PART L EXPERIMENTAL -...

1

PART L

EXPERIMENTAL

PART L

E X P E R I M E N T A L

SECTION I PREPARATION OF SUBSTITUTED ANILINES

2:4-DICHLORO ~~ILINE

• •

2:4-dichloro acetanilide was prepared by chlorination

of acetanilide in presence of fused sodium acetate in

glacial acetic acid, according to the method of Reed and

Orton ( J. c. s., 1907, 1553 ). The chloro acetanilide

on hydrolysis by heating it with four times the quantity

of concentrated hydrochlori~ acid for four hours, gave

2:4-dichloro aniline; crystallised from alcohol, white 0 needles, M.P. 63 c. Pierson and Heumann record the

same melting point ( Ber., 1883, 1049 ).

2:5-DICHLORO ANILINE

2:5-dichloro nitrobenzene, obtained by nitration of

p-dichloro benzene with fuming nitric acid, gave on

reduction by tin and concentrated hydrochloric acid,

2:5-dichloro aniline, which on crystallisation from alcohol

gave white needles, M.P. 51° c. Lesimple and Witt record

- 76 -

the same melting point ( Ann. z., 1868, 226 ).

3:5-DICHLORO-~-METHOXY ANILINE

(i) Preparation of 3:5-dichloro-~-hydroxy nitrobenzene

Para nitrophenol ( 6.4 g. ) was dissolved in hot

concentrated hydrochloric acid ( 250 c.c. ). The solution

was then cooled under tap and to the cold solution was

added drop by drop a solution of potassium chlorate

( 3.6 g. in 75 c.c. water ) with occasional shaking. A

yellow solid began to separate in a few minutes after the

addition was over. A good amount of heat was evolved

during the addition; and the reaction mixture was allowed

to attain room temperature by leaving it aside for some

time. It was then filtered, washed with water to remove

the traces of the acid and dried. It crystallised as 0

small white needles from benzene, M.P. 125 C ( decamp.);

yield : 5 g.

Analysis :

0.198 g. of substance gave 0 .• 2733 g. AgCl

Found : Cl, 34.15 per cent.

Cl, 34.13 per cent.

l

77

(ii) Derivatives of 3:5-dichloro-~-hydroxy nitrobenzene

(a) The sodium salt. -- Sodium ( 2 g. ) was carefully

dissolved in absolute alcohol (. 30 c. c. ) and 3:5-dichloro

-4-hydroxy nitrobenzene ( 5 g. ) was added to it. It

went into solution. on· evaporation to dryness, yellowish

red solid was obtained. It was crystallised from minimum

quantity or water; small yellow needles, yield was almost

quantitative.

Analysis :

0.516 g. or the dry salt gave 0.1562 g. Na2so4 Found : Na, · 9. 82 per cent.

c6

H2cl

203

NNa requires : Na, 10.00 per cent.

•

(b) Silver salt. -- The ahove mentioned sodium salt

( 5 g. ) was dissolved in minimum quantity or warm water,

and a concentrated solution of silver nitrate added; a

heavy yellow solid separated. It was filtered, washed

with distilled water and dried. This was sufficiently

pure for the next reaction ; yield was almost quantitative.

Analysis :

0.336 g. of the dry silver salt gave 0.1142 g. Ag.

•

- 78 -

Found : Ag, 34.04 per cent.

Ag, 34.28 per cent.

(c) Met boxy derivative. - The preparation of the

methoxy derivative was attempted by dimethyl sulphate as

well as methyl iodide-potassium carbonate method but the

methylation did not succeed. The following method has

been found to be suitable for the purpose of the yield.

The best conditions are given below :--

The silver salt of 3:5-dichloro-4-hydroxy-nitro

benzene ( 5 g. ) suspended in absolute alcohol ( 30 c.c.)

was mixed with methyl iodide ( 10 g. ) and the mixture

was kept overnight at room temperature. It was then

refluxed for five hours on water bath and was filtaed

hot. On cooling the filtrate, white needles separated, 0 M.P. 102 C ; yield : 1 g.

Anaihysis :

0.168 g. of the substance gave 0.2178 g. AgCl

Found Cl, 32.08 per cent.

- 79 -

REDUCTION OF THE METHOXY COMPOUND : PREPARATION OF -- -

3:5-DICHLOR0-4-METHOXY ANILINE

A mixture of 3:5-dichloro-4-methoxy-nitrobenzene

( 8 g. ), concentrated hydrochloric acid ( 40 c.c. ) and

tin ( in small pieces, 16 g. ) was slowly heated on wire

gauze with a very low flame, and the heating was continued

till tin was completely dissolved. Care was taken to avoid

vigorous reaction during the reduction. The reaction

mixture was then cooled and made alkaline by adding

concentrated solution of sodium hydroxide ( 60 g. in 100

c.c. water ) and was steam-distilled when 3:5-dichloro-4-

methoxy aniline was obtained in the distillate as a white

solid. It was filtered orr and crystallised from alcohol,

white long needles, M.P. 87° C ; yield : 2 g.

Analysis :

0.213 g. or the substance gave 0.3221 g. AgCl


c7

H?cl2 0N requires : Cl, 36.97 per cent.

ACETYL DERIVATIVE OF 3:5-DICHLORO-~-METHOXY-ANILINE

3:5-dichloro-4-methoxy aniline on treatment with

acetic anhydride gave the acetyl derivative. It

- 80 -

crystallised from alcohol, fine white needles, M.P. 195°.

Analysis :



C9HgC12o2N requires : Cl, 30.35 per cent.

SECTION II PREPARATION OF SUBSTITUTED

DIPHENYL ~~INE-2-CARBOXYLIC ACIDS . •

(J.oot\B R __ --X <:.

. ----y l'iH

(I)

2 1 :4'-DICHLORO-~-METHOXY DIPHENYL AMINE-g-CARBOXYLIC ACID

2:4-dichloro aniline ( 7 g. ), anhydrous potassium

carbonate ( 6 g. ) and isoamyl alcohol ( 30 c.c. ) were

mixed together : and to the mixture 6-bromo-3-methoxy

benzoic acid ( 9 g. ) and copper powder ( 0.4 g. ) were

added. It was then refluxed on oil bath at 140° C for

five hours, with CaC12 guard tube to prevent access of

moisture. The resulting brown mass was treated with

- 81 -

water ( 25 c.c. ) and subjected to steam distillation to

remove amyl alcohol. The non-volatile residue in the

flask was treated with animal charcoal, and filtered hot.

The filtrate, on cooling, gave the potassium salt of the

acid as needles. It was filtered and decomposed by

concentrated hydrochloric acid. The acid, thus obtained,

was collected. The filtrate after the removal of the

potassium salt was also acidified when a further quantity

of the acid was o.btained. It was filtered, washed with

water and dried. Both the samples of the acid were mixed

and crystallised from dilute acetic acid, pale green 0 small needles, M.P. 230 c. Yield : 5 g.

Analysis :

(a) 0.1989 g. substance required 5.5 c.c. of 0.1159 N

alkali.

Found eq. wt. : 312.

c14

H11

o3

Ncl2 requires eq. wt. : 312.

(b) 0.198 g. of substance gave 0.1836 g. AgCl


Cl, 22.76 per cent.

The acid is sparingly soluble in hot alcohol and

insoluble in hot water, benzene, chloroform and petroleum

- 82 -

ether.

The above reaction was carried out in presence of

nitrobenzene instead of amyl alcohol, the quantity of

the reactants being kept unchanged. The temperature was.

maintained at 160° C for five to six hours. On working

up the reaction mixture as before, the same acid was

obtained in slightly better yield.

Derivatives :

(i) Acid chloride. -- The acid ( 1 g. ), dry benzene

( 30 c.c. ) and thionyl chloride ( 1 c.c. ) were heated

for about fifteen minutes on water bath. On evaporation

of benzene, the acid chloride separated as yellow

crystalline substance, recrystallised from behzene, yellow

needles, M.P. 142° c. Yield : almost quantitative.

Analysis

0.176 g. of the substance gave 0.2347. g. of AgCl.


c14

H10

o2Ncl3

requires : Cl, 32.23 per cent.

(ii) Ethyl ester. -- The above acid chloride (0.5 g.)

and absolute alcohol (5 c.c.) were refluxed for fifteen

minutes on water bath; the reaction mixture was then left

~ --------------------

- 83 -

at room temperature. The ester separated on standing as 0 small colourless plates,. M.P. 96 c.

Analysis :

0.236 g. ~f the substance gave 0.200 g. of AgCl


c16H15o3Ncl2 requires : Cl, 20.88 per cent.

(iii) Methyl ester. -- It was similarly prepared using

methyl alcohol. It crystallised from alcohol as colourless 0 tiny needles, M.P. 114 c.

Analysis :

0.216 g. of the substance gave 0.1904 g. of AgCl.


c15H13o3Ncl2 requires Cl, 21.78 per cent.

2 1 :4 1-DICHLORO-DIPHENYL AMINE-2-CARBOXYLIC ACID

(I) R(4) = H and X(2) and Y(4) = Cl

2:4-dichloro aniline ( 16 g. ), dry potassium

carbonate ( 14 g. ), amyl alcohol ( 30 c.c. ), o-chloro

benzoic acid ( 14 g. ) and copper powder ( 0.4 g. ) were

mixed together. The mixture was then refluxed on oil bath

- 84 -

0 at 150 C for five hours, with CaC12 guard tube. The

reaction mixture was worked up as before after the steam

distillation of amyl alcohol to get the acid. A yellow

solid was obtained. It was collected and crystallised

from acetic acid, small white needles, M.P. 245° c.

Yield : 7 g. Ullmann records M.P. 249° C ( Ann., 1909,

355, 340 ).

Analysis

(a) 0.201 g. of the acid required 6.3 c.c. of

0.1133 N alkali.

Found : eq. wt. 281.6

(b) 0.215 g. of the substance gave 0.2235 g. AgCl


Calculated for c13

H9

02Ncl2 Cl, 25.19 per cent.

The acid is sparingly soluble in hot alcohol, but

insoluble in hot water, benzene, chloroform and petroleum

ether.

Derivatives :

(i) Acid chloride. -- The acid ( 1 g. ), dry benzene

- 85-

( 30 c.c. ) and thionyl chloride ( 1 c.c. ) were refluxed

for.about fifteen minutes on water bath. The mixture was

then left at room temperature : the yellow crystals of

the acid chloride began to separate on evaporation of 0 benzene as small yellow plates, M.P. 158 c. Yield :

almost quantitative.

Analysis :

0.168 g. or the substance gave 0.2421 g. AgC1


c13HgONC13 requires : Cl, 35.44 per cent.

{ii) Ethyl ester. The acid chloride ( 0.5 g. )

and absolute alcohol { 5 c.c. ) were refluxed for about

ten minutes on water bath as before. The ester separated 0 on standing in clusters of prismatic needles, M.P. 96 c.

Anal~sis :




(iii) Methyl ester. This ester was prepared as

before using methyl alcohol and crystallised from alcohol, 0

tiny colourless needles, M.P. 104 c.

- 86 -

Analysis :

0.207 g. of the substance gave 0.2049 g. of AgCl


c14Hl1o2Ncl2 requires : Cl, 23.99 per cent.

2 1 :5 1-DICHLOR0-4-METHOXY DIPHENYL M~INE-2-CARBOXYLIC ACID - - - --( I : R(4) = OCH3 ; X(2) and Y(5) = Cl )

2:5-dichloro aniline ( 5 g. ), 6-bromo-3-methoxy

benz9ic acid ( 7 g. ), anhydrous potassium carbonate

( 4 g. ), isoamyl alcohol ( 30 c.c. ) and copper powder

( 0.3 g. ) were refluxed on oil bath at 140° C for nearly

four hours. The acid was isolated by working up the

reaction mixture as described previously. The acid

obtained crystallised from acetic acid, small gre~n

needles, M.P. 216° c. Yield : 2 g.

!nalYsis :

(a) 0.2605 g. of the acid required 7.2 c.c. of

0.1159N alkali

Found eq. wt. 312.2

(b) 0.214 g. of the substance gave 0.1974 g. of AgCl

- 87 -

Found : cl, 22.83 per cent.


Derivatives :

(i) Aci£ chloride. -- The acid chloride was prepared

as before. It crystallised from benzene as green plates, 0 M.P. 104.105 c. Yield : nearly quantitative.

AnalYsis :

0.2468 g. or the substance gave 0.3243 g. of AgCl



(ii) Ethyl ester. The above acid chloride was

refluxed with absolute alcohol as before. The ethyl ester 0 separated on standing as needles, M.P. 96-97 c.

Analysis :



C16H15o3NCl2 requires : Cl, 20.88 per cent.

(iii) Methyl ester. -- It was prepared as before.

It crystallised from alcohol as greenish needles, 0 M.P. 115 C.

- 88 -

Analysis :




2':5 1-DICHLORO DIPHENYL AMINE-2-CARBOXYLIC ACID - - -( I : R(4) = H ; X(2) and Y(5) = Cl ) • •

A mixture of 2:5-dichloro aniline ( 5 g. ), o-chloro

benzoic acid ( 14 g. ), dry potassium carbonate ( 4 g. ),

amyl alcohol ( 30 c.c. ) and copper powder ( 0.3 g. ) was

refluxed on oil bath at 140° C for five hours. Following

the usual procedure as described previously, the acid was

isolated. It crystallised from acetic acid, small white 0 needles, M.P. 235 c. Yield : 3 g. Gomberg and D. L.

Tavern record the same melting point 235° C ( J.A.C.s.,

1926, ~' 1356 ).

Analys~.s

0.2029 g. of acid required 6.2 c.c. of 0.1159N alkali.

Found eq. wt. : 282.3

c13Hg02Ncl2 requires eq. wt. : 282.

The acid is sparingly soluble in hot water, benzene

l

- 89 -

and petroleum ether.

Derivatives :

A (i) Acid chloride. -- 2 1 :5 1-dichloro diphenyl

amine-2-carboxylic acid prepared as described before

crystallised from benzene, thin plates, M.P. 150° c.

Analysis :

0.1953 g. or the substance gave 0.2871 g. AgC1


c13HgONC13 requires : Cl, 35.45 per cent.

(ii) Ethyl ester. -- The ethyl ester prepared from

the acid chloride as before crystallised from alcohol,

long needles, M.P. 90° c.

Analysis :



C15H1302Nc12 requires C1, 22.91 per cent.

(iii) Methyl ester. The methyl ester prepared as 0

before crystallised from alcohol, small needles, M.P. 120 •

Analysis :

0.1648 g. or the substance gave 0.1620 g. Agel.

l

- 90 -


c14H11o2Ncl2 requires Cl, 23.99 per cent.

3 1 :5 1-DICBLOR0-4 1 -METHOXY-DIPHENYL AMINE-2-CARBOXYLIC ACID - - - -{ II : R{4) = H; X{3) and Y{5) ~ Cl; R1(4 1 ) = OCH3 )

Z{5)

R

z /

NH

(II)

y

A mixture of 3:5-dichloro-4-methoxy aniline { 4 g. ),

o-chloro benzoic acid ( 3 g. ), anhydrous potassium

carbonate ( 3 g. ), amyl alcohol ( 30 c.c. ) and copper

powder { 0.2 g. ) was refluxed at 155° C for five hours.

The crude acid was isolated as before. On crystallisation

from suitable solvent, the substance obtained did not give

a sharp melting point. It gave a range of temperature,

indiacting that it was a mixture. To separate it,

various attempts were made and it was found that boiling

water removed one of the constituents, leaving an

insoluble residue (R). The filtrate on working up gave

a small quantity of unchanged o-chloro benzoic acid,

•

- 91 -

identified by mixed melting point. The residue (R) was

crystallised from acetic acid, small white needles, 0

M.P. 213 C. Yield : 1.5 g.

Analysis :

(a) 0.1241 g. of acid required 4.6 c.c. of

0.0864N alkali

Found eq. wt. : 312•3

c14H11N~3c12 requires eq. wt. : 312.

(b) 0.198 g. of the substance gave 0.160 g. of Ag61



In this reaction it has been found that whatever may

be the experimental conditions, some unchanged o-chloro

benzoic acid is recovered. The experimental details

given above gave the minimum quantity of the unchanged

chloro benzoic acid with the best yield of the diph~nyl

amine-2-carboxylic acid.

Derivatives :

(i) Acid chloride. -- The above acid was converted

into its acid chloride as before. The acid chloride

separated on long standing as yellowish green plates,

- 92 -

M.P. 195° C.

Analysis :


• Found Cl, 32.99 per cent.

c14H10o2Nc13 requires : Cl, 32.23 per cent.

(i{) Ethyl ester. -- The acid·chloride obtained

above was converted into its ethyl ester, small needles, 0 M.P. 188 C.

Analysis :



c16H15o3Nc12 requires Cl, 20.88 per cent.

{iii) Methyl ester. This ester similarly prepared

crystallised very slowly from alcohol, fine needles, 0

M.P. 184 C.

!nalysis

0.216 g. of the substance gave 0.1904 g. AgC1

Found : C1, 21.81 per cent.

c15H13o3Ncl2 requires : c1, 21.78 per cent.

l

- 93 -

~ 1 :.§ 1 :.§- TRICHLOR0-1: 1-METHOXY DIPHENYL .AMINE-g-CARBOXYLIC ACID

( II : R(4) = H; X(3 1 ), Y(5 1 ), Z(5) = Cl ) . .

3:5-dichloro-4-methoxy aniline ( 4 g. ) , 2:4-dichloro

benzoic acid ( 4 g. ), dry potassium carbonate (4 g.),

amyl alcohol ( 30 c.c. ) and copper powder ( 0.2 g. )

were refluxed at 150° C for six hours. The acid was

isolated as before. It crystallised from dilute acetic

acid, small pale yellow needles, M.P. 217° c. Yield : 1 g.

In this reaction also, some 2:4-dichloro benzoic

acid was always recovered unchanged. During

crystallisation it remained in the mother liquor, as it

is highly soluble in acetic acid.

!nalysis :

(a) 0.1375 g. of acid required 4.6 c,c. of

0.0864U alkali

Found eq. wt.

c14

H10c13No3 requires eq. wt.

346.2

346.5

(b) 0.201 g. of the substance gave 0.245 g. AgCl


c14H1ocl3No3 requires Cl, 30.73 per cent.

- 94-

Derivatives :

(i) .Acid chloride. -- The acid was converted into

its acid chloride by the method described before. It

crystallised from benzene, green needles, M.P. 125° C

( decomp. ) •

Analysis :

0.123 g. of the substance gave O.l9p g. AgCl.


c14Hg02Ncl4 requires : Cl, 38.90 per cent.

(ii) Ethyl ester. -- The acid chloride was heated

under reflux with absolute alcohol for ten minutes. The

ester separated on keeping as small clusters of needles, 0 M.P. 108 C.

Analysis : .-




Date post:	08-Sep-2018
Category:	Documents
Upload:	dinhhanh
View:	220 times
Download:	0 times

PART L EXPERIMENTAL -...

Documents