228 



THE ALUMNI JOURNAL, 



" MONONITROQUAIACOL." 



By RAPHAIEL MELDOLA, F. R. S. 



In the course of some investigations on phe- 

 nol derivatives, not yet complete, the author 

 had occasion to prepare mononitroguaiacol. 

 As this compound does not appear to have been 

 described before, and as the author learns that 

 other investigators are engaged on the same 

 subject, the following note on the method of 

 preparation may be found ot use. The diflScul- 

 ty in nitrating guaiacol directly is to prevent 

 the nitration going too far, so as to avoid the 

 formation of dinitroguaiacol on the one hand, 

 or, on the other hand, complete destruction of 

 material. The action of nitric acid on guaiacol 

 is rendered quite manageable by acetylating or 

 benzoylating the compound as a preliminary 

 step. The acetyl derivative is an oil (Tiemann 

 and Koppe, Ber. 14, 2020); the benzoyl deriva- 

 tive is readily formed by the action of benzoyl 

 chloride on guaiacol in the presence of sodium 

 hydroxide in aqueous solution. Crystallized 

 from dilute alcohol it forms small rhombohe- 

 dra, melting 58 to 59°. In order to nitrate the 

 acetyl derivative, it is mixed with about an equal 

 volume of glacial acetic acid, and a consider- 

 able excess of fuming nitric acid is gradually 

 added to the well-cooled mixture. It is advis- 

 able to dilute the nitric acid at first with glacial 

 acetic acid, but the undiluted acid may subse- 

 quently be added in small portions, if the con- 

 tents of the flask are not allowed to become 

 warm. The condition essential for success may 

 be briefly described as being rapid nitration at 

 a low temperature; if allowed to stand too long 

 dinitroguaiacol is formed. The great excess of 

 nitric acid is necessary to form the mononitro- 

 derivative rapidly. The whole operation takes 

 from one and a half to two hours, and the com- 

 pletion of the nitration is best ascertained by 

 stirring a few drops of the solution vigorously 

 with water on a watch-glass. If the oily de- 

 posit does not solidify on being stirred with 

 water in the course of a few minutes, more ni- 

 tric acid is required; when the oily drops soon 

 become crystalline und the conditions mention- 

 ed, the whole contents of the flask must be stir- 

 red into cold water in a thin stream, and allow- 

 ed to stand for some hours. The solid mono- 

 nitroguaiacol acetate is collected, washed with 

 water, and purified by crystallization from boil- 

 ing water. The compound separates on cool- 

 ing in small, whitish needles, having a melting 

 point of loi to 102°. 



0.0985 gave 5.6 c. c. moist nitrogen at 13.5° 



and 764.8 mm. ^6.73. The formula CgHj. N- 

 O2. OCH3. OC3H3O requires N =6.63 per cent. 



It is probable that two nitro- derivatives, an 

 ortho- and a para-, are formed during this pro . 

 cess, but the orthonitro-compound is present 

 only in small quantity, and is removed by the 

 process of crystillization. The final product is 

 most probably the paranitro compound, CgH,.- 

 NO,. OCH3. OH (4: 2: i), for reasons that will 

 appear subsequently. The acetyl derivative is 

 readily hydrolyzed by boiling with dilute caus- 

 tic alkali for a few minutes. An orange solu- 

 tion of the alkaline salt of nitroguaiacol is ob- 

 tained, and, on acidifying, the nitroguaiacol 

 separates out in the form of whitish, ochreous 

 needles. After purification by crystallizing 

 from hot water, it has a melting point of 104°. 



0.0732 gave 5 c. c. moist nitrogen at 12° and 

 771.2 nm. = 8.22. The formula C^Hg.NOa.- 

 OCH3.OH requires N =8.27 per cent. 



Benzoylguaiacol is nitrated in acetic acid by 

 the same method as that described for the 

 acetyl derivative, and, on the whole, is a more 

 satisfactory compound to work with. The first 

 action of the nitric acid is the formation of an 

 oily product, which does not solidify in water, 

 possibly a nitrate. When sufficient nitric acid 

 has been added, the oily deposit solidifies in 

 water, as before, but vigorous stirring on the 

 watch glass is necessary to promote crystalliza- 

 tion. The benzoylnitroguaiacol thus obtained 

 consists of a mixture of two modifications, 

 which can be separated by crystallization from 

 alcohol. The chief product which separates 

 out first consists of prismatic needles, melting 

 at 102 to 103°. The mother liquor deposits the 

 other modification on standing, in the form of 

 rhombic plates, which, after two or three crys- 

 tallizations from alcohol, have a melting point 

 of 88 to 89°, 



0,0976 (needles) gave 4.15 c. c. moist nitro- 

 gen at 14.5° and 765.9 mm. ^= 5.01. 



0.1078 (plates) gave 4.8 c. c. moist nitrogen 

 at 19° and 764.1 mm. = 5.12. 



The formula CsH^.NOa.OCHo.OCfHgO re- 

 quires N^ 5.12 per cent. 



Although no direct proof of the constitution 

 of these two nitro-derivatives has been obtained 

 as yet, there is every reason for believing that 

 they are the ortho- and para-compounds. 



OC.H-O OC.HjO 



OCH, 



NO., 



OCH, 



\, 



NO, 

 M. p. 102 — 103'^ 



M. p. 88—89° 



