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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1980-1-24
pubmed:abstractText
Infrared spectra of amino and dimethylamino derivatives with and without an ortho-methyl group of 4- and 5-substituted pyrimidines, 4-substituted pyridine, benzene and of the respective cytosines were recorded in the region of skeletal ring vibrations. Integrated intensities of ring vibration(s) v8 at about 1600 cm-1 sensitive to the presence of electron-donating substituents were used for elucidation of the steric effects of ortho-methyl on the mesomeric interaction between the -N(CH3)2 group and the ring. Molecular dipole moments were also determined experimentally in benzene for simple pyrimidine and pyridine derivatives and analysed vectorially with the use of component group moments in terms of the N(CH3)2 group conformation. The data point to a progressive twist of the dimethylamino group in hindered derivatives in the order: pyrimidine-5 greater than pyridine-4 greater than pyrimidine-4. They are also in agreement with the essential planarity of sterically crowded m41,4,4,5cytosine.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0001-527X
pubmed:author
pubmed:issnType
Print
pubmed:volume
26
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
39-54
pubmed:dateRevised
2000-12-18
pubmed:meshHeading
pubmed:year
1979
pubmed:articleTitle
Conformation of the N(CH3)2 group in cytosine and in simple model pyrimidines and pyridines. Steric effects of ortho-methyl substitution on infrared spectra and molecular dipole moments.
pubmed:publicationType
Journal Article