !
o-C-
~ CN_cI_S_p / ,
I , "o-~-
/7 s ,
N
!
-~-o S
p//
-~-o / SH
I
0
II
c I
N-c-CI
I I
N
N//
azinphosmethyl DMPA
azinphosethyl: reaction with DEPA instead of DMPA