FIELD OF THE INVENTION 
This invention relates to certain novel alkylphosphonodiamide compounds 
which demonstrate herbicidal activity. 
Some herbicidal alkyl phosphonodiamides are disclosed in British Patent 
1,350,286 of Nissan Chemical Industries, Ltd. and in Bakumenko et al., 
Khim. Sel'sk. Khoz., vol. 4, p. 691 (1966). 
DESCRIPTION OF THE INVENTION 
According to this invention, compounds of the following type have been 
found to exhibit herbicidal activity: 
##STR2## 
in which R.sub.1 is C.sub.2 -C.sub.8 alkyl or C.sub.5 -C.sub.8 cycloalkyl; 
R.sub.2 is hydrogen or C.sub.1 -C.sub.4 alkyl; 
R.sub.3 is phenyl, optionally substituted by C.sub.1 -C.sub.4 alkyl, 
C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 haloalkoxy, one or more 
halogens, one or two C.sub.1 -C.sub.4 alkoxy groups, one C.sub.1 -C.sub.4 
alkyl and one C.sub.1 -C.sub.4 alkoxy group, or if R.sub.2 is C.sub.1 
-C.sub.4 alkyl, R.sub.3 may also be phenyl substituted by two C.sub.1 
-C.sub.4 haloalkyl groups; pyridyl or tolylsulfonyl; and 
R.sub.4 and R.sub.5 are independently C.sub.2 -C.sub.6 alkyl. 
Two compounds within this genus were synthesized by Mel'nikov et al., Zh. 
Obshch. Khim., 38. 2648 (1968) in the course of research in 
organophosphorus chemistry. They correspond to formula (I) in which 
R.sub.1 is isopropyl, R.sub.2 is hydrogen, R.sub.3 is phenyl or 
3-chlorophenyl, and R.sub.4 and R.sub.5 are both ethyl. 
Most compounds of this invention, however, are novel. The novel compounds 
correspond to formula (I) in which: 
R.sub.1 is C.sub.2 -C.sub.8 alkyl or C.sub.5 -C.sub.8 cycloalkyl; 
R.sub.2 is hydrogen or C.sub.1 -C.sub.4 alkyl; 
R.sub.3 is phenyl, optionally substituted by C.sub.1 -C.sub.4 alkyl, 
C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 haloalkoxy, NR.sub.6 R.sub.7, 
one or more halogens, one or two C.sub.1 -C.sub.4 alkoxy groups, one 
C.sub.1 -C.sub.4 alkyl and one C.sub.1 -C.sub.4 alkoxy group, or if 
R.sub.2 is C.sub.1 -C.sub.4 alkyl, R.sub.3 may also be phenyl substituted 
by two C.sub.1 -C.sub.4 haloalkyl groups; pyridyl or tolylsulfonyl and 
R.sub.4 and R.sub.5 are independently C.sub.3 -C.sub.6 alkyl; provided that 
if R.sub.2 is hydrogen and R.sub.3 is phenyl or 3-chlorophenyl, then 
R.sub.4 and R.sub.5 are both C.sub.3 -C.sub.6 alkyl 
The term "alkyl" includes straight and branched chained saturated acyclic 
hydrocarbyl moieties having the indicated number of carbon atoms. 
Preferred alkyl groups include methyl, ethyl, n-propyl, isopropyl, 
n-butyl, s-butyl, t-butyl, i-butyl, and n-amyl. The term "cycloalkyl" 
includes saturated cyclical hydrocarbyl moieties, such as cyclopentyl and 
cyclohexyl. The term "halogen" includes chloro, bromo, fluoro and iodo. 
The terms "haloalkyl" and "haloalkoxy" include both mono- and 
polyhalogenated groups in which the halogens may be identical or 
different. Substituted phenyl groups may contain one or more of the 
indicated substituents, which may be the same or different. The 
substituted phenyl groups contain from 1 to 3, preferably from 1 to 2, 
substituents, which may be located at convenient points on the phenyl 
ring. 
Preferred compounds are those in which: 
R.sub.1 is C.sub.2 -C.sub.6 (most preferably C.sub.3 -C.sub.6) alkyl or 
C.sub.5 -C.sub.6 cycloalkyl; 
R.sub.2 is C.sub.1 -C.sub.4 alkyl; 
R.sub.3 is phenyl, optionally substituted by methyl, trifluoromethyl, 
trifluoromethoxy, one or two methoxy groups, one methyl and one methoxy 
group, or one or two halogens (most preferably chloro); or pyridyl; and 
R.sub.4 and R.sub.5 are independently C.sub.3 -C.sub.4 alkyl. 
As used herein, the term "herbicide" means a compound or composition which 
adversely controls or modifies the growth of plants. By the term 
"herbicidally effective amount" is meant any amount of such compound or 
composition which causes an adverse modifying effect upon the growth of 
plants. By "plants", it is meant germinant seeds, emerging seedlings and 
established vegetation, including roots and above-ground portions. Such 
controlling or modifying effects include all deviations from natural 
development, such as killing, retardation, defoliation, desiccation, 
regulation, stunting, tillering, leaf burn, dwarfing, and the like. 
The compounds of this invention have been found to be active herbicides, 
particularly post-emergent herbicides; i.e. they may be applied to control 
or kill existing vegetation which has already emerged from the soil. Some 
of the compounds of this invention have demonstrated such post-emergence 
herbicidal activity in a relatively short time, and against some weeds, 
with a very strong effect. Herbicides having such rapid and extensive 
post-emergence activity are sometimes referred to as "contact and burn" or 
"burn-down" herbicides and are used, among other applications, for 
clearing vegetation from land such as building lots, highway median 
strips, railroad track beds, and crop land prior to planting or in minimum 
till or no-till farming. Some of the compounds of this invention also 
demonstrate pre-emergence activity, that is, control or killing of 
vegetation by application prior to the emergence of vegetation from the 
soil. Pre-emergence herbicides may be applied by techniques such as 
incorporation into, or spraying or spreading onto, the surface of the 
soil. 
Compounds showing "contact-and-burn" effect, but little or no pre-emergence 
activity, may be useful in clearing land prior to planting since planting 
of a crop can be done relatively soon after the herbicide is applied. 
According to one process, the compounds of this invention may be prepared 
from starting phosphonodichlorides and appropriate amines, in one or two 
steps, by the general reaction 
##STR3## 
Preferably the two amines are reacted stepwise with the alkylphosphonyl 
dichloride. 
Processes of this type are generally carried out at temperatures of from 
about 0.degree. to about 200.degree. C., preferably from about 25.degree. 
to about 110.degree. C. An inert solvent, such as toluene or methylene 
chloride, is usually employed. In addition, a tertiary amine such as 
triethylamine or dimethylaniline, optionally in combination with lithium 
diisopropylamide, may be used. 
Alternatively, compounds in which R.sub.2 is C.sub.1 -C.sub.4 alkyl may be 
prepared from corresponding compounds in which R.sub.2 is hydrogen, by 
alkylation: 
##STR4## 
(X being chloro, bromo or iodo). 
The following represent examples of preparation of compounds of this 
invention: