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chloride on anthranil :

/CO /CO

+ COC1.C 6 H 5 = C 6 H 4 < | + HC1.

\N.CO.C 6 H 5

It crystallizes from a mixture of benzene and Hgroi'n in long
needles, which melt at 122 123, and dissolve when heated
with dilute alkalis, benzortho-amidobenzoic acid being formed. 1

Dicyanamidobenzoyl, C 9 H 5 N 3 O, is the name given by Griess to
a compound which he obtained by passing cyanogen into a cold
aqueous solution of anthranilic acid :

/NH 2 /NH^-C-CN

C 6 H 4 < +C 2 N 2 rr:C 6 H 4 < || +H 2 O.

: \CO.OH >CO - N

It is slightly soluble in water, readily in hot alcohol, and
crystallizes in small, yellowish prisms ; although it does not
contain a carboxyl group, it has an acid reaction and is a
monobasic acid. 2

Carloxamidocyanamido'benzoyl, C 9 H 7 N 3 2 , is formed when the
preceding compound is heated with strong ammonia in a sealed
tube:

X NH-C-CN /NH-C-CO.NH,.



\CO-N XX) -N

It crystallizes from hot water in fine needles and from alcohol in
plates, has an acid reaction and forms salts with bases, the hydrogen
of the imido-group being probably replaced by the metal.

Carboxylcyanamidolenzoyl, 2C 9 H 6 N 2 O 3 +H 2 O, is obtained by
heating dicyanamidobenzoyl with baryta water:

NH - C - CN /NH - C - CO.OH

CTT / ii i OTT r\ n TT / II _j_ "\TTT

C HX 4- 2H 2 O = C 6 H 4 < + JNH 3 .

\CO - N X CO - N

1 Friedlander and "Wleitgel, Ber. Dcutsch. Chcm. Gat. xvi. 2227.
- Ibid. xi. 1986 and 2180.
VOL. III. PAftT IV. R



242 AROMATIC COMPOUNDS.

It crystallizes in small, white plates, which are slightly soluble
in cold water and alcohol; it is a dibasic acid. When it is boiled
with water or acids, or simply heated, carbon dioxide is evolved
and carbimidamiddbenzoyl, C 8 H 6 N 2 O 2 , formed. This compound
crystallizes from hot water in needles melting at 214. It
possesses basic properties and has the following constitution :

/NH CH

C 6 H 4 < ||

\CO-N.

Griess has also prepared various other derivatives of dicyan-
amidobenzoyl. 1

Ethoxycyanamidobcnzoyl, C 10 H 10 N 2 2 , is formed when an
alcoholic solution of anthranilic acid is saturated with cyanogen,
allowed to stand for some time and then evaporated :



/NH C OC 2 H 5
C 6 H 4 < [| +H 2 + HCN.

XX) N

It crystallizes from hot alcohol in needles, melts at 173, and
can be distilled in small quantities without undergoing
decomposition. 2

2138 Uramidobenzoyl, C 8 H 6 N 2 2 , is prepared by fusing
anthranilic acid with urea or by boiling the preceding com-
pound with hydrochloric acid :



/
C 6 H 4 || + H 9 0=C 6 H 4 < | + HO.C 2 H 5 .



,NH C OC 2 H 5 ,NH CO

^CO N ' 4X \CO NH

It is slightly soluble in water and alcohol, crystallizes in lustrous
plates melting above 350, dissolves in caustic potash solution
and is reprecipitated by carbon dioxide. Fuming nitric acid
converts it into nitro-uramidobenzoyl, C 8 H 5 (N0 2 )N 2 O 2 , which
crystallizes in honey-yellow prisms, and is converted by reduction
into the slightly soluble amido-uramiddbenzoyl, C 8 H 5 (NH2)N 2 2 ,

1 Bar. Deutsch. Chetn. Ges, xviii. 2417.
- Griess, ibid. ii. 415.



BENZOYLGUANIDINE. 243



which forms yellow needles and yields salts, which are also only
slightly soluble and crystallize well (Griess).

Ortho-uramidoljenzoic acid, C 8 H 8 N 2 3 . This compound, which
is the acid corresponding to the anhydride just described, is
formed by the action of potassium cyanate on ortho-amidobenzoic
acid hydrochloride : l

/NH, /NH.CO.NH.,

CH/ ' +CONH=C 6 H 4 <;

X C0 2 H X C0 2 H.

It crystallizes in needles, and on treatment with nitric acid
only yields one dinitro-compound, which will be subsequently
mentioned.

Ortfiobenzoglycocyamidine, or Benzoylguanidine, C 8 H 7 N 3 O, is
obtained by heating ethoxycyanamidobenzoyl with alcoholic
ammonia :



NH-C OC 2 H 5

||
CO-N



NH GrrNH

CO



' C 6 H 4 < | + HO.C 2 H 5 .

'-NH



It may also be obtained by allowing a solution containing
cyanamide and anthranilic acid to stand : 2

C 6 H 4 .NH 2 C 6 H, NH

| +CN.NH 8 = | >C = NH + H,0.

CO.OH CO - NH

It crystallizes in nacreous plates, which are only slightly soluble
in water and alcohol.

Henzoylguanidine nitrate, C 8 H 8 N 3 O.NO 3 , is a very characteristic
salt ; it crystallizes in small plates, which are almost insoluble in
water and alcohol.

2139 a-Methylorthobenzoglycocyamidine, or a-Orthobenzocreatin-
ine, C 8 H 6 (CH 3 )N 3 O, is formed when a strongly alkaline solution
of the preceding compound is treated with methyl iodide and
allowed to stand for some days. It is almost insoluble in cold,
slightly soluble in hot water, more readily in boiling alcohol, and

1 Griess, Journ. Prakt. Chcm. [2] v. 371.

2 Griess, Ber. Deutsch. Chcm. Ges. xiii. 977.

R 2



244 AROMATIC COMPOUNDS.

crystallizes in lustrous needles, which have a slightly bitter taste
and a neutral reaction. The hydrochloride, C 9 H 9 N 3 O.C1H,
crystallizes in narrow plates, which readily dissolve in water
without decomposition.

ft-Orthdbenzocreatinine is obtained by heating ethoxycyan-
amidobenzoyl with aqueous methylaraine. It resembles the
a-compound in forming lustrous needles, which have a very
faintly bitter taste, but differs from it in being soluble in baryta
water and caustic potash solution, and in forming salts which
are decomposed by water.

The constitution of these compounds is shown by the following
formulae :

/3
C 6 H 4 N.CH 3 C 6 H 4 NH

>C=NH >CmNH.

CO - NH CO - - NCH 3

Oxal anthranilic acid, or Orthobenzamoxalic acid, C 9 H 7 NO 5 -|-H 2 0.
Friedlander and Ostermaier first obtained this compound by the
oxidation of carbostyril, C 9 H 7 NO, with potassium permanganate,
and named it carbostyrilic acid. They then found that on
heating with dilute hydrochloric acid or caustic soda solution it
decomposes into anthranilic acid and oxalic acid. 1 Kretschy
recognized it by this property as identical with the cynuric acid
which is formed by the oxidation of cynurenic acid, C 9 H 6 NO
(CO 2 H), a substance occurring in the urine of the dog. He
also prepared it by gradually heating oxalic acid to 150 with
anthranilic acid : 2

/NH 2 /NH.CO.OH

C 6 H 4 < + HO.CO.CO.OH=C 6 H,< +H 2 O.

X CO.OH \CO.OH

It has also been obtained by the oxidation of other substances,
which, like those just mentioned, are derivatives of quinoline, a
compound which has the following constitution :

HO N

s\s\

HC C CH



CH CH

1 Griess, Ber. Deutsch. Chem. Ges. xv. 332. 2 Monatsheft Chem. v. 16.



DlNITttODIPHENYLAMINE-ORTHOCAKBOXYLIC ACID. 245

Oxalanthranilic acid is slightly soluble in cold water, readily
in alcohol and ether, and crystallizes from the latter in hard
needles united to form druses. It is a powerful dibasic acid.

Normal calcium lenzamoxalale, 2l' 9 H 5 NO 5 Ca + 5H 2 O, is the
most characteristic salt of this acid. It separates .out in
glittering prisms when calcium chloride is added to a solution of
the ammonium salt.

2140 Dinitrodiphenylamine-orthocarboxylic acid, C H 4 (NH.
C 6 H 3 (NO 2 ) 9 )COH, is formed when anthranilic acid is heated
with chlorodinitrobenzene, (01 :NO 2 : N0 2 =l : 2 :4), and an
excess of ammonia :

/NH 2

C,H/ + C 6 H 3 C1(N0 2 ) 2 + 2NH 3 =

\CO.OH

NH-C 6 H 3 (N0 2 ) 2

C 6 H 4 < +NH 4 C1.

\CO.ONH 4

The ammonium salt produced in this way forms lustrous, ruby-
red plates ; the free acid is obtained by the addition of strong
hydrochloric acid to this salt, and is almost insoluble in water,
only very slightly soluble in cold alcohol and glacial acetic acid,
crystallizing from a hot mixture of these in small, orange -yellow,
matted needles, which fuse at 262 264 to a brownish red
liquid, which appears almost black when seen in thick layers ;
when it is carefully heated a portion distils without decomposi-
tion, but it detonates when rapidly heated on platinum foil.

Its alkaline salts are slightly soluble in cold, more readily in
hot water, and crystallize in reddish yellow to ruby-red plates,
which detonate on heating. All the other salts are almost
insoluble. The barium salt is a dark cinnabar-red precipitate.

This compound does not yield the corresponding amido-acid
on reduction with tin and hydrochloric acid, but this is converted
into diamidohydro-acridine ketone with elimination of water ; this
substance, which will be subsequently described, has the follow-
ing constitution :

CH NH CNH,



HC CO CH

I! I
C CNH



I II
HC C



H CO CH



246 AROMATIC COMPOUNDS.

Other amido-acids, in which the carboxyl does not stand
in the ortho-position to the amido-group, also yield dinitro-
diphenylaminecarboxylic acids with chlorodinitrobenzene, but
these are converted by reduction into the corresponding diamido-
acids.

This reaction, therefore, may be employed as a ready method
for ascertaining whether or not an aromatic amido-acid belongs
to the ortho-series. The compound to be tested is heated to
boiling with chlorodinitrobenzene, alcohol and some ammonia
for some time. If an ortho-compound be present, the product
yields on reduction a base insoluble in alkalis ; in other cases
an acid is obtained. 1

2141 Mdamidobenzoic acid. Zinin obtained this compound in
1845 by the action of ammonium sulphide on nitrobenzinic acid
(metanitrobenzoic acid) and named it benzamic acid. 2 Chancel,
in 1849, converted nitrobenzamide into amidobenzamide by the
same method, but he looked upon the substance obtained as
aniline urea and named it carbanilamide. By boiling it with
caustic potash solution he obtained carbanilidic acid, which
Gerland subsequently proved to be identical with benzamic acid. 3
Voit, who investigated its salts, remarked that the latter name
is unsuitable, since only the radicals of dibasic acids form amic-
acids, and he therefore proposed the name amidobenzoic acid. 4

In order to prepare it, a solution of metanitrobenzoic acid in
strong ammonia is saturated with sulphuretted hydrogen in
absence of air, concentrated and treated with acetic acid. Meta-
nitrobenzoic acid may also be reduced with tin and hydrochloric
acid and the double tin salt of the amido-acid decomposed with
sulphuretted hydrogen. The amidobenzoic acid is then pre-
cipitated from the nitrate, previously neutralized with ammonia,
by acetic acid.

It is slightly soluble in cold, more readily in hot water and
alcohol, and crystallizes in warty masses of needles, which melt
at 174 and partially volatilize at a higher temperature without
decomposition ; when it is heated with spongy platinum (Chancel)
or baryta, it decomposes into carbon dioxide and aniline. Its solu-
tion has an acid reaction but a sweet taste, and decomposes in
the air with separation of a brown powder, its alkaline solution

1 Jourdan, Her. Deutsch. Chem. Ges. xviii. 1444.
- Journ. Prakt. Chem. xxxvi. 93.

3 Ann. Chem. Pharm. Ixxxvi. 142.

4 Ibid. xcix. 100.



METAMIDOBENZOIC ACID. 247

behaving in a similar manner. Its metallic salts crystallize
well.

Metamidobenzoic acid hydrochloride, C 7 H 7 N0 .C1H, crystallizes
in prisms, which are readily soluble in water, slightly in hydro-
chloric acid; the platinichloride forms golden-yellow needles,
and the double tin salt, C 7 H 7 NO 2 .ClH + SnCl. 2 , crystallizes in
plates (Beilstein and Wilbrand). Its other compounds with
acids also crystallize well.

Metamidolenzamide, C 6 H 4 (NH 2 )CO.NH 2 , is obtained, accord-
ing to Chancel, when ammonium sulphide is added to a boiling
aqueous solution of metanitrobenzamide. It is readily soluble
in water, and forms large, yellow crystals, melting at 75 . 1 Like
amidobenzoic acid it is a monacid base.

Metamiddbenzonitril, C 6 H 4 (NH 2 )CN, is formed when meta-
nitrobenzonitril is reduced with zinc and hydrochloric acid 2 or
tin and acetic acid, 3 as well as by heating meta-uramidobenzoic
acid with phosphoric acid : 4

/CO O x /CN

C,H 4 < >NH 3 = C 6 fl 4 < + C0 2 + H 2 0.

\NRCCK \NH 2

It crystallizes from dilute alcohol in long, white needles, melts
at 53 54, boils at 288 290, and is decomposed by powerful
reducing agents into ammonia and benzonitril, the latter being
partially converted into benzylamine. When it is treated with
alcoholic potash and chloroform, the carbamine, C H 4 (NC)CN,
is formed ; it has an overpowering odour and has not been
further investigated. Metamidobenzonitril is a monacid base
and forms salts which crystallize well.

Methyl metamidobenzoic acid, or Metdbenzosar cosine, C 6 H 4 (NH.
CH 3 )C0 2 H, was obtained by Griess as a decomposition product
of a-benzocreatine ; it is slightly soluble in cold, more readily in
hot water, and crystallizes in small plates.

Dimethylmetamidobenzoic acid, C 6 H 4 .N(CH 3 ) 2 CO 2 H. The
methyl ether of this acid is formed by a molecular change from
the following compound, and is a liquid which has a faint
aromatic odour, and boils at 270. The acid is obtained from it
by decomposition with alcoholic potash, and is also only slightly

1 Beilsteiu and Reichenbach, Ann. Chem. Phartn. cxxxii. 142.

2 Hofinann, Ber. Deutsclt. Chcm. Ges. i. 196.

3 Frickc, ibid. vii. 1321.

4 Griess, ibid. viii. 861.



248 AROMATIC COMPOUNDS.

soluble in hot water ; it crystallizes in dull needles, melting at
151.

Trimethylamidobenzoic acid, or Metabenzobetaine, C 7 H 4 N(CH 3 ) 3
O 2 + H 2 O. The iodide of this compound is formed when a solu-
tion of amidobenzoic acid in methyl alcohol is allowed to stand in
contact with an excess of caustic potash and methyl iodide ; it
forms short prisms of the formula C 7 H 5 O 2 N(CH 3 ) 3 I + H 2 O. The
free base, which is obtained by the action of lead hydroxide,
crystallizes in deliquescent needles, which lose one molecule of
water at 105, and have a neutral reaction and bitter taste.

The anhydrous compound is converted on fusion into the
methyl ether of the preceding compound. 1



C0 (CH 3 ) 3 = CO

^ / \OCH 3

X N(C 2 H 3 0)H
Acetmetamidobenzoic acid, C fi H 4 <^ , is rnetameric

\C0 2 H

with hippuric acid and is formed when metamidobenzoic acid is
heated to 160 with glacial acetic acid. It crystallizes in fine,
white needles, is almost insoluble in cold water, has a bitter
taste, at the same time resembling that of saltpetre, and melts at
245 ; it sublimes, however, at a lower temperature. 2

2142 Amidobenzoic acid percyanide, (C 6 H 4 (NH 2 )C0 2 H) 2 C 2 N 2 ,
is the name given by Griess to a compound to which he had
previously assigned the formula C 6 H 4 (NH 2 )CO 2 HC 2 N 2 , and
which is obtained by passing cyanogen into an aqueous solution
of metamidobenzoic acid. It is a yellow, crystalline substance,
which is insoluble in water, scarcely soluble in alcohol and ether,
and has acid properties. On distillation it decomposes into
water, carbon dioxide, ammonia, ammonium cyanide and met-
amidobenzonitril. When heated to 130 with alcohol, it decom-
poses into metamidobenzoic acid and metabenzamoxalic acid.

C e H 4 .NH.C(NH)C(NH)NH.C 6 H 4
I + 3H 2 =

C0. 7 H C0 H

C 6 H 4 .NH 2 " C 6 H 4 .NH.CO.CO.OH

I + I +2NH 8 .

C0 2 H C0 2 H

1 Griess, Ber. Dcutsch. Chem. Ges. vi. 586.

2 Forster, Ann. Chan. Pharm. cxvii. 165; Kaiser, Bcr. Dcutsch. Chem. Ges.
xviii. 2946.



CYANOCARBOXAMIDOBENZOIC ACID. 249

Metabenzamoxalic acid, or Oxalamidobenzoic acid, is also formed
by heating metamidobenzoic acid with oxalic acid, and crystal-
lizes from hot water in narrow white plates. 1

Cyanocarlimidobcnzoic acid, 3C 9 H 7 N 3 O 2 + H 2 O, is formed
together with the percyanide according to the equation :

NH 2 ON /NH - CmNH

C C H 4 < + | = C 6 H 4 <( |

\CO,H CN \CO 2 H CN

It is only very slightly soluble in cold water, readily in hot
alcohol, and crystallizes in elliptical plates, which have an acid
reaction and combine with bases and acids.

Cyanocarloxamiddbenzoic acid, C 9 H 6 N0 3 , is obtained by the
action of nitrous acid on a cold solution of the preceding com-
pound in hydrochloric acid :



C' 6 H 4 < | + HN0 2 =

\C0 H CN

NH - CO

CH/ | + N 2 + H 2 0.

\C0 2 H CN

It crystallizes in lustrous, white plates, which have a sweet
taste, and are almost insoluble in cold water, but are decomposed
by boiling water with formation of carbon dioxide, hydrocyanic
acid and carboxamidobenzoic acid. When it is dissolved in
ammonia, uramidobenzoic acid is formed :

/NH - CO /NH - CO

C 6 H/ | + NH 3 =C 6 H 4 < I +HCK

CN \COH NH



Methylamine, ethylamine, &c., act in a similar manner, and a
large number of substituted uramidobenzoic acids can, therefore,
be prepared in this way. 2

If cyanogen be passed into an alcoholic solution of metamido-
benzoic acid, the percyanide, which has been already mentioned,

1 Griess, Ber. Deutsch. Chcm. Gcs, i. 191 ; xi. 1985 ; xvi. 336 ; xviii. 2412 ;
Schilf, ibid. xix. 252.
- Griess, ibid, xviii. 2415.



250 AROMATIC COMPOUNDS.

is deposited, and the two following compounds crystallize out
on allowing the mother liquor to stand :

Carbimidamidobenzoic acid.

/C0 2 H
C 6 H 4 <

/NH 2 X NH\

2C 6 H 4 < + C,N 2 = >CNH + HCN,

\C0 2 H /Nti/

C fi H 4 <

\C0 2 H

Ethoxycarbimidamidobenzoic acid.

,XH 2
C 6 H/ + C 2 N 2 -fHO.C. 2 H 5 =



NH - C=N

< |

\C0 2 H OC. 2 H 5



+HCN.



Carlimidamidobenzoic acid, or Guanidodibenzoic acid, C 15 H 13
N 3 O 4 , is obtained from the crude product by extraction with
boiling water ; it separates out on cooling in needles, which
are purified by being dissolved in hydrochloric acid, the solution
neutralized with ammonia and then precipitated by acetic acid.
The precipitate is at first amorphous, but soon changes into
needles. It forms salts with both acids and bases. 1

Mhoxycarbimidamidobenzoic acid, 2C 10 H 12 N 2 3 + 3H 2 O, is
slightly soluble in water, more readily in alcohol, and crystallizes
in needles. 2

Meta-uramiddbenzoii acid, C 8 H 8 N 2 O 3 + H 2 O, is formed when
the preceding compound is boiled with hydrochloric acid :

!=NH /NH CO

+ H 2 0-C 6 H 4 < I +HO.C. 2 H 5 .

>CH 3 \CO 2 H NH 2

Menschutkin obtained it from potassium cyanate and met-
amidobenzoic acid hydrochloride, and named it oxybcnzuramic
acid. 3 Griess then showed that it is also formed by bringing
metamidobenzoic acid into fused urea. 4 It is slightly soluble
in water, more readily in alcohol, and crystallizes in needles or

1 Griess, Zeitschr. Chem. 1867, 534.

2 Jo-urn. Prakt. Chem. [2] iv. 296.

3 Ann. Chem. Phnrm. cliii. 84.

4 Ber. Dcutsch, Chem. Ges. ii. 47.




METABENZOGLYCOCYAMINE. 251

fine prisms. Its salts have been investigated by Menschutkin.
On treatment with concentrated nitric acid it yields three di-
nitro-compounds (p. 255).

Mcta-urcthanebenzoic acid, C 10 H U NO 4> is formed by the action
of nitrous acid on ethoxycarbimidamidobenzoic acid l and by
treating metamidobenzoic acid with ethyl chlorocarbonate :

/NH 2 COC1 /NH CO

C 6 H 4 < + . C 6 H 4 < [ +HC1.

XX) 2 H OC 2 H 5 \C0 2 H OC 2 H 5

It crystallizes in plates, which are slightly soluble in water,
dissolve in alcohol in every proportion, and melt at 189.

Carlioxamidobenzoic acid, or Metacarlamidobenzoic acid, C 15 H ]2
N 2 5 , is obtained by heating uramidobenzoic acid to 200, or by
repeatedly evaporating the solution of its barium salt : 2

/NH /NH.C 6 H 4 .C0 2 H

2CO< ' = CO< + CO(NH 2 ) 2 .

\NH.C 6 H 4 .C0 2 H \NH.C 6 H 4 .C0 2 H

It is also formed when meta-urethanebenzoic acid is heated
above its melting-point, 3 and crystallizes in microscopic needles,
which are insoluble in water, alcohol and ether.

2143 Metabenzoglycocyamine, or Metaguanidobenzoic acid, C 8 H 9
N 3 O 2 + H 2 O, was first obtained by Griess by boiling amido-
benzoic acid percyanide with caustic potash solution ; it is also
formed by the action of ammonia on ethoxycarbimidamido-
benzoic acid, as well as, similarly to glycocyamine (Part II. p.
112), by allowing an alcoholic and ammoniacal solution of
Oyanamide and metamidobenzoic acid to stand : *

C 6 H 4 .NH 2 C = N" -C 6 H 4 .NH C=NH

I +1=1 I

C0 2 H NH 2 C0 2 H NH 2

It is slightly soluble in alcohol, and crystallizes from hot water
in thin, four-sided tablets which dissolve in caustic potash, but
are reprecipitated by carbon dioxide. It forms salts with the

1 Griess, Ber. Dcutxch. Chcm. Ges. ix. 796.

Griess, ZcitscJir. Chem. 1868, 650; Ann, Chcm. Pharm. clxxii. 170.

Wachendorff, Ber. Deutsch. Chcm. Gcs. xi. 701.
4 Griess, ibid. vii. 575 ; viii. 323.



252 AROMATIC COMPOUNDS.

mineral acids, but does not combine with acetic acid. On boil-
ing with baryta water, uramidobenzoic acid is first formed :

/NH.C(NH)NH 2 /NH.CO.NH,

+NH,



On continued boiling, metamidobenzoic acid and urea or de-
composition products of these are produced.

a-Metabenzocreatine, 2C 8 H 8 (CH 3 )N 3 O 2 + 3H 2 O, is formed by
the action of methyl iodide and caustic potash on a solution of
the preceding compound. It is slightly soluble in water and
alcohol, crystallizes in pointed plates, and decomposes into urea
and benzosarcosine when boiled with baryta water.

/3-Metabenzocreatme is prepared from ethoxycarbimidamido-
benzoic acid and methylamine, and crystallizes from hot water
in small plates. On heating with baryta water it yields meta-
amidobenzoic acid, methylamine, and carbon dioxide (Griess).

The metabenzocreatines, like benzoglycocyamine, exist in the
free state as salts, and have the following constitution :



C 6 H 4 .N (OH,,) fcNH C 6 H 4 .NH.C=NH
CO - O - NH 3 CO O N(CH 3 )H 2 '

If these compounds be compared with those of the ortho-series,
it is found that the latter contain a molecule of water less or are
anhydro-compounds, this class of bodies being very readily
formed by and characteristic of the ortho-series.

Phenylmetabenzoglycocyamine, C 8 H 8 (C 6 H 5 )N 3 O 2 + H 2 O,is formed
when cyanocarbimidamidobenzoic acid is heated with aniline :



C ' H



NH - C=NH

coH AN



/NH - CmNH
C C H/ 1 +HCN.

\C0 2 H. NH.C 6 H 5

It is insoluble in alcohol, but slightly soluble in hot water,
readily in hydrochloric acid and caustic potash, and crystallizes
in needles or plates, which have a bitter taste followed by a
sweet after-taste.



PARAMIDOBENZOIC ACID. 253

Amidoplienylmetabenzoglycocyamine, C 8 H 8 (C 6 H 4 .NH 2 )N 3 O;,, is
prepared in a similar manner from paradiamidobenzenc ; it
crystallizes in small prisms, and is a diacid base. 1

2144 Paramidobenzoic acid is obtained by the reduction of
paranitrobenzoic acid with ammonium sulphide, 2 or better with
tin and hydrochloric acid. 3 It is tolerably soluble in water, very
readily in alcohol, and crystallizes in long needles forming
fascicular aggregates ; it melts at 186 187, and decomposes
at a higher temperature into carbon dioxide and aniline, a
decomposition which may also be effected by heating it to 160
180 with hydrochloric acid.

It is characteristic of paramidobenzoic acid that lead acetate
gives with its aqueous solution a crystalline precipitate of the
double salt, C 7 H 4 (NH 2 )0 2 PbC 2 H 3 O 2 . 4

Paramidobenzoic acid hydrochloride, C 7 H 7 NO 2 .HC1, crystallizes
in small plates or prisms.

Paramidobenzamidc, C 6 H 4 (NH 2 )CO.NH 2 , is formed by the
reduction of paranitrobenzamide with ammonium sulphide, and
forms large, light yellow crystals, which melt at 178 179, and
are much less soluble in water than those of the meta-compound. 5

Paramidobenzonitril, C 6 H 4 (NH 2 )CN, may be prepared from
paranitrobenzonitril, 6 and by the distillation of para-uramido-
benzoic acid with phosphorus pentoxide. 7 It is readily soluble
in alcohol and boiling water, and crystallizes in needles, melting
at 100 (Fricke). It forms crystalline salts with acids.

Dimethylparamidobenzoic acid, C 6 H 4 N(CH 3 ) 2 CO a H, is obtained
by heating the amido-acid with caustic potash, methyl iodide
and wood spirit. It crystallizes in short, broad needles, melt-
ing at 235, and combines with acids and bases, but is insoluble
in acetic acid. 8

Acetparamidobenzoic acid, C 6 H 4 (NH.C 2 H 3 O)CO 2 H. Hofmann
obtained this compound by the oxidation of acetparatoluide
with potassium permanganate. It is slightly soluble in water,
readily in alcohol, and crystallizes in needles, which melt with
decomposition at 250 . 9 On boiling with hydrochloric acid it is
converted into paramidobenzoic acid. 10

1 Griess, Ber. Dtutech. Chcm. Ges. xvi. 336.
- Fischer, Ann. Chem. Pharm. cxxvii. 142.

Beilstein and Wilhrand, ibid, cxxviii. 264.

Ladenburg, Bcr. Dcutsch. Chcm. Ges. vi. 130.

Beilstein and Reichenbach, Ann. Chem. Pharm. cxxxii. 144.

Engler, ibid, cxlix. 302 ; Fricke, Bcr. Dcutsch. Chem. Ges. vii. 1322.

Griess, ibid. viii. 861. 8 Michler, ibid. ix. 401.

Ibid, ix 401. 10 Kaiser, ibid, xviii. 2942.



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