𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Solution 1H and 13C NMR of new chiral 1,4-oxazepinium heterocycles and their intermediates from the reaction of 2,4-pentanedione with α-L-amino acids and (R)-(—)-2-phenylglycinol

✍ Scribed by M. Concepción Lozada; Carlos E. Lobato; Raúl G. Enríquez; Benjamín Ortíz; Rubén A. Toscano; Dino Gnecco; Alberto Galindo; William F. Reynolds

Publisher
John Wiley and Sons
Year
2003
Tongue
English
Weight
145 KB
Volume
41
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

The reaction of 2,4‐pentanedione (1) with (R)‐(—)‐2‐phenylglycine methyl ester (2), (R)‐(—)‐2‐phenylglycinol (3) and the proteinogenic amino acids (2__S__,3__R__)‐(—)‐2‐amino‐3‐hydroxybutyric acid (L‐threonine) (4) and (R)‐(—)‐2‐amino‐3‐mercaptopropionic acid (L‐cysteine) (5) methyl esters was investigated. The corresponding enamines 6, 7 and 8 were isolated and characterized spectroscopically whereas 9, which is unstable, was transformed in situ into 13. Treatment of 7, 8 and 9 with boron trifluoride etherate afforded the new [1,4]oxazepines 10, 11 and [1,4]thiazepine (12) as their BF~3~O^−^ salts. The structures of the enamines and their corresponding seven‐membered heterocycles were assessed by 1D and 2D NMR spectroscopy. Variable‐temperature experiments revealed different molecular mobility behavior among these heterocycles. Copyright © 2003 John Wiley & Sons, Ltd.

📜 SIMILAR VOLUMES

Azomethine ylides from the reaction of 4
Azomethine ylides from the reaction of 4-(dicyanomethylene)-3-methyl-1-phenyl-2-pyrazoline-5-one with α-amino acids and their esters
✍ Metwally, Saoud A. M. ;Aly, Moustafa F. ;Abd-Alla, Mohamed A. ;Atta, Ferial M. ; 📂 Article 📅 1991 🏛 John Wiley and Sons 🌐 English ⚖ 255 KB 👁 1 views

## Abstract 4‐(Dicyanomethylene)‐3‐methyl‐1‐phenyl‐2‐pyrazoline‐5‐one (1) readily reacts with α‐amino acids and their esters by Michael addition and subsequent elimination of HCN to the adducts 2a–k. One of these, 2i (obtained from methyl glycinate), adds stereoselectively to __N__‐phenylmaleimide

The rα-structures of partially oriented
The rα-structures of partially oriented 1,2,4,5-and 1,2,3,4-tetrachlorobenzene determined from their proton magnetic resonance spectra with natural abundance 13C-satellites
✍ P. Diehl; G. Dombi; H. Boesiger 📂 Article 📅 1980 🏛 John Wiley and Sons 🌐 English ⚖ 413 KB

## Abstract By recording two spectra of the same molecule in different nematic liquid crystals, and analysing the data simultaneously, information has been obtained on the molecular structures of 1,2,4,5‐ (1) and 1,2,3,4‐tetrachlorobenzene (2). Carbon–hydrogen and carbon–carbon internuclear distanc