Amino lactones

Tables V-LVII detail H and F shift and coupling information, and Tables LVIII to LXXI incorporate the C-n.m.r. data. The data within this compilation are arranged according to the following outline hexoses prior to pentoses, followed by anhydro sugars, sugar acids and lactones, amino sugars (and their synthetic, A -containing precursors), mono-, di-, and tri-deoxy sugars, branched derivatives, ketoses, polyfluorinated monosaccharides, and, finally, difluorinated amino sugars. Within this compilation, and even within each table, pyranoid derivatives are listed prior to their furanoid counterparts, hexoses prior to pentoses, functionalized prior to deoxy compounds the arrangement within each sub-table is made alphabetically.

Hydrogen abstraction by ketone sensitizers forms the basis of an elegant alkylation procedure for ethers, amides, lactones, amino acids, and peptides developed by Elad and his group.94 Terminal olefins, for example, can be added to y-butyrolactone (15) in good yield.95... 

Chiraldex B-PH Structural isomers, unsaturated no aromatie eompounds. Linear and cyclic amines and alcohols, acids, lactones, amino aleohols, sugars, bicyclic compounds and epoxides. 

Smaller linear and saturated amines, alcohols, carboxylic acids, and epoxides Most structural types of compounds, including linear and cyclic amines and alcohols, carboxylic acids, lactones, amino alcohols, sugars, bicyclics, epoxides, haloaUcanes, and more... 

Scheme 19.13 Synthesis of a not naturally occurring lactone amino acid. Reagents and conditions a) BH3 THF, 0 °C - RT b) spontaneous c) i) MsCl, pyridine, CH2CI2 ii) NaN3, DMF iii) R/Pd-C...

This newly created species proved to be of high value due to its easy transformation into nitrogen containing molecules. The lactone amino acid does not occur naturally and was generated by reduction of the free carboxylic acid with borane tetrahydrofurane complex, followed by the spontaneous rearrangement of the... 

However, the term cycHc depsipeptide is often used ia the Hterature to refer to heterodetic homomeric peptide lactones ia which ester bonds to amino acid hydroxyls are present ia the ring. 

Almost all actinomycins have the same chromophore, a planar phenoxa2inone dicarboxyUc acid called actinocin. In dactinomycin, the stmcture of which is shown in Figure 12, the two pendent pentapeptide lactones are identical, but in other actinomycins these lactones may be different. In other actinomycins the first amino acid, amide linked with actinocin, is usually L-threonine, as in dactinomycin the second position is sometimes D-aHo-isoleucine instead of D-valine the third position may be sarcosine or oxoproline the fourth position is sarcosine and the fifth position is sometimes /V-methyl isoleucine instead of /V-methylvaline. The lactone ring is always present. 

L-Homoserine (2-amino-4-hydroxybutyric acid) [672-15-1] M 119.1, m 203", [cc]d +18.3" (in 2M HCI), pKEst(i) -2.1, pl st(2) 3. Likely impurities are A -chloroacetyl-L-homoserine, N-chloroacetyl-D-homoserine, L-homoserine, homoserine lactone, homoserine anhydride (formed in strong solns of homoserine if slightly acidic). Cyclises to the lactone in strongly acidic soln. Crystd from water by adding 9 volumes of EtOH. 

The NMR experiments 55 are obtained from actinomycin D in order to check the amino acid sequence, to assign proton-proton and some carbon-proton connectivities, and to deduce informations concerning proton distances and the spatial structure of both cyclopentapeptide lactone rings. Conditions CDCI3, 10 mg per 0.3 ml, 25 °C, 500 MHz H), 125 MHz ( C). (a) HH COSY plot ... 

Amino-4,6-dimethyl-3-oxo-3//-phenoxazine-l,9-dicarboxylic acid also named actinocin is the chromophor of the red antineoplastic chromopeptide aetinomyein D (formula A). Two cyclopenta-peptide lactone rings (amino acids L-threonine, D-valine, L-proline, sarcosine, and 7V-methyl-L-valine) are attached to the carboxy carbons of actinocin by two amide bonds involving the amino groups of threonine. 

The reaction of 5-methoxy-2(5//)-furanone 168 with amines was also studied (89T6799). The conjugated addition of ethanolamine to the furanone 168 gave the racemic amino lactone 275 (R = CH2CH20H). Similarly, piperazine reacted with two equivalents of 168 to provide the diadduct 276 as a single diastereomer (no traces of the other isomer were detected). With tryptamine, the reaction was nearly quantitative with the the formation the tran -adduct 277 (R = tryptophanyl) (Scheme 72) (89T6799). 

Aziridine lactone 235 (Scheme 3.87) underwent ring-opening with allyl alcohol to give a 53% yield of a-amino lactone 236, which was successfully transformed to the unnatural enantiomer of polyoxamic acid (—)-237 [32],... 

In y-alkoxyfuranones the acetal functionality is ideally suited for the introduction of a chiral auxiliary simultaneously high 71-face selectivity may be obtained due to the relatively rigid structure that is present. With ( + )- or (—(-menthol as auxiliaries it is possible to obtain both (5S)- or (5/ )-y-menthyloxy-2(5//)-furanones in an enantiomerically pure form293. When the auxiliary acts as a bulky substituent, as in the case with the 1-menthyloxy group, the addition of enolates occurs trans to the y-alkoxy substituent. The chiral auxiliary is readily removed by hydrolysis and various optically active lactones, protected amino acids and hydroxy acids are accessible in this way294-29s-400. 

The use of enantiomerically pure (R)-5-menthyloxy-2(5.//)-furanone results in lactone enolates, after the initial Michael addition, which can be quenched diastereoselectively trans with respect to the /J-substituent. With aldehydes as electrophiles adducts with four new stereogenic centers arc formed with full stereocontrol and the products are enantiomerically pure. Various optically active lactones, and after hydrolysis, amino acids and hydroxy acids can be synthesized in this way317. 

Abstract The photoinduced reactions of metal carbene complexes, particularly Group 6 Fischer carbenes, are comprehensively presented in this chapter with a complete listing of published examples. A majority of these processes involve CO insertion to produce species that have ketene-like reactivity. Cyclo addition reactions presented include reaction with imines to form /1-lactams, with alkenes to form cyclobutanones, with aldehydes to form /1-lactones, and with azoarenes to form diazetidinones. Photoinduced benzannulation processes are included. Reactions involving nucleophilic attack to form esters, amino acids, peptides, allenes, acylated arenes, and aza-Cope rearrangement products are detailed. A number of photoinduced reactions of carbenes do not involve CO insertion. These include reactions with sulfur ylides and sulfilimines, cyclopropanation, 1,3-dipolar cycloadditions, and acyl migrations. 

Riho-hexonsanre 3-Desoxy-D- -7-lacton 225 Zucker 604 markierte 223 -tosylhydrazon 370 Amino- 483... 

Deoxy-D-nbo-hexono-1,5-lactone 5-Amino-5-deoxy-D-mannono-1,5-lactam Acyl halides are named by changing the ending -onic acid to -onoyl halide Example ... 

Oxazolones (azlactones) are a form of activated lactones, so they are included in this section. CAL-B is an effective catalyst for the DKR of various racemic four-substituted-5 (4H)-oxazolones, in the presence of an alcohol, yielding optically active N-benzoyl amino acid esters as illustrated in Figure 6.24 [40]. Enantioselective biotransformations of lactides [72,73] and thiolactones ]74] have also been reported. 

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