Organic 2 Review Problem 288

Organic 2 Review Problem 288 - 272 P RACTICAL O RGANIC C...

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272 PRACTICAL ORGANIC CHEMISTRY as colourless crystals, m.p. 127°. Yield of recrystallised material, 6-0-6-5 g- The tautomerism shown by the pyrazolones is of considerable interest. Thus the above methyl-phenyl-pyrazolone when fused or in solution can exist in the tautomeric forms (C), (D), and (E). CH 3 C : N-NC 6 H 6 CH 3 C-NHNC 6 H 6 CH 3 CrN-NC 9 H 6 I I ^ Il I ^ I I CH 2 -CO (C) CH — CO (D) CH = C(OH) (E) When the methyl-phenyl-pyrazolone is heated with methyl iodide in methano- lic solution, it acts in the form (D), the -XH- group undergoing methy- lation, with the formation of the hydriodide of 2,3-dimethyl-i-phenyl- 5-pyrazolone, or antipyrine (F), a drug used (either as the free base or as the CH 8 C-N(CHs)-NC 6 H 6 CH 3 C-N(CH,)-NC 6 H 5 Ii I Il I CH - CO (F) (CH 3 ) 2 N C --- CO (G) salicylate) to remove pain and also to reduce the body temperature. Anti- pyrine in turn can be converted to 2,3-dimethyl-4-(dimethylamino)-i-phenyl-5- pyrazolone, or pyramidon (G), a drug which has physiological properties similar
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

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