Thiol carboxylic acid

Trimethylsilyl trichloroacetate, K2CO3, 18-crown-6, 100-150°, 1-2 h, 80-90% yield.This reagent silylates phenols, thiols, carboxylic acids, acetylenes, urethanes, and /3-keto esters, producing CO2 and chloroform as byproducts. 

There are a few isolated cases of the addition of amines, thiols, carboxylic acids, and a phosphorus ylide to doubly bonded germanium compounds. Again, the reactions are regioselective, with the nucleophilic portion of the weak acid adding to the germanium and the proton adding to the heteroatom. 

Compounds with an acidity constant, pK, in the range of 4 to 10, i.e. weak organic acids or bases, are present in two species forms at ambient pH. This pA a.i. range includes aromatic alcohols and thiols, carboxylic acids, aromatic amines and heterocyclic amines [15]. Conversely, alkyl-H and saturated alcohols do not undergo protonation/deprotonation in water (pA iw 14). 

Mercaptoacyl pharmacophore library. Zinc metalloproteases are inhibited by small molecules that contain mercaptans (thiols -CH2SH), carboxylic acids (-CO2H), and hydroxamic acids (-CONHOH). These functional groups chelate the active-site metal disrupting normal enzyme function. The angiotensinconverting enzyme (ACE) inhibitor Captopril is an example of a thiol-based metalloprotease inhibitor. Thiols, carboxylic acids, and hydroxamic acids are consequently affirmed pharmacophores for this protease family. A historical example of a pharmacophore-... 

Catalytic vinylation has been applied to the manufacture of a wide range of alcohols, phenols, thiols, carboxylic acids, and certain amines and amides. Vinyl acetate is no longer prepared this way in many countries, although some minor vinyl esters such as vinyl stearate may still be manufactured by this route. However, the manufacture of vinyl-pyrrolidinone and vinyl ethers still depends on acetylene as the starting material. 

Fig. 3.9. Schematic showing the piace exchange of octanethioi molecules on the surface of gold nanoparticles by co-thiol carboxylic acid molecules. (Reprinted with permission from [74], 2000, Royal Society of Chemistry).

The conversion of thiol carboxylic acid 54 derived from the, vj -amide, sy -64 (Fig. (31)) to 8 was then investigated. Employing Poetsch and co-workere protocol [85] using DCC in the presence of p-TsOH in pyridine gave a moderate yield (57%) (Table 10, Entry 1). 

In many cases, the electrochemical technique recently developed has been shown to be a fruitful alternative to chemical deprotection. Thus, organic chemistry functions that are mainly involved in protection/deprotection processes are mostly aldehydes and ketones, amines, alcohols, and thiols carboxylic acids can also be quoted, although their esterification as well as their ester hydrolyses are not straightforward. 

Because these enzymes are zinc metal-lopeptidases, all of their inhibitors contain a metal coordinating group such as a thiol, carboxylic acid, or hydroxamic acid. The first potent synthetic inhibitor of NEP, thiorphan (253 = 4.7 nM) (978), was based on a model... 

Thiiranone (142) reacts with methanol and benzylamine to yield a-thiol carboxylic acid derivatives (143) and (144) (Scheme 52) <77AG(E)722>. 

This step is a thiol-carboxylic acid reaction to yield a thioester, acetyl coenzyme A. 

The resultants, 1,1,2,2-tetrahydroperfluoroalkyl iodides, can be easily converted, e.g., into alcohols, thiols, carboxylic acids and ethoxylated products. Thus, direct hydrolysis of 2-perfluoroalkyl iodides leads to perfIuoroalkyl-2-ethanols which show surface activity in non-aqueous solvents. Such approaches to fluorosurfactant synthesis have been put on stream by Du Pont, Ciba-Geigy, Hoechst, Asahi Glass and Daikin Kogyo. 

Olefin derivatives with electron-attracting substituents, such as, for example, acrylic compounds and dienes, as well as lactams, lactones, oxiranes, thiiranes, isocyanates, and A -carboxy anhydrides of a-amino acids, a-hydroxy carboxylic acids, and a-thiol carboxylic acids can be polymerized anionically ... 

Low-molecular-mass aldehydes, amines, thiols, carboxylic acids, phenols, NO2, HNO3, NH3, SO2, pesticides... 

Iranpoor, N., Firouzabadi, H., Akhlaghinia, B., and Azadi, R. (2004). Conversion of alcohols, thiols, carboxylic acids, trimethylsilyl ethers, and carboxylates to thiocyanates with triphenylphosphine/diethy-lazodicarboxylate/NH4SCN. Synthesis, 92-96. 

Silanating reagents Alkane thiols Carboxylic acids Sulfonyl halides,... 

Thioesters, Selenoesters, and Thioamides.—Commercially available phenyl dichlorophosphate has been reported to be a superior reagent to MV-dimethyl-phosphoramidic dichloride (4, 244) for the preparation of thioesters directly from carboxylic acids and thiols. Carboxylic acid chlorides can be efficiently converted into thioesters by reaction with adducts formed between thiols and l-methylpyridine-3,5-dicarboxylates. Alternatively, copper(i) mercaptides, formed from thiols and CuaO, or thallous thiophenoxide can be used. The latter method can also be used to prepare selenoesters as well as a-phenylthio-and a-phenylseleno-acids and esters from a-halo-acids and a-halo-esters, respectively. 

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