Synthesis of pyrimidin-2-one deoxyribosides and their ability to support the growth of the deoxyriboside-requiring organism Lactobacillus acidophilus R26

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Abstract
Pyrimidin-2-one, 5-methylpyrimidin-2-one and the corresponding 2-deoxyribosides were isolated after reduction of uracil, thymine and their 2[image]-deoxyribosides with sodium amalgam in aqueous acetic-acid. The pyrimidin-2-ones have UV-absorption maxima in the region 292-324 m[mu], the location of the maximum being pH-dependent. They all exhibit a dissociation constant at pH 2 due to the protonization of the N(3) of the ring. Pyrimidin-2-one and 5-methyl-pyrimidin-2-one have a dissociation constant at pH 9 due to the dissociation of the group -C(2) O-N(1) H[long dash]. The 2[image]-deoxyribosides do not dissociate in this region. The 2[image]-deoxyribosides of pyrimidin-2-one and 5-methyl-pyrimidin-2-one possess an acid-labile glycosidic linkage. The 5-methylpyrimidin-2-one 2[image]-deoxyriboside supports the growth of the deoxyriboside requiring organism La. acidophilus R 26. Its activity as a growth factor is about 85% of that of thymidine. By using 5[H3] methyl-pyrimidin-2-one 2[image]-deoxyriboside it was shown that the 5-methyl-pyrimidin-2-one ring was not incorporated into deoxyribonucleic-acid (DNA).