Studies towards the synthesis of the fluorescent bases of phenylalanine transfer ribonucleic acids: synthesis of 7-methylwye isolated from extremely thermophilic archaebacteria.
Acid- or base-catalyzed acylation of 1-benzylwye (7) provided the 7-substituted derivatives 9, 10, and 11 in poor yields. Although the reactions of lithiated 7 with electrophiles gave the 2-substituted derivatives 14, 15, 17, 20, 21, and 22, lithiation of 1-benzyl-7-bromo-2-chlorowye (23) followed by treatment with Me2CHCH2CHO (13) successfully introduced a side chain at the 7-position to afford 1-benzyl-2-chloro-7-(1-hydroxy-3-methylbutyl)wye (24). Cyclization of 1-benzyl-3-methylguanine (5) with 3-bromo-2-butanone followed by catalytic hydrogenolysis afforded 7-methylwye (2b), the hypermodified base isolated from archaebacterial transfer ribonucleic acids. A more efficient route for the synthesis of 2b has been developed via a series of reactions: the Vilsmeier-Haack reaction of 7, reduction with NaBH4, and catalytic hydrogenolysis over Pd-C.
Itaya
T
T
Mizutani
A
A
Takeda
M
M
Shioyama
C
C
D001105:Archaea / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D006147:Guanine / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D010649:Phenylalanine / Q000378:metabolism*; D012329:RNA, Bacterial / Q000138:chemical synthesis*; D012345:RNA, Transfer, Amino Acid-Specific / Q000138:chemical synthesis*; D012360:RNA, Transfer, Phe / Q000138:chemical synthesis*
D005456:Fluorescent Dyes; D012329:RNA, Bacterial; D012345:RNA, Transfer, Amino Acid-Specific; D012360:RNA, Transfer, Phe; D010649:Phenylalanine; D006147:Guanine; C060310:7-methylwye