Vol. 15—1961 - NorthEastern Weed Science Society

14.
Roth (19) had spe~ulated as a result ·of his studies on this
tain .polypheno I subat anees which he found in the sa? were th
etabolismthat ceragents
responsible
for this metabolism. Gysin (8) had suggested from chemical onsiderations that
the first product ot metabolism would most likely be the hyd oxy triazine. To investl'gate
thb ,possibility, the expressed sap of corn buffer d to an appropriate
.;>Hwas used to incubate with tbe solution of atrazine. One amt>le of tbe juice
was boiled to destroy any.enzymes ,that might be present; tbe other was used fresh.
After an appropriate incubation period, tbe water ~hase was xtracted withchloroform
and tbe chloroform extract then chromatograpbed on ~ai?e. With the fresh
corn sap two radioactive peaks were found, one of which was trazine, the other
which we 'were able to show was hydroxy atrazine
sample of this produce
sap, however, only one
by comparing the Rf of a synthetic
to that found in the incubated mixtur. With the boiled
peak was found and that corresponded' 0 the original atrazine.
From these studies it was'possib1e to demonstrate that' he first product of
the metabolic attack on the triazine herbici~es was the hydr xy compound. It then
became of interest to attempt to follow o~t this process in rder to learn more
about subsequent products of metabolism of the hydroxy compo nd, We speculated
that the next step in the breakdown involved the oxidation a the hydroxy compound
to a keto form resulting in a structure which would re di1y undergo hydrolytic
cleavage of the ring. Careful study of the infrared a sorption spectra of
the hydroxy compound clearly revealed the presence of a carb nyl stretchiag group
at 1680 cm-t. If the hydroxy compound existed Qnly.in the 0 form, this particular
band would not be expected. However, if rearrangement or ox dation occurred on
this particular compound, then the carbonyl group would ap.;>e producing a structure.
susceptible to attack by hydrolysis.'
.,It now appears possible ,to write some of the chemical actions and structures
of the compounds ut> tlu"ough breakage of the ring. This is en in the following
reaction scheme.
Ill'l C2HS 0
H2N-C=N-C=N-C-OH,~
~H3)2CHNH
~ CO other products
2,
H +
20
It will be noted that the structure resulting from the ydrolysis of the
ring would be highly unstable and susceptible to further att ck giVing release
to radioactive carbon dioxide and affording products that wo ldbe further incorporated
into the plant by enzymatic actio~
In concluding the presentation of information on metabo ism of triazines, it
may be of interest to note 'that considerable variation in th ability of plants
to metabolize these compounds has. been found. It apJ?ears th t the certain ..susmuch
'less able to metabolize the triazin than some of those
ce~tible plants are
that are resistant. In perennial plants tolerant to these C mpounds, one does