61 B-J.] 



ORTHOCRESOL 



127 



which can be converted into 2-hydroxy- 

 m-toluic acid and o-cresol as under A. 



NOTE : The generators of mesitylene and 

 uvitic acid referred to under benzyl alcohol 

 (54 ; D to Q,) thus become generators of o-cresol. 



[C.] From cymene [6] through the 

 a-sulphonic acid (Glaus and Cratz, Ber. 

 13, 901; Spica, Ber. 14, 653; Glaus, 

 Ibid. 2139), 2-sulpho-p-toluic acid by 

 oxidation of the sulphonic acid (Remsen 

 and Burney, Am. Ch. Journ. 2, 411; 

 Meyer and Baur, Ann. 220, 18), 2- 

 hydroxy-p-toluic acid by potash fusion, 

 &c., as under A. 



Or from cymene through the 2-(a)- 

 sulphonic acid (see above), 3-brom-6- 

 sul phonic acid by bromination (Kelbe 

 and Koschnitzky, Ber. 19, 1730; Glaus 

 and Christ, Ibid. 2165), 3-bromcymene 

 by heating the latter with sulphuric acid 

 (Ibid.}, 3-brom-6-nitro-p-toluic acid by 

 the action of nitric acid on latter (Fileti 

 and Crosa, Gazz. 16, 297), 6-nitro-3- 

 amino-p-toluic acid by heating the brom- 

 nitro acid with alcoholic ammonia (Ibid. 

 18, 303), 6-nitro-m-toluidine by heating 

 the iiitramino-p-toluic acid with hydro- 

 chloric acid at 150 (Ibid.\ and then 

 through o-nitrotoluene and o-toluidine 

 to o-cresol as under F and A. 



Or 3-bromcymene may be nitrated 

 (Mazzara, Gazz. 16, 193; Fileti and 

 Crosa, Ibid. 18, 289), the 3-brom-6- 

 nitrocymene oxidised to 3-brom-6-nitro- 

 p-toluic acid (F. and C. Ibid. 300), and 

 then treated as above. 



[D.] From thymol [67] through 3- 

 amino-p-cymene (cymidine) by heating 

 with ammonium bromide and ammonio- 

 zinc bromide at 350-360 (Lloyd, Ber. 

 20, 1260), and then as under G-. 



Or thymol can be converted directly 

 into 3-bromcymene by phosphorus 

 pentabromide (Fileti and Crosa, Gazz. 

 16, 291), and then into o-cresol as 

 under C. 



[E.] Carvacrol [66] on heating with 

 phosphorus pentoxide and hydrolysis of 

 the phosphate gives o-cresol (Kekule, 

 Ber. 7, 1006). 



Or carvacrol by the action of phos- 

 phorus pentasulphide can be converted 

 into thiocarvacrol (Roderburg, Ber. 6, 

 669), which by oxidation with nitric 



acid gives 2-sulpho-p-toluic acid (Flesch, 

 Ber. 6, 480; Bechler, Journ. pr. Ch. 

 [2] 8, 170). The latter can be con- 

 verted into the hydroxy-acid and o- 

 cresol as before. 



[F.] Metacresol (see below) on heating 

 with ammonio-zinc chloride and am- 

 monium chloride at 330-340 is con- 

 verted into m-toluidine (Merz and 

 Miiller, Ber. 2O, 548), the acetyl-de- 

 rivative giving on nitration 6-nitro-m- 

 toluidine (Beilstein and Kuhlberg, Ann. 

 158, 348 : see also Noelting and Stb'ck- 

 lin, Ber. 24, 564), which by the diazo- 

 method gives o-nitrotoluene (B. and K.). 

 The latter can be reduced to o-toluidine 

 and converted into o-cresol as under A. 



Or m-cresol may be ethylated, the 

 ether nitrated (Stadel, Ann. 217, 161), 

 the 6-nitro-m-cresol ether converted into 

 6-nitro-m-toluidine by heating with 

 strong ammonia (Stadel and Kolb, Ann. 

 259, 214), and the latter converted into 

 o-cresol as before. 



[G.] From cumic aldehyde [116] 

 through the 3-nitro-derivative by nitra- 

 tion, nitrocymylidene chloride by the 

 action of phosphorus pentachloride, 3- 

 amino-p-cymene (cymidine) by reduc- 

 tion, 3-amino-p-cymene-6-sulphonic acid 

 by sulphonation, 3-brom-p-cymene-6- 

 sulphonic acid by the diazo-method, 

 and then through 3-bromcymene, 3- 

 brom-6-nitro-p-toluic acid, 6-nitro~3- 

 amino-p-toluic acid, 6-nitro-m-toluidine, 

 and o-nitrotoluene to o-cresol as under C. 



[H.] From phenylacetic acid [Vol. II] 

 through the 2 : 4-dinitro acid, 2 : 4- 

 dinitrotoluene and o-nitrotoluene (see 

 under quinol [71; I]), o-toluidine, &c v 

 as under A. 



[I.] Methylheptenone [ill] by heating 

 with zinc chloride or with 75 per cent, 

 sulphuric acid gives dihydro-m-xylene 

 (Verley, Bull. Soc. [3] 17, 181). The 

 latter on nitration gives 6-nitro-m- 

 xylene (Wallach, Ann. 258, 330), and 

 this can be converted into 6-amino- 

 and 6-hydroxytoluic acid and o-cresol 

 as under A above. 



[J.] Carvone [127] through carvacrol 

 [66] gives o-cresol (see above under E). 

 Or from carvone through dihydrocarveol 

 by reduction and the ketone-alcohol 

 by oxidation. The latter by extreme 



