Development of cytokinin activity by rearrangement of 1-substituted adenines to 6-substituted aminopurines: inactivation by N6, 1-cyclization.

In Vivo Biosynthesis of Terpene Nucleosides Provides Unique Chemical Markers of Mycobacterium tuberculosis Infection

“…A plausible mechanism to account for the biological origin of N 6 -TbAd is that 1-TbAd is converts to N 6 -TbAD by a Dimroth rearrangement, which involves attack of a nucleophile (such as hydroxide or an amine) at C-2 to form a ring-opened intermediate followed by ring closure by the unsubstituted nitrogen to give the N 6 -linked form (Figure 5A), (El Ashry et al, 2010; Fujii and Itaya, 1998; Grimm and Leonard, 1967; Leonard et al, 1966; Macon and Wolfenden, 1968; Ottria et al, 2010; Snyder and Adams, 2011). Products from recombinant Rv3378c enzyme showed a strong signal for 1-TbAd and no signal for N 6 -TbAd, demonstrating that the latter is not a primary product of this enzyme (Figure 5B).…”

The Cytokinins

“…However, some treatments, including heating, convert them into active compounds (21,43). A recent study (23) combining the highly specific tobacco callus bioassay with a sys- (2).…”

“…Leonard and Fujii (56) noticed that such a substituent directed alkylation to the 1-position and thereby produced another good synthesis for 1-substituted adenines. Furthermore, the 1-substituted compounds easily rearrange to Nff-substituted (43). Recently Grimm and Leonard prepared 6 -(y,'y-dimethylallylamino) -9 -,8-D-ribofuranosyl purine-5'-phosphate by alkylation of the sodium salt of AMP and subsequent rearrangement of the 1-isomer to the N6-compound (59) (Fig.…”

“…Treatments of this type are known to cause a 1 to 6 cyclization of 6-(y,y-dimethylallylamino)purine and a subsequent complete loss of cytokinin activity (23,43,70,71). Thus it would appear that a change im a cytokinin in the tRNA can modify, in some way, the biological activity of the tRNA.…”

Synthesis of Triazole-Linked SAM-Adenosine Conjugates: Functionalization of Adenosine at N-1 or N-6 Position without Protecting Groups

“…N 6 -alkylation of adenosine derivatives is mainly achieved through aromatic nucleophilic substitution (S N Ar) of diverse electrophilic adenosine derivatives [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ] or by Dimroth rearrangement of 1- N -alkylated adenosines [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. In the context of S N Ar, synthetic strategies involving non classic leaving groups were developed using peptide-coupling agents for activation of the amide group of inosine derivatives [ 53 , 54 , 55 , 56 ].…”