Purines rearrangement

The pathways for thiamine biosynthesis have been elucidated only partiy. Thiamine pyrophosphate is made universally from the precursors 4-amino-5-hydroxymethyl-2-methylpytimidinepyrophosphate [841-01-0] (47) and 4-methyl-5-(2-hydroxyethyl)thiazolephosphate [3269-79-2] (48), but there appear to be different pathways ia the eadier steps. In bacteria, the early steps of the pyrimidine biosynthesis are same as those of purine nucleotide biosynthesis, 5-Aminoimidazole ribotide [41535-66-4] (AIR) (49) appears to be the sole and last common iatermediate ultimately the elements are suppHed by glycine, formate, and ribose. AIR is rearranged in a complex manner to the pyrimidine by an as-yet undetermined mechanism. In yeasts, the pathway to the pyrimidine is less well understood and maybe different (74—83) (Fig. 9). 

Dimroth rearrangement, 5, 562 Purine, 2-aIkyI-synthesis, S, 587 Purine, 6-aIkyI-I-oxide... 

Purine, 1,6-dihydro-8,9-dimethyl-6-thioxo-synthesis, 5, 583 Purine, 2,6-dimethoxy-synthesis, 5, 596 Purine, 2,6-dimethoxy-7-methyl-rearrangement, 5, 558 Purine, 2,7-dimethyl-halogenation, 5, 547 Purine, 7,9-dimethyl-UV spectra, 5, 517 Purine, 8,8-dimethyl-synthesis, 5, 580 Purine, 6-dimethylamino-mass spectra, 5, 519 occurrence, 5, 600 Purine, 6-dimethylamino-9-benzyl-alkylation, 5, 531 Purine, 3,7-dimethyl-6,8-dioxo-methylation, 5, 534 Purine, 6,8-dioxo-alkylation, 5, 534... 

Purines, N-alkyl-N-phenyl-synthesis, 5, 576 Purines, alkylthio-hydrolysis, 5, 560 Mannich reaction, 5, 536 Michael addition reactions, 5, 536 Purines, S-alkylthio-hydrolysis, 5, 560 Purines, amino-alkylation, 5, 530, 551 IR spectra, 5, 518 reactions, 5, 551-553 with diazonium ions, 5, 538 reduction, 5, 541 UV spectra, 5, 517 Purines, N-amino-synthesis, 5, 595 Purines, aminohydroxy-hydrogenation, 5, 555 reactions, 5, 555 Purines, aminooxo-reactions, 5, 557 thiation, 5, 557 Purines, bromo-synthesis, 5, 557 Purines, chloro-synthesis, 5, 573 Purines, cyano-reactions, 5, 550 Purines, dialkoxy-rearrangement, 5, 558 Purines, diazoreactions, 5, 96 Purines, dioxo-alkylation, 5, 532 Purines, N-glycosyl-, 5, 536 Purines, halo-N-alkylation, 5, 529 hydrogenolysis, 5, 562 reactions, 5, 561-562, 564 with alkoxides, 5, 563 synthesis, 5, 556 Purines, hydrazino-reactions, 5, 553 Purines, hydroxyamino-reactions, 5, 556 Purines, 8-lithiotrimethylsilyl-nucleosides alkylation, 5, 537 Purines, N-methyl-magnetic circular dichroism, 5, 523 Purines, methylthio-bromination, 5, 559 Purines, nitro-reactions, 5, 550, 551 Purines, oxo-alkylation, 5, 532 amination, 5, 557 dipole moments, 5, 522 H NMR, 5, 512 pJfa, 5, 524 reactions, 5, 556-557 with diazonium ions, 5, 538 reduction, 5, 541 thiation, 5, 557 Purines, oxohydro-IR spectra, 5, 518 Purines, selenoxo-synthesis, 5, 597 Purines, thio-acylation, 5, 559 alkylation, 5, 559 Purines, thioxo-acetylation, 5, 559... 

Chlorocyclononatetraene 267 rapidly rearranges in liquid sulfur dioxide to 1-chloro-8,9-dihydroindene 268, which forms the cycloadduct 269 with the triazolinedione 264 (equation 145)137. The vinylimidazole 270 affords the purine analogue 271 (equation 146)138. 

Compound 610 was transformed thermally to the tetrazolo[5,l-b]purin-7(8//)-one 639 through Curtius rearrangement via the isocyanate intermediate 638 (86H1899). Reaction of 626 (R = Ph) with bromine or sulfuryl chloride led by ring opening and decarboxylation to the halogenated tetra-... 

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