Linked Life Data

10732441

Source:http://linkedlifedata.com/resource/pubmed/id/10732441

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2000-5-1
pubmed:abstractText
The photochemical reactions of cytosine (Cyt) and uracil (Ura) with ethylamine, an analog of the side chain of the amino acid lysine, have been studied. After irradiation of Cyt in aqueous ethylamine at lambda = 254 nm, N-(N'-ethylcarbamoyl)-3-aminoacrylamidine (Ia) and N-(N'-ethylcarbamoyl)-3-ethylaminoacrylamidine (Ib) were isolated as products, while irradiation of Ura gave N-(N'-ethylcarbamoyl)-3-aminoacrylamide (IIa) and N-(N'-ethylcarbamoyl)-3-ethylaminoacrylamide (IIb) as products. Studies in which Ia and IIa were incubated with ethylamine at various pH values indicate that Ib and IIb are secondary products produced via thermal reactions of Ia and IIa with ethylamine. Heating of Ia and Ib leads to ring closure with the resultant formation of 1-ethylcytosine; small amounts of 1-ethyluracil are also produced. Heating of IIa and IIb produces 1-ethyluracil as the sole product. Spectroscopic properties were determined for each of these opened ring products, as well as for N-(N'-ethylcarbamoyl)-3-amino-2-methylacrylamidine (III) and N-(N'-ethylcarbamoyl)-3-amino-2-methylacrylamide (IV). Quantum yield measurements showed that Ia was formed with a phi of 1.6 x 10(-4) at pH 9.8, while phi for formation of IIa was 7.2 x 10(-4) at pH 11.5. A profile of the relative quantum yield for formation of Ia, determined as a function of pH, showed that the maximum quantum yield occurs at around pH 9.5; the analogous profile for IIa shows a maximum quantum yield at pH 11.3 and above. Acetone sensitization does not produce Ia in the Cyt-ethylamine system, which indicates that the known triplet state of Cyt is not involved in reactions leading to this opened ring product.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0031-8655
pubmed:author
pubmed:issnType
Print
pubmed:volume
71
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
243-53
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Ring opening photoreactions of cytosine and uracil with ethylamine.
pubmed:affiliation
Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, 994143-0446, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.