ZOO TlTHERLEY : 8-PHENYL-1 : 3-BEKZOXAZINE-4-ONE.

XXII. -2 -Phen yl- 1 : 3 -benzoxaxine-4-one, BY ARTHUR WALSH TITHERLEY.

IN his criticism of the metoxazone theory of labile isomerism in the acylsalicylamide group, Auwers (Bey. , 1907, 40, 3506) attributed the change of N-benzoylsalicylamide (I) to 0-benzoylsalicylamide (111) (by boiling with acetic acid) to the intermediate formation of the unsatur- ated ring (11) by loss of water, which then immediately decomposed this hypothetical ring, yielding the 0-benzoyl derivative, thus :

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online / Journal Homepage / Table of Contents for this issue

TlTHERLEY : 2-PHENYL-1 : 3-BENZOXAZINE-4-ONE. 201

This view was shown to be untenable by Titherley and Hicks (Trans., 1909, 95, 908), but it appeared desirable to effect if possible the synthesis of this ring-compound in order that a study of its properties might be made in relation to the derivatives in the acyl- salicylamide group. Several attempts were made to prepare it from

phenylbenzometoxazone," C 6 H 4 < ~ ~ ~ ~ & , h , by eliminating two hydro-

gen atoms, and from 0- and N-benzoylsalicylamides by the action of dehydrating agents, like phosphoric oxide and zinc chloride, but without success.

Eventually the compound was synthesised from phenyl salicylate and phenylbenzamidine by loss of phenol and aniline, thus :

c6H4<O--C 'O*p Ph + PhOH + PhNH,,

and i t was later found that the same ring-compound could be obtained when special precautions were observed, by the action of hydrogen chloride on either N- or 0-benzoylsalicylamide at temperatures between l l O o and 140O. These independent syntheses, which are discussed later, and the properties of the compound place its consti- tution beyond doubt, and i t is, therefore, 2-phenyl-1 : 3-benzoxazine- 4-one.

The compound has the same melting point, 1 0 6 O , as that of its isomeride, benzoylsalicylnitrile, CN*C6H4* OBz, from which, however, it differs greatly. It is markedly additive in properties, and its most striking addition is with water. With pure water or dilute alkalis it is almost unaffected, but in presence of hydrogen ions it rapidly adds one molecule of water, a quantitative yield of N-benzoylsalicylamide being produced. This simple circumstance finally disposes of AUWBL'S~S hypothetical contention which involves direcb hydrolytic rupture at the double linking, but is intelligible on the author's theory tha t the intermediate hydroxy-derivative (IV) is too unstable to exist, as already frequently indicated, and at once rearranges to N-benzoyl- salicylamide, thus. :

The still alternative explanation that hydrolytic rupture takes place

* The correct name of this compound is 2-phenyldihydro-1 : 3-benzosazine-4-one but in view of its use in previous papers, '' phenylbenzometoxazone " is retained in the present one.

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online

202 TI’I’HERLEY : 8-PHENYL-1 : 3-BENZOXAZiNE-4-OKE.

between the phenolic oxygen atom and the carbon atom to which the phenyl group is attached, is discounted by the comparatively great stability of the unsaturated ring-compound with alkali, which would favour such a rupture, and the only possible mechanism appears to be the above, which is identical with that occurring in the conversion of nitriles into amides through the agency of acids.

The above mechanism throws some light upon the decomposition by water in presence of hydrogen ions of certain allied compounds in which the double linked C:N pair appews in the molecule. Auwers observed (Ber., 1904, 37, 2249) that the comparatively stable unsatur- ated ring (V) yields a hydrobromide which in aqueous solution adds water and passes into the salt of o-aminobenzyl acetate (VII), whilst J. F. Thorpe has shown that all true imino-compounds (VIlI) are at once decomposed by dilute acids, giving ketonic derivatives (X). In these cases a similar mechanism is evidently at work, in which (1) the hydroxyl group attaches itself to carbon arid the hydrogen atom to nitrogen, and (2) the resulting unstable compcund (VI or IX) changes either by wandering of a hydrogen atom or by loss of ammonia into a stable derivative :

(VIII. ) (IX.) (X. That such intermediate hydroxy-compounds are first formed in the

cases observed by Auwers and Thorpe appears to follow from the complete analogy of these reactions to that of 2-phenyl-1 : 3-benz- oxazine-4-oneY where the production of the intermediate hgdroxy- compound must be admitted on the grounds already stated and in view of’ the author’s previous observations.

Contrasting the intermediate hydroxy-derivatives in the author’s case (XI) with that of Auwers (XII) :

CO*TH NH*QMe*OH

(XI. 1 (XII.) %H4<()-CPh.()H C6H4<CH2. 0 2

it is clear tha t when the hydrogen atom of the hydroxyl group wanders, (XI) yields an N-acyl derivative, whilst (XII) yields a n 0-acyl derivative. Theoretically, each could yield an 0- or N-acyl derivative according to whether the hydrogen atom wandered to nitrogen or to the phenolic oxygen atom, and the final result probably depends on the conditions which favour one or other of these alternatives. Thus, in Auwers’s case it is natural that the hydro-

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online

TITHERLEY : 2-PHEKYL-1 : 3-BENZOXAZINE-4-ONE. 203

bromic acid would favour the production of the 0-acyl derivative, which is a base and yielded the salt, rather than the neutral N-acyl derivative, which is an amide. I n the author's case neither the 0- nor N-benzoylsalicylamide is a base, and the rearrangement yields Bimply the stable form (N-benzoyl). A t t,he same time it must be noted that, although neither of the isomerides is a base in the ordinary sense, 0-benzoylsalicylamide as a primary amide must be more basic than its isorneride, which is secondary. Experiments which have been made on the two isomerides show that the former is more basic, and yields a definite hydrochloride when treated in presence of benzene with hydrogen chloride. It might therefore be anticipated that hydrogen chloride should effect the rearrangement of N-benzoyl- salicylamide into its isomeride [through the hydroxy-form (Xl)]. Such a change has already been partly effected by continued boiling with pure acetic acid (McConnan and Titherley, Trans., 1906, 89, 1331), a fact which supports the supposition that the intermediate hydroxy-form may open in either of the two alternative ways according to conditions (acetic acid favouring the production of the more basic 0-benzoyl derivative). Experiments on the action of hydrogen chloride on N-benzoylsalicylamide in benzene showed that no change took place in the cold, but that in presence of boiling xylene slow and incomplete rearrangement to 0-benzoylsalicylamide occurred. As the experiments proceeded, however, it became apparent that, besides rearrangement, chemical elimination of water was taking place at about 130'. By using ethylene dibromide or anisole as solvents and distilling off the water as produced, the latter action was accelerated, and 3-phenyl-1 : 3-benzoxazine-4-one was formed in large quantities. The latter was even more easily obtained by the action of hydrogen chloride on 0-benzoylsalicylamide in boiling toluene or xylene if the water formed was continually removed. The hydrogen chloride virtually behaves as a catalyst, since relatively small quantities were found to be suf€icient to effect the change. It is probable that the loss of water is not due to direct dehydration, but to the intermediate formation of the chloro-derivative (XIII), which immediately loses hydrogen chloride and apparently is incapable of existence :

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online

204 TITHERLEY : 2-PHENYL-1 : 3-BENZOXAZINE-4-ONE.

When 2-phenyl-1 : 3-benzoxazine-4-one (11) in benzene solution is treated with dry hydrogen chloride, a white, crystalline compound containing chlorine is precipitated, which on exposure to atmospheric moisture rapidly passes into N- benzoylsalicylamide, but on treatment with aniline yields a yellow, crystalline solid, melting at 106", which was found to have the constitution OH*C6H4*CO*N:CPh*NKPh (ealicylphenylbenzamidine). From this behaviour it was supposed that the ring-compound had added hydrogen chloride, giving the chloro-compound (XIII), or, by rearrangement, the compound OH*C,H,*CO*N:CCIPh, either of which might be expected to behave as above with water and aniline (see below). But from the fact that the hydrogen chloride additive product in presence of benzene regenerates the original ring-compound (1.1) with alkali, and from its other properties, it must be concluded that the product is merely the

salt, C,H,<Co*8'Hc1, which with water would a t once give N-benzoyl- 0-GPh

salicylamide (as explained above) ; whilst its curious behaviour with aniline subsequently became clear when it was found that the free ring-compound itself readily unites with aniline, producing the above amidine derivative according to the following scheme :

(XIV.) CO-IjTH

c6H4<OH CPh:NPh

co-fi C6H4<OH CPh-NHPh'

(XVI.)

The reaction is reversible, and the anilino-derivative (salicylphenyl- benzamidine) is a tautomeric substance. Its tautornerism comprises the three forms (XIV), (XV), and (XVI), of which the last two represent ordinary amidine tautomerism, and it is evident tha t one of these two formuls must be given to the substance itself, melting at 106O, because of its phenolic properties. It loses aniline, however, below looo, and passes quantitatively into 2-phenyl-1 : 3-benzoxazine- 4-oneY provided that the aniline is removed, and the easy reversibility of the above process would seem to imply that the compound is bordering on the verge of ring-formation (XIV). That the phenolic hydroxyl group and the group *CPh:NPh are in intimate steric association is confirmed by the difficulty with which the substance

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online

TITHERLEY 2-PHENYL-1 : 3-RENZOXAZINE-4-ONE. 205

dissolves in dilute aqueous sodium hydroxide, and at first it was supposed that the ring formula (XIV) must be adopted for the substance. This view, however, is inconsistent with the bright yellow colour of the substance, for whilst phenylbenzometoxazone and 2-phenyl- 1 : 3-benzoxazine-4-one are colourless, the alkali and ammonia derivatives of N-acylsalicylsmides are bright yellow, and the phenolic nature of the anilino-derivative is confirmed by the strong ferric chloride reaction it gives.

In the synthesis of 2-phenyl-1 : 3-benzoxazine-4-0110 by heating phenyl salicylate with phenylbenzamidine, t h i s anilino-compound is the first product of the reaction, and it is owing to its reversible decomposition, as above, that the unsaturated ring compound (IT) is obtained, and for the same reason the yield of the latter is comparatively small, thus :

(11.1 A considerable quantity of diphenylbenzamidine (XVII) is also

produced as a, result of a secondary reaction, which also appears to be reversible, between the aniline and salicylphenylbenzamidine, thus :

CO-YH PhNHz CO*NH, NPh C6H4<OH CPh:NPh C6H4<OH CPheNHPh.

(XVII.)

EXPERIMENTAL.

2-Phenyl-l : 3-benxoxnxine-4-one.

(a) Pmparation, from PIkn,yZ SaZicylate :-(a) 21.4 Grams of phenyl salicylate and 19.6 grams of phenylbenzamidine were heated at 110' for six and a-half hours, during which aniline and phenol were produced in quantity. On cooling, the resulting viscid, yellow syrup was stirred with 150 C.C. of water and 100 C.C. of 10 per cent. sodium hydroxide to remove phenol and salicylphenylbenzamidine, and the yellow alkaline solution was decanted off. The remaining syrup was washed with water, dissolved in 200 C.C. of pure benzene, and the benzene solution washed with alkali and water. In order to remove aniline and diphenylbenzamidine, the benzene solution was shaken for a few minutes with abont 300 C.C. of 5 per cent. sulphuric acid, the upper benzene solution washed with water, and $hen as rapidly as possible

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online

206 TITHERLEY : 2-PHENYL-1 : 3-BENZOXAZlXE-4-ONE.

shaken with dilute alkali, to remove the N-benzoylsalicylamide formed during washing with acid and to neutralise the remaining traces of acid. (During the former operation some losl; was entailed, because of the great instability of the ring compound* in presence of dilute acid.)

The alkali extract was found to contain besides phenol, a considerable quantity of ssllicylphenylbenzamidine, which was pre- cipitated on adding acid and then decomposed, giving N-.benzoylsalicyl- amide. The acid extract contained aniline and diphenylbenz.lmidine. The latter was isolated (4 grams), and found to be identical with Wallach's compound (Armalen, 1877, 184, 83).

The clear benzene solution WAS washed twice with water, dried, and evaporated a t about 40". Massive crystals remained, together with a syrupy portion, which crystallised after several hours. After mashing .with a little ether and draining on porous porcelain, the crude product (12.5 grams) was crystallised from 700 C.C. of light petroleum, the solution being allowed to cool very slowly to avoid deposition of syrup. White or transparent, colourless leaflets or plates (m. p. 104"; 10.5 grams) separated, which on recrystallisation from light petroleum were obtained in the pure state and then molted sharply a t 106-107°:

0.2193 gave 0.6024 CO, and 0.0759 H,O. 0.1688 ,, 9.3 C.C. N, (moist) at 20° and 757 mm. N=6*28.

C1,H,O,N requires C: = 75.34 ; H = 4.03 ; N = 6.27 per cent.

2- Plienyl-1 : 3-6enxoxaxine.4-one is very soluble in chloroform or acetone, readily so in benzene, methyl alcohol, or ethyl acetate, and rather less so in ethyl alcohol, ether, or pyridine. It dissolves in about '70 parts of light petroleum (b. p. 90-120"). It may be recovered unchanged after solution in these solvents, even pyridino. Its solutions give no coloration with alcoholic ferric chloride. I n glacial acetic acid it readily dissolves, but owing to the presence of rnoistur2 the solution soon deposits N-benzoylsalicylamide.

Behuvwu?* with Water.-Ths cornpound is insoluble in wLtter, but on boiling an oil is produced which dissolves appreciably. The clear hot aqueous solution if rapidly cooled becomes turbid, and after a short time fine needles of the unaltered compound separate, but not without production of some N-benzoylsalicylamide. was studied by diluting an alcoholic solution largely, but insufficiently, to induce separation. The clear solution remained clear for about three hours, after which it became faintly turbid, owing to separatior~

+i If ether is used instead of benzene as a solvent, the whole of the ring-compound is decomposed during the washing with acid.

C = 74.92 ; R = 3.85.

0.3480, by Kjeldahl's method, required 16.0 c,c. N/lO-HGl. N = 6.3'3.

Its bchaviour with

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online

TITHERLEY : 2-I'HENTL-1 : 3-BENZOXAZINE-4-ONE. 207

of the highly insoluble N-benzoylsalicylamide, which, however, was not completely precipitated in twenty-four hours. Whether pure water free from carbonic acid would behave like ordinary distilled water has not been tried. Traces of acids jinorg$nic and organic) enormously accelerate the action of the water, and it was shown roughly tha t the velocity depends on the concentration of the acid added. If 20c.c. of a 0.05. per cent. solution are treated with 0.05 C.C.

of 10 per cent. hydrochloric acid, the decomposition is complete in about seventy seconds. Accurate velocity measurements have not been made, but the quantitative nature of the conversion was easily shown by decomposing a known weight in dilute alcohol. On acidifying the clear solution with a few drops of hydrochloric acid, after a few seconds a voluminous, microcrystalline precipitate * separated, which was collected and dried at 100' :

0.2 2 30 gave 0.23 9 8 N-benzoylsalicylsmide.

The purity of the N-benzoylsalicylamide was shonn by the sharp melting point (206') before recrystallising.

Behaviour with Acids.-The cyclic compound has only a weakly basic character, and with aqueous acids is decomposed without previously dissolving. It does not yield a picrate in benzene or alcoholic s o h tion. Dry hydrogen chloride in benzene solution precipitates its hydrochloride, which, however, could not be isolated in a pure condition for analysis, owing to the great ease with which it is decomposed by atmospheric moisture.

Behuviour with Alkalis.-With cold aqueous sodium hydroxide and ammonia, the compound is comparatively stable and only very slowly changed to the salt of N- benzoylsalicylamide, but sodium hydroxide immediately decomposes it in alcoholic solution. Dry ammonia produces a yellow colour with an alcoholic solution of the compound, and probably an additive compound like tha t obtained with aniline is formed ; this is under investigation.

Behaviour with Phosphorus Pentachloride-The compound, on treat- ment with phosphorus pentachloride in presence of chloroform, instantly gives a bright lemon-yellow, crystalline solid,

C,4H,0NCI,,POC13, identical with th :t obtained by Titherley and Hicks (Zoc. cit.) by the action of phosphorus pentachloride on phenylbenzometoxazone a t higher temperatures.

Beduction.-The reduction of 2-phenyl-l : 3-benzoxazine-d-one * The reaction affords a very delicate test for 2-phenyl-1 : 3-benzoxazine-4-one.

On dissolving mintite amourit in a drop of alcohol and treating with about 1 C.C. of water and a trace of any dilute acid, a precipitate appears suddenly after a few seconds.

C,,H,02N requires 0.2410 N-benzoylsalicylamide.

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online

208 TITHERLEY : 2-PHENYL-1 : 3-BENZOXAZINE-4-ONE.

cannot be effected by sodium amalgam, in alkaline solution, or by acid reducing agents, owing to ring rupture, With aluminium amalgam, however, the reduction proceeds rapidly.

A dilute alcoholic solution of the substance was treated with an excess of aluminium amalgam, and water added gradually. When the reduction was complete, the alcoholic solution mas filtered and allowed to evaporate. The resulting solid was washed with dilute alkali, dried, and extracted with boiling alcohol. A white, sparingly soluble solid remained behind, which has not yet been identified, and the alcoholic solution deposited needles consisting of impure phenylbenzo- metoxazone. By carefully recrystallising from alcohol, the latter was obtained pure in fine needles melting at 169", and was easily identified. The melting point after mixing with a specimen of phenylbenzometoxazone synthesised from salicylamide and benz- aldehyde mas 168-169'. The yield was about 30 per cent., and a similar reduction performed in an ethereal solution containing 5 per cent. of alcohol gave a yield of 40 per cent.

(b) Preparation from O-BenxoyEsaZic~Zamide.-A mixture of 3 grams of 0-benzoylsalicylamide and 30 C.C. of xylene contained in a distilling flask was heated in a bath to 145O, and when the solution became clear a stream of dry hydrogen chloride was passed in for a few minutes. By gradually raising the temperature of the bath to 155O, the xylene was allowed to distil over drop by drop, carrying with it the water formed in the reaction. The hydrogen chloride acted catalytically, and only a relatively small quantity was necessary, but in order to make good that lost by distillation, a few bubbles of the gas were passed into the liquid at intervals of three minutes, The rate of distillation was regulated so that the majority of the xylene had passed over in an hour. About 0.2 gram of water passed over with it, and an oil remained in the flask which partly crystallised on cooling and consisted of a mixture of 2-phenyl-1 : 3-benzoxazine-4-0110 and its hydrochloride and unchanged 0-benzoylsalicylamide, together with a little xylene. When cold it was treated with 20 C.C. of benzene and well shaken with an excess of 3 per cent. sodium hydroxide. A considerable quantity of lemon-yellow solid (the sodium derivative of N-benzoylsalicylamide produced by rearrangement of O-benzoyl- salicylamide) separated, which was mostly removed by repeatedly washing the benzene extract with water. The benzene extract was then dried, filtered, and evaporated at 50°, when large, colourless plates were left, together with an oil which crystallised on cooling. The solid was practically pure 2-phenyl-1 : 3-benzoxazine-4-one, and weighed 1.8 grams, or 65 per cent. of the theoretical yield. On recrystallising from about 100 C.C. of light petroleum and cooling slowly,

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online

TITHEIiLEY : 2-PHENYL-1 : 3-BENZOXAZINE-4-0EE. 209

it separated in small, colourless, glistening plates, which melted sharply at 106*, and a mixture with a specimen obtained by the amidine method of synthesis also melted at 106':

0.2128 gave 0.6003 CO, and 0,0755 H,O. C=76.8; H=3.9.

0.2362 ,, 13.7 C.C. N, (moist) at 23" and 755 mm. N = 6-49. C,,H90,N requires C = 75.34 ; H = 4.03 ; N = 6.27 per cent.

The properties of the substance agreed in every particular with those of the compound obtained by the amidine method.

I n a similar preparation to the above, using toluene instead of xylene as solvent, the compound was also obtained, but the yield was lower (36 per cent. of the theoretical).

(c) Prepccration from ~ - ~ e n ~ o y ~ s c c ~ ~ c ~ ~ ~ r n ~ ~ e . - A similar method to the above was employed, using anisole as a solvent at 130'. About two and a-half hours mere required for the completion of the change, and a yield of 60 per cent. of 2-phenyl-1 : 3-benzoxazine-4-one (m. p. 106-107°) mas obtained. Ethylene dibromide mas also used with success as a solvent, but xylene mas unsatisfactory, owing to the small solubility of ni-benzoglsalicylamide. During the action of the hydrogen chloride, some of the N-benzoylsalicylamide is rearranged to O-benzoyl- salicylamide, and this was isolated in smal1:quantity in one experiment, when xylene was used as solvent, as needles melting with rearrange- ment a t 144".

0.1812 ,, 0.50'70 CO, ,, 0.0635 H,O. C=76*39 ; H=3'89.

Saliey Zpheny Zbenxamidine, OH*C,H 4* COON : CPh*NH P= OH* C6H,* CO *NH CPh: NPh,

was obtained by the sction of aniline on 2-phenyl-1 : 3-benzoxazine- 4-one or its hydrochloride by the following methods.

One gram of 8-phenyl-1 : 3-benzoxazine-4-one and 0.5 ,gram of aniline were warmed t o 50°, and the resulting yellow oil, which did not crystallise on cooling, was dissolved in 50 C.C. of boiling light petroleum and the clear yellow solution allowed to cool slowly. A yellow syrup was deposited, which, after being kept for twelve hours in contact 'with the mother liquor, changed to a mass of beautiful transparent, yellow needles (1.3 grams), and the mother liquor yielded a further quantity (0.1 gram), the total yield being 93 per cent. of the theoretical.

When instead of light petroleum as a solvent, ether (15 c.c.) was used, the pure compound separated after several hours in clusters of needles (0.9 gram) without any syrup being firsti deposited, and a further quantity (0.2 gram) was obtained from the mother liquor. The substance was also prepared in the pure state by treating a benzene suspension of 2-phenyl-1 : 3-benzoxazine-4-one hydrochloride with aniline. The identity of the yellow needles obtained by the

VOL. XCVlI. P

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online

210 TITHERLEY : 2-PHENYL-1 : 3-BENZOXAZINE-4-0NE.

different methods was shown by a comparison of melting point (1 05-10ri0) and other properties :

0.2750 gave 19.8 C.C. N, (moist) at 17" and 772 mm. C,oH,,0,N2 requires N = 8.86 per cent.

Salicylphenylbe~~xamidine is somewhat sparingly soluble in ether, moderately so in alcohol, and readily soluble in chloroform or benzene. Its solutions give a reddish colour with alcoholic or ethereal ferric chloride. Its solutions on evaporation at the laboratory temperature yield syrups which crystallise completely only after several days, and it is probable that two or more isomeric forms in equilibrium are produced by labile change when the yellow needles are dissolved in any solvent. If heated in a light petroleum solution for any length of time, as in crystallising large quantities, the substance more or less dissociates into aniline and 2-phenyl-1 : 3-benzoxazine-4-one, which separates to some extent on cooling in colourless needles or tufts alongside the yellow needles of the unchanged substance. Prolonged boiling leads to decomposition of a portion, owing to the action of the aniline (see below) forming diphenylbenzamidine.

Salicylphenylbenzamidine possesses weakly basic and weakly phenolic characters; i t is soluble in, but at once decomposed by, hydrochloric acid, yielding N-benzoylsalicylamide. I n a condition of fine powder it is only very slowly soluble in dilute sodium hydroxide ; a yellow solution of the sodium salt results, from which, however, it is apparently impossible to recover the original substance ; on acidifica- tion with hydrochloric acid, a yellow precipitate is formed, soluble in excess of acid to a nearly clear solution, from which dV-benzoyl- salicylamide is almost instantly precipitated. When salicylphenyl- benzamidine is heated a t 9 5 O , it dissociates, and eventually melts to a clear yellow liquid with an odour of aniline ; i f the latter is allowed to evaporate slowly in an open shallow vessel, the yellow colour becomes less conspicuous, and at the end of some hours a colourless liquid results, which finally sets to a mass of colourless plates, con- sisting of 2-phenyl-1 : 3-benzoxazine-4-one, 'the yield of which was almost theoretical. When heated with aniline at 100' for several hours, salicylphenylbenzamidine is partly decomposed into salicyl- amide and diphenylbenzamidine, the latter obtained in a yield of 35 per cent.

N=S.50.

ORGANIC LABORATORY, [JNIVERSITY OF LIVERPOOL.

Publ

ishe

d on

01

Janu

ary

1910

. Dow

nloa

ded

by S

tate

Uni

vers

ity o

f N

ew Y

ork

at S

tony

Bro

ok o

n 25

/10/

2014

10:

04:4

1.

View Article Online