Note: Descriptions are shown in the official language in which they were submitted.
~ 1~90~3~
125
B,: CXG ROUND
Thls inveneion relates to the manufacture of
ehlobiscarbamates having ~he formula
\
CH3-C - N-O-C-N_t S (I)
S-Rl CH3¦2
\' /
wherein Rl is methyl, ethyl/ n-propyl, isopropyl, n-butyl
or isobutyl and
O
( R2-C ~ N-0-C-N t S (II)
\ R3
wherein R2 is ~ethyl, e~hyl, n-propyl, isopropyl, n-bu~yl,
isobutyl, Ror CH3S(CH3)2C - and R3 is H or CH2X where X is
- SCH3,.- 5CH3 9 or - SCH3. These biscarbamate compounds
are known to have pesticidal ac~ivi y.
U.S. Patent No. 4004031 discloses a method of
making th~se compounds ~nvolving simultaneous react~on
Of carbamate, base 9 and sulfur chlorid~ (SC12 or S2C12).
A disadvantage of this prior ar~ method is it~ relatively
.ow yield of products and high production of undesirable
~i-produots.
12581-1
O~JECTS
Ie is an object of this invention to provide
~ method for making thiobiscarbamate compounds tha~
produces higher yields.
It is another object of ehis invention to
provide a method or making thiobiscarbamate compounds
that produces less biproduct.
SUMMARY OF THE INV~NTION
These.and other objects are attained by the
present invention one aspect of which comprises:
A method for making a compound of the
formula
~C~ -C-N-0-s-N ~ S
S-Rl O CH3/2
wherein R, is methyl, ethyl, n-propyl, isopropyl, n-butyl
or isobutyl c~mprising the steps of:
(a) ln presence of solvent, reacting nitrogen-
containing heterocyclie base with` a sulfur chloride selected
from the groups of SC12, S2C12, and mixtures thereof to form
base-sulfur chloride adduct, and thereafter
(b) in presence of solvent, reacting said adduce
with carbamate of the formula
Rl ~ ~H3
wherein R, is as previou~ly defined.
A second as~ect of the invene~on comprise~:
A method for making a c~mpound of ehc
formula ~ O
~ R2_~ 8 N-0-C-~ ~ S
\ ~3 GH3J 2
\
,
~16~
12581-1
wherein R2 1~ methyl, ethy~ 9 n-propyl, isopropyl, n-butyl,
or CH3S(CH3~2C - and R3 is H or-CH2X wherein X is - SCH3,
9 0
- SC~3 or - S -CH3 comprising the s~eps of
(a)~in presence of solvent, rearting n~trogen-
containing he~erocyclie base with a sulfur chloride
selecPed from the g~ ups of SC12, S2Cl~, and mixtures
l thereof to form base-sulfur chloride adduet, and
(b) in presence of solvent, reacting said
adduct with carbamate of the formula
o
R2 ~ C ~ N - O - C - N - H
R3 CH3
wherein R2 and R3 are as previously defined.
This invention i5 predicated on the discovery that
c~mplexing nitrogen-contalning heterocyclic base with
sulfur chloride in presence of a solvent eo form an adduct
and thereafter reacting carbamate with the adduct
provides a surprising increase in yield. This change in
the order of addition of the reao~ants over ~hat of the
prior art ~s especially ~ffec~ive if ehe so~vent is xylene,
and if the sulfur chloride used is SC12.
The flrst step ln maklng thlobiscarbamate c~mpound
in aecortance wlth the present invention is to reaee nitrogen-
containing heterocyclie base and sulfur chloride in pre~ence
of ~ol~ent to form base-sulfur chloride adduot, ~believed to oc~ux
30 în accordance with the following equatiorl:
12581~1
2 B ~ SC12~ S - B
~1 Cl
base sulfur a~du~t
or
2 B I S Cl ~ B - S ^ S - B
Cl Cl
Base sulfur mono
chloride adduct
Preferably sufficien~ base is used so that all of
the sulfur cnloride is reacted. The preferred bases are
pyridine and 2-e~hyl-5-methyl pyridine.
The most preferred solve~ts are commercial
grade xylene and pyridine. However many solvents are
acc~ptable, including but not limited to halogenated
hydrocarbons such a~ dichloromethane, chloroform,
carbon tetrachloride, tetrachloroeehane; ethers sueh as
diethyl ether, tetrahydrofuran, 1,4-dioxane, daisopropyl ether,
diphenyl ether~ anisole; aroma~ic solvents such as benzene,
~oluene, o-xylene, m-xyle~e, p-xylene, ethylbenzene, ~esitylene,
tbueylbenzene, chlorobenzene, nitrobenzene; a~d other organic
~olv~nes such as N,Nodimethylacet~n)ide, N,N-di~ethylfonnamide9
: : aceeonierile, hexane9 cyclohexane and methylcyclohexane.
Sulf~r dichlorlde is the pref2rred sulfur chloride.
However, this compound deco~poses slowly accordlng to ~he
equatioff
2 SC12~ -- S2C12 ~ C~2.
Uence c~mmerelal SC12, whlch currently is believet eo cont~in
roughly 70 eo 857~ SCl~, i9 a prac~ical and acceptable sulfur
chlorLde. Sulur monoc~loride, S2Cl29 is also acceptable, a8
: ~ 5
I :~6~6
125
are mixeures of SC12 and S2C12.
The reactio-l b~tween base and sulfur chloride
is preferably carried out for about 0.25 to 1 hour
at temperatures between abouè -10 and 50C.
~ore preferably the reaction temperature ls about
-10C to 30C and the reaction time about 20 min eo
60 min;
The second step in the process is to react
the adduct with carbamate in the presence of solvene.
A preferred car~amate is methomyl. With pyridine
as the base, the reaction between methomyl and base~
sulfur dichloride adduct is believed ~o proceed
as follows
~CH3 _ S ~
C1 C1
Adduct
20 me ~homyl
(CH3-C - N-0-C-N ~ S ~ 2 ~
a preferred thiobiscarbamate H Cl
The solvent5 acceptable for the firs~ step in the process,
the atduct forming seep, are also ~ccepeable for ehe second
step, the reaction with carbamate. The preferred solvents
. for the second step are again pyridine and xylene, but
30 other solvents are acceptable. Since the first step
yields an adduct-solven~ mixture, preferably the second
~ ~ ~9~
12581-1
step is perfomed by adding carbamate to the adduce-solvent
mixture resulting from ~he first step. Of course, t~e
adduc~ could be separaeed from the solvent used for the
first step and a different solvent used for the second
step, but such extra processing is not necessary.
The second step is preferably carried out a~ a
temperature of from about 0C to 45C, more preferably
about l5C to 32C, and for a reacton time of about 1
hour to 95 hours, more preferably about 1 hour to 20 hours.
When pyridine is used as both solvent and base,
purification of the product mixture from the second s~ep is
preferably effected by washing and/or slurrying with wa~er
or C-l to C-5 alcohol.
EXA~LES
Examples 1 to 12 illus~rate practice of the in~enti~
and examples 13 to 28 illustrate the prior ar~ method. All
e~perimentC were conducted under nitrogen a~mosphere in a
500 ml, four-necked flask equipped with a thermometer, a
mechanical stirrer, a drying tube, and a pressure equalizi~g
addition funnel attaehed to a ni~rogen inlet eube. The
assembled apparatus was dried wi~h a heat gun under a nierogen
atmosphere prior to ehe experiments.
The first s~ep was performed as follows:
The adduct was formed by pr~pari~g a solution of
28~5 g. pyridine and 200 g. solvent at about 2C. Sulfur
chloride in the amount of 20.74 grams was added to ~he
~lution dropwise o~er a 15 minute perlod while mai~taining
~emperaeure of 2-4JC. The addurt precipieated. The
atduc~-solven~ mixture was s~irred for 30 ~inuees.
The 5econd step in the process was performed as
~oll~wso
~ 1690B6
12581-1
Mee~omyl in the amount of 53.53 g was added to
the mixtures and the te~perature was allowed to rise ~o the
reaction tempaature. This temperature was maintained for
the reac ion time while stirring.
The reaction mixture was filteret and t~ cake
washed twice with a 150 g of ~resh solvent. The filtered
cake ~as then washed four times with 150 g of water at 40C.
The cake was dried and analyzed for purity of the ~hiobiscar-
b~mate compound. The yield was calculated mul~iplying the
weight of the dried fil~er cake by the purity in weight Z
and dividing by the theoritical yield of the biscarbamate
compound. The results appear in Table I.
PROCEDURE FOR EXA~LES 11 and 12
These experiments were preformed the same
as example l to 10 except as no~ed in foot no~es c and d
in Table I.
~ ~6908~
12581- 1
~ D ~ ~ O r~
a:~ ~ ~ o o
C ~
CJ o o
~_ u~ ~ O ~ ~ I~ ~ u~ o a~
_ ~ c~ ~ C~ ~ --
r ~ E
JO CJ V
_~ ~c r u~
C~ V ~ ~ r~ ~ O ~O ~~ 3
I~ O ~ O CO ~r ~O ~ 0 ~ U: Cl~
a: C ~ ~ I~ )~ ~ ~ u~ O _ o ~ CO ~ ~ S
Z I CJ L o
-I CLGJ
.- ~ v a~
~ ~ O-- ~ O C '
L O C ~ ~ J N C~ e c
, ~ O~ ~ o
t~ C~. Z ~ 3
_ 1 1 C ¦ r_ In _ O N ~ O C ~ V ¦ = ~ 8
C . D ~ ~ O
_ C C~ C
LLI ~ 0~ v ~ ~ ~ 3 ~
s_ ~ . s
~ ,_ D ~ E L ~ '-
.o A ~ sU v~ E ~ L ~ L
,~ N ~ ~ _ _ a~ 5~
1~ ? ~s ~5 0 e~ ~L) o i~?
cn V~
_ _ c ~ O E
~ ~ Qo~D u
~
X _ N t~ e,~ sO r~ n O _ N L t 5
t_~5,,~ S
~2581-1
Procedure for Examples 13 to 28
_._
A suspension of 50 g methomyl, 25 g base, and
300 ml solvent was prepared and warmed to the reaction
temperature. To the suspension was added 16.5 g sulfur
chloride dissolved in 20 ml solvent. The reaction tempera-
ture was maintained for the reaction time listed in ehe
table. The resulting slurry was filtered and the cake
washed with 300 ml of cold water twice, and then triturated
ewice with 300 ml of methanol and filtered. The solid was
vacuum dried at 45C for 2 hours. The resul~s are listed
in Table II. The yield was calculated the same way it was
for Examples l to 12.
Variations to the above procedure for certain
ex~ ples are described in the foot note to Table II G
-10-
~ lB9086 ~
12581- 1
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--I r- ~ er ~r ~O ~D WO ~ ~ U- ~ --
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g C N O N 1~ _ ~ 0 ~q N 1~ ~ ~q 1~ 0
3 ~: ~ ~ N ~r q' I'~ N tq ~
z ~ u7 o o o o o ~,
r~o ~ J N
TO ~-- ~ Il~ ~ ~ :1 .
l _ ~ 4J ~ ~ ~J ~-1 ~ N N ~ ') 1~1 e
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c 21 ~ ~ ~ ~ ~ -- ~ ~ ~ _ _ _ ~ ~ e
n ~ L 2
~ ~ ~ ~ c 2 ~e e ~ e c C u e c c e _ ~ c~ ~ ~
c I w o ~ o o ~ ~ o o ~ o ~ _ e c ~ L
J I ~ L L L L ' L L L L L ~ J L g L ~ O ~ ~ _ ~
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.
~1: ~ _ I N N N ~ N N ~d ~ N N N N N N _ _ C ~n ~J _
N D e .0 ~ V) Itl
g oJ " .a 3 V~ O _
- U~ ~C cc~ ~ ~ ~ ~c x a~ e eO u ~7~ _ c
z ~ ' z 2 ~g 2 a~ o m 3 ~ ~ e
:: J N _ ~ ? L LL. ~ O _ N L~ ~ D . L
t, ~, ,~ o hJ > ._ ~ 3 ~ .. ~ ~ ~ ~ e, _ e
~ o c~ ~ o
~ e~ _ N ~ ~ ~ ~ 1~ 0 ~ J U C _ o
C ~ I N N ~ N ~ N N ~I r~ J:l U ~-
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08~ i
125~ - L
The superiorlty of the present invention can
readily be seen by compar~ng examples 4, 5 and 6 wherein
yields of 76.6, 81.3 and 91~3% were attained, with prior
art examples 17, 20 and 22 wherein yields of only 70.7,
60.9 and 56.9 were attained using ehe same or similar
solvent and the same base. Further evidence of the
present methods superiority can be ascertained by
comparing examples 7 and 8 (49.0 and 50.7% yields)
with prior art example 13 wherein only 37.1% yield
was attained using CH2C12 as the solvent, and pyridine
as the base in both methods.
Example 11 shows that good yields (here 74.
can be attained by the present invention using S2C12.
Likewise, example 12 shows that the present invention
can achieve a good yield with 2-ethyl-5-methyl pyridine
as the base.
l 16g~6
12581-1
Example 29 - Reaction Using ~yridine as Both Solvent
and Base
_
The first step was performed as follows:
The adduct was formed by adding 23 grams of sulfur
dichloride to 90 grams of pyridine dropwise over a period
of about 15 minutes at 5C. The adduct precipitated to
form an adduct slurry.
The second step was performed as follows:
Into a separate reactor was placed 53.5 grams o
methomyl and 60 grams of pyridine. The resulting mixture
was stirred until the methomyl dissolved. The solution was
maintained at a temperature of 20C to 25C.
The adduct slurry was pumped into the methomyl
(pyridine solution with stirring while m~intaining a reaction
temperature of 20C to 25C. Adduct addition was completed
aft~r about 1 hour. A reac~ion temperature of 20C to
2SC wa~ maintained for an additional four hours for the
resulting mixture.
Purification of product was effected as follows:
300 grams of methanol was added to the above mixture to form
a slurry. The slurry was then cooled to -5C wi~h s~irring.
The slurry was filtered to form a filter cake. The filtar
cake was washed with 150 grams of methanol at -5C. The
filter cake was then re-slurried in 150 grams of methanol
at -5C. The re-slurry was filtered and then washed twice
~ith 150 grams of methanol at ~5C. The cake was dried in a
vacuum oven at 40C and 40 mm Hg. pressure. The cake
con is~ed of 50.0 grams o product having a melting point of
169C t~ 170C.
.~
