Acid-analogous

This method is widely used for the resolution of chiral amines and carboxylic acids Analogous methods based on the formation and separation of diastereomers have been developed for other functional groups the precise approach depends on the kind of chem ical reactivity associated with the functional groups present m the molecule... 

Ho, the acidity function introduced by Hammett, is a measure of the ability of the solvent to transfer a proton to a base of neutral charge. In dilute aqueous solution ho becomes equal to t d Hq is equal to pH, but in strongly acid solutions Hq will differ from both pH and — log ch+. The determination of Ho is accomplished with the aid of Eq. (8-89) and a series of neutral indicator bases (the nitroanilines in Table 8-18) whose pA bh+ values have been measured by the overlap method. Table 8-19 lists Ho values for some aqueous solutions of common mineral acids. Analogous acidity functions have been defined for bases of other structural and charge types, such as // for amides and Hf for bases that ionize with the production of a carbocation ... 

Much of what is known about the chymotrypsin mechanism is based on studies of the hydrolysis of artificial substrates—simple organic esters, such as /Miitrophenylacetate, and methyl esters of amino acid analogs, such as... 

He observed that fatty acid analogs with even numbers of carbon atoms yielded phenyl acetate, whereas compounds with odd nnmbers of carbon atoms produced only benzoate. 

The synthesis of kalnlc acid, acromehc acid, and related compounds such as domoic acid has been the subject of considerable investigation A simple and direct toiue to neurophysi-ologically active kalnlc acid analogs has been reported, as shovm in Scheme 10 31 ... 

Takemoto, K. and Inaki, Y. Synthetic Nuclei Acid Analogs. Preparation and Interactions. Vol. 41, pp. 1 — 51. 

Up to now, far more than 5000 retinoic acid analogs have been synthesized, out of which the following three generations have been established for therapy of various disorders First, the nonaromatic retinoids (3-carotene (provitamin A), alWraras-retinoic acid (RA) (tretinoin) and 13-cis-RA (isotretinoin), second, the monoaromatic retinoid derivatives trimethyl-methoxyphenyl analog of RA (etretinate) and9-(4-methoxy-2,3,6-trimethylphenyl)-... 

A CONVENIENT PREPARATION OF AN ORTHOGONALLY PROTECTED C ,C -DISUBSTITUTED AMINO ACID ANALOG OF LYSINE l-tert-BUTYLOXYCARBONYL-4-((9-FLUORENYLMETHYLOXYCARBONYL)AMINO)-PIPERIDINE-4-... 

It has been found that cyclohexa-2,4- and -2,5-dienones undergo a light-induced valence isomerization reaction in strong acid analogous to the alkylbenzenes, to yield 2-hydroxy-bicyclo[3,l,0]hexenyl cations. The hydroxybenzenium ion (34), for example, underwent a clean photoisomerization to 35 at temperatures below — 60° (Paxrington and Childs, 1970). Cation 35 was also produced upon similar irradiation of 36. 

Drugs (nonsteroidal anti-inflammatory, antineopiastic agents, aicohoi) Denatured proteins (amino acid analogs)... 

Naidook S. Separation of Acetic and Propionic Acid Analogs of I Thyroxine and l ltiiodotKynHiine by Thin-Layer Ctoomatography , AnaL Biochem. 1978,91, 543-547. 

Fig. 1 Chemical structures of backbone modifications used in therapeutic nucleic acid analogs. Shown are the unmodified DNA/RNA chemical structures in addition to a selection of first (PS), second (OMe, MOE), and third generation (PNA, LNA, MF) nucleic acid modifications...

Ito A, Hirai K, Inoue M, Koga H, Suzue S, Irikura T, Mitsuhashi S. In vitro antibacterial activity of AM-715, a new nalidixic acid analog. Antimicrob Agents Chemother 1980 17 103-8. 

Both enantiomers of the auxiliary are available, so either enantiomeric product can be obtained. This methodology has been applied to a number of enantioselective syntheses.95 For example, the glycine derivative 14 can be used to prepare a-amino acid analogs.96... 

Various salts can achieve chelation but ZnCl2 and MgCl2 are suitable for most cases. The rearrangement is a useful reaction for preparing amino acid analogs and has also been applied to synthesis of modified dipeptides.250... 

This version of the Curtius rearrangement has been applied to the synthesis of amino acid analogs and structures containing amino acids. Several m-2-aminocyclopropane carboxylate esters were prepared by selective hydrolysis of cyclopropane-1,2-dicarboxylates, followed by reaction with DPPA.267... 

Synthesis of Amino Acid Analogs. J. Amer. chem. Soc. 77, 1 (1955). 

Figure 17.11 Amino acid analogs containing either azido or alkyne modifications can be fed to cells and these monomers incorporated into expressed proteins.

L-Rhamnosone was prepared by the action of hydrochloric acid on L-rhamnose phenylosazone9 and was identified by reconversion to the osazone. This method was later employed186 as a stage in the synthesis of the ascorbic acid analog, L-rhamnoascorbic acid. The benzaldehyde decomposition of the osazone gave a low yield of osone93 and o-nitrobenzaldehyde was not a satisfactory aldehydic substitute. 

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