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Pfeiffer, W. D., Science of Synthesis, (2007) 35, 158.
An aqueous solution of formaldehyde can also be used for the chloromethylation of arenes. The treatment of benzene with formaldehyde, hydrogen chloride gas, and zinc(II) chloride affords benzyl chloride in 76% yield.[28] The chloromethylation of 1,3,5-trimethylbenzene with a 37% formaldehyde solution leads to 2-(chloromethyl)-1,3,5-trimethylbenzene (55–66%).[29] 1,2,3,4-Tetramethylbenzene (9) reacts with aqueous formaldehyde–hydrogen chloride to give 1-(chloromethyl)-2,3,4,5-tetramethylbenzene (10) (Scheme 6).[30] 1-(Chloromethyl)-2,3,4,5,6-pentamethylbenzene is obtained from 1,2,3,4,5-pentamethylbenzene with 37% formaldehyde solution and hydrogen chloride.[30] The reaction of naphthalene with 30% aqueous formaldehyde gives 1-(chloromethyl)naphthalene.[6] A mixture of 40% aqueous formaldehyde–hydrogen chloride reacts with phenanthrene to give 9-(chloromethyl)phenanthrene.[31] Treatment of thiophene with aqueous formaldehyde–hydrogen chloride affords 2-(chloromethyl)thiophene[32–35] {see also Science of Synthesis, Vol. 9 [Fully Unsaturated Small-Ring Heterocycles and Monocyclic Five-Membered Hetarenes with One Heteroatom (Section 9.10.1.4.1.59.10.1.4.1.5)]}. Thiophene reacts with an excess of 37% formaldehyde solution to give 2,5-bis(chloromethyl)thiophene.[36] Treatment of uracil with 38% aqueous formaldehyde–hydrogen chloride affords 5-(chloromethyl)uracil in 45% yield.[37]
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References
| [6] | Meeee, M. M.; Meeee, M. M., M. Me. Meee. Mee., (8888) 88, 888. |
| [28] | Meee, M. M., MM 8 888 888, (8888); Meee. Meeee., (8888) 88, 8888. |
| [29] | Meeee, M. M.; Meeeeee, M.; Meeeeeee, M. M.; Meeeee, M. M.; Meeeeee, M. M., Mee. Meeee., Meee. Mee. MMM, (8888), 888. |
| [30] | Meeeeeeee, M.; Meeee, M. M.; Meeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
| [31] | Meeeeee, M. M.; Meeeeeee, M. M., M. Me. Meee. Mee., (8888) 88, 8888. |
| [32] | Meeeee, M. M.; MeMeeee, M. M.; Meeeeeee, M. M.; Meeeee, M. M., Mee. Meeee., Meee. Mee. MMM, (8888), 888. |
| [33] | Meeeee, M. M.; Meeeeeee, M., M. Me. Meee. Mee., (8888) 88, 8888. |
| [34] | Meeeeeeee, M.; Meeee, M., Meee. Meee. Meee., (8888) 888, 888. |
| [35] | Meeeeee, M.; Meeee, M., M. Mee. Meee., (8888) 88, 8888. |
| [36] | Meeeeeee, M. M.; Meeeeeeee, M. M., M. Me. Meee. Mee., (8888) 88, 8888. |
| [37] | Meeeeeeeeee, M. M.; Meeeeee, M. M.; Meeeeeeeeee, M. M., M. Me. Meee. Mee., (8888) 88, 888. |
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- 8.Meeeee-Meee, (8888) 8/8, 8888.
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