Tartaric acid derivatives amides

The Swern conditions were applied to a number of substrates with different functional and protecting groups, such as sugar derivatives, protected amino acid derivatives, tartaric acid derivatives, and optically active synthetic intermediates. Both acid-sensitive (epoxide, acetonide, silyl, NBoc, NCBz) and alkaline-sensitive groups (Ac, Bz, ester, silyl) were found to be completely unaffected. The proposed mechanism begins with tautomerisation of the amide to the hydroxy imine, followed by reaction with the dimethylchlorosulfonium species. The resulting oxysulfonium species 63 collapses when treated with base to regenerate DMSO and produce the nitrile. 

The directive effect of allylic hydroxy groups can be used in conjunction with chiral catalysts to achieve enantioselective cyclopropanation. The chiral ligand used is a boronate ester derived from the (VjA jA N -tetramethyl amide of tartaric acid.186 Similar results are obtained using the potassium alkoxide, again indicating the Lewis base character of the directive effect. 

Among the different types of compounds whose complexation properties have been studied are various amides linear oxoamide 9 [22], fumaramide 10 [23,24] and methanetricarboxamide 11 [25], biphenyl derivatives 12 [26], and derivatives of tartaric acid 13-16, that can also be prepared in an optically active form [27], The above-mentioned chiral hosts have been found to form inclusion complexes with chiral guests 17 and 18. Molecular recognition between chiral hosts and... 

Some amide derivatives have been reported to form inclusion complex with a wide variety of organic compounds.9 Optically active amide derivatives are expected to include one enantiomer of a racemic guest selectively. According to this idea, some amide derivatives of tartaric acid (11-13) were designed as chiral hosts.10 As will be described in the following section, these amide hosts were found to be useful for resolution of binaphthol (BNO) (14) and related compounds (15,16). 

Ryhlewska, U., and Warzajtis, B. Interplay between dipolar, stacking and hydrogen-bond interactions in the crystal structures of unsymmetrically substituted esters, amides and nitriles of (R,R)-0,0 -dibenzoyltartaric acid, Acta Cryst., Sec. B. 2001, B57, 415-427. Isostructuralism in a series of methyl ester/methylamide derivatives of (R,R)-0,0 -dibenzoyl tartaric acid inclusion properties and guest-dependent homeotypism of the crystals of (2R,3R)-0,0 -dibenzoyltartaric acid diamide, Acta Cryst., Sec. B. 2002,B58, 265-271. 

In the last two decades, chiral receptors containing amidic functions were designed almost exclusively for binding protected amino acids [49-57], oligopeptides [54,58], and lactic [59], tartaric [60,61] or camphoric acid derivatives [62]. Usually, chiral building blocks such as spirobifluorene [49, 60], binaphthalene [51,57],or amino acid chains containing macrocycles [52-56,58] were employed. An interesting receptor was synthesized via connection of the calix[4]arene moiety with an aza-crown derivative [61]. 

Epoxidation catalyzed by (+)-tartramidesJ Epoxidation of (E)-a-phenylcinnamyl alcohol (2) catalyzed by Ti(0-i-Pr) and the amide 1 derived from l-( + )-tartaric acid gives an unexpected result. When the usual ratio (2 2.4) of Ti(0-/-Pr)4 to the amide 1 is... 

Fractional distillation after synthesis of volatile amides or esters met with little success, due to low differences in boiling points (4-5 K or < 1 K) and laborious transformations. [7] An early distillation approach using different volatilities of diastereomeric salts of various amines with tartaric acid or its diben-zoyl- (also di-p-toluoyl-) derivatives yielded optical purities of the distillates from 5 to 47 % with a better performance in the case of methamphetamine (56.5-66.5 %). [8] However, probably due to the ban or restrictions with this drug (and most further drugs that might be misused) for use in scientific research by many countries, that publication did not find its due recognition. A further rea-... 

The monoaminomonophosphonic acids, either in the free state or, very often, as their diethyl esters, have been resolved by the usual techniques of repeated crystallization of appropriate salts those of L-(+)-tartaric acid (2,3-dihydroxybutanedioic acid) or its mono-or di-benzoyl derivativesor of D-(-)-mandelic acid, have been widely employed the use of di-O-benzoylated L-tartaric anhydride, which is based on the separation of diastereoisomeric amides (111), has also been employed to a limited extent. In selected cases, such as the monoaminomonophosphonocarboxylic acids or A -acylated (aminoalkyl)phosphonic acids, resolution following salt formation with organic bases has also been carried out ephedrine, quinine and both enantiomers of l-phenylethylamine have all been used. In many cases, only one enantiomer of the (aminoalkyl)phosphonic acid (or diester) has been isolated in optically pure form. Sometimes, the acidity of the substrate, and hence choice of base for resolution, can be modified by using a mono- (as opposed to di-) ester or (or even in addition to) protection of the amino group as, for example, the phthalimido, benzyloxycarbonyl (cbz) or r r -butyloxycarbonyl (boc) derivative. Resolved di- and mono-esters can be hydrolysed to the free acids under acidic conditions, and A -protection can also be removed through the customary procedures. 

Unlike the acid, its amides that have been so far examined theoretically appear to favour the G-t- (i.e. gauche+) conformation of the carbon chain with 6-membered ring type of hydrogen bonding, namely C=O...HO(P) (cf Fig. 3). The G+ conformation in the gas phase, on the semiempirical level, has also been found favoured in a non-symmetric derivative methyl ester of tartaric acid monoamide (In Fig. 1 X=NH2, Y=OCH3). This type of conformation has been observed experimentally only in TMDA via NMR in a non-polar solvent. (Gawrohski et al.,... 

Another approach for the total synthesis of anisomycin derivatives from (+)-tartaric acid has been reported via the N -benzyl tartarimide (95) (Scheme 11) [89]. Thus, (+)-tartaric acid was refluxed with benzyl amine in a xylene solution to give 95, which was subjected to reaction with the Grignard reagent of anisyl chloride in THF to give the keto-amide 96 in 55% yield. 

Further work on the preparation of chiral a-amino-acids reported in the past year (see also the section on asymmetric hydrogenation) includes an extension of the utility of anions derived from lactim ethers (228) in the synthesis of such compounds by condensations with aldehydes and ketones chiral inductions are somewhat lower than in the alkylations of (228) reported previously (4, 320). Enzyme-mediated hydrolysis of 5(4H)-oxazolones by chymotrypsin or subtilisin gives a-acylamino-acids with good enantiomeric enrichments, especially if the substrate carries bulky substituents. Schiff s bases of a-amino-esters can be enriched enantiomerically to an extent of up to 70% by sequential deprotonation with a chiral lithium amide and protonation with an optically pure tartaric acid. ... 

---