Carboxylic acids alkylated

Aliphatic carboxylic acids Alkyl ethyl ethers Cyclic polyethers Phosphorous compounds Rearrangement peak in dioxanes... 

E. L. Shock (1990) provides a different interpretation of these results he criticizes that the redox state of the reaction mixture was not checked in the Miller/Bada experiments. Shock also states that simple thermodynamic calculations show that the Miller/Bada theory does not stand up. To use terms like instability and decomposition is not correct when chemical compounds (here amino acids) are present in aqueous solution under extreme conditions and are aiming at a metastable equilibrium. Shock considers that oxidized and metastable carbon and nitrogen compounds are of greater importance in hydrothermal systems than are reduced compounds. In the interior of the Earth, CO2 and N2 are in stable redox equilibrium with substances such as amino acids and carboxylic acids, while reduced compounds such as CH4 and NH3 are not. The explanation lies in the oxidation state of the lithosphere. Shock considers the two mineral systems FMQ and PPM discussed above as particularly important for the system seawater/basalt rock. The FMQ system acts as a buffer in the oceanic crust. At depths of around 1.3 km, the PPM system probably becomes active, i.e., N2 and CO2 are the dominant species in stable equilibrium conditions at temperatures above 548 K. When the temperature of hydrothermal solutions falls (below about 548 K), they probably pass through a stability field in which CH4 and NII3 predominate. If kinetic factors block the achievement of equilibrium, metastable compounds such as alkanes, carboxylic acids, alkyl benzenes and amino acids are formed between 423 and 293 K. 

The transformation of lithio derivatives of dibenzothiophene into alkyl, alkenyl, hydroxyalkyl, formyl, acetyl, carboxylic acid, alkyl and arylsilyl, boronic acid, aryl and carbinol derivatives of dibenzothiophene is dealt with in the appropriate sections. In addition, the four mono-tritio derivatives of dibenzothiophene have been prepared from the corresponding lithio derivatives via hydrolysis with tritiated water (Section III, 0,2). ... 

Considerable work has been devoted to the search for agents devoid of the sedative effect that accompanied some of the earlier antihistamines. One stratagem for achieving that comprises adding a function that will diminish the likelihood that the dmg will cross the blood-brain barrier. The antistamine emedastine (41-3), for example, incorporates a terminal ether that can be potentially metabolized to a carboxylic acid. Alkylation of the imidazole (41-1), available from imidazol-2-one by reaction with phosphoms oxychloride, with the chloroether (41-2) leads to a reaction on nitrogen to afford (41-3). Displacement of the enol chloride in that intermediate with A-methyl-l-4-diazepine (41-4) leads to emedastine (41- 5) [43]. 

Solutions of triethylamine (Et3N) 14 (1.0M), premixed carboxylic acid/alkyl chloroformate (1.0 M respectively), and 4-dimethylaminopyri-dine 15 (0.5 M) in MeCN were introduced into the reactor from separate inlets and the reaction products collected at the outlet in MeCN, prior to analysis by gas chromatography-mass spectrometry (GC-MS). Under optimized reaction conditions, the authors were able to synthesize the methyl 16, ethyl 17, and benzyl 18 esters in quantitative conversion, with no anhydride or deprotection by-products detected (as observed in conventional batch reactions). In addition to the Boc-glycine derivatives illustrated in Scheme 4, the authors also esterified a series of aromatic carboxylic acids with yields ranging from 91 to 100%, depending on the additional functional groups present. 

Phenols, carboxylic acids Electron capture Phenols and carboxylic acids alkylated with pentafluorobenzyl bromide, then GLC 1- 10pg L-1 [647]... 

All other carboxylic acid derivatives in Table 6.1, in which the leaving group is bound to the carboxyl carbon through an O atom, are increasingly better acylating agents than carboxylic acid alkyl esters (entry 3) in the order carboxylic acid phenyl ester (entry 4) < acyl isourea (entry 7) < mixed carboxylic acid/carbonic acid anhydride (entry 8) < carboxylic acid anhydride (entry 9) < mixed carboxylic acid anhydride (entry 10). 

Hydrides from carboxylic acids Carboxylic acids from hydrides Carboxylic acids from hydrides Esters from hydrides Hydrides from aldehydes Hydrides from aldehydes Alkyls from aldehydes Ketones from methylenes Ketones from ketones Alkyls from olefins Acetylenes from halides also acetylenes from acetylenes Esters from alcohols also esters from carboxylic acids Alkyls from olefins Alkyls from olefins... 

Alkynes from halides also alkynes from alkynes Esters from alcohols also esters from carboxylic acids Alkyls from alkenes (Conjugate Reduction)... 

Cyclic nitrones 1490 (A -imidazoline 3-oxides) react regioselectively with alkyl phenylpropiolates 1491 (or with dimethyl acetylenedicarboxylate) to give the corresponding 2-phenyl-3a,4,5,6-tetrahydroimidazo[l,5- ]isoxazole-3-carboxylic acid alkyl esters 1492. Subsequent thermal, base (piperidine, triethylamine, or alkoxide) induced ringopening reactions led to imidazoles 1493 (Scheme 385) <2004SC1617, 2000TL5407>. 

Alkyl derivatives of 7r-electron-deficient heterocyclic compounds may be oxidized anodi-cally to carboxylic acids alkyl and arylalkyl pyridines can be oxidized to the corresponding acids in good yields at a lead dioxide anode in aqueous sulfuric acid [229, 230, 376-378]. 

Extraannular and chelate-enforced intraannular chirality transfer in enolate alkylations of carboxylic acid derivatives may occur in cases where (i) the chiral center, e.g. a 3-carbon atom, is present and remains in the carboxylic portion of the molecule or (ii) the substrate contains a chiral auxiliary, e.g. the alcohol portion of an ester or the amine portion of an amide, which is removed after the alkylation to generate a chiral carboxylic acid. Alkylations of the former type will be discussed in this section. Alkylations of systems containing chiral auxiliaries are described in Section 1.1.6.4. 

Dianions derived from cc, P- or P, y-unsaturated carboxylic acids alkylate at the C carbon if the dianions are associated with alkali metal cations.22 24 However, high proportions of y-substitution are observed when Cu( i) dianions are employed.22 The preparation of dl-lanceol illustrates synthetic use of y-alkylation,22 and the preparation... 

For the neutral loss scan, the first mass analyzer (Qj) scans all the masses (Figure 7(d)). The second mass analyzer (Q3) also scans, but at a fixed offset from the first mass analyzer. This offset corresponds to a neutral loss that is commonly observed for a particular class of compounds for example, the loss of 44 u (C02) from [M — H] ions will be indicative of carboxylic acids. Alkyl loss (C H2b+i) will be seen in the loss of 15, 29, or 43, etc. and the loss of 18 u (H20) will be indicative of a primary alcohol. A comprehensive table of common neutral fragments may be found in McLafferty and Turecek.32 The mass spectrum is then a record of all precursor ions that lose the specified neutral fragment. Again, neutral loss scans cannot be performed with trap-type MS instruments or with ToF analyzers. However, postacquisition analysis software can be used to search for the specified neutral loss. 

Cation Exchange Extractants. This class of extractants includes phenols, branched alkyl carboxylic acids, alkyl phosphoric acids, diketones, and alkyl-aryl sulfonic acids. The last group listed, sulfonic acids, are analogous to sulfonic-acid cation exchange resins and have very little selectivity. Diketones, alkyl phosphoric acids and carboxylic acids can provide both cation exchange functions and coordination functions. This feature has made bis(2-ethylhexyl)phosphoric acid one of the most versatile and powerful extractants of this type. (5) The nation below illustrates simple cation exchange extraction. 

Figure 191. Accumulation of carboxylic acid alkyl ester from polypropylene container at 25°C and pH 2.-------------,...

Hydroxylamines and Nitramines.—Oximes are readily reduced to hydroxylamines under various conditions, but when the reduction is carried out using sodium borohydride in the presence of a carboxylic acid alkylation also takes place, affording a useful new synthesis of NiV-dialkylhydroxylamines (Scheme 12). The yields of nitramines obtained from the reduction of nitrimines by sodium borohydride may be improved by carrying out the reactions in the presence of acetic acid. ... 

Carboxylic acids) (alkyl) Esterification -C03-CH3C,H5 -C03-CH3C,F3 2 ... 

Solvating reagents such as neutral compounds (e.g., ethers, ketones, alcohols, and esters of carboxylic acids, alkyl phosphates, phosphonates, phos-phinates, phosphine oxides, and phosphine sulfides) and also esters of pyridinecarboxylic acids and certain benzimidazole derivatives that have electron-withdrawing substituents form solvates with extracted neutral species. For example, dialkylpyridine-3,5-carboxylates extract Cu(II) at pH 3 from concentrated chloride solutions ... 

Beside 4-nitrophenyl esters, other activated esters and amides (e.g. of pentafluorophenol, imidazole and meanwhile even 3-chlorophenol) have been shown to be viable substrates. However, substantial additional progress in catalyst development is required to extend the scope of the reaction further to carboxylic acid alkyl esters, which can be regenerated by in situ esterification. This is strictly required, as a two-step process is not likely to be able to compete with the standard Mizoroki-Heck reaction from a purely economical standpoint. 

General procedure for the synthesis of 1,4,7,8-tetrahydro-2,7,7-trimethyl-4-aryl-5(6H)-oxo-quinolin-3-carboxylic acid alkyl ester (5). A mixture of aldehyde (1 2 mmol), dimedone (2 2 mmol), p-ketoester (3 2 mmol), and ammonium acetate (4 3 mmol) was thoroughly mixed in a mortar followed by grinding till the completion of reaction as indicated by TLC (12-45 min). The resultant mass was washed with water to remove any unreacted ammonium acetate and was air-dried to give a crude product which on recrystallization from ethanol afforded the pure desired compound (5) in excellent yield (80-95%). 

Solid-liquid phase transfer catalysis—carboxylic acid alkylation... 

---