Trans-4-hydroxy-L-proline

The use of backbone-modified poly (amino acids) as biomaterials was first suggested by Kohn and Langer (17) who prepared a polyester from N-protected trans-4-hydroxy-L-proline, and a poly(itiuno-carbonate) from tyrosine dipeptide as monomeric starting material (12,18). 

Most papers deal with diethylzinc. Chiral (3/f,5/f)-dihydroxypiperidines (75), derived from trans-4-hydroxy-L-proline, give up to 98% ee in its additions to benzaldehyde and heptanal.212... 

Schotten-Baumann type N-benzoylation was carried out on trans-4-hydroxy-L-proline 34,39 giving amide 43 in a satisfactory yield of 65%. The disappointing yield here could be attributed to difficulties experienced in recrystallization of the product 43. The amide 43 was esterified to give tert-butyl ester 44 using a modification of a procedure described by Widmer40 with dimethylformamide-dineopentyl acetal and tert-butanol as reagents. This provided crystalline 44 in 71% yield from 43 with no evidence of terf-butyl ether formation at the C-4 hydroxyl group (Scheme 12). 

Proline derivatives trans-4-hydroxy-L-proline (Hyp) is an important component of animal supportive and coimective tissues Free all-cis-4-hyAoxy-L-proline occurs m Santalum album and other pUmts Small quantities of 3-hydroxy-L-proline are also present m collagen. 4-Hydroxy-L-proline is formed mainly by hydroxylation of ribosome-bound peptidylpro-lyl-RNA, a reaction requiring ascorbic add and catalysed by proline hydroxylase (see Oxygenases). Flee 4-hydroxy-L-proline is formed by cyclization of y-hy-... 

Remuzon, R (19%). Trans-4-hydroxy-L-proline, a useful and versatile chiral starting block. Tetrahedron, 52,13803-13835. 

RN 33996-33-7 MF C HnNO MW 173.17 EINECS 251-780-6 CN trans-1 -acetyl-4-hydroxy-L-proline... 

Several syntheses of the hepatatoxic alkaloid (+)-retronecine have been reported although the most succinct has utilized a chiral azomethine ylide cycloaddition to construct the bicychc skeleton. The ylide processor 175, which was obtained in five efficient steps from commercially available tran -(l )-4-hydroxy-L-proline, underwent double desilyation in the presence of AgF (described in detail in Section 3.1.1) and in situ cycloaddition with methyl propiolate, to deliver a 3 1 mixture of cycloadducts in favor of the desired regioisomer. DiisobutyMuminum (DIBAL) reduction of 176 furnished enantiopure (-F)-retronecine (Scheme 3.50). 

It has been shown that phosphorylation changes the local conformation of a protein and thereby affects the activity of the complete protein. 341 Phosphorylation of serine and threonine side chains often occurs (Scheme 2). Phosphoamino acids are readily characterized using 3H and 31P NMR experiments. The H and 31P NMR parameters are distinct for phosphorylated serine, threonine, and tyrosine and have also been used to identify both cis-and trans-O-phospho-4-hydroxy-L-proline. 35 Phosphorylation of Cys is rare, but it can be identified by NMR even in large proteins. 36 ... 

Methanesulfonyl chloride Diethylaluminium chloride Orpholinopropanesulfonic acid buffer Benzyl-a-bromopropionate trans-l-(p-Nitrobenzyloxycarbonyl)-4-hydroxy-L-proline Methanesulfonyl chloride t-Butyldimethylsilyl chloride... 

Figure 7. Hydroxylation of L-proline to trans-4-hydroxy-L-pro-line by proline 4-hydroxylase. The cosubstrate a-ketoglutarate is continuously supplied by the metabolism of growing E. coli W1485 (pWFHl), which served as biocatalyst.

The acromelic acid A 5 obtained had physical properties (including specific rotation) identical to natural material, the overall yield from tran.s-4-hydroxy-L-proline 34 being 9%. Initial experiments led to the isolation of 60 mg of purified 5 although this synthetic route would be amenable to preparation on a significantly larger scale. 

C5H8N2 1,4-dimethyl-1 H-imidazole 6338-45-0 16.00 0.9960 1 5241 C5H9N03 trans-3-hydroxy-L-proline 4298-08-2 25.00 1.1397 2... 

C7H9N30 (2-aminobenzoyl)hydrazide 1904-58-1 25.00 1.1892 2 11303 C7H11N04 trans-1-acetyl-4-hydroxy-L-proline 33996-33-7 25.00 1.1985 2... 

C5H9NO3, 4-Hydroxy-L-proline, 15, 493 16, 445 39B, 349 C5H9NO3S, N-Acetyl-L-cysteine, 46B, 471 C5H9NO4, L-Glutamic acid (a form), 46B, 471 C5H9NO4, L-Glutamic acid (/3 form), 19, 529 38B, 481 C5H9NO4, 2,3-cis-3,4-tranS 3,4- Dihydroxy-L-proline, 34B, 278 35B, 307... 

Free hydroxyproline (4-hydroxy-L-proline) interferes not only with the incorporation of C-proline into protein, but also with the subsequent conversion of proline into protein-bound hydroxyproline, as in collagen formation. The hydroxylation mechanism was ascertained by the use of two isomeric fluoroprolines, -cis- and /roiu-4-fluoroprolines. Although both amino acids were incorporated into protein from homogenates of guinea-pig granuloma, the sole trans- isomer behaved as an efficient precursor for hydroxyproline. Therefore the hydroxylation mechanism involves a direct oxidative attack upon, and displacement of, the trans-H atom at the 4-position. 

A trifunctional linker molecule is required to attach the insoluble support, the desired reporter or carrier molecule, and the future oligonucleotide sequence together. A simple glycerol linker has been used to attach vitamin E onto LCAA-CPG as shown in Fig. 9(52). Another readily available trifunctional linker is the amino acid serine. This linker has been used to prepare commercially available CFG supports containing either biotin, rhodamine, fluorescein, or acridine (53) as shown in Fig. 9. A more complex linker with a rigid structure and defined stereochemistry, trans-4-hydroxy-L-prolinol, was prepared by the hy drogenolysis of commercially available N-Cbz-hydroxy-L-proline (54). This linker was then used to attach either cholesterol or acridine molecules to LCAA-CPG as shown in Fig. 9. 

Salzman, L. A., H. Weissbach, and E. Katz Conversion of C - and cis- or trans-4-H -L-proline to 4-hydroxy-L-proline and 4-oxo-L-proline by Streptomyces anti-bioticus. Proc. Natl. Acad. Sci. U.S. 54, 542 (1965). 

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