HU181417B - Process for preparing substituted carbamates - Google Patents

Description

The present invention relates to a process for the preparation of carbamates of the formula I. In the formula (I):

R ¹ is C 1-4 alkyl or tolyl;

R ^{2 is} hydrogen or 1,3-dioxolanyl;

R ^{3 is} hydrogen or C 1-4 alkoxycarbonyl; obsession

R ² and R ³ together are -0-CH ₂ -C (CH ₃ ) -.

Carbamates of formula (I) include a number of highly potent pesticides. According to known processes, they are prepared from phenols of the formula II with substituted isocyanates or urea chloride in the presence of tertiary bases.

A common disadvantage of these processes is that said substituted isocyanates or carbamic acid chlorides are produced with phosgene under both difficult and hazardous conditions, both technologically and in terms of safety.

The process of the present invention overcomes these drawbacks because it is suitable for the preparation of compounds of formula (I) with simple reagents and under readily obtainable reaction conditions.

In process (a), the compound of formula (III) is reacted with sulfuryl chloride, optionally in an inert organic solvent, and then reacted with a phenol derivative of formula (II) in the presence of an acid acceptor. The carbamate formed is isolated by aqueous precipitation or by distillation of the solvent. The reaction is carried out at a temperature of 0 ° C to 50 ° C in an aromatic hydrocarbon, chlorinated hydrocarbon, C 2 -C 5 alkyl alkanoate or C 3 -C 5 ketone solvent, preferably dichloromethane, chloroform, dichloroethane, benzene, ethyl acetate, acetone. The acid acceptor is a tertiary amine, preferably triethylamine, pyridine, dimethylaniline and the like. Or an alkali metal or alkaline earth metal carbonate or hydroxides or an aqueous solution thereof.

In process (b), a compound of formula (IV) is reacted with sulfuryl chloride followed by an amine of formula (V) in the presence of an acid acceptor.

The reaction is carried out under the same conditions as in the previous version. In addition to the above, an excess of the amine of formula (V) may be used as an acid binder.

The process of the present invention is illustrated by the following embodiments.

Example 1

To a mixture of 13.5 g of sulfuryl chloride and 10 ml of dichloromethane was added dropwise 5.9 g of N-methylformamide at 0-5 ° C, followed by dropwise addition of 13.1 g (0, 08 mole) of 3,3-dimethyl-2,3-dihydro-8-hydroxybenzofuran and 12.5 g (0.124 mole) of triethylamine in 80 ml of dichloromethane. The reaction mixture was stripped of the triethylamine hydrochloride by washing with water to give 13.3 g (60%) of N-methyl-3,3-dimethyl-2,3-dihydro-8-benzofurylcarbamate after distilling off the solvent. Mp 155-157 ° C. IR (KBr): 3310, 2930, 1720, 1520, 1480, 1225, 1110, 875, 775 cm ⁴

-1181417

Example 2

From 13.5 g (0.1 mol) of sulfuryl chloride, 5.9 g (0.1 mol) of N-methylformamide and 12.9 g (0.08 mol) of 2- (2'-hydroxyphenyl) - From 1,3-dioxolane (salicylaldehyde-ethylene glycol diacetal), 14.3 g (65%) of 2- (2'-N-methylcarbamoyloxyphenyl) -1,3-dioxolane are obtained.

M.p .: 118-120'C.

IR (KBr): 3300, 2930, 2870, 1720, 1530, 1400, 1220, 1080, 750 cm ^-1

Example 3

From 13.5 g (0.1 mol) of sulfuryl chloride, 5.9 g (0.1 mol) of N-methylformamide and 13.1 g (0.08 mol) of 3,3-dimethyl-2,3-dihydro-8 N-methyl-3,3-dimethyl-2,3-dihydro-8-hydroxy-benzofuran was prepared in a similar manner to Example 1, but using K ₂ CO ₃ as an acid scavenger and acetone as the solvent. -benzofuryl carbamate.

Mp: 155-156 "C.

Example 4

13.5 g (0.1 mol) of sulfuryl chloride, 5.9 g (0.1 mol) of N-methylformamide and 12.9 g (0.08 mol) of 2- (2-hydroxyphenyl) - From 1,3-dioxolane, as in Example 1, but using 10% aqueous NaOH as the acid scavenger and benzene as the solvent, 71% yield of 2- (2'-N-methylcarbamoyloxyphenyl) was obtained. -l, 3-dioxolane.

115-118 ° C.

Example 7

A solution of 19.5 g (0.1 mol) of 3-methoxycarbonylaminophenyl formate in 80 ml of chlorobenzene was added dropwise to 15.5 g (0.1 mol) of sulfuryl 5-chloride and the gas evolution After completion, the reaction was quenched with a mixture of 10.7 g (0.1 mol) of m-toluidine and 15.5 g of N, N-dimethylaniline at 25 ° C. The precipitate is filtered off and washed with alcohol.

Yield: 24.3 g (81%) of methyl [N- (3'-tolylcarbamoyloxy) 10-phenyl] -carbamate.

144-146 'C.

Example 8

13.5 g of sulfuryl chloride in 10 ml of dichloromethane

At 25-30 ° C, 10.1 g (0.1 mol) of N-butylformamide was added dropwise, and then, after gas evolution had ceased, 7.5 g of phenol and

A solution of triethylamine (10.1 g) in dichloromethane (80 ml) was added. In the following, the procedure of Example 1 is followed. 13.1 g (80%) of N-butylphenylcarbamate are obtained.

M.p. 92-95 'C / 26.6 Pa.

Example 5

13.5 g (0.1 mol) of sulfuryl chloride, 5.9 g (0.1 mol) of N-methylformamide and 12.9 g (0.08 mol) of 2- (2'-hydroxyphenyl) - From 1,3-dioxolane as in Example 1 but using Ν, Ν-dimethylaniline as acid acceptor and benzene as solvent, 64% of 2- (2'-N-methylcarbamoyloxyphenyl) is obtained. 1,3-dioxolane.

Mp: 115-118 'C

Example 6

To a solution of 19.3 g (0.1 mol) of 3,3-dimethyl-2,3-dihydro-8-phenyloxybenzofuran in 80 ml of benzene was added dropwise 13.5 g (0.1 mol) of sulfuryl chloride at 25 ° C. and stirred for 3 hours. Then, 60 g of a 10% NaOH solution and 7.4 g (0.11 mol) of methylamine hydrochloride are reacted with stirring at 5-10 ° C. After separation of the aqueous phase, the organic phase was concentrated to give 15.4 g (70%) of N-methyl-3,3-dimethyl-2,3-dihydio-8-benzofurylcarbamate.

Mp: 154-155 ° C.

Claims (1)

25 Claims Process for the preparation of substituted carbamates of formula (I) - In formula (I): R ^{1 is C} 1 -C 4 alkyl or tolyl; R ^{2 is} hydrogen or 1,3-dioxolanyl; R ^{3 is} hydrogen or C 1-4 alkoxycarbonylamino; or R ² and R ³ together are -O-CH ₂ -C (CH ₃ ) ₂ - 35 characterized by a) (III) formamides of formula - in formula (III), ^R1 is as defined above - with sulfuryl chloride in an equimolar amount or an excess of reacted optionally in an organic inert solvent jelenlété40 in and the reaction mixture an acid binding agent - preferably a tertiary amine, an alkali metal carbonate or reacting, in the presence of an excess of an alkali metal hydroxide, a phenol derivative of formula (II): wherein R ² and R ³ are as defined above; obsession 45 b) reacting a compound of formula IV, wherein R ² and R ³ are as defined above, with an equimolar amount of sulfuryl chloride in an inert organic solvent, then reacting the reaction mixture with an amine of formula V in the presence of an excess of an acid scavenger. - in formula (V), R ¹ is as defined above; and then separating the carbamate derivatives of formula (I) from the reaction mixture obtained according to process variant (a) or (b), preferably by evaporation and / or filtration of the reaction mixture.