Alkylation carboxylic imide

The Akzo Nobel alkyl ammonium carboxylate (zwitterionic)/SDBS (molar ratio 4 1) surfactant mixture is DR in both water and ethylene glycol/water systems. However, better DR results were obtained at lower temperatures by a new alkyl amin-imide zwitterionic in both water and ethylene glycol/water solutions [Zhang et al., 2005b], This was attributed, in part, to the presence of the oleyl chain, which enhances low-temperature solubility. 

C for 6 h afforded the alkylated imides in 60-84% yields. The last approach was extended to unsaturated carboxylic amides. The diene 0,N-acetal 86 was prepared from the amide 85 in high yields and subsequently treated with azoinitiator V-70 to afford the desired products (Scheme 13). ... 

Condensation of the triacid with aniline gave an imide 8 for which the barrier to rotation about the CaryrNimid<, bond indicated was about 13 kcal/mole9). However, ortho substituents stop this rotation and fix the conformation in such a way that the alkyl (or practically any other group) is directed away from the carboxyl function as in 9. The seemingly passive methyl groups of this structure thereby limit the internal rotations and enforce a fairly rigid structure. 

Isocyanates are derivatives of isocyanic acid, HN=C=0, in which alkyl or aryl groups, as well as a host of other substrates, are direcdy linked to the NCO moiety via the nitrogen atom. Structurally, isocyanates (imides of carbonic acid) are isomeric to cyanates, ROC N (nitriles of carbonic acid), and nitrile oxides, RO Nf—>0 (derivatives of carboxylic acid). 

Asymmetric aikyiation of imide etiolates.1 The sodium enolates of 3 and 7 are alkylated with marked but opposite diastereoselectivity by alkyl halides. The selectivity is improved by an increase in the size of the electrophile, with methylation being the least stereoselective process. The asymmetric induction results from formation of (Z)-enolates (chelation) with the diastereoselectivity determined by the chirality of the C4-substituent on the oxazolidone ring (equations I and II). The products can be hydrolyzed to the free carboxylic acids or reduced by LiAlH4 to the corresponding primary alcohols and the unreduced oxazolidone (1 or 2). 

The reaction under consideration is typified by the formation of saturated carboxylic acids from olefins, carbon monoxide, and water. Other compounds have been used in place of olefins (alkyl halides, alcohols), and besides water, a variety of compounds containing active hydrogen may be employed. Thus, alcohols, thiols, amines, and acids give rise to esters, thio-esters, amides, and acid anhydrides, respectively (15). If the olefin and the active hydrogen are part of the same molecule, three or four atoms apart, cyclizations may occur to produce lactones, lactams, imides, etc. The cyclizations are formally equivalent to carbonylations, however, and will be considered later. 

Figure 7.2 illustrates the phosphorus pentoxide-mediated dehydration of a primary amide to a nitrile, using the transformation of nicotine amide (A) into nicotine nitrile (B) as an example. The reaction of phosphorus pentoxide at the carboxyl oxygen furnishes the partially ring-opened iminium ion E (simplified as F) via the polycyclic iminium ion C. E is deprotonated to give the mixed anhydride G from imidic acid and phosphoric acid. Imidic acids are characterized by the functional group R-C(=NH)-OH. This anhydride is transformed into the nitrile B by an El elimination via the intermediate nitrilium salt D. Nitrilium salts are iV-pro-tonated or V-alkylated nitriles. 

Reagents like NH2—R —Si(OR)3 are useful for the synthesis of functional precursors with an imido group. This is possibly achieved by reacting the alkyl(trialkoxysilyl)amine with at least three types of substrates (1) with a suitable carboxylic acid chloride114,116120, (2) by transimidation of bisimides, e.g. in the preparation of 52 according to equation 13115, and (3) by the imidization of an anhydride as in the preparation of 53 (equation 14)112. 

For alkyl amines, a direct correlation between the steric bulk at the a-carbon and the yield of the reaction was found amines attached to a secondary carbon gave higher yields than amines connected to a tertiary carbon, while amines connected to a quaternary carbon led only to the formation of an amide-carboxylic acid intermediate, rather than the corresponding imide. In the case of amino acids whose ot-carbons are tertiary, a lower temperature was surprisingly required for high NMI selectivity in the first step (40 °C instead of 75 °C). This was explained by the presence of the COOR group, which assists in the collapse of the tetrahedral intermediate precursor to the imide formation. The amino acid derived NMIs were obtained as a mixture of open and closed forms due to the addition of triethylamine in the reaction. At high temperatures this promotes the formation of... 

An acid—base reaction forms a nucleophilic anion that can react with an unhindered alkyl halide— that is, CH3X or RCH2X—in an 5 2 reaction to form a substitution product. This alkylated imide is then hydrolyzed with aqueous base to give a 1° amine and a dicarboxylate. This reaction is similar to the hydrolysis of amides to afford carboxylate anions and amines, as discussed in Section 22.13. The overall result of this two-step sequence is nucleophilic substitution of X by NH2, so the Gabriel synthesis can be used to prepare 1° amines only. 

Microwave irradiation of a mixture of an acid anhydride, an amine adsorbed on silica gel, and TaCl5/Si02 is a solvent-free method for the synthesis of A-alkyl and A-aryl-imides [47]. Ni(II) promotes the conversion of an acrylamide to ethyl acrylate via a Diels-Alder adduct with (2-pyridyl)anthracene [48], Aromatic carboxylic acids [49] and mandelic acid [50] are efficiently esterified with Fc2(S04)3 XH2O as catalyst. Co(II) perchlorate in MeOH catalyzes the methanolysis of acetyl imidazole and acetyl pyrazole [51]. Hiyama et al. used FeCb as a catalyst for the acylation of a silylated cyanohydrin. The resulting ester was then cyclized to 4-amino-2(5H)-furanones (Sch. 5) [52]. 

Optically active imidazolines are generally obtained from enantiopure 1,2-diamines. For example, chiral ferro-cenylimidazolines are prepared from ferrocenyl carboxylic acid 1241 (Scheme 310). Amide 1242 is activated by 0-alkylation with Et30 BF4, generating iminium ether tetrafluoroborate salt 1243. The formation of the imidazoline ring in 1244 is accomplished by condensation of 1243 with the chiral diamine 1245 at room temperature without the need to isolate the intermediate imidate 1243 <20050L4137>. 

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