Isopropylidene adenosine

Adenosine, N -dimethyI-5 -0-methyI-2, 3 -0-isopropylidene-methylation, 5, 537 Adenosine, homocitrullyamino-biological activity, 5, 603 Adenosine, 1-isopentenyI-synthesis, 5, 594 Adenosine, 2 -0-methyI-occurrence, 5, 600 Adenosine, 2-phenyIamino-synthesis, 5, 590 Adenosine, 2, 3, 5 -tri-0-acetyl bromination, 5, 540 Adenosine-8-earboxylic acids synthesis, 5, 593 Adenosines, isopropylidene-synthesis, 5, 584... 

Other sulfide photoreactions result when appropriate nucleoside derivatives are photolyzed. Upon irradiation in acetonitrile, 9-[5-deoxy-2,3-0-isopropylidene-5-(phenylthio)-/3-D-ribofuranosyl]-adenine (53) is converted into the anhydronucleoside 8,5 -anhydro-(5 -deoxy-2, 3 -0-isopropylidene-adenosine) (55) in 66% yield.111 Similar reactions were observed when other sulfur-containing nucleosides were irradiated (see Table XIII). The reaction of the sulfide 53... 

The reactions of 23 with 2, 3 -0-isopropylidene derivatives of purine nucleosides, or with free adenosine, give the corresponding N3,5 -anhydronucleosides in high yield a 5 -deoxy-5 -iodo deriv-... 

Fig. 12. A method for converting an alcohol, R—CH2OH, into the arsonomethyl analogue of its phosphate. This was used to make the arsonomethyl analogue of AMP. R—CH2OH represents adenosine, and R —CH2OH its 2, 3 -isopropylidene derivative.

Adenosine 3 -phosphate dihydrate180 Aristeromycin hydrobromide181 5, 8-Anhydro-2, 3 -0-isopropylidene-8-endo-mercaptoadenosine hydrate182... 

As regards compound 5 (Table III), it may be noted that the O-tosyl-oxy group reacts, but the iV-tosyl group does not. A so-called 2,3-0-isopropylidene-5-0-tosyl-adenosine is said363 to undergo the iodination reaction with simultaneous cyclization, to yield 2,3-0-isopropylidene-5,3 -cycZo-adenosine iodide. 

ISopropyliden-adenosin-5 - -(1-methoxy-carbonyl-2-phenyl-ethylamid)-ester XII/2, 398f. 2, 3 -0-lsopropyliden-adenosin-5 - -phenylester XII/2, 233... 

Pyrophosphorsaure (Forts.) P-(2, 3 -0-Isopropyliden-adenosin-5 )-P -ribofla-vin-S - XII/2, 894f. 

Alkylation of many iV-oxides affords corresponding iV-alkoxypurines although xanthine 1-oxide produced the 1-hydroxybetaine, and the 3-oxide behaves in a similar manner. Alkylation often proceeds better in the presence of hydrogen peroxide (74CPB2466) as in the conversion of adenine 1-oxide into l-methoxy-9-methyladenine with methyl iodide. Similarly alkylation of adenosine 1-oxide and its 2, 3 -0-isopropylidene derivative Afforded the corresponding 1-alkoxy nucleosides <73CPB1676). 

Mono-isopropylidene derivatives of adenosine and guanosine have also been prepared by Levene and Tipson. They are probably, likewise, the 2,3-isopropylidene derivatives, but their structures have not yet been proved. 

Jachimowicz claimed to have synthesized 5-phosphoadenosine (in poor yield) by direct phosphorylation of adenosine with phosphorus oxychloride in pyridine, but Bredereck showed that a mixture of phosphoric esters of adenosine actually results, as might have been anticipated. Levene and Tipson succeeded in synthesizing 5-phospho-adenosine (in poor yield) by phosphorylation of 2,3-diacetyl-adenosine to give AT-phos-pho 5-phospho-2,3-diacetyl-adenosine, followed by deacetylation by alkali, and removal by acid-hydrolysis of the labile phospho group attached to nitrogen. (This synthesis was confirmed by Bredereck, et al. ) In a similar manner they phosphorylated 2,3-isopropylidene-adenosine to iV,5-di-phospho-2,3-isopropylidene-adenosine from which the acid-labile iV-phospho and isopropylidene groups were hydrolyzed, giving 5-phospho-adenosine. 

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