𝔖 Bobbio Scriptorium
✦   LIBER   ✦

The regiospecific N-derivatization of histidine side chains: reinvestigation of a supposed Nτ to Nπ migration

✍ Scribed by John H. Jones; Victoria L. Walker

Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
98 KB
Volume
3
Category
Article
ISSN
1075-2617

No coin nor oath required. For personal study only.

✦ Synopsis

A report claiming that AcHisOMe reacts regiospecifically with 4-fluoronitrobenzene to give AcHis[tPh(NO 2 )]OMe, which on treatment with H 2 /Pd(C) undergoes a partial t±p shift to give some AcHis[pPh(NH 2 )]OMe, cannot be substantiated. 4(5)-Methylimidazole, a model for AcHisOMe, gives on reaction with 4-fluoronitrobenzene a 4 : 1 mixture of the regioisomers 1-(4-nitrophenyl),4-methylimidazole, corresponding to t-substitution, and 1-(4-nitrophenyl),5-methylimidazole, corresponding to p-substitution, each of which has been isolated and fully characterized, including proof of orientation. In both cases, treatment with H 2 /Pd(C) gives a single product, without any change of orientation in either case.

📜 SIMILAR VOLUMES

A reinvestigation of the synthesis of [1
A reinvestigation of the synthesis of [15N2]hydroxymethylimidazole: Useful in an improved synthesis of (D,L)-[τ,π-15N2]histidine
✍ Louis A. Silks III; Erik Dunkle; Clifford J. Ünkefer; James L. Sudmeier; Michael 📂 Article 📅 1995 🏛 John Wiley and Sons 🌐 French ⚖ 297 KB

## Abstract We have reinvestigated the synthesis of [^15^N~2~]hydroxymethyl imidazole from dihydroxyacetone, formaldehyde, and labelled ammonia in an attempt to optimize the yield from the isotope. Conversion of the hydroxymethyl imidazole to histidine was accomplished in good yield without the nee

Effect of side chains on the conformatio
Effect of side chains on the conformational energy and rotational strength of n–π* transition for some α-helical poly-α-amino acids
✍ John N. Vournakis; Johnson F. Yan; Harold A. Scheraga 📂 Article 📅 1969 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 59 KB 👁 1 views

On page 1533, in the last term of eq. (2), (alm[O) should be (alml0). On page 1538, in line 3 of the Results section, R,,\* should be Rn,\*; in the next line, RB should also be Rn,\*, and the first "in" should be "is.

Derivatives of Coenzyme F430 with a Cova
Derivatives of Coenzyme F430 with a Covalently Attached α-Axial Ligand. Part II : Partial Synthesis of the Five Coenzyme F430 Tetramethyl Esters and of a Derivative with a Coordinating Nπ-Methyl-L-histidine Ligand Covalently Attached to the Side Chain at C(3) of F430 via a Peptidic Linker
✍ Carsten Bauer; Bernhard Jaun 📂 Article 📅 2003 🏛 John Wiley and Sons 🌐 German ⚖ 222 KB

## Abstract Coenzyme F430 pentamethyl ester **2** was partially hydrolyzed to a mixture of the five F430 tetramethyl esters **7**–**11**, which were separated by HPLC and identified by means of a full NMR characterization. The tetramethyl ester with a free COOH group at the side chain at C(3) of F4