Bases, 0-acetyl derivatives

QHgNiOiS. Colourless crystals, m.p. 164 5-166-5" C. It is usually prepared by treating p-acetamidobenzenesulphonyl chloride with ammonia, and hydrolysing the acetyl derivative to the base. Used for the treatment of streptococcal infections, gonorrhoea, meningococcal meningitis and urinary infections. Liable to cause unpleasant reactions, such as nausea, cyanosis and skin rashes. 

Reflux gently in a test-tube under a short air condenser 1 g. of the base with 2 5 mols or 3 0 g. (3 0 ml.) if the molecular weight is unknown of redistilled acetic anhydride for 10-15 minutes. Cool the reaction mixture and pour it into 20 ml. of cold water (CAUl ION). Boil to decompose the excess of acetic anhydride. When cold, filter the residual insoluble acetyl derivative and wash it with a little cold water. Recrystal-/ise from water or from dilute alcohol. 

Triazoles are acylated with acyl halides, usually initially at the 1-position, but the acyl group may migrate to the 2-position on heating or on treatment with base. Thus acetylation with acetyl chloride often gives 1-acetyl derivatives, which rearrange to the 2-isomers above 120 °C (74AHCil6)33). 

Purification as their N-acetyl derivatives is satisfactory for primary, and to a limited extent secondary, amines. The base is refluxed with slightly more than one equivalent of acetic anhydride for half to one hour, cooled and poured into ice-cold water. The insoluble derivative is filtered off, dried, and recrystallised from water, ethanol, aqueous ethanol or benzene (CAUTION toxic ). The derivative can be hydrolysed to the parent amine by refluxing with 70% sulfuric acid for a half to one hour. The solution is cooled, poured onto ice, and made alkaline. The amine is steam distilled or extracted as above. Alkaline hydrolysis is very slow. 

Pellotine and Anhalonidine. The A -acetyl derivative of mezcaline (I NHj— NHAc), on treatment with phosphoric oxide, yields 6 7 8-trimethoxy-l-methyl-3 4-dihydrowoquinoline (picrate, m.p. 181-2°), which, on successive catalytic hydrogenation and treatment with methyl sulphate, yields 6 7 8-trimethoxy-l 2-dimethyl-l 2 3 4-tetrahydro-isoquinoline identical with 0-methylpellotine (picrate, m.p. 167-8°), whence it appears that pellotine must be a dimethyl ether of 6 7 8-trihydroxy-1 2-dimethyl-l 2 3 4-tetrahydrowoquinoline. Pellotine and anhalonidine on complete methylation yield the same product, and as anahalonidine is a secondary base and differs from pellotine by containing —CHj less, it must be a dimethyl ether of 6 7 8-trihydroxy-l-methyl-1 2 3 4-tetrahydrowoquinoline, and pellotine should be A -methyl-anahalonidine. 

Addendum. In a recent paper Bertho et al. have described a new process for the isolation of kurchi alkaloids. From the final residue a new base, C23H34N2, m.p. 129 5°, was isolated as the carbonate, m.p. 91° it provides the following salts B, 2HI, 2H2O, dec.) 174° B, 2HCIO4, 2.5H2O, m.p. 283°, and a mono-acetyl derivative, m.p. 254°. In a second paper Bertho, Schonberger and Kaltenbom describe further products obtained in the oxidation of conessine by chromic acid and by potassium permanganate. ... 

This structure rationalizes (a) the formation of mono- and, under more vigorous conditions, tetra-acetyl derivatives, (b) the methyla-tion to a dimethyl derivative still containing two active hydrogens, (c) the pyrolysis back to monomeric indole, (d) the formation of a benzylidene derivative containing the Ph CH=N— Ar ehromophore, (e) the failure to form a simple nitroso derivative, (f) the Zn/AcOH reduction of the dimethyl trimer to base C18H20N2, shown to be identical with the dihydro derivative of (26). 

Hunter and Nelson (41 Mil) attempted the preparation of 4(5)-aminoimidazole (25 R = H) from its acetyl derivative (28 R = H, R1 = Me), which they obtained by reduction of 4(5)-nitroimidazole (27 R = H) with tin(II) chloride in acetic anhydride. The authors noted that hydrolysis of compound (28 R = H, R = Me) with aqueous acids resulted in fission of the imidazole ring and formation of acetic acid, formic acid, ammonia, and glycine. Base hydrolysis gave similar results (41 Mil), although a trace of 4(5)-aminoimidazole (25 R = H) was detected. 

Cyclization of a-cyanoalkyl cyanamides (74) with hydrogen bromide gave 4-aminoimidazoles (77) as their hydrobromide salts. These compounds (77) were found to be unstable as the free base but gave stable (V-acetyl derivatives (84 R2 = Br, R3 = COCH3) (33-82%) when treated with acetic anhydride in pyridine (64JOC153 66CA12211). 

In a study of isomerization in some partially acetylated derivatives of mt/o-inositol, weak bases were found to catalyze migration between all of the oxygen atoms, and cis and trans migrations occurred with almost equal facility.546 Equilibration of DL-2-O-acetyl-... 

Since an acetyl derivative of an alcohol is easily cleaved by LiAlH4, the reagent is often used in the deacetylation of compounds sensitive to acids or bases. 

Dry the ethereal solution with a small piece of potassium hydroxide and evaporate the ether, when the diamine formed algng with the sulphanilic acid remains it can be recognised by the colour reaction described on p. 319 (Wurster s red). It becomes crystalline on cooling. Its acetyl derivative, which is obtained by warming the crude base on the water bath for a short time with 0-5 c.c. of acetic anhydride (in a test tube,) is also suitable for characterising the diamine. The solution is diluted with water and, since the acetyl... 

The second new compound, pseudopterosin Y (2) was also purified a yellow gum. Its UV and IR spectra were identical to those of compound 1, indicating the presence of same n system and functional groups in 2. The HREIMS of 2 showed the M+ at m/z 516.2420 corresponding to the molecular formula A combination of H-, C-NMR, COSY, HSQC and HMBC spectral data revealed that compound 2 was C-3 acetyl derivative of compound 1. Based on these spectral data, stmcture 2 was assigned to this new compound. 

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