63-A.] 



PARACRESOL 



131 



Ann. 77, 18 ; Brieger, Zeit. physiol. 

 Ch. 4, 204 : see also under o-cresol 

 [6l] for further references). 



A product of putrefaction of animal 

 proteids (Baumann and Brieger, Zeit. 

 physiol. Ch. 3, 149; Ber. 12, 706), of 

 p-kydroxypkenylaceiie and kydroparacou- 

 maric acids [Vol. II] (Baumann, Zeit. 

 physiol. Ch. 4, 304), and of tyros in 

 [Vol. II] (Weyl, Zeit. physiol. Ch. 3, 

 312; Baumann, Ibid. 4, 304). 



The p-cresol complex may be con- 

 tained in podocarpic acid, which con- 

 stitutes the chief portion of the resin 

 of Podocarpns cupressina, var. imbricate 

 (Oudemans, Ann. 170, 259). 



The methyl ether appears to exist in 

 the perfume ' Cananga Essence ' (ylang- 

 ylang) from Caiianga odorata (Reychler, 

 Bull. Soc. [3] 13, 140). p-Cresyl 

 acetate exists also in this oil (Darzens, 

 Bull. Soc. [3] 37, 83). 



SYNTHETICAL PROCESSES. 



[A.] From toluene [54 ; A, &c.] 

 through p-nitrotoluene (see under ortho- 

 cresol [61; A]), p-toluidine by reduction, 

 and thediazo-reaction with latter (Griess, 

 Jahresber. 1866, 458; Korner, Zeit. 

 [2] 4, 326). 



Or p-nitrotoluene on mild reduction 

 gives p-toluylhydroxylamine (see under 

 toluquinol [72 ; A]), and this gives 

 p-cresol among the products of decom- 

 position by hot dilute sulphuric acid 

 (Bamberger, Ber. 28, 246; for produc- 

 tion of p-toluylhydroxylamine by the 

 oxidation of p-toluidine by monoper- 

 sulphuric acid see Bamberger and 

 Tschirner, Ber. 32, 1677). 



Or from toluene through the p-sul- 

 phonic acid and potash fusion of the latter 

 (Wurtz, Ann. 144, 122; 156, 258; 

 Engelhardt and Latschinoff, Zeit. [2] 

 5, 618). 



From toluene through m-xylerie (see 

 under orthocresol [61 j A]), m-xylene- 

 4-sulphonic acid by sulphonation (Jacob- 

 sen, Ann. 184, 188; Ber. 10, 1015; 

 11, 19), and potash fusion of latter so 

 as to form 4-hydroxy-m-toluic (a-cre- 

 sotic = p-homosalicylic) acid (Engelhardt 

 and Latschinoff, loc. cit. 712). The 

 latter acid on heating with strong 



hydrochloric acid at 180-185 gives 

 p-cresol. 



Or m-xylene may be oxidised to m- 

 toluic acid (Tawildaroff, Zeit. [2] 7, 

 419; Ber. 4, 410; Bruckner, Ber. 9, 

 406 ; Reuter, Ber. 17, 2028), the latter 

 brominated (Jacobsen, Ber. 14, 2351), 

 and the 4-brom-m-toluic acid thus 

 formed fused with potash (Ibid.}. 



Or m-toluic acid may be sulphonated 

 (Jacobsen, loc. cit. 2355), the 4-sulpho- 

 m-toluic acid converted into 4-hydroxy- 

 m-toluic acid by potash fusion (Ibid.], 

 and then into p-cresol as before. 



Or m-toluic acid may be nitrated 

 (Ibid. 2353), the 4-nitro- reduced to the 

 4 - amino - m - toluic (methylanthranilic) 

 acid (Ibid.}, the latter converted into 4- 

 hydroxy-m -toluic acid by the diazo- 

 reaction (Ibid. : see also Panaotovic, 

 Journ. pr. Ch. [2] 33, 64), and into 

 p-cresol as before. 



Or m-xylene-4-sulphonic acid (see 

 above) may be converted into 1:3:4- 

 xylenol by potash fusion (Jacobsen, Ber. 

 11, 28), or the corresponding 1:3:4- 

 nitroxylene into i : 3 :4-xylidine and into 

 the same xylenol by the diazo-reaction 

 (Harmsen, Ber. 13, 1558). This 1:3:4- 

 xylenol (or its /3-sulphonic acid) gives 4- 

 hydroxy-na-toluic acid by potash fusion 

 (Jacobsen, Ber. 11, 375 ; Ann. 195, 283), 

 and this gives p-cresol as before. 



Toluene may also be converted into 2 : 

 4-dinitrotoluene (Deville, Ann. 44, 307), 

 the p-nitro-group in the latter replaced 

 by bromine (Beilstein and Kuhlberg, 

 Ann. 158, 340), the 4-brom-2-nitro- 

 toluene heated with alcoholic potassium 

 cyanide at 220, and the nitrile hydro- 

 lysed to 4-brom-m-toluic acid (Richter, 

 Ber. 5, 425), which can be converted 

 into 4-hydroxy-m-toluic acid and p- 

 cresol as above. 4-Brom-2-nitrotol- 

 uene is also formed (with 4-brom-3- 

 nitrotoluene) by the nitration of p- 

 bromtoluene (Wroblewski, Ann. 168, 

 176). 



Or toluene may be converted into 

 methyl-m-toluyl ketone by the action 

 of acetyl chloride in presence of alu- 

 minium chloride (Essner and Gossin, 

 Bull. Soc. [2] 42, 95) ; or p-bromtoluene 

 into p-bromtoluyl-m-methyl ketone by 

 the same process. The latter on oxida- 



