CA1151200A - Process for the preparation of n-substituted imido- dicarboxylic acid diaryl esters - Google Patents

Abstract

Abstract of the Disclosure The present invention relates to a process for the preparation of N-substituted imido-dicarboxylic acid diaryl ester compound of the formula R1 - N(CO-OR2)2 (I) wherein R1 is an optionally substituted aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic radical; and R2 is an optionally substituted aryl radical, which are useful as intermediates for the production of known herbicides, which process comprises reacting a primary amine of the formula R1 - NH2 (II) with a carbonic acid aryl ester halide of the formula X - CO - OR2 (III) wherein X is a halogen atom, at a temperature between 100° and 300°C.

Description

~5~
.

The invention relates to an unobvious one-stage process for the preparation of N-substituted imido-dicarboxylic acid diaryl esters.
According to our prior copending Canadian patent application No. 371,153 (corresponding to German Patent Application P 30 06 226.1), it is possible to prepare N-substituted imido-dicarboxylic acid diaryl esters by reacting corresponding carbamic acid aryl esters with carbonic acid aryl ester halides, if appropriate in the presence of a diluent, at elevated temperatures (100 to 300C). The carbamic acid aryl esters required must be prepared from the corresponding primary amines in a separate process stage, by react~on with carbon;c acid aryl ester hal;des or carbonic acid diaryl esters.
The p,esent invention now provides a process for the production of an N-substituted imido-dicarboxylic acid diaryl ester of the general formula Rl _ N(C0-OR2~2 (I~
in which R1 represents an optionally substituted aliphatic, cycloaliphatic, araliphatic, or aroma~ic radical and R represents an optionally substituted aryl radical, in which a primary amine o~ the general formula Rl _ NH2 (II) in which Rl has the aLovemeiltioned meaning, is reacted with a carbonic acid aryl ester hal;de of the general formula ~1.5~`0 X - C0 - oR2 (III) ir, which R2 has the abovementioned meaning and X represents a halogen atom, optionally in the presence of an additional dil~ert, at a temperature between 100 and 300C.
The present invention further provides, as new compounds N-substituted imido-dicarboxylic acid diaryl esters cf the general formula (I), as defined above, in which R1 represents a neopentyl (=2,2-dimethylpropyl) radical and R2 represents a 4-methylphenyl or 4-chloro-phenyl radical or in which R represents a phenyl radical and R represents a methyl, l,l-dimethylpropyl, 1,2,2-trimethylpropyl, 2,2-dimethylbutyl, 1-isopropyl-2-methyl-prcpyl, l-ethyl-pentyl, l-methyl-octyl, allyl, 4-tert.-butyl-cyclohexyl, (4-methyl-cyclohexyl)-methyl, cyclohex-3-enyl-methyl, 3,4-dimethyl-cyclohex-3-enyl-methyl, cyclododecanyl, cyclododecanyl-methyl, 2-(b~yclo[2.2.1]heptyl)-methyl, 6-(2,3,3a,4,5,6,7,7a-octahydro-4,7-methano-indenyl)-methyl, 2-(1,2,3,4,5,6,7,~8a,4a-decahydro-1,4:5,8-dimethano-naphthyl)-methyl, 2-chloroethyl, 3,3-dichloro-3-fluoro-propyl, 3,3,3-trifluoro-propyl, 2,2-difluoro-propyl, 2,2,2-trifluoro-1-methyl-ethyl, 6-chloro-hexyl,

2-methoxy-ethyl, 3-methoxy-propyl, 5-cyano-pentyl, 2-ethoxycarbonyl-ethyl, phenyl, 3,4-dichlorophenyl, benzyl, fur-2-yl-methyl or tetrahydropyran-2-yl-methyl radical.
It is to be described as surprising that the reaction according to the invention, which very probably proceeds via the int~rmediate stage of the corresponding ~0 carbamic acid aryl esters (Rl-~H-C0-OR2), leads smoothly, and with high yields, to the desired imido-dicarboxylic acid diaryl esters cf formula (I), since carbamic acid aryl esters do not react with carbonic acid aryl ester halides of formula (III) in the desired manner in the presence of an acid-binding agent: it is indeed known that N-~ubstituted Le A 20 566 _., QO

dialkyl imido-esters can be prepared by reacting N-substituted carbamic acid alkyl esters with carbonic acid alkyl ester chlorides in the presence of metallic sodium (see J. Amer. Chem. Soc. 69, 2616 - 2618 (1947)).
~owever, attempts to apply this methcd to the corresponding car~amic acid aryl esters fail completely.
For example, neopentyl-carbamic acid phenyl ester reacts with carbonic acid phenyl ester chloride under the reaction conditions according to the state of the art to gi~e exclusively neopentyl isocyanate and diphenyl carbonate.
Even with butyl-lithium as the acid-trappin~
agent, no neopentylimido-dicarboxylic acid diphenyl ester is formed. It is all the more surprising that the reaction according to the invention proceeds smoothly at elevated temperature and in the absence of an acid-trapping agent. According to the ~tate of the art, it would have been expected that, at elevated temperature, total re-splitting of the carbamic acid aryl ester initially formed into isocyanate and phenol would take place (see Houben-Weyl: Methoden der organischen Chemie (Methods of Organic Che~istry), 4th Edition, ~olume 8, page 127 (1952)).
If neopentylamine and carbonic acid phenyl ester chloride are used as starting substances, the course of the reaction for the production of compounds of the present invention is illustrated by the following equation:
(H3C)3C-cH2 NH2 2 Cl-CO-O

CO-O~
~ (H3C)3C-C~2-N
:~ CO-O~
Preferred primary amines to be used as starting substances are those of formula (II) in ~-hich R represents a straight-chain or branched alkyl ra~ical which has 1 to 10 carbon atoms and is opticnally substituted by lo~er Le A 20 566 115~20~) alkoxy, lower alkylmercapto, halogen (in particular fluorine or chlorine), cyano or nitro; an alkenyl radical with 3 to ~ carbon atoms, an alkinyl radical with 3 to 8 carbon atoms; a cyclo-aliphatic ring which has 3 to 8 carbon atoms and is optionally substituted by lower alkyl; an araliphatic radical with a total of 7 to 12 carbon atoms, the aromatic ring system optionally being substituted by halogen, nitro, trifluoromethyl, cyano, lower alkyl and/or lower alkoxy; an aromatic radical which has 6 to 12 carbon atoms and is optionally substituted by halogen, nitro, trifluoromethyl, cyano, lower alkyl and/or lower alkoxy~ The expressions "lower alkyl", "lower alkoxy" and "lower alkylmercapto" in the context of this invention are intended to denote appropriate radicals with in each case 1 to 4 carbon atoms~
The primary amines of the formula (II) which can be used according to the invention are already known, or they can be prepared by customary, known processes (see, for example, Houben-Weyl, Methoden der organischen Chemie (Methods of Organic Chemistry), 4th Edition, Volume XI/l, pages 9 -1033 (1957)~
Specific examples of primary amines of the formula (II) which may be mentioned are: methylamine, ethylamine, propylamine, isopropylamine, 1,1-dimethyl-propylamine, 1,2-dimethyl-propylamine, 2,2-dimethyl-propylamine (neopentylamine), 1,2,2-trimethyl-propylamine, l-ethyl-propylamine, l-isoproyl-2-methyl-propylamine, butylamine, isobutylamine, sec.-butylamine, tert.-butylamine, l-methyl-butylamine, 2,2-dimethyl-butylamlne, 3.3-dlmethyl-butylamine, l,3,3-trimethyl-butylamine, pentylamine, l-methyl-pentylamine, 2,2-dimethyl-pentylamine, 1,2,2-trimethyl-pentylamine, hexylamine, 2-ethyl-hexylamine, l-methyl-octylamine, allylamine, 2-methyl-allylamine, propargyl-amine, cyclopropylamine, cyclopropyl-methylamine, cyclobutylamine, cyclopentyl-amine, cyclopentyl-methylamine, cyclohexylamine, cyclohexyl-ZO~) methylamlne, 3-~ethyl-cyclohexylamine, 4-methyl-cyclohexylam me, 4-tert.-butyl-cyclc~lexylamine, 4-methyl-cyclohexyl-methylamLne, 3,3,5-trimethyl-cyclohexyl-a ne, cyclohex-3-enyl-methylamine, 3,4-di~ethyl-cyclohex-3-enylamine, 3,4-dimet~lyl-cyclohex-3-enyl-methylamine, cycloheptanylamine, cycloheptanyl-methyl-amine, cyclooctanyl-amLne, cyclooctanyl-methylamine, cyclododecanylamine, cyclo-dodecanyl-methylamine, adamantyl-methylamine, 2-(bicyclo[2.2.1]heptyl)-methyl-amine, 6-(2,3,3a,4,5,6,7,7a-octahydro-4, 7-methano-indenyl-methylamine, 2-(1,2,3, 4,5,6,7,8,8a,4a-decahydro-1,4:5,8-dimethanonaphthyl)-methylamine, 5-(4,5,6,7,7a,3a-hexahydrorindenyl)-methylamine, 2-chloro-ethylamine, 2,2,2-trifluoro-ethyl-amine, 3,3-dichloro-3-fluoro-propylamine, 3,3,3-trifluoro-propylamine, 2,2-difluoro-propylamine, 2,2,2-trifluoro-1-methyl-ethylamine, 6-chloro-hexylamine,

3-trifluoromethyl-cyclohexylamine, 4-trifluoromethyl-cyclohexylamine, 3-tri-fluoromethyl-cyclohexyl-methylamine, 4-trifltloromethyl-cyclohexyl-methylamine, 2-methoxy-ethylamine, 3-methoxy-propylamine, 5-cyano-pentylamine, 2-ethoxy-carbonyl-ethylamine, aniline, 2-chloroaniline, 3-chloroaniline, 4-chloroaniline, 2,4-dichloroaniline, 3,4-dichloroaniline, 3,5-dichloroaniline, 2,4,5-trichloro-aniline, 3-nitroaniline, 4-nitroaniline, 3-chloro-4-nitroaniline, 2-methyl-aniline, 2-chloro-6-methylaniline, 4-chloro-2-trifluoramethylaniline, 3-methyl-aniline, 3-trifluoromethylaniline, 4-methylaniline, 2,6-dimethylaniline, 2-ethylaniline, 2-ethyl-6-methylaniline, 2,6-diethylaniline, benzylamine, l-phenyl-ethylamine, 2-phenyl-ethylamine, 2-chloro-~enzylamine, 2,4-dichloro-benzylamine, fur-2-yl-methylamine, tetrahydro-fur-2-yl-methylamine, tetrahydro-pyran-2-yl-methylamine and tetrahydro-pyran-3-yl-methylamine.
Preferred carbonic acid aryl ester halides also to be used as starting substances are those of formula (III) in which R2 represents a phenyl or naphthyl radical which is optionally substituted by chlorine, methyl and/or methoxy; and X represents a chlorine or fluorine atom.

115120~

me carbonic acid aryl ester halides of the formula (III) which can be used according to the invention are known, or they can be prepared by known pro-oesses. m us, for example, the carbonic acid phenyl ester chlorides can be pre-pared in a manner which is in itself kncwn, by phosgenation of phenols (see Houben-Weyl, Methoden der organischen Chemie (Methods of Organic Chemistry), 4th ~;tion, Volume 8, page 103 (1952)); the corresponding carbanic acid phenyl ester fluorides can be obtained analogously from phenols and difluorophosgene (see J. Chem. Soc. [London] 1948, page 2183).
Specific examples of starting ccmpounds of the formula (III) which may be mentioned are: the carbonic acid ester chlorides of phenol, 4-chlorophenol,

4-cresol and l-naphthol and the carbonic acid ester fluoride of phenol. A part-icularly preferred oombination of starting compounds of formula (II) and (III) is neopentylamine hydrochloride and carbonic acid phenyl ester chloride.
The reaction according to the invention may be carried out using a diluent for the primary amine of formula (II).
It is appropriate to follow a procedure in which the carbonic acid aryl ester halide of formula (III) is initially introduced into the reaction vessel and is warmed to the reaction temperature, and a solution of the primary amine in a suitable diluent is slcwly added. Suitable diluents for the amine to be added are low-boiling inert organic solvents, such as hydrocarbons and chlorinated hydrocarbons (for example petroleum ether, cyclohexane, methylene chloride, chloroform or difluorodichloro-methane, preferably petroleum ether (boiling range 30 - 50&)); these solvents evaporate at the reaction temperature and thereby simLltaneously serve as "entraining agents" for removal of the hydrogen halide formed.
It is also possible, and in many cases particularly advantageous, to OE ry out the reaction in an exoess of the carbonic acid aryl ester halide of 1~5~%~

formula (III) used as a reactant, as the alternative to using the additional diluellt.
me carbonic acid aryl ester halide of formula (III), which is in general initially introduced, can also be employed in the form of a dilute solu-tion. Diluents which are suitable for this are high-boiling inert organic sol-vents, such as chlorinated or nitrated aromatic hydrocarbons (for example chloro-benzene, the dichlorobenzenes, the trichlorobenzenes or nitrobenzene). However, using such an additional diluent in general provcdes no noticeable advantage.
It has proved to be more appropriate to carry out the reaction without such an additional diluent, and instead to employ the carbonic acid aryl ester halide of formula (III) in excess amDunts.
If the reaction according to the invention is carried out without using an additional diluent for the (initially introduced) carbonic acid aryl ester halide of formula (III), up to 20 moles, but appropriately 4 to 15 moles and pre-ferably 8 to 12 moles, of carbonic acid aryl ester halide can be employed per mole of a primary amine of the formula (II).
If a diluent is also used for the carbonic acid aryl ester halide of formwla (III), in general 2 to 15, preferably 3 to 12, moles of carbonic acid aryl ester h~l;de of form~la (III) are employed per mole of the primary amine of formula (II). In the latter case, it is thus also advisable to employ the car-bonic acid aryl ester halide of fornula (III) in amounts which are greater than the stoichiometric am~unt.
me process according to the invention is ried out without the addi-tion of an acid-binding agsnt. However, by usin~ a low-boiling, inert orqanic solvent a~ the diluent for the primary a~ me, it is possible for a large propor-tion of the hydrogen halide formed in the course of the reaction to be removed from the reaction ~s~zo~

mixture, since, as mentioned above, the solvent simultaneously serves as an "entraining agent". In order to expel all of the hydrogen halide formed, it is a~visable additionally to pass a continuous stream of air or nitrogen through the reaction mixture (see the Preparative Examples).
The reaction temperatures can be varied within the substantial range, as indicated above, of between 100 and 300C, preferably between 170 and 250C.
The reaction according to the invention is in general carried out under normal pressure.
The reaction products are isolated in a simple manner by separating the reaction mixture by distillation. Solid, higher-melting imido-dicarboxylic acid diaryl esters can also be easily purified by recrystallisation.
The new N-substituted imido-dicarboxylic acid diaryl esters (I) according to the present invention and the compounds produced by the process of the present invention can be used as intermediate products for the prepara-tion of known herbicidal active compounds from the l,3,5-triazine-2,4-(lH,3H)-dione series (see, for example, DE-OS (German Published Specification) 2,254,200 and U.S. Patent Specification 4,056,527).
According to a process which has not hitherto belonged to the state of the art (and which is the subject of our copending Canadian patent applica-tion No. 371,154),1,3,5-triazine-2,4-(lH,3H)-diones of the general formula Rl _ N"-" N N : C
R4 tIV) N ~ SR5 o ~ 5~ZOO

n w~Lch Rl has the abovementioned meaning and R3, R4 and R5 in each case represent identical or different alkyl radicals, can be prepared with a high yield and purity when the N-substituted imido-dicarboxylic acid diaryl esters according to the invention, of the general formula 1 ~CO-OR
R -N 2 (I) ~CO-OR
in which Rl and R2 have the abovem~ntioned meaning, are reacted with an isothiosemicarbazone of the general formula ,R3 HN-N2C ~ 4 (V) HN=C-S-R
in which R3, R4 and R5 have the akovem~ntioned meaning, in approximately stoichiometric am~unts, without using a diluent and without adding a base as an auxiliary, at temperatures between 50 and 150&, preferably between 70 and 120&.
m e triazinediones of form~la (IV) can be worked up and isolated, for example, ,by a prooedure in which the (optionally substituted~ phenol formed in the condensation reaction - (I) + (V) ~ (IV) - is distilled off in vacuo and the residhe is purified, if necessary, by distillatiQn under a high vacuum or by recrys~llisation.
The 1,3,5-triazine-2, 4(1H,3H)-diones of form~la (IV) thus prepared are themselves herbicidal active oompounds; hcwever, they can also be easily con-verted into the corresponding l-amino-1,3,5-triazine-2, 4(IH,3H)-diones of the general formula ., ~

115~200 --~o --o /~1 i~ 5 s~
in which Rl and R5 have the abovementioned meaninG, ~Jhich are likewise excellent.herbicides, by hydrolytic spli~tinc off of the alkylidene radical ~=CR3R4) which serves as a protective group. Furthermore, the S-alkyl radicals (-SR5) in compounds of formulae (I~) and ~Vl) can be replaced by alkylamino or dialkylamino groups by reactior.
with primary or secondary amines, herbicidal active compounds which are also known being obtained ~see likewise DE-OS ~German Published Speci~ication) 2,254,200 and U.S.
Patent Specification 4,056,527).
The new process ~iven here for the preparation of the herbicidal active compounds of the general formulae (IV) and tVI) and 6-amino derivati~es thereof, in wbich the ' ::imido-dicarboxylic acid diaryl esters of formula (I) according to the invention are used as starting compounds, has considerable and surprising advantages compared with the processes already known, for example from DE-OS (German Published Specification) 2,254,200. Thus, the cycli-æation reaction can be carried out in the mQlt of the starting materials without using solvents. No ~her auxiliaries, such.--as organic bases, are required in this procedure. The.only by-products are phenols tno hydrogen halides being p~oduced), which can easily be separated off and re-used. Finally, the imido-dicarbox~lic acid diaryl ester~ o~ formula (I) employed as starting substances can be prepared' in high'yiel'ds in an industrially simple manner from readily accessible precursors by the process claimed-in-the-above-mentioned copending patent application.
The isothiosemicarbazones o~ the'general formula (~) .are'known or. they-can be prepared by known processes, for ~ example by S-alkylation of thiosemicarbazones (see Le A 20 56 6 11 5~?~

Houben-Weyl, Methoden der or~anischen Che~.ie ~lethods . of Org2nic Chemis~ry)~ 4th Edition, Volume 9, page 912).
The synthesis of the particularly effecti~e herbicidal active compound l-amino-6-ethyl'hio-3-nec-pentyl-1,3,5-triazine-2, 4(1H,3~)-dior.e cf formula (Vlz) (see for example, ~anish Patent Specification 136,C67), starting from the co~pound N-neopentylimi~o-dicarboxylic acid diphenyl ester of formula (Ia) accordins to t~e in~ention, is described below by way of example; the course of the reaction can be represented by the following equation:
H3~3c-cH2-N 6Hs HN-N=C ~
COOC6H5 1 , CH3 HN SC H
(lo ) . 2 5 ~Va~

.
O

~J~sc H

tIVa) ,,. ,, O
.H20 'tCH ) C C~C2H5 A mixture o~ 65.4-g(0.2 mole) of ~-neopentyli~ido-dicarboxylic acid diphenyl ester (see Preparative Example 1) and 31.8g (0.2 mola) o~ acetone S-ethyl-is.othiosemicarba~one of formula.(Va.) is ~elted and the ~e1t is stirred..at:100C fo~-5 hours. The phenol for~èd is Le A 20 566 .

.

~5Sl200 then distilled off in v~cuo. The residue~ which . essentially consists of l-isopropylideneamino-6-ethylthio-3-neopentyl-1,3,5-tria71ne-2, 4(1H,3H)-dione of formula (IVa), is dissolved in 200 ml of isopropanol. To split off the isoprop~lidene protecti~e group hydrolyticall~-, 2.8g of p-toluenesulphonic acid are added, and 14.4 ml of water are added drcpwise at a temperature of 60C and under a pressure of 200 - 300 mbar in the course of half an hour.
The acetone formed is distilled off during the reaction, together with about 100 ml of isoprop~no~l. The l-amino-6 -ethylthio-3-neopentyl-1,3,5-triazine-~, 4(1H,3H)-dione o~
formul~ (VIa) which has crystallised out is filtered off ? t 0C and washed with methanol. 38.2g of the compound of formula (~tIa) of melting point 202C are obtained, corresponding to a yield of 74% of theory.
Herbicidally active l-amino-3-isobutyl-6-methy~nio -1,3,5~triazine-2, 4(1H,3H)-dione of formula (VIb), which is known (see, for example, Danish Patent Specification -136,067), can be prepared in an analogous manner startin~
~rom the compound N-isobutyl-imido-dicarboxylic acid diphenyl ester offormula (Ib) according to the invention, it being possible for the interFIediate product l-isoprop~lidene -amino-3-isobutyl-6-methylthio-1,3,5-triazine-2, 4(1H,3~)-dione of formùla (IVb) to be isolated:
1~st s~age:' ~

(cH3)2c~-cN2-N p~~=CtCH3)2 (IVb) ~ ~ N SCH3 34.6g (O.lI mole) of N-isobutyl-imido-dicarboxylic acid diphenyl ester of formula (IB) (see Preparative Example

5) and 16.0g (O.ll..mole) of acetone ~-methyi-isothi`osèmi-carbazone'are' meIted at 50C and the melt is stirred for 4hours in an oil ba~h of 100C. The phenol ~ormed is distilled off under a pressure of 18 mbars, the bath temperature being increased to 14QC. The res'idue (30.3g) .solidi~ies:; it-.is boiled up wi'th 150 ml of Le A 20 56-, . ~

~15~00 cyclohexane, 22.4 g of pure 1-isopropylidenea~.ino-3-isobutyl-6-methylthio-1,3,5-tria~ine-2,4(1H,3H)-dione o formula (IVb) of melting point 125 -127C remaining as undissolved material. A further 6.4g of the compound of formula (IVb) crystallise frcm the filtrate of the ~.ixture. The total yield is 28.8g (97% of theory). The compound of formula (IVb) can be distilled: boilin~ point:
165C under 0.38 mbar.
2nd sta~e . o Jl ~CH3)2cH-cH2-N `N NH2 (VIb) o SCH3 27.0g (0.1 mole) of the compound of formula (IVb) are dissolved in 200 ml of isopropanol at 60C in a distillation apparatus and a pressure of 260 to 200 mbars is established, so that the solvent starts to boil and is condensed in the descending condenser. The internal temperature is 45 - 50C. A solution of 0.4 ml of concentrated sulphuric acid in 7 ml of water is then added dropwise in the course of 15 minutes, about 70 ml of isopropanol, together with the acetone formed, being distilled off during this period. 14.5g of 1-amino-3-iso-butyl-6-methylthio-1,3,5-triazine-2,4(1H,3H)-dione of formula (VIb) of melting point 167 - 169C crystallise out, at 0C, from the solution which remains; a further 4.5g are obtained from the concentrated filtrate of the mixture.
The total yield of l9.0g corresponds to 83% of theory.
The Preparative Examples which follow illustrate the process of the present invention in more detail.
Preparative Examples Example' 1 (CH3)3C-CH2-N(co-o-c6H5)2 (1) A 4 litre three-necked flask was provided with a stirrer and reflux condenser, to which a descending distillation bridge was connected via a Reitmeler attachment. A coarse-pored gas inlet frit was immersed as low as possible into the flask. A dropping funnel, Le A 20 566 with pressure compensation, was connected ~o the gas inlet frit via a grcund glass joint. The gas inlet tube o~
the frit was ccnnected tc a nitrogen line and to a ~lercury bubbler. The reflux condenser was operated at 90 -100C and the descending condenser at ~20C. All theground glass connections before the frit were ~.&de secure towards excess pressure.
2.54 litres = 3.13 kg (20 moles) of carbonic acid phenyl ester chloride were initially introduced and were heated to the reflux temperature, and a solution of 174.0g (2 moles) of neopentylamine in 500 ml of petroleum ether was uniformly added dropwise into the gas inlet frit in the course of 8 to 9 hours, whilst stirrin~ ~igorously.
In addition, a vigorous stream of nitrogen was passed through. The internal temperature was not allowed to exceed 185C; towards the end of the reaction a temperature of 189 to 190C was reached. Because of encrustation of the frit, a gauge pressure of up to 60 mm Hg t80 mbars) was established in the frit during the initial phase (5 to 30 minutes after the start of the drcpwise addition), and finally fell to 10 to 15 mm Hg (about 13 to 20 ~hars).
The petroleum ether used was condensed in the descending condenser, to~ether with some neopentyl isocyanate`and a little carbonic acid phenyl ester chloride.
At the end of the dropwise addition period, the mixture was boiled under reflux for another hour~ whilst passing further nitrogen through.
Analysis of this reaction solution by gas chromatography gave the following values, without taking into consideration the carbonic acid phenyl ester chloride employed in excess: 14.3% of diphenyl carbonate, ~3.9%
of N-neopentyl-imido-dicarboxylic acid diphenyl ester (1) and 0.7% of orthocarbonic acid tetraphenyl ester.
The resulting reaction solution was worked up by distillation: after separating off a small amount of first runnings, most of the excess carbonic acid phenyl ester Le ~ 20 566 -chloride (boiling pcint: 76-78C/l9 mbars) was distilled off, until the bottom tem~erature reached 140C. 1.94 litres (=2.39 kg) of a 99.5% ~ure ester chloride, which could be re-used for the same reaction, were recovered in this manner.
Residual amounts of the carbonic acid phenyl ester chloride as well as the diphenyl carbonate were then distilled o~f under a high vacuum over a short Vigreux column, until a boiling point of 160GC under 0.2 mbar was reached. 578 g of a residue which solidified and had a purity, determined by gas chromatography, of 98.5%
were obtained, cerresponding to a yield of 87% of theory of N-neopentyl-imido-dicarboxylic acid diphenyl ester (l);
melting point 81C (from petroleum ether), boiling point:
156C/0.02 mbar.
The compounds listed in the following Table were prepared in an analogous manner:

Le A 20 566 512~0 O ~
S~ ~ ~ I` ~ O ~
O O ~ O O
rl O ~ : O -- O O O O
o~ ~ I
~_ u~ u~ o o . u~

u~
. o .
bO ' ~ u~ o ~ _ ~1 ~ O ~ ~r ~ ~ ~ c~
~ ~ _ ~7 : ' ~ _\

. U U U U U
C~ ~ .
.
.
~:; . 5 .
. I I ~ U C~
:: V ~ U U U U U
,~ ~ IU ~ U ~ ~ ~ r~
., . :~ U ~ U ~ U U U
U -- U -- ~
~ ' 'I
~ * * * *

.' ,~ . ~ ~ ~ L'~ C~
' ~O
:
. Le A 20 566 ~5~200 ~1~ N
O O
O O ~ o ~ o ~ ~ c~ N
_~ O O O ~ O O
I I ~
O G~ I ~ o U~ In0 r~ er . ~ .

b~
v r ~ o H~ O . a~

~ :
., ~ .
^
., O
O
c> O
V
~ z; : u~ u~ ~ ~n Lr~ ~ In rl N . S~
n I P;
' Y Y y y y y c~

:
:
~ . I ~ I 1~ ~
.
~' I5~ N ~ ~ U - U ~
. . I ^ I t'~ I Ir) U') :' , In ~ ~ 5 ~ -- --r~ U ~ U ~ u~
P; ~ -- U ~ C) . o ,, :
~ ~o . ~Z
~ ~c ;
Le ~A 20 _66 l~lZOO

!

, ..
~ O ~G~ r-b~ ~ O O O O
o o o o 'I~rl O -- O O C~ O L~
~ o ~ o 0 o ~
o PO, o o o ~ ~ ~ o m ~, ~ ~ ~ I I I I ~
. ~ o ~ ~ ~ ~ o o . 1` ~ ~ C~ O
.

bO
~ ~rlO . '~
_~~1 o Ha) ~ t~
_, ~_ .
~0 J~ .
.

~0 _~ O
_ u~ L~ L~ n L~
~1 Z ~ ~ . X
I
~ ~1~;

. 1~ 1 ~ ;

.

CO G~ O
~ ' _ --' k O
X Z' Le A 2~ 566 ~o ~ ~ o o o o o o o o Q,-- O
. ~
.

~ oo ~ ~ , ~ ~--,_ . CO C~
o : .,1 , ^
.,,C~l o o V o V
a) z . -~
~1 ~ I :
~ l l l l l l l ~ tr; ~ ' .
~' .

U

*
~ U~~D!`COG~ O
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Claims (35)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Process for the production of an N-substituted imido-dicarboxylic acid diaryl ester compound of the formula R1 - N(CO-OR2)2 (I) wherein R1 is an optionally substituted aliphatic, cycloaliphatic, aralipha-tic, or aromatic radical; and R2 is an optionally substituted aryl radical, which process comprises reacting a primary amine of the formula R1 - NH2 (II) in which R1 is defined as above with a carbonic acid aryl ester halide of the formula X - CO - OR2 (III) in which R2 is defined as above, and X is a halogen atom at a temperature between 100° and 300°C.

2. Process as claimed in claim 1 wherein the reaction is carried out at a temperature between 170° and 250°C.

3. Process as claimed in claim 1 wherein the reaction is carried out in the presence of a diluent.

4. Process as claimed in claim 3 wherein the diluent is a hydrocarbon.

5. Process as claimed in claim 3 wherein the diluent is a chlorinated hydrocarbon.

6. Process as claimed in claim 3 wherein the diluent is petroleum ether.

7. Process as claimed in claim 1 wherein the carbonic acid aryl ester halide of formula (III) is employed in a greater than stoichiometric amount.

8. Process as claimed in claim 1 wherein the carbonic acid ester halide of formula (III) is (a) introduced into a reaction vessel;
(b) warmed to reaction temperature; and (c) a solution of the primary amine of formula (II) is slowly added at the desired reaction temperature, with a low boiling inert organic solvent being used as the diluent.

9. Process as claimed in claim 1 wherein R1 is alkyl of from 1 to 10 carbon atoms.

10. Process as claimed in claim 1 wherein R1 is substituted alkyl where-in the substituents are selected from lower alkoxy, lower alkyl-mercapto, halogen, cyano or nitro, the alkyl having from 1 to 10 carbon atoms.

11. Process as claimed in claim 1 wherein R1 is alkenyl or alkynyl of from 3 to 8 carbon atoms.

12. Process as claimed in claim 1 wherein R1 is cycloaliphatic with from 3 to 8 carbon atoms.

13. Process as claimed in claim 1 wherein R1 is substituted cycloali-phatic wherein the substituents are selected from lower alkyl, the cycloali-phatic having from 3 to 8 carbon atoms.

14. Process as claimed in claim 1 wherein R1 is an araliphatic radical with from 7 to 12 carbon atoms.

15. Process as claimed in claim 1 wherein R1 is a substituted arali-phatic radical wherein the aromatic ring is substituted by halogen, nitro, trifluoromethyl, cyano, lower alkyl or lower alkoxy, the araliphatic having from 7 to 12 carbon atoms.

16. Process as claimed in claim 1 wherein R1 is an aromatic radical of from 6 to 12 carbon atoms.

17. Process as claimed in claim 1 wherein R1 is a substituted aromatic radical wherein the substituents are selected from halogen, nitro, trifluoro-methyl, cyano, lower alkyl and lower alkoxy, the aromatic radical having from 6 to 12 carbon atoms.

18. Process as claimed in claim 16 or 17 wherein the aromatic radical is a phenyl radical.

19. Process as claimed in claim 1 wherein R1 is a straight chain or branched alkyl with from 1 to 10 carbon atoms optionally substituted by lower alkoxy, lower alkylmercapto, halogen, cyano or nitro; alkenyl or alkynyl with from 3 to 8 carbon atoms; a cycloaliphatic with from 3 to 8 carbon atoms optionally substituted by lower alkyl; an araliphatic with from 7 to 12 carbon atoms optionally substituted in the aromatic ring by halogen, nitro, trifluoro-methyl, cyano, lower alkyl or lower alkoxy; an aromatic radical with from 6 to 12 carbon atoms optionally substituted by halogen, nitro, trifluoromethyl, cyano, lower alkyl or lower alkoxy.

20. Process as claimed in claim 1 or 19 wherein a carbonic acid aryl ester halide of formula X - CO - OR2 (III) in which R2 is a phenyl or naphthyl radical optionally substituted by chlorine, methyl or methoxyi and X is a chlorine or fluorine atoms, is employed.

21. Process as claimed in claim 1 wherein neopentylamine hydrochloride is reacted with carbonic acid phenyl ester chloride.

22. Process as claimed in claim 1 wherein sec.-butylamine is reacted with carbonic acid phenyl ester chloride.

23. Process as claimed in claim 1 wherein isobutylamine is reacted with carbonic acid phenyl ester chloride.

24. Process as claimed in claim 1 wherein neopentylamine is reacted with carbonic acid tolyl ester chloride.

25. Process as claimed in claim 1 wherein 2-aminohexane is reacted with carbonic acid phenyl ester chloride.

26. Process as claimed in claim 1 wherein 2,2-dimethyl-1-aminobutane is reacted with carbonic acid phenyl ester chloride.

27. Process as claimed in claim 1 wherein 2,4-dimethyl-3-aminopentane is reacted with carbonic acid phenyl ester chloride.

28. Process as claimed in claim 1 wherein 5-methylaminoheptane is reacted with carbonic acid phenyl ester chloride.

29. Process as claimed in claim 1 wherein 3-aminopentane is reacted with carbonic acid phenyl ester chloride.

30. Process as claimed in claim 1 wherein 3-amino-1-propylene is reacted with carbonic acid phenyl ester chloride.

31. Process as claimed in claim 1 wherein cyclopentylamine is reacted with carbonic acid phenyl ester chloride.

32. Process as claimed in claim 1 wherein cyclohexylamine is reacted with carbonic acid phenyl ester chloride.

33. Process as claimed in claim 1 wherein 2-methylaminobicyclo-[1,2,2] -heptane is reacted with carbonic acid phenyl ester chloride.

34. Process as claimed in claim 1 wherein 2,2,2-trifluoroethylamine is reacted with carbonic acid phenyl ester chloride.

35. Process as claimed in claim 1 wherein 1,1,1-trifluoro-2-aminopropane is reacted with carbonic acid phenyl ester chloride.