JPS5925788B2 - Process for producing N-substituted oxazolidines - Google Patents

Description

[Detailed description of the invention] The present invention is based on the general formula [wherein, in the (4) group compound, R is C1-C,.

It is a haloalkyl group, R and R2 are independently a hydrogen atom C1-Cl2 alkyl group, lower alkoxyalkyl group or lower alkylol group, R3, R4, R5
and R6 are independently a hydrogen atom, a lower alkyl group, a lower alkoxyalkyl group, or a lower alkylol group, or in group (B) compounds, R is a haloalkyl group or a chloroalkenyl group, and R1 is a hydrogen atom, lower alkyl group, phenyl group, naphthyl group, or substituted phenyl group (however, the substituent is a mono- or dichloro group, -nitro group, -methyl group, -methoxy group or -hydroxy group), R2 is a hydrogen atom or is a lower alkyl group, R3 is a hydrogen atom, a lower alkyl group, a hydroxymethyl group, an N-methylcarbamoyloxymethyl group,
or a dichloroacetoxymethyl group, R4 is a hydrogen atom or a lower alkyl group, R5 is a hydrogen atom, a lower alkyl group, or a phenyl group, and R6 is a hydrogen atom (provided that at least one of R1 or R5 is a phenyl group, a substituted phenyl group, or a naphthyl group)]. In describing the groups of the above compounds, "alkyl groups" and "haloalkyl groups" in the above (4) group compounds are defined as straight chain and branched chain configurations as described above.
Including members containing from 1 to 10 or 12 carbon atoms, "halo" includes chlorine and sulfur, where the substitution is either mono, di, tri, tetra, and/or di.

For example, alkyl moieties include methyl, ethyl, n
-propyl group, isopropyl group, n-butyl group, secondary butyl group, 1,1-dimethylbutyl group, amyl group, isoamyl group, 2,4,4-trimethylpentyl group, n-hexyl group, isohexyl group, These include n-heptyl group, n-octyl group, isooctyl group, nonyl group, decyl group, dimethylheptyl group, and the like. "Lower alkyl group", "lower alkoxyalkyl group" and "lower alkylol group"
preferably includes a group having 1 to 6 carbon atoms, most preferably a group having 1 to 4 carbon atoms, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group,
Examples include isobutyl group, secondary butyl group, tertiary butyl group, pentyl group, hexyl group, methoxymethyl group, ethoxyethyl group, hydroxymethyl group, hydroxy-n-propyl group, and the like. For clarity, these compounds are
Hereinafter referred to as “aliphatic-substituted oxazolidine” (this term is
containing a hydrogen atom as a substituent as in compound 1)
. In the compounds of group 03) above, the following embodiments are used for various substituents.

For R, a "haloalkyl group" preferably includes members having from 1 to 6 carbon atoms in both straight-chain and branched chain configurations, and a "halo group" includes chlorine as mono-, di-, tri- and tetra-substitution. and contains sulfuric acid. Examples of alkyl moieties within preferred embodiments include: Methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, secondary butyl group, 1,1-dimethylbutyl group, amyl group, isoamyl group, n-hexyl group and isohexyl group. Regarding R, the "chloroalkenyl group" preferably has 2 to 4 carbon atoms and contains at least one olefinic double bond, and the chlorine substituent is
Examples as mono-, di-, tri- or tetra-substitutions. For example, it includes members present as trichlorovinyl groups. For R1, R2, R3, R4 and R5, in each instance the "lower alkyl group" preferably includes members having from 1 to 4 carbon atoms in a straight chain and branched chain configuration;
Examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, secondary butyl group, tertiary butyl group, and the like. For clarity, these compounds are
In the following, it is referred to as "aromatically substituted oxazolidine". A preferred type of aromatic substituted oxazolidine is one in which R1 and R2 are both lower alkyl groups (R, and R2
are the same or different) and R5 is a phenyl group. These types of compounds are known to have activity as herbicidal antidotes and in some cases as herbicides, for example in Pelkey Patent No. 182,120.
No. 806,038 and No. 806,040, and German Published Application No. 2341810.

Aromatically substituted oxanolysines are further disclosed in Eugene George Teach, filed on November 3, 1975.
neG. US patent application Ser. No. 627,986 to ``Each''. Representative examples of these types of compounds are:
As shown in the table below.

In one preferred embodiment of the alkyl-substituted oxazolidine, R1 and R2 are independently a hydrogen atom, a lower alkyl group, a lower alkoxyalkyl group, or a lower alkylol group.

According to the known art, oxazolidines are generally prepared by condensing alkanolamines with suitable aldehydes or ketones in a solvent such as benzene and removing them from the reaction product.

Such a method can be used, for example, in the field of park pine (Bergma pine).
nn) et al., JACS75358 (1953).

To produce N-monosubstituted oxazolidines of the type described herein, the products of the invention are further treated with acid chlorides in the presence of a hydrogen chloride acceptor such as triethylamine. The reaction is carried out under anhydrous conditions, the water being removed after condensation of the alkanolamine with the carbonyl compound. Methods of this type are described, for example, in the aforementioned Pelkey patent and US Pat. No. 3,707,541. Substituted oxazolidines prepared in this manner are often contaminated by by-products, which generally result from the reaction of acid chlorides with by-products or reaction intermediates formed during the condensation step.

These by-products often prove difficult to separate either due to their quantity or their chemical behavior or both. In the production of substituted oxazolidines on a small scale, for example for laboratory or testing purposes, the desired product can be obtained in substantially pure form by sufficient purification. However, such purification steps result in large product losses that may be detrimental if the desired product is produced on a large scale, eg, industrially. Moreover, the elimination or reduction of such purification steps is advantageous in industrial installations, since the equipment and/or operating costs are reduced by the costs of unnecessary equipment and/or solvents. It is an object of the present invention to provide an improved process for the preparation of N-monosubstituted oxazolidines.

It is another object of the present invention to provide a process for preparing N-monosubstituted oxazolidines of suitable purity.

It is another object of the present invention to provide a method for preparing N-monosubstituted oxazolidines that requires fewer purification steps than previously available. It is also an object of the present invention to provide a process for making N-monosubstituted oxazolidines that minimizes the formation of undesirable by-products.

The present invention relates to compounds of the general formula [wherein, in the (4) group compound, R is a C1-ClO haloalkyl group, and R1 and R2 are independently a hydrogen atom, a C1-Cl2 alkyl group, a lower alkoxyalkyl group, or a lower is an alkylol group, R3, R4, R5 and R6 are independently a hydrogen atom, a lower alkyl group, a lower alkoxyalkyl group or a lower alkylol group, or in the group (B) compound, R is a haloalkyl group or It is a chloroalkenyl group, and R is a hydrogen atom, a lower alkyl group, a phenyl group, a naphthyl group, or a substituted phenyl group (however, the substituent is a mono- or dichloro group, -nitro group, -methyl group, -methoxy group) or -hydroxy group), R2 is a hydrogen atom or a lower alkyl group, R3 is a hydrogen atom, a lower alkyl group, a hydroxymethyl group, an N-methylcarbamoyloxymethyl group, or a dichloroacetoxymethyl group, and R4 is a hydrogen atom or a lower alkyl group; atom or a lower alkyl group, R5 is a hydrogen atom, a lower alkyl group, or a phenyl group, and R6 is a hydrogen atom (provided that at least one of R1 or R5 is a phenyl group, a substituted phenyl group, or a naphthyl group). In the method for producing an N-monosubstituted oxazolidine represented by
is a halogen atom) in the presence of a hydrogen halide acceptor and water.

In a preferred embodiment, the present invention provides N
In the method for producing monosubstituted oxazolidine, (a) the general formula (
In the formula, R3, R4, R5 and R6 are the same as before) and the general formula (wherein, R1 and R
2 is the same as before) to form a reaction product consisting of oxazolidine and water, and (b) reacts the oxazolidine in the presence of water and a hydrogen halide acceptor with a carbonyl compound of the formula is the same as above,
(wherein, X is a halogen atom).

In other aspects, the invention provides a method for providing (a) the general formula (wherein R
3, R4, R5 and R6 are the same as before) and a carbonyl compound represented by the general formula (wherein R1 and R2 are the same as before) are reacted to produce a reaction product consisting of oxazolidine and water. to generate (
b) removing water from the reaction product of (a), and (c)
reacting the oxazolidine from step (b) in the presence of a hydrogen halide acceptor and water with a compound of the formula (wherein R is the same as above, in which X is a halogen atom), It consists of a method for producing an N-monosubstituted oxazolidine represented by the above formula.

This variant of the process according to the invention is a process for preparing aromatically substituted oxazolidines and is also suitable for preparing aliphatically substituted oxazolidines.

As is well known in the art, when alkanolamines are condensed with aldehydes or ketones, the resulting products are oxazolidines.

However, oxazolidines are generally believed to be in tautomeric equilibrium with Schiff bases. For example, reaction of an alkanolamine with acetone in the presence of a solvent such as benzene produces a mixture of 2,2-dimethyloxazolidine and Schiff's base of the formula and water.

Long chain alkanolamines in which the hydroxyl group is attached to the carbon atom adjacent to the amino group react in a similar manner to yield oxazolidines containing various substituents on the ring. Generally, both the desired oxazolidine and the unwanted Schiff base are present in the reaction mixture. In known technology,
Water is removed from the reaction mixture by stripping or distillation, and the remaining product reacts with acid chloride in an anhydrous system to form the N-monosubstituted oxazolidine plus hydrogen chloride. However, Schiff bases also react with acid chlorides to produce various types of undesirable by-products, which appear to be primarily esters.

In order to use the desired N-monosubstituted oxazolidine for industrial or other uses, these by-products must be separated. In many cases good separation is difficult to achieve, in other cases it is achieved but requires several purification steps. However, if, contrary to the practice of the prior art, the reaction of the oxazolidine with the acid chloride is carried out in the presence of water, the purity of the substituted oxazolidine obtained is substantially higher and the purification requires fewer steps. I found out.

Additionally, the yield of the desired oxazolidine is also increased.
Generally, the process of the invention is carried out by reacting an oxazolidine with an acid halide, preferably an acid chloride, in the presence of water and a hydrogen halide acceptor, preferably a hydrogen chloride acceptor, such as sodium hydroxide.

The hydrogen halide acceptor generally has a molecular weight of about 5(f) to about 500
1). In one embodiment, the water produced during the condensation of the alkanolamine with the aldehyde or ketone is retained in the reaction system and the entire reaction product (including oxazolidine and water) is converted into acetic acid chloride in the presence of a hydrogen chloride acceptor. come into contact with. In other embodiments, water is removed from the condensation reaction product but reintroduced into the system in the form of an aqueous solution of the hydrogen halide acceptor, such as sodium hydroxide.

In other preferred embodiments, about 5-50(f) NaO
An aqueous alkaline solution containing H is added to the system prior to the addition of acid chloride.

The strong base acts as a hydrogen chloride acceptor in the next step and is also thought to be effective in lowering the water vapor pressure above the reaction system, promoting the formation of oxazolidine from the diol intermediate more than the Schiff base. . If the NaOH concentration is greater than 20 (Ff), sodium chloride will precipitate from the system, requiring dilution of the mixture or removal by filtration or similar manner before purification. Another advantage of the process of the invention is that since the reaction of the oxazolidine with the acid halide is carried out in aqueous solution, a hydrogen halide acceptor, preferably a hydrogen chloride acceptor such as triethylamine, is suitable for carrying out this reaction efficiently. However, the use of these relatively expensive materials is unnecessary. The hydrogen halide acceptors utilized are less expensive substances, such as weak alkaline solutions or other alkali metal hydroxides, such as potassium hydroxide (in the form of an aqueous solution). - The most common hydrogen halide acceptors are those which are miscible or soluble in water under the conditions of use; however, water immiscible hydrogen halide acceptors such as dimethylaniline are also used. As mentioned above, if an aqueous alkali solution is added to the reaction product before addition of the halide, this alkali also serves to function as a hydrogen halide acceptor. Preferably, the reaction is carried out at low temperature, for example -5 to +5°C.

However, the reaction is carried out at slightly higher temperatures, such as up to about 25°C, although at these temperatures the product yield is somewhat reduced. The alkanolamine used can be any lower alkanolamine, i.e. having about 2 carbon atoms, provided that the hydroxyl and amino groups are attached to adjacent carbon atoms.
~about 6 may be sufficient. The carbonyl compound has the formula RlCO
It is any suitable aldehyde or ketone represented by R2 (wherein R and R2 are the same as above).

The following examples illustrate how the method of the invention may be carried out.

Production of 2,2-dimethyl-3-dichloroacetyloxazolidine (compound 2 in the table).

Example 1 (Conventional method) 2 dissolved in 50 ml of benzene
, 2-dimethyloxazolidine 5.19 was treated with triethylamine 5.59 and dichloroacetyl chloride 7
．． 49 was added dropwise while stirring and cooling in an ice bath.

The mixture was poured into water, the benzene solution was separated, dried over anhydrous magnesium sulfate, and the solvent was stripped under vacuum. The product was a waxy solid with a melting point of 113-115 diC recrystallized from diethyl ether.
Example 2 122 ml (1229) of ethanolamine, 150 ml of acetone and 600 ml of benzene were introduced into a 21 volume reactor.

Heat the mixture to reflux, strip off the water, cool the reaction mixture and add 200 ml of 37% NaOH and 17 ml of water.
Added 5ml. While the mixture was kept at approximately 5°C, 100 ml of ditaloloacetyl chloride was added. The mixture was allowed to stand for 1 hour, then an additional 93ml of dichloroacetyl chloride was added. Lower the pH of the mixture to below 13,
25 ml of 20% NaOH was added to bring the pH within 13.8. The reaction product was neutralized with concentrated hydrochloric acid, stripped of benzene O, and the product was filtered and dried. Melting point 117
．． 5 to 119.5 to C solid 2829 (theoretical amount of 66.
7%). Example 3 Ethanolamine 122ml (1229), acetone 1
50 m1 (1169) and 600 m1 of benzene at 21
was introduced into the reactor.

The reaction was carried out at a temperature of about 33-34°C. The reaction mixture was stirred for 1 hour, 33% NaOH2OOml was added, the temperature was lowered to about 5° C. with an acetone/ice bath, and the mixture was stirred for an additional 3 hours. Dichloroacyl chloride 110
m1 (168.5') over 1 hour, 3301)
25 ml of NaOH and a second portion of 110 ml of dichloroacetyl chloride were added (gradually). The reaction product was neutralized with concentrated hydrochloric acid. Water (190ml) was added to dissolve the sodium chloride formed, the benzene was stripped off and the product was filtered and dried. Melting point 117.5-119
A solid 3479 (82% of theory) of composition C was obtained. 2,2
, 5-trimethyl-3-dichloroacetyloxazolidine (compound 3 in the table).

Example 4 (Conventional method) 18 d of benzene solution containing 4.6 y of 2,2,5-trimethyloxazolidine was mixed with 2 y of benzene.
5ml and 4.59ml of triethylamine.

5.9 y of dichloroacetyl chloride was added dropwise while stirring and cooling in an ice bath. When the reaction is complete,
The mixture was poured into a bath, the benzene layer was separated, dried over anhydrous magnesium sulfate, and the benzene was removed in vacuo. The yield was oil N3O=1.4950, 7.790D.

Example 5 150 g of isopropanolamine (162 m (density 0)
．． 961) was mixed with acetone 150d (1169) and benzene 600a.

Strip the water, cool the reaction mixture, and
2OOml aOH and 175wf3 water were mixed with the product. Then 202 m2 (3109) of 96% pure dichloroacetyl chloride were added. The temperature was maintained at 5°C. The reaction product was neutralized with concentrated hydrochloric acid, transferred to a separatory funnel, and washed once with distilled water. Stripped of benzene. 2,2,5-trimethyl-3-dichloroacetyloxazolidine 3431 was recovered.

(76% of theory) Melting point 77-84°C0 Example 6 Isopropanolamine 1509 (162d), acetone 150ml! (116f1) and benzene 600m
1 was introduced into a 21 volume reactor.

The product was heated to 4' and stirred for 1 hour.

200 ml of 33% sodium hydroxide was added and the resulting mixture was stirred for a further 2 hours.

The resulting mixture was cooled to 5° C. in an ice bath using acetone, and 110 ml of dichloroacetyl chloride was gradually added over 1 hour. The mixture was allowed to stand for a further 1.5 hours and then an additional 110 ml of dichloroacetyl chloride was added over the next hour, when a further 330 ml of dichloroacetyl chloride was added over the next hour. )Na
Added OHlOd. The pH of the reaction product was 11.1. The reaction product was neutralized with hydrochloric acid until the pH was approximately 3. Water (185ml) was added to dissolve the sodium chloride formed. Benzene was stripped under vacuum. The product was filtered, stripped and dried without further crystallization. 346.2f! was recovered.

(theoretical amount of 7701)), melting point 87-88℃02,2-
Selection of dimethyl-5-phenyl-3-dichloroacetyl-oxazolidine (compound 63 in the table).

Example 7 (Conventional method) 1009 of 1-phenyl-2-aminoethanol was dissolved in 250 ml of benzene and 459 of acetone was added.

The mixture was heated under reflux for several hours, during which time approximately 15 ml of water was removed by means of a modified Dean starter apparatus. The mixture was cooled, 75 ml of triethylamine were added and dichloroacetyl chloride 1089 was added dropwise with stirring and cooling in a water bath at room temperature. The solution was left with anhydrous magnesium sulfate and the solvent was stripped under vacuum. The thick oil 1701 crystallizes on standing and when triturated with anhydrous ether gives the desired compound 132y (63% of theory).
I got it. It is a white solid with a melting point of 99.5-100
．． It was 5℃. Example 8 11 lbs of benzene containing 531.69 lbs of 1-phenyl-2-aminoethanol and 2509 lbs of acetone was heated under reflux and the water removed in a modified Dean Stark apparatus.

When about 70 TL of water had been collected, the mixture was cooled to 5°C in an isopropanol dry ice bath and added with 50% NaOH.
Add solution 4709 and then dichloroacetyl chloride 6 in 500 ml of benzene at a rate keeping the temperature between 1 and 3 °C.
309 was added. When the addition was complete, the temperature of the mixture was brought to room temperature and neutralized to pH 3 with concentrated HCI. At this time, a precipitate is formed, which is filtered off and solid, melting point 103 ~
4589 was obtained at 105°C. When the benzene solution is washed with water, dried, and the benzene is stripped, it becomes a solid, melting point 81~
91°C 3749 was obtained. This was triturated with ether to give a solid, mp 102-103°C. This was combined with the first product to give a total of product 7789. Yield 70
%. As can be seen from the examples, use of any embodiment of the present invention in the preparation of alkyl-substituted oxazolidines produced a product of higher purity than using known techniques operating in anhydrous systems.

In the production of 2,2-dimethyl-3-ditaloloacetyl oxazolidine, removing water from the system and then reintroducing it in the form of an alkaline aqueous solution (as in Example 2) produced a much purer product than the prior art, and the product did not require recrystallization.

When water was maintained in the system (Example 3), products with similarly improved purity were obtained, as well as in high yields. Similar results are seen by comparing the preparation of 2,2,5 trimethyl-3-dichloroacetyloxazolidine in Examples 4-6.

Both methods according to the invention lead to crystalline products, but
The known technology produced an extremely impure product, oil. Maintaining water in the system (Example 6) produced the highest purity product. Similarly, in the production of aromatic substituted oxazolidines, water is removed from the system and then it is
The method of re-introducing aOH as a solution is a known technique (
(Example 8) gave a higher yield and higher purity product than Example 7).

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R is a dichloromethyl group; R_1 and R_2 are lower alkyl groups; R_3 and R_4 are hydrogen atoms; R_
5 and R_6 are a hydrogen atom or either a lower alkyl group or a phenyl group) This is a method for producing an N-substituted oxazolidine represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R_1, R_2, R_3, R_4, R_5 and R_6 are the same as above), and the oxazolidine represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R is the same as above; X is a halogen atom ), in the presence of an organic solvent, a hydrogen halide acceptor, and water. 2. The method according to item 1 above, wherein the reaction temperature is about -5°C to +5°C. 3. The method according to item 1 above, wherein the hydrogen halide acceptor is an alkali metal hydroxide. 4. The method according to item 1 above, wherein the hydrogen halide acceptor is sodium hydroxide. 5. The method according to item 1 above, wherein the organic solvent is an aromatic hydrocarbon solvent. 6 N-substituted oxazolidine is 2,2-dimethyl-3-
The method according to item 1 above, which is dichloroacetyl oxazolidine. 7 The first above, wherein the N-substituted oxazolidine is 2,2,5-trimethyl-3-dichloroacetyl oxazolidine
The method described in section. 8 N-substituted oxazolidine is 2,2-dimethyl-3-
The method according to the above item 1, which is dichloroacetyl-5-phenyloxazolidine. 9 General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R is a dichloromethyl group; R_1 and R_2 are lower alkyl groups; R_3 and R_4 are hydrogen atoms; R_
5 and R_6 are hydrogen atoms or either a lower alkyl group or a phenyl group), (a) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (Formula In the formula, R_3, R_4, R_5 and R_6 are the same as above), and the alkanolamine represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R_1 and R_
2 is the same as above) is subjected to a condensation reaction to produce oxazolidine and water, and while this water is retained in the reaction system, the oxazolidine produced in step (b) (a) and the general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R is the same as above, and X is a halogen atom), in the presence of an organic solvent, a hydrogen halide acceptor or an aqueous solution thereof. A method for producing an N-substituted oxazolidine, which comprises reacting with: 10. The method of claim 9, wherein step (b) is carried out at a temperature of about -5[deg.]C to +5[deg.]C. 11. The method according to item 9 above, wherein the hydrogen halide acceptor is an alkali metal hydroxide. 12. The method according to item 9 above, wherein the hydrogen halide acceptor is sodium hydroxide. 13. The method according to item 9, wherein the aqueous solution of the alkali metallized oxide is added to the reaction system before carrying out step (b). 14 The above-mentioned No. 9, wherein the organic solvent is an aromatic hydrocarbon solvent.
The method described in section. 15 N-substituted oxazolidine is 2,2-dimethyl-
10. The method according to the above item 9, which is 3-dichloroacetyloxazolidine. 16. The method according to item 9, wherein the N-substituted oxazolidine is 2,2,5-trimethyl-3-dichloroacetyl oxazolidine. 17. The method of claim 9, comprising recovering the N-substituted oxazolidine from the product of step (b). 18 General formula ▲ There are numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R is a dichloromethyl group; R_1 and R_2 are lower alkyl groups; R_3 and R_4 are hydrogen atoms; R_
5 and R_6 are hydrogen atoms or either a lower alkyl group or a phenyl group), (a) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (Formula Alkanolamine represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (where R_1 and R_2 are the same as above) Condensation reaction with the compound, removing water produced in the reaction from the reaction system during or after the reaction, (b) (a)
The oxazolidine produced in the process and the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R is the same as above,
A method for producing an N-substituted oxazolidine, which comprises the step of reacting a compound represented by (X is a halogen atom) in the presence of a hydrogen halide acceptor, an organic solvent, and water. 19. The method of claim 18, wherein step (b) is carried out at a temperature of about -5[deg.]C to +5[deg.]C. 20. The method according to item 18, wherein the hydrogen halide acceptor is an alkali metal hydroxide. 21. The method according to item 18 above, wherein the hydrogen halide acceptor is sodium hydroxide. 22 N-substituted oxazolidine is 2,2-dimethyl-
Said No. 18 which is 3-dichloroacetyloxazolidine
The method described in section. 23. The method according to item 18, wherein the N-substituted oxazolidine is 2,2,5-trimethyl-3-dichloroacetyl oxazolidine. 24 N-substituted oxazolidine is 2,2-dimethyl-3
-dichloroacetyl-5-phenyloxazolidine.