Note: Descriptions are shown in the official language in which they were submitted.
AG 989
~V~ S
OXAZOLIDINONE PHOSPHONATES
This invention relates to a new cla~ of organic chem-
ical compounds. More particularly, this invention is concerned
with novel heterocyclic compounds which can generally be desig-
nated as derivatives of oxazolidin-5-one. The specific deriva~
tives herein are those wherein a methylene phosphonic acid ester
group is substituted at the nitrogen atom of the heterocyclic
ring. This class of compounds has been found to display de-
sirable herbicidal activity when applied to certain varieties
of weeds or undesired plants.
The compounds of the present invention may be repre-
sented by the structural formula
H2
O=C - C\ O /OR
¦ N - CHz-P\
H2
wherein R and R' are each selected from alkyl of 1 to 6 carbon
atoms, alkenyl of 3 to 4 carbon atoms, and the mono-chloro
derivatives of such alkyl and alkenyl. As employed herein, the
terms "alkyl" and "alkenyl" designate the straight and branched
chain hydrocarbon radicals having the specified number of car-
bon atoms.
The novel compounds of this invention are prepared
by reacting methyl or ethyl glycinate with formaldehyde and a
dialkyl phosphite, the ratio of reactants being approximately
1:2:1. The glycinate and formaldehyde are preferably reacted
first in accordance with the following equation J and the entire
reaction sequence proceeds more readily in the presence of HCl
as a catalyst.
ROzCCH2NH2 + 2 CH20 ~ Ro2ccH2N(cH2oH)2
The phosphite can then be added, and it is believed that the
2 ~
- . . . :
104'~45
reactlon ls then sequential, giving Or~ first water and then
alcohol durlng cyclizatlon as seen ln the equation.
2 2 ( 2H)2 + HPO3R2 RO2CCH2NCH2PO3R' ~ H 0
CH20H
0-C C 2
Ro2ccH2~cH2po3R 2 ¦ N-~H2PO3R 2~ ROH
CH20H O C
H2
It has also been found that the use Or the methyl glycinate ls
preferred since the resultant N-methylol intermediate ls more
easily cycllzed.
The following illustrative, non-limitlng examples
will serve to further demonstrate to those skllled in the
art the manner in whlch specif~c compounds of thls lnvention
can be prepared.
EXAMPLE 1
A sultable reactlon vessel is charged with 25.2 grams
(0.2 mole) Or methyl glycinate hydrochloride in 100 ml. of
methanol~ The solution is stlrred durlng neutrallzation wlth
25~ sodium methozide solution in methanol, after which 2.5 grams
o~ hydrochloride is added. The resultant solution is filtered
to remove salt, and 32 grams (0.4 mole) of 37% formalin is added
slowly with cooling to maintain the temperature below 30C.
After stirring for about 15 minutes, 27.6 grams ~0.2 mole) of
diethyl phosphite is added at one time.
The mixture is stirred and heated to distill methanol,
and then 250 ml. of toluene is added and the temperature raised
to azeotrope water. The mixture in toluene is heated at about
115C. for 1 hour, after which it ls cooled, and the cooled
solution decanted from a small insoluble residue. The toluene
is distllled down to 1 mm./70C., and the residual oll i~
--3--
:'' ' ' .. ' . '
~ y~y
~42445
cooled, followed by the addition of 300 ml of ether. The
solution is then filtered, and the ether is stripped leaving a
dark amber oil
This oil is distilled in a molecular ~till at 155-
165C. wall temperature at 3~, and the yellow oil obtained isredistilled in a magnatically stirred molecular still at 100-
129C. bath temperature at 4~. The product obtained is N-(di-
ethoxyphosphinylmethyl)oxazolidin-5-one, nDZ 1.4548. Elemental
analysis gives 40.34% carbon, 7.04% hydrogen, 5.73% nitrogen
and 13.07% phosphorus as against calculated values of 40.51~,
6.80%, 5.91% and 13.06% for C8Hl~o5p.
EXAMPLE ?
The procedures described in the preceding Example are
followed except that 32.4 grams (0.2 mole) o diallyl phosphite
are substituted for the diethyl phosphite. The initial distill-
ation is carried out at 144-156C. at 6-7~, and the redistilla-
tion is at 107-132C. at 3~. The product obtained is N-(di-
allyloxyphosphinylmethyl)oxazolidin-5-one, nD2 1.4741. Elemental
analysis gives 45.68% carbon, 6.85% hydrogen and 12.62% phos~
phorus as against calculated values of 45.9%, 6.18% and 11.9%
for CloH1~N05P.
_XAMPLE ~
The procedures described in the preceding Examples
are followed using 22.0 grams (0.2 mole) of dimethyl phosphite.
The product obtained is N-(dimethoxyphosphinylmethyl)oxazolidin-
5-one, ~2 1.4658. Elemental analysis gives 35.49% carbon,
6.66% hydrogen and 14.37% phosphorus as against calculated
values of 34.5%, 5.78% and 14.8% for CaH12N05P.
EXAMPLE 4
~he procedures described in Example 1 are followed
except that 38.8 grams (0.2 mole) o~ di-n-butyl phosphite is
--4--
104~445
employed. The lnitial distlllatlon ls carrled out at 155-170C.
at 5~, and the redistillation ls at 129-134C. at 5~. The
product obtalned ls N~(di-n-butoxypho~phinylmethyl)oxazolidin-
5-one~ nD22 1.4473. Elemental analysl~ gives 48.19% carbon,
8.72% hydrogen and 9.68~ phosphorus as against calculated
values Or 49.14%, 8.25% and 10.56% for C12H24N05P.
EXAMPLE 5
The procedures described in Example 1 are ~ollowed
except that 33.4 grams (0.2 mole) Or dlisopropyl phosphite i8
employed. The initlal dlstillatlon i9 carried out at 155-172C.
at 5~, and the redistillation is at 95-107C. at 5~. The
product obtained is N-(diisopropoxyphosphinylmethyl)oxazolidln-
5-one, nD22 1.4441. Elemental analysis gives 11.12% phosphorus
as against a calculated value of 11.68% for CloH20N05P.
EXAMPLE 6
A suitable reactlon ve~sel is charged with 12.5 grams
(0.1 mole) o~ methyl glycinate hydrochloride in 50 ml. of
methanol. The solution is stirred during neutralization wlth
25~ sodium methoxide solution in methanol, after which 1.3 grams
of additional hydrochloride is added. The resultant solution
is stirred for about 30 minutes and filtered. The ~iltrate is
placed in an ice bath, and 16 grams (0.2 mole) of formalin is
added. After stirring for about 1 hour, the solution is con-
centrated in a rotary evaporator at~30C. to remove methanol.
It is then diluted with benzene, dried over anhydrous sodium
sulfate, and ~urther concentrated in the rotary evaporator.
The residual oil is dlssolved in 100 ml. of benzene
and treated immediately with 23.5 grams (0.1 mole) of di(2-
chloropropyl)phosphite. About 4 drops o~ concentrated HCl is
added3 and the product is concentrated in the rotary evaporator
starting atC20C. and up to steam temperature, finally at
--5--
~4~445
~0.5 mm. An o~l ls obtained, and a portlon o~ that oil is
dlstilled ln a molecular stlll at 145-159C. wall temperature
at 5-8 ~, and finally at 1 lu. The product obtained a~ a vi3cous
oil ls N-[di(2-chloro-1-propoxy)phosphlnylmethyl]oxazQlldin-5-
one, N~2 1.4812.
Elemental analy~ls glves 21.24% chlorlne, 4.13%
nitrogen and 9.19% phosphorus as agalnst calculated values Or
21.22%, 4.19% and 9.27% for CloHl8cl2No5p-
The post-emergent or contact herbicidal activlty of
various compounds of this inventlon is demonstrated by means of
greenhouse testing. A good grade of top soil ls placed ln
aluminum pans and compacted to a depth of 0.95 to 1.27 cm. ~rom
the top of the pan. A pre-determined number of seeds o~ each
of several broadleaf and grassy plant species are placed on top
of the soll in the pans. The seeds are covered with soil and
the pans leveled. The pans are then placed on a sand bench ln ~
the greenhouse and watered from below as needed. After the `
plants are the desired age, each pan of plants is sprayed with
a glven volume Or 0.2% concentration solution of the candldate
chemical, corresponding to rates of approxlmately 28 and 5S Kg.
per hectare. This solution is prepared rrom an aliquot Or a 2%
solution of the candidate compound in acetone, a known amount
o~ cyclohexanone-emulsifying agent mix, and suf~icient water to
make up to volume. The emulsifying agent ls a mixture comprislng
35 wt. percent butylamine dodecylbenzene sulfonate and 65 wt.
percent of a tall oil-ethylene oxide condensate having about 6
moles of ethylene oxide per mole Or tall oil. The inJuries to
the plants are ~hen observed approximately 14 days later and
the results are recorded.
i6;)~Z44~
The plant species tested included 7 broadlea~ weeds
and 4 grassy weeds. At the 28 Kg. rate, the compounds of
Examples l and 4 caused grass chlorosi~, whlle the compounds Or
Examples 2 and 3 caused general chlorosls and stunting at both
test rates. The compounds of Examples 1 and 5 were ineffectlve
against the grassy weeds at the rates testsd, while the com~
pound of Example 4 was inef~ective against 3 gras~y weeds but
caused 26-74% kill on crabKrass. The compounds of Examples 2
and 3 caused 26-99% klll on the 4 grassy weed species tested.
Agalnst the broadleaf weeds, the compound of Example
5 caused 26-50% kill on cocklebur and morning glory, while the
compounds of Example l caused the same kill on cocklebur, wild
buckwheat and velvet lear. These compounds were iner~ective
against the other broadleaf weeds at the rates tested. The
compounds o~ Examples 2 and 3 were ef~ective against the broad-
lea~ weeds at both rates except that both compounds had no
ef~ect on wild buckwheat at 28 Kg., and the ~ormer compound
also had no e~fect on smartweed at 28Kg. Finally, the com-
pound Or Example 4 caused 26-49% klll of cocklebur and velvet
leaf at the 28 Kg. rate, with no kill of the other broadlear
weeds, At the higher rate, only smartweed did not show at
least 26% klll.
While the lnvention has been descrlbed herein with
regard to certain representative examples for the purpose o~
lllustrating its practice, it is not to be construed as llmited
thereto. Those skilled ln the art will readlly recognize the
variations and modiflcations which can be made without departing
~rom the spirit and scope of this inventlon.
