Amino acid/zwitterion equilibria II: vibrational and NMR studies of substituted thiazolidine-4-carboxylic acids

1991 ◽  
Vol 69 (11) ◽  
pp. 1721-1727 ◽  
Author(s):  
H. E. Howard-Lock ◽  
C. J. L. Lock ◽  
M. L. Martins
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Amino Acid ◽  
Carboxylic Acids ◽  
Infrared And Raman Spectra ◽  
Solid Samples ◽  
Nmr Studies ◽  
Nuclear Magnetic Resonance Spectra ◽  
Key Words Amino Acid ◽  
Methyl Derivatives ◽  
Derivatives Of

Infrared and Raman spectra (4000–100 cm) of solid samples of seven different 2-phenyl-, N-benzoyl-, and 2-ethyl-2 methyl derivatives of L-cysteine and D-penicillamine have been observed and assigned. Proton and 13C nuclear magnetic resonance spectra for the compounds have also been measured. Amino acid/zwitterion equilibria are discussed with reference to pK values and the vibrational spectra. Key words: amino acid/zwitterion equilibria, thiazolidine carboxylic acids.

Amino-acid zwitterion equilibria: vibrational and nuclear magnetic resonance studies of methyl-substituted thiazolidine-4-carboxylic acids

1986 ◽  
Vol 64 (6) ◽  
pp. 1215-1219 ◽  
Author(s):  
H. E. Howard-Lock ◽  
C. J. L. Lock ◽  
M. L. Martins ◽  
P. S. Smalley ◽  
R. A. Bell
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Amino Acid ◽  
Magnetic Resonance ◽  
Infrared Spectra ◽  
Nmr Spectra ◽  
Infrared And Raman Spectra ◽  
Solid Samples ◽  
Magnetic Resonance Studies ◽  
Cysteine Hydrochloride ◽  
C Nmr

Infrared and Raman spectra (4000–100 cm−1) of solid samples of six different methyl substituted thiazolidine products of D-penicillamine and L-cysteine hydrochloride have been observed and assigned. Infrared spectra in D2O solutions have been obtained for comparison in order to study the amino-acid zwitterion equilibria. Proton and 13C nmr spectra for the compounds have also been measured.

Titanium tetrachloride promoted conversion of carboxylic acids to carboxamides

1970 ◽  
Vol 48 (6) ◽  
pp. 983-986 ◽  
Author(s):  
James D. Wilson ◽  
Harold Weingarten
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Carboxylic Acids ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Titanium Tetrachloride ◽  
Nuclear Magnetic Resonance Spectra ◽  
Derivatives Of ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

In the presence of approximately stoichiometric amounts of TiCl4, carboxylic acids and amines react at room temperature and atmospheric pressure to form carboxamides in good yields. The mono- and diformyl derivatives of 1,2-dimethylhydrazine exhibit unusual nuclear magnetic resonance spectra which are briefly discussed.

Carbon-13 nuclear magnetic resonance spectra in the identification of N-, O or S-methyl derivatives of some tautomeric hydroxy and mercapto nitrogen heterocycles

1984 ◽  
Vol 37 (11) ◽  
pp. 2391 ◽  
Author(s):  
GB Barlin ◽  
DJ Brown ◽  
MD Fenn
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nitrogen Heterocycles ◽  
Resonance Spectroscopy ◽  
Methyl Groups ◽  
Nuclear Magnetic Resonance Spectra ◽  
Methoxy Groups ◽  
Methyl Derivatives ◽  
Derivatives Of ◽  
Nuclear Magnetic

Carbon-13 nuclear magnetic resonance spectroscopy, in contrast to 1H n.m.r. spectroscopy, has been shown to provide a clear distinction in a variety of nitrogen heterocyclic systems between O-methyl and nuclear N-methyl groups. Methoxy groups were found to occur in the range δ�53.20-61.87, nuclear N-methyl groups at 34.29-49.62, and methylthio groups at 12.35-14.55 for the compounds examined in (D)chloroform. Data for N- and O-methyl derivatives of pyridin-2- and -4-ol,* the corresponding pyrimidines, and some sulfur analogues have been compared with those for the unmethylated parent compounds.

Transannular reactions in the dibenzo[a,d]cycloheptene series. II. Preparation of 10,11-dihydro-10,5-(epoxymethano)-5H-dibenzo [a,d] cyclohepten-13-one and derivatives

1968 ◽  
Vol 46 (17) ◽  
pp. 2843-2854 ◽  
Author(s):  
T. A. Dobson ◽  
M. A. Davis ◽  
A.-M. Hartung ◽  
J. M. Manson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Acid Catalysis ◽  
Aliphatic Amines ◽  
Anti Isomer ◽  
Nuclear Magnetic Resonance Spectra ◽  
Electrophilic Reagents ◽  
Neutral Conditions ◽  
Derivatives Of ◽  
Primary Aliphatic Amines

The reaction of electrophilic reagents with the 5-substituted 5H-dibenzo[a,d]cycloheptene derivatives (13a–e) and with their 10,11-dihydro analogues (19a–b) occurs with transannular participation of the 5-substituent to yield derivatives of 10,11-dihydro-10,5-(epoxymethano)-5H-dibenzo[a,d]cycloheptene. The epimeric 10,11-dihydro-10-hydroxy-5H-dibenzo[a,d]cycloheptene-5-carboxamides (22, 23) are described. The syn-hydroxy isomer 22 is readily transformed to the lactone 16c under neutral conditions whereas the anti isomer 23 requires acid catalysis for this conversion. Treatment of anti-11-bromo-10,11-dihydro-10,5-(epoxymethano)-5H-dibenzo[a,d]cyclohepten-13-one (16b) with ammonia or primary aliphatic amines gives the epoxyamides 21a–d which can react with secondary aliphatic amines to give the anti-11-dialkylamino-10,11-dihydro-10,5-(epoxymethano)-5H-dibenzo[a,d]cyclohepten-13-ones (25a–d). The epimeric syn-11-dialkylamino compounds 24a–e are obtained from the interaction of 16b with secondary aliphatic amines. The nuclear magnetic resonance spectra of the products are tabulated.

Sign in / Sign up

Export Citation Format

Share Document