Ornithine methyl ester

Diaminobutanoic acid methyl ester, L Ornithine methyl ester, L Lysine methyl ester, L... 

Home was able to provide support for the biosynthetic hypothesis that mauritiamine (197) results from dimerization of an oroidin-like species. Upon examination of the natural product stmcture, it appears to be the union of oroidin (25) and dispacamide (196) (Scheme 13.34). Home was able to dimerize vinyl aminoimidazole 26 under oxidative conditions to provide the core of mauritiamine (199) [130]. After installation of the dibromopyrroles via acylation, the natural product was realized in six steps from ornithine methyl ester (198), without the need for PGs. 

The interaction with both synthetic and naturally occurring amino acids has been studied extensively glycine (138, 173, 219-221), a-(173, 219) and /3-alanine (138, 220), sarcosine (219), serine (222), aspartic acid (138, 173, 222-226), asparagine (222), threonine (222), proline (219), hydroxyproline (219), glutamic acid (138, 222-225), glutamine (222), valine (219, 227), norvaline (219), methionine (222, 226), histidine (228, 229), isoleucine (219), leucine (219, 230), norleu-cine (219), lysine (222), arginine (222), histidine methyl ester (228), phenylalanine (138, 222), tyrosine (222), 2-amino-3-(3,4-dihydroxy-phenyl jpropanoic acid (DOPA) (222), tryptophan (222), aminoiso-butyric acid (219), 2-aminobutyric acid (219,231), citrulline (222), and ornithine (222). 

Michael addition of glycinate Schiff base 28 to a,/ -unsaturated carbonyl substrates with high enantioselectivity (Scheme 4.19) [53, 54]. With methyl acrylate as an acceptor, a-tert-butyl y-methyl ester of (S)-glutamic acid can be formed this functionalized glutamic acid derivative is very useful for synthetic applications because the two carboxyl groups are differentiated. Moreover, naturally occurring (S)-ornithine has been synthesized as its dihydrochloride in a concise manner by using acrylonitrile as an acceptor, as also included in Scheme 4.19... 

The pyrrolopyrimidine antifolate masked ornithine analog 240 is prepared from methyl esters of lysine 238 and substituted benzoic acid 239 using DEPC.88... 

Bacchi, C. J., Nathan, H. C., Clarkson, A. B., Bienen E. J., Bitonti, A. J. and McCann P. O. (1987) Effects of the ornithine decarboxylase inhibitors DL-alpha-dilluoromethylornithine and alpha-monofluroromethyldehydroornithine methyl ester alone in combination with serum against Trypanosoma brucei brucei central nervous system models. Am. J. Trop. Med. Hyg. 36 46-52. 

Convert the alcohol to a tosylate and displace with excess ammonia 24.42. aspartylphenylalanine methyl ester. 24.43. Phe-Ala-GIy-Met-Ala. 24.46. (a) C-terminal amide (CONH2), or amide (Gin) of Glu (b) The N-terminal Glu is a cyclic amide (a pyroglutamyl" group) that effectively blocks the N-terminus. The C-terminal Pro is an amide (c) cyclic pentapeptide. 24.49. Ornithine is H2N(CH2)3CH(NH2)C00H, a homolog of lysine, with a similar lEP. 24.51. Ala-Lys-Phe-Glu-Gly-Tyr-Arg-Ser-Leu-Ile. 

By thin-layer chromatography this lipid was isolated and named cerilipin. On hydrolysis, it gave ornithine and a sulphur-containing component identified as taurine. By alkaline transmethylation, cerilipin was deacylated and the resulting methyl ester was found to be identical with methyl 2-hydroxyhexadecanoate (with a small amount of methyl 2-hydroxylactobacillate). Acid hydrolysis of the deacylated lipid gave a fatty acid identified as 3-hydroxyhexadecanoic acid as well as ornithine and taurine, in the molecular ratio 1 1 1. Treatment of cerilipin with dinitrofluorobenzene gave -ornithine as the only DNP derivative. From these data, structure (14) was proposed for cerilipin 45). 

In view of this finding, it was proposed (135-138) (Scheme 22) that in the case of cocaine (98) the ornithine (201) is incorporated through free putrescine (202), which is a symmetrical intermediate and therefore would afford the pyrrolinium salt 206 equally labeled at C-2 and C-5. As above, condensation of the (V-methyl-A1 -pyrrolinium salt (206) with acetyl coenzyme A leads to the coenzyme A ester of hygrine-1 -carboxylic acid (207), which by transester-... 

Several 0-aminoacyl sugars were prepared to study a relationship between taste and chemical structure. Methyl a-D-glucopyranoside, methyl a-D-galactopyranoside and methyl a-D-mannopyranoside were selected as sugar skeletons. As basic amino acids, esters of lysine, ornithine, a,Y-diaminobutyric acid, and a,p-diaminopropionic acid were introduced into 2-0-, 3-0-, and 4-0- positions of sugars leaving only 6-hydroxyl group free. The results of sensory analysis are list in Table VI. O-... 

Use of the preformed Z-silyl enol ether 18 results in quite substantial anti/syn selectivity (19 20 up to 20 1), with enantiomeric purity of the anti adducts reaching 99%. The chiral PT-catalyst 12 (Schemes 4.6 and 4.7) proved just as efficient in the conjugate addition of the N-benzhydrylidene glycine tert-butyl ester (22, Scheme 4.8) to acrylonitrile, affording the Michael adduct 23 in 85% yield and 91% ee [10]. This primary product was converted in three steps to L-ornithine [10]. The O-allylated cinchonidine derivative 21 was used in the conjugate addition of 22 to methyl acrylate, ethyl vinyl ketone, and cydohexenone (Scheme 4.8) [12]. The Michael-adducts 24-26 were obtained with high enantiomeric excess and, for cydohexenone as acceptor, with a remarkable (25 1) ratio of diastereomers (26, Scheme 4.8). In the last examples solid (base)-liquid (reactants) phase-transfer was applied. 

Quite surprisingly V. aerophoba failed to incorporate radioactivity from [U- " C]-L-tyrosine into aerothionin (7), aeroplysinin-1 (4) and the dienone (1) inactive aerothionin was also isolated when the animals were fed with [U- " C]-L-ornithine (71). However the sponges utilized these aminoacids for the synthesis of fatty acids. A very slow rate of biosynthesis might account for these results. A dietary origin for these compounds can be also suspected in this connection the recent report of the isolation of the brominated esters (19) and (20) (after methylation) from hydrolyzed extracts of the red alga Halopytis incurvus (41) seems relevant. 

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