Pyridine acetamido

P3Tidazine 1-oxide, 3-hydroxy-, 361 Pyridazinones, 364-368 Pyridine acetamido-, 331 acylamino-, 418-421 alkoxy-, 347 alkyl-, 426, 427 amino-, 323, 333, 404 408 benzamido-, 418... 

Imidazo[4,5-6]pyridine, 5-acetamido-7-chloro-3-jS-D-ribofuranosyl-N-benzylation, 5, 619... 

Benzyl-2-acetamido-4,6-(7-benzylidene-2-deoxy-a-D-glucopyranoside [13343-63-0] M 399.4, m 256-261 , 263-264 , [alp +120 (c 1, pyridine). Wash with cold isoPrOH and crystallise from dioxane/isoPrOH. [/ Org Chem 32 2759 1967.]... 

It has been shown that acetamidothiophenes 22 can be converted to either chlorothieno[2,3-h]pyridines 23 or chlorothieno[2,3-h]pyridinecarboxaldehydes 24 using POCI3 and DMF by appropriate choice of reaction conditions. However, unlike the acetanilides, initial ring formylation rather than side-chain formylation is believed to lead to the formation of the pyridine ring. These reactions have been extended to the synthesis of the isomeric thieno[3,2-I>]- and thieno[3,4-I>]pyridines, 25 and 26, from 3-acetamidothiophene and 3-acetamido-2,5-dimethylthiophene, respectively. 

The infrared spectra of 2-, 3-, and 4-acetamido- and 2- and 3-benzamido-pyridine 1-oxides show bands characteristic of the 2-, 3-, or 4-substituted pyridine 1-oxide and of the —NHCOCH3... 

The corresponding [5,4-6]-compound (107) was prepared similarly and treated with methyl iodide to give a quaternary salt which was shown to have structure 108, because mild alkaline hydrolysis gave 3-acetamido-l-methyl-2-pyridone. Again, quaternization took place on the pyridine-nitrogen, which is different from the behavior of the corresponding 1,4-diazaindene mentioned above. 

The reaction of 6-amino[l,2,4]triazin-5(2//)-ones or its thione derivatives 680 with acetic anhydride gave the 6-acetamido derivatives 681 and 682, respectively. Treatment with phosphorus pentasulfide in pyridine gave thiazolo[5,4-e][l,2,4]triazines 683 (84LA283 87AJC491) (Scheme 142). 

A mixture of 156.6 g. (159 ml., 1.98 moles) of pyridine (Note 1), 239.9 g. (224 ml., 2.35 moles) of acetic anhydride (Note 2), and 35.1 g. (0.394 mole) of vacuum-dried alanine (Notes 3 and 4) is heated with stirring (Note 5) on the steam bath for 6 hours after solution is complete (Note 6). The excess pyridine and acetic anhydride, and the acetic acid, are removed at reduced pressure. The residue is distilled through a 15-cm. column, packed with glass helices, to give 41.5-47.5 g. of crude product, boiling at 110-125°/3 mm. Refractionation gives 41-45 g. (81-88%) of 3-acetamido-2-butanone b.p. 102-106°/2 mm. 1.4558-1.4561 (Note 7). 

AW, Acid-washed Choi, Cholesterol DMAP, 4-(Dimethylamino)pyridine DMF, N,/V-Dimethylformamide DMTr, Di(p-niethoxyphenyl)phenyl methyl GalNAc, N-Acetylgalactosamine, 2-acetamido-2-deoxy-D-galactose HMF, 5-Hydroxymethylfur-fural, 5-(hydroxymethyl)-2-furaldehyde INOC, Intramolecular nitrile oxide-alkene cycloaddition Lea, Lewisa Lex, Lewisx MOM, Methoxymethyl MP, p-Methoxyphe-nyl MS, Molecular sieves NIS, N-Iodosuccinimide PCC, Pyridinium chlorochromate PDC, Pyridinium dichromate PMA, Phosphomolybdic acid PMB, p-Methoxybenzyl ... 

The acetamido derivative (118 R1 = triacetylribonucleoside, R2 = H, R3 = Me) (86%) was prepared from a mixture of isomeric precursors (96 R = diacetylribonucleoside, R2 = H) by treatment of a dichloromethane solution with acetic anhydride in the presence of pyridine (90JA4891). 

V-(4-Amino-l-isoquinolinyl)aminomethylenemalonate (1457, R = NH2) was acetylated with acetic anhydride in pyridine at ambient temperature to give the 4-acetamido derivative (1457, R = NHAc) [84JAP(K) 172472]. 

A somewhat different procedure was needed for purifying the limpet enzyme to the same extent.48 The activity of a-D-mannosidase from this source was rapidly destroyed by pyridine. Selective inactivation of 2-acetamido-2-deoxy-/3-D-glucosidase was, therefore, effected by warming the preparation in 60% ethanol. /3-D-Galacto-sidase was removed in the course of fractionation. 

The following abbreviations are used in Tables I and II A = acetone, B = benzene, C = chloroform, D = dichloromethane, E = ethanol, M = methanol, P = pyridine, W = water, eq = equilibrium rotation value, / = furanoside, p = pyranoside, and R = 2-acetamido-2-deoxy-D-glucose see also Ref. 99. 

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