Alkyl ammonium acetate

Cyclization of l-(acylamino)pyrimidine hydroiodides (1) with alkyl ammonium acetates gave 3//J5//-l,2,4-triazolo[l,5-a]pyrimidines (2) (87 EGP246999 89ZC378). Condensation of the l-(acylamino)pyrimidinium salt 3 with hydrazine hydrate gave 4, which upon cyclization with acetic acid in the presence of perchloric acid afforded the 3-amino-l,2,4-triazolo [l,5-a]pyrimidinium salt 5 (89EGP270711) (Scheme 2). 

The effect of the chain length of alkyl ammonium acetates on the zeta-potential of quartz is shown in Fig. 2.18. With an increase in amine concentration, zeta-potential is reversed to positive values and with an increase in the chain length, n, the concentration required... 

Fig. 2.18. Effect of chain length of alkyl ammonium acetates on zeta potential of quartz (Somasundaran, 1964).

Fig. 2.19. Concentration of alkyl ammonium acetate required for = 0 as a function of alkyl chain length, n (Somasundaran, 1964).

Fig. 4.13. Least square plot of Ccsc of alkyl ammonium acetates from zeta potential data as a function of the number of carbon atoms in the chain.

An interesting new synthesis of 2,4,5-trisubstituted and 2,4-disubstituted alkylthiazoles has been reported by Dubs (807). Heating the easily obtainable derivatives (276) with ammonium acetate in acetic acid gives thiazoles (10), Rj, Rj = alkyl and R3 = H or alkyl in good yields (Scheme 143). 

Physical Properties. Sulfuryl chloride [7791-25-5] SO2CI2, is a colorless to light yellow Hquid with a pungent odor. Physical and thermodynamic properties are Hsted ia Table 7. Sulfuryl chloride dissolves sulfur dioxide, bromine, iodine, and ferric chloride. Various quaternary alkyl ammonium salts dissolve ia sulfuryl chloride to produce highly conductive solutions. Sulfuryl chloride is miscible with acetic acid and ether but not with hexane (193,194). 

The synthesis of 4-unsubstituted DHPs in a focused microwave reactor has been reported using alkyl acetoacetates and hexamethylenetetramine 19 as the source of both formaldehyde and ammonia, with additional ammonium acetate to maintain the stoichiometry [57], Irradiation for 100 s under solvent-free conditions gave, for example, 1,4-DHP 20 in 63% isolated yield (Scheme 5). 

A number of microwave-assisted multicomponent methods for the synthesis of imidazoles have been reported [68-71 ]. The irradiation of a 1,2-diketone and aldehyde with ammonium acetate in acetic acid for 5 min at 180 °C in a single-mode reactor provides alkyl-, aryl-, and heteroaryl-substituted imidazoles 39 in excellent yield (Scheme 14) and this method has been used for the rapid and efficient preparation of two biologically active imidazoles, lepidiline B and trifenagrel [68]. 

This transformation can also be carried out under solvent-free conditions in a domestic oven using acidic alumina and ammoniiun acetate, with or without a primary amine, to give 2,4,5-trisubstituted or 1,2,4,5-tetrasubstituted imidazoles, respectively (Scheme 15A) [69]. The automated microwave-assisted synthesis of a library of 2,4,5-triarylimidazoles from the corresponding keto-oxime has been carried out by irradiation at 200 ° C in acetic acid in the presence of ammonium acetate (Scheme 15B) [70]. Under these conditions, thermally induced in situ N - O reduction occurs upon microwave irradiation, to give a diverse set of trisubstituted imidazoles in moderate yield. Parallel synthesis of a 24-membered library of substituted 4(5)-sulfanyl-lff-imidazoles 40 has been achieved by adding an alkyl bromide and base to the reaction of a 2-oxo-thioacetamide, aldehyde and ammonium acetate (Scheme 15C) [71]. Under microwave-assisted conditions, library generation time was dramatically re-... 

A different multicomponent route to imidazoles has been described by the group of O Shea, involving the diversity-tolerant three-component condensation of an aldehyde, a 2-oxo-thioacetamide, and an alkyl bromide (5 equivalents) in the presence of ammonium acetate (Scheme 6.201) [364]. This allowed the preparation of a 24-membered 4(5)-alkylthio-lH-imidazole demonstration library from 21 different aldehydes, 12 alkyl bromides, and two 2-oxo-thioacetamides. The library was synthesized in a parallel format using a custom-built reaction vessel. Alkylthioimidazoles... 

CE using fused-silica capillary and the buffer solution containing 30 mM ammonium acetate in water at pH 5.3 with 40% acetonitrile. Under cathodic detection conditions, LAS homologues elute in order of decreasing alkyl chain length. 

Fig. 2.12.4. FIA-APCI-MS-MS(+) CID product ion mass spectrum of selected [M]+ parent ion of cationic quat surfactant blend RR N (CH3)2X at mtz 304 characterised as alkyl di-methylbenzyl ammonium acetate fragmentation pattern presented in the... 

When chromatographic resolution of species based on modifications located at the protein surface is desired, it may be advisable to use conditions that favor retention of native conformation.17 Here, the standard acidic conditions described in the preceding text may be inappropriate, and mobile phases buffered near neutrality may be required. Buffers based on ammonium acetate, ammonium bicarbonate, and triethylammonium phosphate may prove more useful in resolving polypeptide variants with differing posttranslational modifications, amino acid substitutions, or oxidation and deamidation products. The addition of more hydro-phobic ion-pairing agents may be needed to obtain polypeptide retention, and a variety of alkyl sulfonates and alkyl amines have been described for specific applications.17... 

Stractures of 3-alkyl-5-methylindolizidines, found in thief ants, Solenopsis species (Table II), arrived at by gas chromatographic and mass spectral analysis were confirmed by coinjection and direct comparison with the synthetic sample. Indolizidine 15a from S. conjurata exhibits characteristic peaks at miz 152 (M — CHj) and 138 (M — C2H5, a base peak) as well as a parent peak at m/z 167 in the mass spectram. It corresponds to an isomer of 3-ethyl-5-methylindolizidine (15) which was prepared as a mixture of four stereoisomers by reductive amination of triketone 391 with ammonium acetate-sodium cyanoborohydride and sodium borohydride (Scheme 47). 

If a ketone rather than an ester group were present at position 2 of the pyridinium salt (266, Scheme 131), ammonium acetate produced 2-azaquinolizinium salts with an alkyl or aryl group at position 1 (Table 15). 

The yields of primary amines over platinum oxide were improved in the presence of an excess molar equivalent of ammonium chloride in low pressure reductive alkylation of ammonia with ketones in methanol saturated with ammonia.10 With acetophenone and 4-methyl-2-pentanone, the yields of primary amine increased from 37 and 49% in the absence of ammonium chloride to 69 and 57-65%, respectively, in the presence of ammonium chloride. Moller obtained a much higher yield (>90%) of 1-phenethylamine from acetophenone by adding a small amount of acetic acid to methanol-ammonia with Raney Ni (eq. 6.6).15 The reductive amination of benzophenone in the presence of Raney Co and some ammonium acetate gave 70% yield ofbenzohy-drylamine, compared to only 19% under usual conditions with Raney Ni.3... 

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