FORM 2
THE PATENT ACT. 1970
( 39 of 1970 )
COMPLETE SPECIFICATION
(See section 10; rule 13}

Title of invention: A PROCESS FOR THE PRODUCTION Oi;
HERBICIDE ETHOFUMESATE
2-ethoxy-2.3-dihydro3.3'dilviclhyl benzofuran
-5-yl-methanesull'bnate
Application 1: SHALIL SHROFF
Plot no. 645/646. Oberoi Chember 11. 5lh Floor.
New link road. Andheri v\'esi. Mumhai 400053,
Maharashtra state. INDIA
Indian National
Applicant 2: AVTAR SINGH
Plot no. 645/646. Oberoi Chember II. 511' Floor.
New link road. Andheri west. Mumbai 400053.
Maharashtra slate. INDIA
Indian National
The following specification describes the nature of this invention and
the manner in which it is to be performed : .


FIELD OF INVENTION
This invention relates to a process for the preparation of the herbicide
etholuinesate corresponding to the formula.

PRIOR ART
Ethofumesate namely 2-ethoxy-2. 3-dihydro-3. 3-dimelhyl benzofuran-5-yl
methanesulfonate is a systemic herbicide, absorbed by the emerging shoots
(grasses) and roots (broad- leaved plants), with translocation of the foliage -
Inhibits the growth of merisiems. retards cellular division and limits formation
of waxy cuticle. It is commonly used in sugar, beat crops, turf ryegrass and
other pasture grasses.
US 3,689, 507 describes a process for the preparation of ethofumesate
comprising by reaction between 2-3-dihydro-3, 3-dimethyl -5-hydroxy-2-
morpholinc benzofuran in acid accepter medium comprising such as an
organic base like pyridine. triethylamine or as alkali metal carbonate in
organic solvent such as ether.
The pyridine is toxic and its complete removal in purification process requires
longer time to complete the processing. Also there is a precipitation of mass
mainly gum after pouring of .reaction mass in water and complete removal of
gum is difficult because of sticky nature. This makes process further difficult
to carry out.
Also the use of ether as solvent makes the process hazardous due to very low
Hash point and recovery envisages higher losses of solvent ether.

IE 940038 describes;) method -for ethofumisale comprising [lie steps of:
adding methane sulfonyl chloride and triethylamine to a slurry of 2.3-dihydro-
3.3-diinethylo- hydroxy-2 morpholinobenzofuran in xylene: adding ethanol
and concentralcd hydrochloric acid to form a dual phase reaction mixture:
separating the aqueous layer, comprising a solution of ethoiiimisale. from the
organic layer: and washing the ethofumisate solution with water and sodium
carbonate solution:
According to II: 940038. the total addition of both the reagents methane
sulfonyl chloride and triethyl amine is done in one lot: and this makes the
separation of amine salt more difficult and the losses of triethylamine are
more during recovery process.
The present invention, provides a method for producing ethofumisate where
the addition of methane sulfonyl chloride is carried out in four equal parts
requiring less triethylamine in the beginning and regenerating triethylamine
insitu by alkali addition before adding another part of methane sulfonyl
chloride: and this reduces the consumption of triethylamine.
According to IE 940038. ethanol and hydrochoric acid is added into
reaction mass containing ainine salt forming a dual phase reaction
mixture : separating the aqueous layer and recovering ethofumisate
from organic layer:
The present invention, provides a method where the triethylamine salt is
separated as an aqueous layer before addition of ethanol and
hydrochloric acid to the product, precursor;
According to lE 940038. the use of high boiling aromatic solvents xylene
requires more energy for processing and recovery.

OBJECTS OF INVENTION
An object of the invention is to provide a process for the preparation of the
herbicide ethofumesate that is very easy to carryout.
Another object of the invention is to provide for the preparation of the
herbicide ethofumesate. which gives good yields and is economical.
Another object of the invention is to provide a process for the preparation of
the herbicide which eliminates hazardous reagent and is safe to carry out.
DESCRIPTION OF THE INVENTION
According to the invention there is provided a process for the preparation of
herbicide ethofumesate comprising, reacting a mixture of 2,3-dihydro-3.3-
dimelhylo-hydroxy-2-morpholme benzofuran; triethylamine as an acid
acceptor: and benzene as a solvent with methane sulfonyl chloride:
The addition of methane sulfonyl chloride is carried out in four equal parts
requiring less triethylamine in the beginning and regenerating irietlwhimine
insiui by alkali addition before adding another part of methane sulfonyl
chloride and this reduces the consumption of triethylamine.
After addition of fourth part of methane sulfonyl chloride, the reaction mass
is stirred and continued till methane sulphony! chloride is less than 0.05 %
By TLC: The reaction mass is washed with water and allowed to settle
for seperation of organic layer and aqueous layer:
The organic layer is mixed with hydrochloric acid and reacted with ethyl
alcohol at 50-55 °C over a period of 6-7 hours'. The reaction mass is
allowed to settle and-the organic layer is washed with water and dilute alkali
till pH 6.5 is achieved; The washed organic layer is distilled to remove
solvent benzene under reduced pressure: The remaining crude elhofumisate is
dissolved in ethyl alcohol and heated at 60-65 oC over a period for I hour:
The mass is cooled up to 0-5 oC , filtered and ethofumisate is dried under
reduced pressure to get ethofumisate tech.
'The following experimental examples are illustrative of the invention but not
limitative of the scope there of.

EXAMPLE- 1
To a stiired solution of 1,0 parts by vvi, of 2,3 dihydro-3.3-di ethyl-5-hydroxy-
2-morpholine benzofuran iind 0.125 parts by wt. of trielhylamine was added
0.122 parts by wt, of methane sulfonyl chloride in (he presence 2.63 parts by
wt. of benzene as solvent maintain" the reaction temperature at 30 C. To
this mass 0.105 parts by wt. of caustic soda solution (47%) was added and the
mass was heated to relfux temperature to neutralize the hydrochloric acid
formed and to regenerate triethylamine.
This step of addition of 0.122 parts by wt. of methane sulfonyl chloride and
0.105 parts by wt. of caustic soda solution was repeated for further 2
limes to regenerate triethvlamine:
- &*•
To the above reaction mass, the final fourth lot of 0.122 parts by wi of
methane sulfonyl chloride was added and the reaction is completed when
the methane sulfonyl chloride content was less than 0.05 % by TLC method.
To this mixture 1.50 parts by wt of water was added, heated over a period of
2 hrs and was allowed to settle for separation of organic and aqueous layer.
To this organic layer was added 1.65 parts by wt. of hydrochloric acid (25%)
and 1.20 parts by wl. of ethyl alcohol and healed at 50-55 ° C over a period of
6-7 hrs. The mass was allowed to settle and the organic layer was washed
with water and dilute alkali till pH-l 6.5 - 7.0 was achieved. The benzene was
distilled under reduced pressure between 75-85 oC.
The remaining crude ethofumesale was dissolved in 1.20 pacts by wt. of ethyl
alcohol and heated at 60-65 C over a period of 1 hr. The mass was cooled
down to 0-5 oC. filtered and wet cake dried under reduced pressure between
30-35 "C. to get ethofumisate tech.

EXAMPLE- [1
To a stirred solution of 1.0 parts by wt. of 2.3dihydro-3.3-di ethyl-5-hydroxy-
2-morpholine benzofuran and 0.145 parts by wt. of triethylamme was added
0.125 parts by wt. of methane sutfonyl chloride in the presence 2:68 parts by
wi. of benzene us solvent maintain" the reaction temperature al 30 C. To
this mass 0.125 parts by wl. of caustic soda sokuion (47%).was added and the
mass was heated to relfux temperature to neutralize the hydrochloric acid
formed and to regenerate triethylamine.
This step of addition of 0.125 parts by wt. of methane sulfonyl chloride and
0.125 parts by wt. of caustic soda solution was repeated for further 2
limes to regenerate trietliylamine:
To the above reaction mass, the final fourth lot of 0.125 parts by wt of
methane sulfonyl chloride was added and the reaction is completed when
the methane sulfonyl chloride content was less than 0.05 % by TLC method.
To this mixture 1.56 parts by wt. of water was added, healed over a period of
2 hrs and was allowed to settle for separation of organic and aqueous layer.
To this organic layer was added 1.68 parts by wt. of hydrochloric acid (25%)
and 1,22 parts by wt. of ethyl alcohol and heated at 50-55 oC over a period of
6-7 hrs. The mass was allowed to settle and the organic layer was washed
with water and dilute alkali till pH 6.5 - 7.0 was achieved. The benzene'was
dislilled under reduced pressure between 75-85 oC.
The remaining crude elhofumesate was dissolved in 1,22 parts by wt. of ethyl
alcohol and heated at 60-65 oC over a period of 1 hr. The mass was cooled
down to 0-5 C. filtered and wet cake dried under reduced pressure between
3(1-35 oC. 10 net ethofumisate tech.

WE CLAIM,

!. A process for preparation of ethofumesate wherein 2.3-dihydro-3.3-
dimeihyl-5 hydroxy-2-morpholine benzoiuran is reacted with methane
sulfonyl chloride in benzene as solvent medium in the presence ol
triethykimine. wherein methane sulfonyl chloride is added in four
equal parts: and wherein triethylmine hydrochloride formed is
neutralized by adding caustic soda solution (47%) in three equal parts
to regenerate triethylamine insilu: and wherein the muss is allowed
to settle to separate organic layer: and wherein the organic layer is
washed wilh water and dilute alkali to get neutral pN : and wherein the
organic layer is further reacted with ethyl alcohol in the presence of
hydrochloric acid (25%); and wherein benzene is distilled under
reduced pressure to get crude ethofumisaie: and wherein crude
eihofmnesale is reeryslalised in ethyl alcohol, filtered and dried under
reduced pressure.
2. A process as claimed in claim (1) wherein 1.0 parts by- wl. of-2.3-
dihydro-3.3-dimethyl- 5-hydroxy-2-morpholine benzofuran. 0.125 -
0,145 parts by weight of triethylamme is reacted with 0.122 - 0.125
parts by weigh) of methane sulfonyl chloride in the presence of 2.63 -
2.68 parts by weight of benzene as a solvent:
A process as claimed in claim (2) wherein the reaction is carried out
preferably at a temperature between 30 - 35 oC.
4 A process as claimed in claim (1) where in 0.105 - 0.125 parts by
weight of caustic soda solution (47%) is added in 3 lots after each lot
of methane sulfonyl chloride addition to neutralise hydrochloric acid
produced during (he reaction to regenerate iriethylamine insitu:
5 A process as claimed in claim (1) wherein the addition of methane
Sulphonyl chloride is carried out in four equal parts by weight and
regenerating triethylamme by addition of alkali to methane
hydrochloric acid formed before adding another part of methane
sulfonyl chloride (o reduce the total consumption ol trielhylamine.
6 A process as claimed in claim (1) wherein organic layer is further
reacted wilh 1.20-1.22 parts by weight of ethyl alcohol in presence of
1.65 - 1.68 parts by weight hydrochloric acid (25%) preferably at a
temperature between 50 - 55 C.
7 A process as claimed in claim (1) wherein organic layer is washed
with water and dilute alkali (o get pl-l between 6.5-7.0.

8 A process as claimed in claim (1) wherein benzene was distilled under
reduced pressure and preferably between temperature 75-85 ° C.
9 A process as claimed in claim (1) wherein 1.20-1.22 parts by weight of
ethyl alcobol is added in crude ethofumesate and oooked preferably
between temperature 60-65 ° C. reacted
10 A process as claimed in elaim (1) wherein ethofumesate is crystallized
at a temperature preferably between 0-5 ° C.


Dated: 12.01.2005 Signature of the applicant(s)
Shalil Shroff
A vtar Singh