A detailed investigation has been made of the best methods of preparing p-bromoethyl-p-bromo-

butylamine in quantity by the last of the methods outlined in the previous paper. a-Nitro-p-hydroxy- butane (picrolonate, m. p. 154°), is prepared by con­

densation of propaldehyde with nitromethane, and is best reduced (yield 50%) to a-amino-P-hydroxy- butane by aluminium amalgam (cf. Tordoir, A., 1902, i, 265). The interaction of a-butylene oxide (A., 1924, i, 360) and concentrated ammonia gives a-amino-P-hydroxybutane in 33% yield. a-Amino- P-ethoxybutane (picrate, m. p. 152—154° ; picrolonate,

1430 BR IT ISH CHEMICAL ABSTRACTS.— A .

m. p. 169—170°), has been prepared by a modification of Bookman’s method (A., 1896, i, 199) by the inter­

action of a-chloro-P-ethoxybutane and alcoholic ammonia at 140°. The condensation of a-amino-P- hydroxybutane with ethylene oxide (cf. Knorr, A., 1899, i, 461) is effected in the cold, and yields a mixture of the syrupy primary, secondary, and tertiary amines, which are separated only with difficulty by fractional distillation. No crystalline product is obtained by treatment with nitrous acid, but when the mixture is ethylated by treatment with potassium and ethyl bromide, fi-ethoxyethyl-$-ethoxybutylamine, b. p. 105— 107°/9 mm., 210—212°/720 mm. (nitroso- derivative, b. p. 150— 152°), and di-($-ethoxyethyl)-fi- ethoxybutylamine, b. p. 140— 142°/12 mm., are readily separated by fractional distillation. The condens­

ation of a-amino-P-ethoxybutane with ethylene oxide yields similarly fi-hydroxyethyl-fi-ethoxybutylamine, b. p.

115—117°/10 mm. (miraso-derivative, b. p. 165—

166°; picrolonate, m. p. 125—126°), which is readily ethylated. D i-(phydroxy ethyl)-¡3 - ethoxy butylamine, b. p. 162°/11 mm., is obtained with excess of ethylene oxide. B y heating the non-etliylated, partly ethyl­

ated, or completely ethylated bases with hj^dro- bromic acid in sealed tubes there are obtained

¡3-bromoethyl-p-bromobutylamine hydrobromide, m. p.

above 300° (free base, an unstable oil; 'picrolonate, m. p. 148— 150°), and di-($-bromoethyl)-$-bromobutyl- amine hydrobromide, m. p. above 300° (base, an oil;

picrate, decomp. 260°). R . K. Ca l l o w.

H yd roch lorid es of a-am in o-alcoh ols. K. A.

Kr a s u s k i and K . G. Ko s e n k o (Ukraine Chem. J., 1929, 4, 199—209).—By passing dry hydrogen chloride through a cooled ethereal solution of a-amino- alcohols, the hydrochlorides were obtained as crystall­

ine non-hygroscopic precipitates. With excess of hydrogen chloride the salts first became highly hygroscopic, and finally liquefied, forming liquid additive compounds with several molecules of hydrogen chloride which on keeping at the ordinary temperature, • gave oft' hydrogen chloride and reprecipitatcd the solid salts.

If dry solid hydrochlorides were further treated with hydrogen chloride, they liquefied with evolution of heat, but the resulting compounds wore very unstable, and decomposed into the original salts with evolution of hydrogen chloride. Tertiary amines were found to add hydrogen chloride most readily to form additive compounds with two extra molecules ; the secondary were less reactive and added only one extra molecule, whilst the primary reacted only to a very slight extent.

In general, it was found that the less basic are the properties of the amino-alcohol, the more readily it absorbs excess of hydrogen chloride, and the more actively the hydrochloride reacts with the gas to form the unstable additive compounds. M. Zv e g i n t z o v.

A ction of iso a m y la m in e on isop rop yleth ylen e oxide. K . A. Kr a s u s k i and F. F. Kr i v o n o s

(Ukraine Chem. J., 1929, 4, 211—213).—tsoPropyl- ethylene oxide in 33% aqueous or benzene solution reacts with isoamylamine less readily than with ammonia (which reacts at the ordinary temperature), heating for 1 0 hrs. on the water-bath being necessary.

A 50% yield of i&oamylaminomethylisopropylcarbinol,

CHPr0(OH)-CH2-NH-[CH2]2-Pri*, b. p. 125—127°/25 mm. (hydrochloride, m. p. 263°; picrate, m. p. 130—

132°), is obtained. M. Zv e g i n t z o v.

P olysacch a rid es. XL. E n zym ic degradation of chitin. II. P. Ka r r e r and G. v o n Fr a n ç o is

(Helv. Chim. Acta, 1929, 1 2 , 986—988; cf. this vol., 915).— Chitin from mushrooms is decomposed by snail chitinase in the same way as chitin from lobster shells (loc. cit.) with the formation of iV-acetyl- glucosamine in 80% yield, suggesting that plant and animal chitins are identical. When chitosan is acetylated by boiling with acetic anhydride and sodium acetate the product is decomposed by chitinase to yield ÏY-acetylglucosamine, indicating that an acetyl group is necessary for this degradation and supporting the assumption that chitosan is simply de-acetylated chitin. R . K . Ca l l o w.

P rep aration and p rop erties of xan th h yd rol as a rea gen t for carbam id e. F. G. Kn y- Jo n e sand A. M.

Wa r d (Analyst, 1929, 5 4 , 574—575).—Xanthhydrol is very unstable ; it has m. p. about 120— 123° accord­

ing to mode of heating, and decomposes above this temperature. For use in the determination of carbamide it should be freshly prepared by reducing xanthone by means of alcoholic sodium amalgam.

The alkaline alcoholic solution is poured into excess of water, and the product collected and redissolved in methyl or ethyl alcohol, as the alcoholic solution is much more stable than the solid. D. G. He w e r.

C om plex m e ta llic cyanides. III. Com pounds of iron and cob alticyan ic acid s w ith b iva len t h eavy m e ta ls. H. Re i i i l e n and W. Zi m m e r m a n n

(Annalen, 1929, 4 7 5 , 101— 119).—A systematic investigation of the complex salts formed by the action of cadmium sulphate on potassium ferro- and ferri-cyanide. When a hot solution of potassium ferricyanide is treated with an excess of cadmium sulphate solution the potassium salt

[{(H20 )2Fe'"(CN)6Cd}3Cd][K(H20)],12H 20 (I) is formed. If the precipitate obtained with cold solutions is treated at 1 0 0° with cadmium sulphate solution it is converted into the cadmium salt, [{(H2O)2F e-(C N )6Cd}3Fe-(?Cd)][Cd(H2O)4]0.5,22H2O.

In the presence of 3-5iV-ammonia solution I is not stable, the precipitate then consisting of the basic salt [{(HO)2Fe"'(CN)0Cd}3Cd][Cd(NH3)4]3NH4 (II), pro­

viding the ratio Cd : Fe in the solution is > 2 :1 . If this ratio is less than this value initial crystallisation of II is followed by separation of the compound

[{Cd(CN)0F e-(O H )2}3Cd][Cd(NH3)4]2(NH4)3,3H2O.

With potassium cobalticyanide a basic cobalt salt similar to II is obtained. When I is dissolved in 2N- ammonia and the solution is saturated with ammonia at —15° the complex ammonium salt

[{(HO)2Fe"'(CN)GCd}3Cd](NH4)7 crystallises, contam­

inated with the compound,

[{Fe(CN)0Cd(OH)2}3Cd][Cd(NH3)6]0.3(NH4)G.35,14H2O.

B y similar methods the corresponding complex zinc and nickel salts,

[{(0H)2FeZn(CN)G}3Zn](NH4)6K ,8H ,0 and

[{(OH)2Fe(CN)6Ni}3Ni][Ni(NH3)6](NH4)4.5K0.5,27H2O, are obtained. Degradation of the complex hepta- basic anion [Fe3Cd4(CN), s(OH) G] to derivatives of the simple anion [FeCd(CN)6] may be effected in

ORGANIC CHEM ISTRY. 1431 two ways. First by dissolving any’salt of type I in

ammonia, adding ammonium sulphate to depress the hydroxyl-ion concentration, and removing the excess of ammonia over sulphuric acid in a vacuum, and thus is obtained the hexammine cadmium salt, [Fe(CN)8Cd]2[Cd(NH3)6],2H20 . Fission of the co­

ordination complex to yield the corresponding ferri- cyanide, [Fe(CN)0][Cd(NII3)6]3, is not possible in solution. The second method consists in the addition of cadmium sulphate solution to a hot solution of potassium chloride and ferricyanide, no precipitation occurring, but on cooling the potassium salt, [Fe(CN)Cd]K, slowly crystallises. The chief differ­

ences between the complex cadmicyanides of bi- and ter-valent iron is that the polymerised (polynuclear) co-ordination complex which the former are also presumed to form is much more readily broken down to the simple anion [Fe*'Cd(CN)G]" (which is stable to

6iV-ammonia), and the salts contain no water molecules combined in the co-ordination complex. The sodium salt, [Fe’'(CN)flCd][NaH20]2 H20 , is obtained either by heating cadmium sulphate solution with an excess of sodium ferrocyanide solution (Fe : C d = 2i5 : 1), or by shaking the precipitate obtained when an excess of cadmium su phate is used for a long period with con­

centrated sodium chloride solution. The correspond­

ing potassium (-)-4H20) and ammonium (+ 6 H20 ) salts are similarly prepared. In the presence of a high concentration of ammonia the hexammine cadmium salt [Fe”(CN)6Cd][Cd(NH3)8],H20 , and with lower concentrations the teliammine cadmium salt [Fe"(CN)6Cd][Cd(NH3)4] + H 20 and + 6 H20 , are obtained. That the precipitate obtained by heating together solutions of sodium ferrocyanide and cadmium sulphate is a mixture of the compounds [FeCd(CN)e]Na2 and [FeCd(CN)„]Cd,H20 and not the complex [{Fe"'Cd(CN)0}3Cd]Na4 is proved by the fact that the ratio Cd : Fe in the precipitate remains the same as that in the mother-liquor when its value in the latter is altered. The structure of these complex salts and their bearing on the constitution of insoluble Prussian blue are discussed. J . W. Ba k e r. .

A lkylation of hexacyanocobaltic acid. F.

Ho l z l, T. Me i e r-Mo h a r, and F. Vi d i t z (Monatsh., 1929, 5 3 and 5 4 , 237—255).—When hexacyano­

cobaltic acid or its alkoxonium derivatives (this vol., 898) are heated with alcohols in a sealed tube at 100°, alkylation occurs. Thus the acid and alcohol give the compound [(CN)5*Co*CNEt]H2, isolated as its dipyridine salt. Treatment of the reaction product from methyl alcohol and the methoxonium derivative of the acid with pyridine affords a substance, [(CN)5,Co,CNMe]H2(C5H5N)3 or

[(CN)4-Co-(CNlMe)2]H(C5H5N)3. Propylation is similar to ethylation, but proceeds more slowly.

Carbylamine is formed during the reactions. The relation between time of reaction and corrected amount of O-lIV-alkali hydroxide necessary for neutralisation of the reaction mixture is studied. The mechanism of the formation of the alkylated products is discussed; the production of an intermediate imino-compound is postulated. H . Bu r t o n.

P h o to sen sitiv en ess of n itrop ru ssid es. H.

Le f f m a n n and C. C. Pi n e s (Bull. Wagner Free Inst.,

1929, 4 , 41—42).—When a concentrated aqueous solution of sodium nitroprusside is mixed with aqueous solutions of uranium acetate, silver nitrate, mercuric nitrate, ferrous sulphate, or ferric chloride, precipit­

ates, presumably of the corresponding nitroprussides, are formed in all cases except with ferric chloride. All the precipitates, except that of uranium, were notably changed after exposure to sunlight for 1 0 min.

A. I. Vo g e l.

P o ssib ility of formation, of tetrazom eth an e, CN,,. H. H o L T E R a n dH. Br e t s c h n e i d e r (Monatsh., 1929, 5 3 and 5 4 , 963—984).—Treatment of methylene- bisurethane (I) with nitrous fumes in ethereal suspension affords impure dinitrosomeihylenebis- urethane (II), a yellow oil, which decomposes readily when heated; II does not give Liebermann’s reaction.

Decomposition of II with dilute alkali hydroxide (whereby tetrazomethane might be produced) causes evolution of nitrogen; with concentrated aqueous or methyl-alcoholic alkali hydroxide in the cold, a sodium salt is first formed and decomposes on warming or diluting with water. Decomposition of an ethereal solution of II with water gives a trace of formaldehyde (isolated as the “ dimedon ” compound); the amount of formaldehyde is increased when aqueous sodium hydroxide is used. With sodium propoxide in ethereal propyl-alcoholic solution, II gives a small amount of a substance, probably formaldehyde dipropylacetal, b. p. 134— 142°, hydrolysed by 50% sulphuric acid to formaldehyde.

Treatment of pyrocatechol with an ethereal solution of II in presence of 25% methyl-alcoholic potassium hydroxide solution affords a small amount of methyl- enedioxybenzene. Similarly, 3 : 4-dihydroxyaniline, methyl protocateehuate, and the phenolic base from rfZ-tetrahydroberberine (Spilth and Mosettig, A., 1926, 965) all furnish varying amounts of the corresponding methylenedioxy-derivatives. The above reactions are to be expected with tetrazomethane. It is sug­

gested that the tetrazomethane reacts only with free phenols and not with phenoxides; it is shown that an ethereal solution of diazomethane does not react with sodium ¡3-naphthoxide until methyl alcohol is added.

The by-reactions occurring during the decom­

position of II by alkali hydroxide have been studied.

With methyl-alcoholic potassium hydroxide, I and ethylmethoxymethylurethane (III), b. p. 103—104°/9 mm. [obtained from methoxyacetamide by Blaise’s method (A., 1926, 943)], were isolated. Hydrolysis of III with 10% sulphuric acid gives methyl alcohol and formaldehyde; benzylamine and III at 200° yield dibenzylcarbamide. When II is decomposed with sodium benzyloxide in benzyl alcohol-ether solution, ethylbenzylqxymethylurethane, b. p. 185— 190°/10 mm., is produced. The formation of these alkvloxy-deriv- atives probably occurs th u s : [C02E t'N (N 0),]2CH„

+H,0 KOH

— ;0-> C02Et-N(N0)-CH2-NH-C02E t ---- >

N2CH’NH*C02E t 0R-CH2-NH-C02Et. An ethereal solution of II gradually decomposes to I and nitrogen oxides. H. Bu r t o n.

Influence of p o les and p olar lin k in g s on the course p ursued b y elim in a tio n reaction s. V.

T h erm a l d ecom p osition of quaternary p h osp h

on-1432 B R IT ISH CHEMICAL ABSTRACTS.---- A .

iu m h yd roxid es. G. W. Fe n t o n and C. K. In g o l d

(J.C.S., 1929, 2342—2357).—The decomposition of quaternary ammonium hydroxides results in the production of defines, whilst the simpler phosphonium hydroxides yield paraffins. I t is suggested that in the latter case, paraffinic degradation takes place at a lower temperature than that required for olefinic degradation. The facility of olefinic degradation depends largely on the extent to which the (3-hydrogen atom eliminated from the cation is activated or de­

activated by the |3-substituents of the group forming the define. Electron-repelling alkyl groups de­

activate, and consequently phosphonium hydroxides which should be capable of forming simple aliphatic defines are not favourable cases for observation of olefinic degradation. For this reason the decom­

position of the following complex phosphonium hydroxides was studied. The (3-phenylethyl-triethyl compound gave some styrene and triethvlphosphine at the temperature of paraffinic decomposition, which was still the main reaction, whilst |3B-diphenylethyl- tri-n-butylphosphonium hydroxide yielded os-di- phenylethylene and tri-w-butylphosphine as the main products. The presence of paraffinic degradation products was just discernible. Olefinic degradation of phosphonium hydroxides is thus possible and the conditions for its facilitation are similar to those established for the ammonium series. A table is given showing quantitatively the hydrocarbon products of the decomposition of a number of phosphonium hydroxides.

The phosphonium hydroxides were prepared by interaction of the corresponding phosphines and alkyl halides followed by treatment with moist silver oxide under suitable conditions. The following compounds are described : tetramethylphosphonium picrate, m. p. > 290°. The residue after decomposition

of the hydroxide was trimethylphosphine oxide, b. p. 210—212°, m. p. 140— 141° (liydroxytrimetliyl- phosphonium trichloroacetate, m. p. 64°); trimethyl- ethylphosphonium picrate, m. p. 290°; dimethylethyl- phosphine oxide, b. p. 223—225°, m. p. 73— 75° ; methyl- triethylphosphonium picrate, m. p. 239°, triethyl- phosphine oxide, b. p. 238—240°, m. p. about 46°

(chromato, 99— 100°) ; triethyl-n-propylphosphonium picrate, m. p. 91°; ethyltri-n-propylphosphoniunj, iodide and picrate, m. p. 64°; tri-n-propyl-n-butyl- phosplionium iodide, m. p. 239—240°, and picrate, m. p.

67° ; tri-n-propyl-n-octylphosphonium cliloroaurate, m. p. 38° ; phenyltrimethylphosphonium iodide, m. p.

236° ; benzrjltrimethylphosphonium bromide., m. p.

2 2 2°; triphenylbenzylphosphonium bromide, m. p.

288°; $-phenylethyltriethylphosphonium picrate, m. p.

70°. fi$-Diphe?iylethyllri-n-butylphosphonium hydr­

oxide, no salts described. n-Propyltri-n-bulylphos- phonium hydroxide, no salts described. co-Carb- ethoxytelrametliylphos'phonium chloride, m. p. 160°

(decomp.), and picrate, m. p. 124— 125°. Full details are given of the thermal decomposition products of the above phosphonium hydroxides. J. W. Po r t e r.

C onstitution and d isso cia tio n of th e G rignard reagen t. H. Gi l m a n and R. E. Fo t h e r g i l l (J.

Amer. Chem. Soc., 1929, 51, 3149—3157).—Magnes­

ium alkyl, aralkyl, and aryl halides have been treated

with an equivalent of magnesium and benzophenone in ether-benzene solution, and the amounts of benz- pinacd formed determined. With magnesium ethyl and benzyl chlorides and phenyl bromide no pinacol results. Amounts varying from 0-057 to 17-3% (on benzophenone used) are formed with magnesium methyl and n-butyl iodides and benzyl bromide.

With magnesium w-butyl iodide, tert.-butyl chloride, and benzyl bromide and no added magnesium no pinacol is formed, but magnesium triphenylmethyl chloride and bromide give, under the same conditions, 22-0 and 31-6% of the pinacol respectively; at the same time triphenylmethyl peroxide (55-3 and 57-9%) is also formed. This is explained by a dissociation of the Grignard reagent, CPh3-M gX— -> CPh,- + -MgX;

the pinacol formation is a function of the -MgX. A mixture of magnesium diethyl, magnesium iodide, magnesium, and benzophenone in ether-benzene solution and an atmosphere of hydrogen yields after prolonged stirring benzpinacol (12-83%) and diphenyl- ethylcarbinol. When the reaction is carried out in an atmosphere of nitrogen for a short time, only diphenyl- ethylcarbinol (18%) is isolated. The following change occurs : MgEt24-MgI2 — 3>- 2Et-MgI. I t is con­

cluded that the equilibrium 2R,-MgX R2M g+

MgX2 and the dissociation R-M gX— >- R -+-M gX probably occur to some extent with all Grignard

reagents. H. Bu r t o n.

S ter o l group. V. C on stitu tion of chole- sterilen e. A. C. Bo s e and W. Do r a n (J.C.S., 1929, 2244— 2248).—The action of heat on methyl chole- sterylxanthate, m. p. 127°, [a]'“ —51-1° in toluene (best prepared by the action of carbon disulphide and methyl iodide on potassium cholesteryl oxide obtained by the action of emulsified potassium on a dry benzene solution of cholesterol) (Tschugaev and Fomin, A., 1910, i, 734), forms only one hydrocarbon, cholester- ilene, m, p. 79°, identical with the product obtained by the dehydration of cholesterol with anhydrous copper sulphate (Mauthner and Suida, A., 1896, i, 425; a cleaner product being obtained by heating the reactants at 200°/5 mm.), since either product is reduced by hydrogen and palladium-black to the same mixture of cholestane and ^-cholestane. The supposed isomeride

“ (3-cholesterylene ” described by Tschugaev and Fomin (loc. cit.) is an impure form of cholesterilene containing sulphur which is removed only by repeated treatment with concentrated alcoholic potassium hydroxide or by liquid sodium-potassium amalgam.

J. W. Ba k e r.

^ Q uantitative evidence of th e structure of the benzene rin g and th e orien tation of its six hydrogen a to m s. R . Re i n i c k e (Z. Elektrochem., 1929, 35, 780—789).—A theory of the structure of benzene, based on the tetrahedral quadrivalency of carbon and the value of the space-lattice o f’ the diamond obtained by Ehrenberg (Z. Krist., 1926, 63, 320), is advanced, in support of which various physical data, e.g., dielectric constants, of some benzene derivatives are quoted. H. T. S. Br i t t o n.

C atalytic h ydrogen ation of h alogen ated organic com pou n ds. M. Bu s c h and W. Sc h m i d t (B e r .,

1929, 62, [£], 2612—2620; cf. A., 1925, ii, S23).—

ORGANIC CHEM ISTRY. 1433 During the quantitative removal of bromine from

bromobenzene, by means of hydrogen, diphenyl is produced in considerable amount in addition to benzene. Hydrogen derived from hydrazine does not act more advantageously, although more rapidly, than that derived from other sources. Apparently the proportion of diphenyl produced is connected with the dielectric constant of the solvent. In methyl alcohol the yield is 60%, whilst in ethyl alcohol it is 30%

(depressed by addition of water) and reaches a minimum in isopropyl alcohol. Hydrogenation of the nucleus is not observed. Partial poisoning of the catalyst by benzene, phenol, or dimethylaniline depresses the yield of diphenyl, which attains its maximum when the halogen is removed from the nucleus as rapidly as possible. Other reducing agents (zinc dust and potassium hydroxide or ammonia) do not affect bromobenzene, which, however, affords about 1 0% of diphenyl when treated with methyl- alcoholic potassium hydroxide and palladised calcium carbonate at 140°. The presence of substituents in halogenobenzenes influences the production of diaryls in proportion as it affects the mobility of the halogen atoms, but, in general, the yield of diaryl is somewhat lower than with the unsubstituted compounds.

1-Bromonaphthalene does not yield dinaphthyl.

o-Dibromobenzene behaves as a normal disub­

stituted product, either remaining intact or being reduced to benzene. p-Dibromobenzene gives di­

phenyl, p-diphenylbenzene, and y-diphenyldiphenyl containing halogen. jp-Di-iodobenzene behaves similarly. Bromo- and iodo-diphenyl yield homo­

geneous jj-diphenyldiphenyl. The tendency towards the production of long ring chains finds its limitation in the physical properties of the complex compounds which cause their immediate separation from the alcoholic solution, thus preventing further action.

Benzyl halides afford dibenzyls in appreciable amount. If palladium as catalyst is replaced by platinum or nickel, cliaryls are not produced or are formed only in minor amount; this may be connected with their much slower rate of reaction. H. Wr e n.

P o l y m e t h y l b e n z e n e s . I . J a c o b s e n r e a c t i o n w i t h p e n t a m e t h y l b e n z e n e , a n d p r e p a r a t i o n o f p r e h n i t e n e [ 1 : 2 : 3 : 4 - t e t r a m e t h y l b e n z e n e ] . L. I.

Sm i t h and A. R. L ux (J. Amer. Chem. S oc, 1929, 51, 2994r—3000).—The formation of hexamethylbenzene (I) and prehnitenesulphonic acid (II) from penta­

methylbenzene, by treatment with sulphuric acid at the ordinary temperature (cf. Jacobsen, A , 1887, 660), has been studied in detail. Reaction occurs essentially in the manner described by Jacobsen (loc. cit.). The initial reaction mixture is decomposed by a specific amount of ic e ; this precipitates I and II. These are separated by extraction with water. Prehnitene is obtained conveniently from sodium prehnitenesulphon- ate by slow addition of a saturated solution of the sodium salt to sulphuric acid at 140—155°, and removing the hydrocarbon formed in a current of steam. The yield is 80—90%. When pentamethyl- benzenesulphonic acid is kept in a desiccator over sulphuric acid for 8 weeks small amounts of I and II appear to be formed. This indicates that the first stage of the Jacobsen reaction is sulphonation with

subsequent rearrangement of the sulphonic acid

produced. H. Bu r t o n.

P olym eth ylb en zen es. II. M . p. of tetra-, p enta-, and h exa -m eth ylb en zen es, and f.-p.

d ia gram of m ix tu r e s of durene [ 1 : 2 : 4 : 5-tetra- m ethylbenzene] and isodurene [ 1 : 2 : 3 : 5-tetra- m ethylbenzenej. L. I. Smith and F. H. Ma c- Do u g a l l (J. Amer. Chem. S oc, 1929, 51, 3001—

3008).—Bromination of mesitylene in carbon tetra­

chloride solution and treatment of the product formed with alcoholic sodium ethoxide (to remove bromo- methyl derivatives) affords bromomesitylene, b. p.

102-5— 103-5°/14 m m , m. p. —1 to 1°. Conversion of this into the Grignard reagent and treatment with methyl sulphate gives a 60% yield of isodurene, b. p.

86-5°/18 mm. When bromoprehnitene, m. p. 26-2—

26-4° (lit. 30°), is converted into the Grignard reagent and this is decomposed by dilute acid, a 61 % yield of prehnitene is obtained. The f. p. of this is identical with that prepared by the Jacobsen method (preceding abstract). The f. p. (corr.) of the hydrocarbons prepared are: durene, 7 9 -2 8 i0 -0 5 °; isodurene,

—24-O iO -l0; prehnitene, —O-iOj^O-OS0; penta­

methylbenzene, 5 4-0 ± 0 -l°; hexamethylbenzene, 164-8¿0-1°. The f.-p. diagram for the system durene-isodurene is given, and the molar latent heats of fusion of durene and isodurene are calculated to be 5022 and 2550 g.-cal, respectively. H. B u rton .

S y n th e sis of p rop yl- and propenyl-benzene and th eir h o m o lo g u es. L. Be r t and M. An g l a d e

S y n th e sis of p rop yl- and propenyl-benzene and th eir h o m o lo g u es. L. Be r t and M. An g l a d e