Process for producing saccharin

1,2-Benzoisothiazole-3-on-1, 1-dioxide having the formula ##STR1## wherein X represents hydrogen, halogen, nitro, lower alkyl or lower alkoxy and Y represents hydrogen, halogen, lower alkyl, or lower alkoxy is prepared by reacting phosgene with an o-sulfobenzoic acid compound having the formula: ##STR2## or an alkali metal salt or alkaline earth metal salt thereof in the presence of dimethylformamide, thereby producing a mixture of a dichlorotolylsultone and a chlorosulfonylbenzoylchloride; (b) reacting the reaction products of step (a) with an alcohol of the formula ROH wherein R represents a lower alkyl group; and then (c) reacting the product of step (b) with ammonia.

BACKGROUND OF THE INVENTION: 
1. Field of the Invention: 
The present invention relates to a new process for producing 
1.2-benzoisothiazole-3-on-1.1-dioxide (saccharine derivatives) which is 
useful as a medicinal agent (sweetener for diabectics) food additives 
sweetener and as an intermediate for agricultural chemicals such as 
germicides to obtain hygienically nontoxic products. More particularly, 
the invention relates to a process for producing 
1.2-benzoisothiazole-3-on-1.1-dioxides possesing high purity in high yield 
without contamination by toluenesulfonamide which may be hygienically 
toxic, by a sequence of new reaction steps from o-sulfobenzoic acid. 
2. Description of the Prior Art: 
It is known that 1.2-benzoisothiazole-3-on1.1-dioxides can be produced by 
the reactions of Reaction scheme (1) in which the first steps in the 
chlorosulfonation of toluene; the second step is the separation and 
purification of o-toluenesulfochloride and p-toluenesulfochloride which 
are produced in the first step the; third is the reaction of the 
o-toluenesulfochloride separated and purified in the second step with 
ammonia; and fourth step is the oxidation of o-toluenesulfonamide produced 
in the third step with a solution of bichromate in concentrated sulfuric 
acid J. Am. Chem. Soc. Vol. 1. page 426, 1879; BP 174, 913 and BP 
682.800). 
REACTION SCHEME (1): 
##STR3## 
It is also known that 1.2-benzoisothiazole-3-on-1.1dioxide can be produced 
by the reactions of Reaction scheme (2) in which the first step is the 
reaction of phthalic anhydride with ammonia, the second step is the 
Hoffmann reaction of the phthalimide produced in the first step; the third 
step is the diazotation of the o-aminobenzoic acid produced in the second 
step; the fourth step the reaction of sodium sulfide with the diazobenzoic 
acid produced in the third step the fifth step is the treatment of the 
sodium dithiodibenzoate produced in the fourth step with an acid; the 
sixth step is the methyl-esterification of the dithiodibenzoic acid 
produced in the fifth step; the seventh step is the reaction of the 
dimethyl dithiodibenzoate produced in the sixth step with chlorine; and 
the eighth step is the reaction of the methyl o-sulfochlorobenzoate 
produced in the seventh step with ammonia (Chemical Engineering, Vol. 61, 
No. 7 page 128, 1954). 
REACTION SCHEME (2): 
##STR4## 
In the conventional process of Reaction scheme (1) which employs toluene, 
as a reactant a large amount of p-toluene-sulfochloride is produced as a 
by-product together with o-toluenesulfochloride in the first step. 
Accordingly, the separation and purification procedure of the second step 
is quite troublesome. That is, the reaction mixture formed in the first 
step must be poured into water to precipitate crystals of 
p-toluenesulfochloride and the crystals are centrifugally separated. The 
remaining oily product of o-toluenesulfochloride is further cooled to 
precipitate crystals of p-toluenesulfochloride, and the operation is 
repeated. However, it is difficult to separate all of the 
p-toluenesulfochloride from the oily o-toluenesulfochloride. Consequently, 
it is necessary to separate p-toluenesulfonamide as a byproduct after the 
reaction with ammonia in the third step. Moreover, it is necessary to 
treat a large amount of the waste bichromate conc. sulfuric acid mixture 
used in the oxidation reaction of the fourth step. In order to recover and 
reuse chromium oxide formed from the bichromate, it is necessary to use a 
large electrolyzer. Moreover, another serious disadvantage of the 
conventional process is the fact that both o-toluenesulfonamide and 
p-toluenesulfonamide are believed to cause cancer. For these reasons, in 
the conventional process, it is necessary to separate the toxic compounds 
to purify the product. If the toxic compounds remain with the 
1.2-benzoisothiazole-3-on-1.1-dioxide when it is used as a food additive, 
there is the possibility that it will adversely effect the human body. 
Accordingly, the conventional process is not a hygienically safe process. 
In the conventional process of the Reaction scheme (2) which was phthalic 
anhydride as the starting material, it is necessary to use a full eight 
step process. Consequently, the scheme is complicated and it is hard to 
achieve high yields of 1.2-benzoisothiazole-3-on-1.1-dioxide such as about 
50 % based on the phthalic anhydride used as the starting material. None 
of the known processes are satisfactory as industrial methods. 
SUMMARY OF THE INVENTION 
One object of the present invention is to provide a process for producing 
1.2-benzoisothiazole-3-on-1.1-dioxides in high yield free of contaminating 
toluenesulfonamide which may be toxic. This object and other objects of 
the invention have been attained by providing a process for producing 
1.2-benzoisothiazole-3-on-1.1-dioxides having the formula 
##STR5## 
wherein X represents hydrogen halogen, nitro lower alkyl or lower alkoxy 
and Y represents hydrogen, halogen a lower alkyl or a lower alkoxy by 
reacting phosgene with an o-sulfobenzoic acid having the formula or an 
alkali metal salt or alkaline earth metal salt thereof, in the presence of 
dimethylformamide; reacting the reaction product with an alcohol having 
the formula R--OH (II), wherein R represents a lower alkyl group; and then 
reacting ammonia with the resulting reaction product. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: 
Various processes for producing 1.2-benzoisothiazole-3-on-1.1-dioxides have 
been studied. As the result, it has been foundthat both the carboxylic 
group and the sulfonic acid group bonded to o-sulfobenzoic acid can be 
simultaneously chlorinated by reacting phosgene with an o-sulfobenzoic 
acid, an alkali metal salt thereof or alkaline earth metal salt in the 
presence of dimethylformamide, whereby a mixture of 
o-chlorosulfonylbenzoylchloride and dichlorotolylsultone is produced, 
thereafter, o-chlorosulfonylbenzoylchloride is esterified by reacting the 
resultant mixture with an alcohol 1.2-Benzoisothiazole-3-on-1.1-dioxide is 
produced as the single product by reacting ammonia with the esterified 
mixture. In the reaction scheme (1) of the invention, as shown by the 
following reaction dimethylformamide reacts with phosgene, and the 
reaction product (a) is used as the chlorinating agent for the aromatic 
sulfocarboxylic acid (b), or an alkali metal salt derivative thereof [(c), 
(d) and (e)] or an alkaline earth metal thereof [(f) (g) and (h)], whereby 
the chlorination reaction is conducted as shown in reaction scheme (ii) to 
produce a mixture of chlorosulfonylbenzoylchloride (1 V) and 
dichlorotolylsultone (V). Dimethylformamide is recovered from the 
reaction. As shown by Reaction scheme (iii), chlorosulfonylbenzoylchloride 
(IV) in the mixture is esterified by reacting the alcohol (II) with the 
mixture of chlorosulfonylbenzoylchloride (IV) and dichlorotolylsultone (V) 
to produce the alkyl chlorosulfonylbenzoate (VI). Both compound (VI) and 
compound (V) are converted to the desired 
1.2-benzothiazole-3-on-1.1-dioxide product by reacting the mixture of 
compound (VI) and compound (V) with ammonia. 
REACTION SCHEME (i) 
##STR6## 
REACTION SCHEME (ii) 
##STR7## 
REACTION SCHEME (ii) 
##STR8## 
In all of the reaction schemes above, X and Y are as defined above, M is 
an alkali metal and M' is an alkaline earth metal. 
In the process of the invention, an o-sulfonylbenzoic acid of formula (I) 
or an alkali metal salt or alkaline earth metal salt therefore is used. In 
formula (I), X and Y can be bonded at any desired position on the benzene 
ring, and X can be hydrogen halogen, nitro, lower alkyl or lower alkoxy 
and Y can be hydrogen, halogen, lower alkyl or lower alkoxy. The scope of 
the term halogen atom includes chlorine, bromine, iodine and fluorine. 
Suitable lower alkyl groups include methyl, ethyl, n-propyl, iso-propyl 
n-butyl, iso-butyl or tert-butyl. Suitable lower alkoxy groups include 
methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, and 
tertbutoxy. 
The alkali metal salts or alkaline earth metal salts of the o-sulfobenzoic 
acid having formula (I), can be the alkali metal salts (c), (d) and (e) 
and the alkaline earth metal salts (f), (g) and (h) or mixtures thereof. 
Suitable alkali metals include sodium, potassium and suitable the like and 
alkaline earth metals include magnesium, calcium, barium and the like. 
The o-sulfobenzoic acid (I) can be produced by the oxidation of 
toluenesulfonic acid or the sulfonation of an aromatic carboxylic acid. 
The monometal salts (c) and (f) can be prepared by salting out the 
corresponding o-sulfobenzoic acid (I). The dimetal salts (e), (g) and (h) 
can be prepared by neutralizing the corresponding o-sulfobenzoic acid (I) 
with an alkali metal hydroxide or an alkaline earth metal hydroxide. 
The process of the invention includes a first step of reaching phosgene 
with the o-sulfobenzoic acid (I) or an alkali metal salt or alkaline earth 
metal salt thereof in the presence of dimethylformamide; a second step of 
reacting the alcohol with the reaction product of the first step; and a 
third step of reaching ammonia with the reaction product of the second 
step. The reaction of phosgene with an o-sulfobenzoic acid (I) or the 
alkali metal salt or alkaline earth metal salt thereof in the presence of 
dimethylformamide in the first step can be usually conducted in an inert 
organic solvent. The amount of dimethylformamide used in the reaction is 
in a range of less than 1 mole, usually 0.01 - 0.3 mole, preferably 0.03 - 
0.1 mole per mole of the o-sulfobenzoic acid, or the alkali metal salt or 
alkaline earth metal salt thereof. It is possible to use an excess amount 
of dimethylformamide, in the reaction, although it is not economical to do 
so. Phosgene can be used in amounts greater than equivalent amounts 
preferably 5 - 20 % in excess. Phosgen can be directly introduced into the 
reaction system or it can also be used by dissolving it in an inert 
organic solvent such as carbon tetrachloride, toluene or the like. 
Suitable inert organic solvents used in the reaction include aliphatic 
hydrocarbons such as cyclohexane, n-hexane and the like; halohydrocarbons 
such as chloroform, carbon tetrachloride, trichloroethylene, 
tetrachloroethylene and the like; aromatic hydrocarbons such as benzene, 
toluene, xylene, chlorobenzene and the like; ethers such as diethyl ether, 
dibutyl ether, dioxane and the like; ketones such as acetone, methylethyl 
ketone, methylisopropyl ketone and the like; nitriles such acetonitrile, 
propionitrile and the like and esters such as ethyl acetate, butyl acetate 
and the like. The reaction temperature and the reaction time are selected 
depending upon type of the aromatic sulfocarboxylic acid used, or alkali 
metal salt or alkaline earth metal salt thereof and the rate at which is 
fed. The reaction temperature is usually in a range of 20.degree. - 
150.degree. C, preferably 40.degree. -100.degree. C. The reaction time can 
be less than 8 hours and is usually in a range of 5 - 7 hours. 
In the second step of the reaction of the alcohol (II) with the reaction 
mixture produced in the first step, it is possible to directly react the 
alcohol with the reaction mixture without any treatment after the first 
step. Thus, it is possible to react the alcohol with the condensed 
reaction product which is produced by removing the inert organic solvent 
from the reaction mixture after the first step by distillation. Suitable 
alcohols (II) used in the reaction are preferably lower alcohols such as 
methanol, ethanol, n-propanol, n-butanol and the like. The amount of 
alcohol employed is usually in a range of 0.5 - 8.0 mole, preferably 1.0 - 
5.0 mole per mole of the o-sulfobenzoic acid (I) or the alkali metal salt 
or alkaline earth metal salt thereof. The reaction temperature is in a 
range of 5.degree. - 40.degree. C preferably 15.degree. - 30.degree. C. 
The reaction time can be less than two hours and usually is in a range of 
0.5 - 1 hour. 
In the third step the reaction of ammonia is reacted with the reaction 
product produced in the second step. It is possible to react the 
components by injecting ammonia into the reaction mixture after the second 
step. Thus, it is preferable to react ammonia and the second step product 
by mixing an aqueous solution of ammonia with the reaction mixture after 
the second step. The amount of ammonia employed is preferably in a range 
of 3.5 - 4.5 mole per mole of the o-sulfobenzoic acid (I) or the alkali 
metal salt or alkaline earth metal salt thereof. Preferably, a 4 - 28 % of 
an aqueous solution of ammonia is used. The reaction temperature is 
usually in the range of 5.degree. - 35.degree. C, and if desired, the 
reaction is conducted while cooled. After the reaction with ammonia, the 
ammonium salt of 1.2-benzoisothiazole-3-on-1.1-dioxide (III) is obtained. 
The desired compound, i.e. 1.2-benzoisothiazole-3-on-1.1-dioxide (III) can 
be separated by precipitation by treating the solution with a mineral acid 
such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid or 
the like. In accordance with the process of the invention, the desired 
1.2-benzoisothiazole-3-on-1.1-dioxide compound (III) having high purity 
can be easily produced in substantial industrial efficiency in yields 
greater than 80 % based on the o-sulfobenzoic acid. 
The positions of the substituents in the 
1.2-benzoisothiazole-3-on-1.1-dioxides compounds (III) can be shown as 
follows. 
##STR9## 
Suitable 1.2-benzoisothiazole-3-on-1.1-dioxides (III) produced by the 
process of the invention include 1.2-benzoisothiazole-3-on-1.1-dioxide, 
6-fluoro-1.2-benzoisothiazole-3-on-1.1-dioxide, 
6-chloro1.2-benzoisothiazole-3-on-1.1-dioxide, 
6-bromo-1.2-benzoisothiazole3-on-1.1-dioxide, 
6-iodo-1.2-benzoisothiazole-3-on-1.1-dioxide, 
5.6-dichloro-1.2-benzoisothiazole-3-on-1.1-dioxide, 
5-nitro-1.2-benzoisothiazole-3-on-1.1-dioxide, 
6-nitro-1.2-benzoisothiazole-3-on-1.1-dioxide, 
6-methyl-1.2-benzoisothiazole-3-on-1.1-dioxide, 
5.7-dimethyl-1.2-benzoisothiazole-3-on-1.1-dioxide, 
5-methyl-6-nitro1.2-benzoisothiazole-3-on-1.1-dioxide, 
6-methoxy-1.2-benzoisothiazole3-on-1.1-dioxide, 
5.6-dimethoxy-1.2-benzoisothiazole-3-on-1.1-dioxide, 
6-ethoxy-1.2-benzoisothiazole-3-on-1.1-dioxide and the like. 
The characteristics and advantages of the process of the invention will now 
be enumerated. 
1. The reaction steps are short. The desired of 
1.2benzoisothiazole-3-on-1.1-dioxide compounds (III) can be continuously 
produced in high yield from o-sulfobenzoic acids without separating the 
intermediates from the reaction to effect purification without complicated 
operations. 
2. The desired 1.2-benzoisothiazole-3-on-1.1-dioxide compounds (III) can be 
produced in high purity without contaminating amounts of 
toluenesulfonamide which may be toxic to the human body. Consequently, the 
1.2-benzoisothiazole-3-on-1.1-dioxide can be used safely as a sweetner for 
human beings. 
3. The chlorosulfonylbenzoylchlorides as intermediates have been 
conventionaly produced by chlorinating the alkali metal salt or ammonium 
salt of sulfobenzoic acid with a mixture of phosphorus pentachloride and 
phosphorus oxychloride or chlorosulfonating benzoic acid and then 
chlorinating it with thionyl chloride. These processes are quite 
complicated. On the contrary, in the first step of the present process, 
both the carboxyl group and the sulfonic acid group of the o-sulfobenzoic 
acid can be simultaneously chlorinated under mild conditions. 
The invention will be further illustrated by certain examples.

EXAMPLE 1 
Preparation of 1.2-benzoisothiazole-3-on-1.1-dioxide 
First step: 
In a four necked flask equipped with a stirrer, a thermometer, a condenser 
and a dropping funnel, 20.2 g (0.1 mole) of o-sulfobenzoic acid, 75 ml of 
carbon tetrachloride and 0.22 g (0.003 mole) of dimethylformamide were 
charged. The mixture was stirred at 70.degree. -75.degree. C and 75 ml of 
carbon tetrachloride solution of phosgene (phosgene content of 30% WV: 
0.22 mole) were added dropwise and the mixture was reacted for 7 hours. 
After the reaction, nitrogen gas was injected to remove excess phosgene. 
Second step: 
In a three necked flask equipped with a stirrer, and a thermometer, 12.8 g 
(0.4 mole) of methanol were charged and all the reaction mixture obtained 
in the first step was added to the methanol solution and the resulting 
mixture was reacted with stirred at 15.degree. C for 1 hour. 
Third step: 
In a four necked flask equipped with a stirrer, a thermometer, a condenser 
and a dropping funnel, 90 g (0.42 mole) of an 8 % aqueous solution of 
ammonia was charged. The reaction mixture produced in the second step was 
added dropwise to the aqueous solution of ammonia at 15.degree. - 
20.degree. C with stirring and the reaction was continued for 4 hours. 
After the reaction, the organic phase was separated from the aqueous 
solution phase, and 6N - HCl was added dropwise to the aqueous solution 
phase with stirring to adjust the pH to 1. The precipitated crystals were 
filtered and washed with 30 ml of water and dried whereby 15.1 g of white 
crystals of 1.2-benzoisothiazole3-on-1.1-dioxide having a melting point of 
227.degree. - 229.degree. C (yield of 82.4 % o-sulfobenzoic acid were 
obtained. The purity of the resulting 
1.2-benzoisothiazole-3-on-1.1-dioxide was 99.8% by neutralization 
titration analysis. 
EXAMPLE 2 
Preparation of 1.2 -benzoisothiazole-3-on 1.1-dioxide 
First step 1: 
Into a four necked flask equipped with a stirrer, a thermometer, a 
condenser and a phosgene inlet, were charged 24.0 g (0.1 mole) of the 
monopotassium salt of o-sulfobenzoic acid 
##STR10## 
150 ml of toluene and 0.22 g (0.003 mole) of dimethylformamide. The 
mixture was stirred at 80.degree. C and 23 g of phosgene were introduced 
into the mixture over 4 hours. The reaction was continued by maintaining 
the temperature at 80.degree. - 90.degree. C under refluxing with stirring 
for 3 hours. After the reaction, nitrogen gas was injected into the 
mixture to remove excess phosgene. The reaction mixture was filtered to 
remove potassium chloride and the filtrate was condensed and a colorless 
condensate was obtained. 
Second step: 
Into a three necked flask equipped with a stirrer and a thermometer, was 
charged 13.8 g (0.3 mole) of ethanol. The condensate produced in the first 
step was also charged. The reaction was continued with stirring at 
10.degree. C for 1 hour. 
Third step: 
Into a four-necked flask equipped with a stirrer, a thermometer, a 
condenser, and a dropping funnel, was charged 71.0 g (0.42 mole) of a 10 % 
aqueous solution of ammonia. The reaction mixture produced in the second 
step was added dropwise to the aqueous solution of ammonia at 15.degree. - 
20.degree. C with stirring and the reaction was continued for 4 hours. 
After the reaction, 6N - HCl was added dropwise to the reaction mixture 
with stirring to adjust the pH to 1. The precipitated crystals were 
filtered and washed with 30 ml of water and dried whereby 16.0 g of white 
crystals of 1.2-benzoisothiazole-3-on-1.1-dioxide having a melting point 
of 228.degree. -229.degree. C (yield of 87.3 % based on o-sulfobenzoic 
acid) were obtained. 
EXAMPLE 3: 
In accordance with the process of Example 2, phosgene was introduced into 
several solutions each containing on o-sulfobenzoic acid (i) or an alkali 
metal salt or alkaline earth metal salt thereof an inert organic solvent 
in the presence of dimethylformamide as the first step, and an alcohol was 
added to each solution and reacted in the second step an aqueous solution 
of ammonia was added to each solution and reacted in as the third step. 
The product was precipitated by adding hydrochloric acid to each solution 
whereby various 1.2-benzoisothiazole-3-on-1.1-dioxide compounds were 
obtained. The conditions of the first, second and third steps are shown in 
Table 1 and the results are shown in Table 2. 
Table 1 
__________________________________________________________________________ 
First step 
Amount Amount 
Starting of of 
Experi- 
material dimethyl 
Solvent 
phos- 
Reaction Conditions 
ment (Amount form- 
Amount 
gene Temp. 
Time 
No. (g)) amide(g) 
(ml) (g) (.degree. C) 
(hr) 
__________________________________________________________________________ 
##STR11## 0.25 chloro- benzene 120 
22.0 90 7 
2 
##STR12## 0.25 xylene 120 
23.0 90 7 
3 
##STR13## 0.22 carbon- tetra- chloride 120 
23.0 75 7 
4 
##STR14## 0.25 chloro- benzene 120 
23.5 95 7 
5 
##STR15## 0.25 toluene 120 
22.0 90 7 
6 
##STR16## 0.22 tetra- chloro- ethylene 120 
22.0 90 7 
7 
##STR17## 0.30 isopropyl methyl- ethyl- ketone 120 
__________________________________________________________________________ 
22.0 80 7 
Table 1' 
______________________________________ 
Second step Third step 
Ex- Reaction 
peri- 
ROH (II) Reaction Amount Conditions 
ment Amount Temp. Time of 10% Temp. Time 
No. (g) (.degree. C) 
(hr) NH.sub.3 aq 
(.degree. C) 
(hr) 
______________________________________ 
methanol 
1 12.8 15 1 70 20 4 
methanol 
2 16.0 15 1 70 20 4 
ethanol 
3 18.4 15 1 70 20 4 
methanol 
4 15.0 15 1 70 20 4 
n-propanol 
5 24.0 15 1 70 20 4 
ethanol 
6 17.0 15 1 70 20 4 
methanol 
7 15.0 15 1 70 20 4 
______________________________________ 
Table 1" 
______________________________________ 
Ex- Mel- 
peri- ting 
ment point Amount Yield 
No. Product .degree. C 
(g) % 
______________________________________ 
##STR18## 215 - 217 
21.5 82.0 
2 
##STR19## 215 - 217 
22.0 83.9 
3 
##STR20## 216 - 218 
18.0 82.7 
4 
##STR21## 216 - 218 
17.7 81.3 
5 
##STR22## 200 - 202 
16.6 82.5 
6 
##STR23## 207 - 209 
19.3 84.6 
7 
##STR24## 207 - 209 
19.0 83.3 
______________________________________ 
table 2 
__________________________________________________________________________ 
First step 
Amount Amount 
Starting of of 
Experi- 
material dimethyl 
Solvent 
phos- 
Reaction Conditions 
ment (Amount form- 
Amount 
gene Temp. 
Time 
No. (g)) amide(g) 
(ml) (g) (.degree. C) 
(hr) 
__________________________________________________________________________ 
8 
##STR25## 0.22 aceto- nitrile 120 
23.0 75 7 
25.4 
9 
##STR26## 0.30 carbon- tetra- chloride 120 
23.0 75 7 
23.0 
10 
##STR27## 0.30 chloro- benzene 120 
23.0 80 7 
29.9 
11 
##STR28## 0.30 xylene 120 
23.0 85 7 
27.0 
12 
##STR29## 0.40 toluene 120 
22.0 80 7 
24.6 
13 
##STR30## 0.40 chloro- benzene 120 
22.0 85 7 
30.0 
__________________________________________________________________________ 
Table 2' 
______________________________________ 
Second step Third step 
Ex- Reaction Reaction 
peri- 
ROH (II) Conditions Amount Conditions 
ment Amount Temp. Time of 10% Temp. Time 
No. (g) (.degree. C) 
(hr) NH.sub.3 aq 
(.degree. C) 
(hr) 
______________________________________ 
8 n-butanol 20 1 70 20 4 
22.2 
9 methanol 20 1 70 20 4 
15.0 
10 ethanol 20 1 70 20 4 
16.0 
11 ethanol 20 1 70 20 4 
16.0 
12 methanol 20 1 70 20 4 
15.0 
13 methanol 20 1 70 20 4 
15.0 
______________________________________ 
Table 2" 
__________________________________________________________________________ 
Experi- Melting 
ment point Amount 
Yield 
No. Product .degree. C 
(g) % 
__________________________________________________________________________ 
8 
##STR31## 247-249 
17.1 86.7 
9 
##STR32## 261-263 
17.5 82.8 
10 
##STR33## 211-213 
20.0 82.6 
11 
##STR34## 269-271 
18.4 86.3 
12 
##STR35## 257-258 
19.2 84.5 
13 
##STR36## 278-290 
20.0 83.0 
__________________________________________________________________________