- Polymer-supported O-benzyl and O-allylisoureas: Convenient preparation and use in ester synthesis from carboxylic acids
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Polymer-supported O-methyl, O-benzyl, and O-allyl-isoureas were prepared by copper(II)-catalyzed reaction of polymer-supported carbodiimide with the corresponding alcohols. These polymer-supported reagents were successfully employed to convert a series of carboxylic acids to methyl, benzyl, or allyl esters, in good yields. The products were obtained with high purity (>95% by NMR) after a simple resin filtration-solvent evaporation sequence.
- Crosignani, Stefano,White, Peter D.,Steinauer, Rene,Linclau, Bruno
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Read Online
- An improved synthesis of β-cyano- l -alanine esters and amides
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We have developed a novel, mild, efficient, and scalable protocol for the synthesis of N-protected β-cyano-l-alanine esters or -amides from N-protected l-asparagin. This protocol avoided the use of toxic or unpleasant reagents and was easy to operate in laboratory.
- Wang, Guoxin,Chen, Longjian,Cai, Xiaodan,Li, Zigang,Luo, Ming
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p. 309 - 312
(2016/01/20)
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- Use of 'click chemistry' for the synthesis of tetrazole-containing analogues of the neuroprotective agent glycyl-L-prolyl-L-glutamic acid
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Tetrazole-containing analogues of glycyl-L-prolyl-L-glutamic acid (GPE) were prepared by coupling of Cbz-glycyl-L-proline with tetrazole-containing glutamic acids followed by hydrogenation of the resultant tripeptide. Synthesis of the tetrazole-containing glutamic acids involved 1,3-dipolar cycloaddition of sodium azide to nitrile derivatives of the corresponding glutamic acids. Georg Thieme Verlag Stuttgart.
- Hung, Kuo-Yuan,Harris, Paul W. R.,Brimble, Margaret A.
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scheme or table
p. 1233 - 1236
(2009/09/06)
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- Synthesis of imidazolidin-2-one-4-carboxylate and of (tetrahydro)pyrimidin- 2-one-5-carboxylate via an efficient modification of the Hofmann rearrangement
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A mild and efficient methodology for the rearrangement of protected asparagine and protected glutamine is reported; good results are obtained with a wide selection of protecting groups. The Royal Society of Chemistry.
- Angelici, Gaetano,Contaldi, Simone,Lynn Green, Sarah,Tomasini, Claudia
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experimental part
p. 1849 - 1852
(2008/10/09)
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- Synthetic approaches to peptides containing the l-Gln-l-Val-D(S)-Dmt motif
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The pseudoprolines S-Dmo (5,5-dimethyl-4-oxaproline) and R-Dmt (5,5-dimethyl-4-thiaproline) have been used to study the effects of forcing a fully cis conformation in peptides. Synthesis of peptides containing these (which have the same configuration as l-Pro) is straightforward. However, synthesis of peptides containing S-Dmt is difficult, owing to the rapid cyclisation of l-Aaa-S-Dmt amides and esters to form the corresponding diketopiperazines (DKP); thus the intermediacy of l-Aaa-S-Dmt amides and esters must be avoided in the synthetic sequence. Peptides containing the l-Gln-l-Val-D(S)-Dmt motif are particularly difficult, owing to the insolubility of coupling partners containing Gln. Introduction of Gln as N-Boc-pyroglutamate overcame the latter difficulty and the dipeptide active ester BocPygValOC6F5 coupled in good yield with S-DmtOH. BocPygVal-S- DmtNH(CH2)2C6H4NO2 was converted quantitatively to BocGlnVal-S-DmtNH(CH2)2C6H4NO2 with ammonia, demonstrating the utility of this approach. Two peptide derivatives (CbzSerLysLeuGlnVal-S-DmtNH(CH2)2C6H4NO2 and CbzSerSerLysLeuGlnVal-S- DmtNH(CH2)2C6H4NO2) were assembled, using these new methods of coupling a dipeptide acid active ester with S-DmtOH and introduction of Gln as Pyg, followed by conventional peptide couplings. The presence of the Val caused these peptides to be cleaved very slowly by prostate-specific antigen (PSA) at Leu ↓ Gln, rather than the expected Gln ↓ Val.
- Suaifan, Ghadeer A.R.Y.,Arafat, Tawfiq,Threadgill, Michael D.
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p. 3474 - 3488
(2008/02/05)
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- Mapping the landscape of potentially primordial informational oligomers: Oligodipeptides and oligodipeptoids tagged with triazines as recognition elements
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(Chemical Equation Presented) Pairing up: Oligodipeptide, oligodeoxy-dipeptide, or oligodipeptoid backbones tagged with the 2,4-diaminotriazine nucleus pair strongly with complementary DNA and RNA. This is in sharp contrast with the behavior of the 2,4-dioxotriazine nucleus, which does not act as a nucleo-base in these systems.
- Mittapalli, Gopi Kumar,Reddy, Kondreddi Ravinder,Xiong, Hui,Munoz, Omar,Han, Bo,De Riccardis, Francesco,Krishnamurthy, Ramanarayanan,Eschenmoser, Albert
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p. 2470 - 2477
(2008/03/11)
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- Fragrance precursor compounds for preventing human malodor
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The invention relates to agents preventing (the formation of) human malodor. In particular, the invention relates to the use of several classes of compounds which can act as such agents in cosmetic products, such as deodorants and antiperspirants. These compounds are normally odorless or nearly so, but upon contacting the skin as for example, in skin care compositions or in personal care compositions, they prevent malodor. The compounds under consideration are compounds of the formula The definition of the substituents is given in the specification.
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- Peptide nucleic acids (PNAs) with a functional backbone
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The synthesis of 10 new T-PNA monomers derived from L-amino acids is presented. The monomers were incorporated into decameric PNA oligomers, and the hybridisation with RNA, DNA and PNA complements studied by thermal stability measurements.
- Pueschl, Ask,Sforza, Stefano,Haaima, Gerald,Dahl, Otto,Nielsen, Peter E.
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p. 4707 - 4710
(2007/10/03)
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- Peptide Synthesis in Aqueous Solution. V. Properties and Reactivities of (p-Hydroxyphenyl)benzylmethylsulfonium Salts for Direct Benzyl Esterification of N-Acylpeptides
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Some (p-hydroxyphenyl)benzylmethylsulfonium salts were prepared. These compounds generated a benzyl cation and converted not only N-acylamino acids but also N-acylpeptides into their corresponding benzyl esters without causing the racemization.
- Nakata, Takashi,Nakatani, Masaru,Takahashi, Masatoshi,Okai, Jiro,Kawaoka, Yoshiaki,Kouge, Katsushige,Okai, Hideo
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p. 1099 - 1106
(2007/10/03)
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- A Thermodynamic and Spectroscopic Study of the Complexes of the Undecapeptide Substance P, of its N-Terminal Fragment and of Model Pentapeptides Containing Two Prolyl Residues with Copper Ions
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Eight pentapeptides have been synthesised which either are models of the N-terminal pentapeptide fragment of Substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2) or assist in understanding its co-ordinating ability; Gly-Pro-Gly-Pro-Gly, Gly-Pro-G
- Pettit, Leslie D.,Bal, Wojciech,Bataille, Michel,Cardon, Claude,Kozlowski, Henryk,et al.
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p. 1651 - 1656
(2007/10/02)
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- Synthesis of Compounds Designed To Inhibit Bacterial Cell Wall Transglycosylation
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Methods for preparation of compounds designed to inhibit the transglycosylation step in bacterial cell wall biosynthesis are described.Two hybrid structures (5 and 31) are synthesized, which combine features of the transglycosylase substrate with those of the natural product moenomycin, a known transglycosylation inhibitor.The compounds are synthesized by a convergent route involving the coupling as a phosphate diester of a protected sugar portion with a glycerate-lipid synthon.Details of the syntheses of the sugar and glycerate precursors are discussed.
- Hecker, Scott J.,Minich, Martha L.,Lackey, Karen
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p. 4904 - 4911
(2007/10/02)
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