Structural assignment of regioisomeric 3‐[2‐ or 5‐anilino‐2‐(alkylamino)phenyl]propanoic acids, 2 H ‐1,4‐benzothiazin‐3(4 H )‐ones and 2,3‐dihydro‐1,5‐benzothiazepin‐4(5 H )‐ones by 1D NOE and gHMBC NMR techniques
Abstract The 1 H and 13 C NMR spectra of compounds 1 – 11 and 16 – 22 in CDCl 3 and DMSO‐ d 6 solutions allowed structural assignment to regioisomers 1/5 and 2/6 and their regioselective cyclization products 16–18 utilizing one‐ and two‐dimensional NMR techniques (APT, DEPT, NOE difference, COSY, NO...
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| Published in | Magnetic resonance in chemistry Vol. 42; no. 7; pp. 648 - 658 |
|---|---|
| Main Authors | , , , , |
| Format | Journal Article |
| Language | English |
| Published |
01.07.2004
|
| Online Access | Get full text |
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| Summary: | Abstract
The
1
H and
13
C NMR spectra of compounds
1
–
11
and
16
–
22
in CDCl
3
and DMSO‐
d
6
solutions allowed structural assignment to regioisomers
1/5
and
2/6
and their regioselective cyclization products
16–18
utilizing one‐ and two‐dimensional NMR techniques (APT, DEPT, NOE difference, COSY, NOESY, HETCOR and gHMQC, gHMBC). Temperature‐dependent
1
H NMR spectra of 8‐anilino‐5‐(4‐methyl‐2‐pentyl)‐2,3‐dihydro‐1,5‐benzothiazepin‐4(5
H
)‐one (
18
) indicated a free energy of activation (Δ
G
‡
) of ca 17 kcal mol
−1
for interconversion between rotamers. The
1
H and
13
C NMR spectra of
20
and
22
containing two chiral centers exhibit duplication of several signals, indicating the existence of two diastereomeric forms. The structure of
4
was unambiguously confirmed by x‐ray crystallography. Copyright © 2004 John Wiley & Sons, Ltd. |
|---|---|
| ISSN: | 0749-1581 1097-458X |
| DOI: | 10.1002/mrc.1373 |