The isopropylidenation of d-ribose diethyl dithioacetal and ribitol. A new synthesis of α- and β-d-ribofuranosylethyne via 2,3:4,5-di-O-isopropylidene-aldehydo-d-ribose

Aslani-Shotorbani, Gaffar; Buchanan, J. G.; Edgar, Alan R.; Shahidi, Parvin

doi:10.1016/0008-6215(85)85184-3

Cited by 36 publications

(31 citation statements)

References 25 publications

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“…In particular, we have chosen the conversion of D-ribose ( 6 ) with n -propylthiol ( Scheme 2 ), since the product 7 (57%) was crystalline [ 26 ]. Diacetonide formation (product 8 , 75%) proceeded as reported for the di(ethylthio) congener [ 24 ]. Finally, the dithioacetyl was cleaved while the isopropylidene moieties were retained, but not with mercury salts, as in original publications for the preparation of aldehyde 9 [ 27 ], but with the use of iodine (95% yield of product 9 ), as recommended by Ohlsson et al .…”

Section: Resultsmentioning

confidence: 67%

A robust synthesis of 7,8-didemethyl-8-hydroxy-5-deazariboflavin

Bender¹,

Mouritsen²,

Christoffers³

2016

Beilstein J. Org. Chem.

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SummaryThe biosynthetic precursor of redox cofactor F420, 7,8-didemethyl-8-hydroxy-5-deazariboflavin, was prepared in four steps from 6-chlorouracil, 2-chloro-4-hydroxybenzaldehyde and bis-isopropylidene protected D-ribose. The latter aldehyde was transformed to the corresponding protected ribitylamine via the oxime, which was submitted to reduction with LiAlH4. Key advantage compared to previous syntheses is the utilization of a polyol-protective group which allowed the chromatographic purification of a key-intermediate product providing the target compound with high purity.

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Section: Resultsmentioning

confidence: 67%

A robust synthesis of 7,8-didemethyl-8-hydroxy-5-deazariboflavin

Bender¹,

Mouritsen²,

Christoffers³

2016

Beilstein J. Org. Chem.

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“…We started from N-(4-bromophenyl)benzamide (47) [13] which was treated with 2 equiv. of BuLi and then with 2,3: 4,5-di-O-isopropylidene-d-ribose (48) [14] …”

Section: Methodsmentioning

confidence: 99%

“…calc. for C 11 H 13 N 5 O 3 (263.3): C 50.18, H 4.98, N 26.60; found: C 49.33, H 5.02, N 26.23.6-(1-Hydroxyethyl)-7-methyl-2-[(2-methyl-1-oxopropyl)amino]pteridin-4(3H)-one(14). As described for 13, with 10 (0.867 g, 3 mmol) in MeOH (20 ml) and NaBH 4 (0.38 g, 10 mmol).…”

mentioning

confidence: 97%

Pteridines. Part CXVIII

Heizmann

Pfleiderer

2007

Helvetica Chimica Acta

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Our approach to achieve a partial synthesis of methanopterin (1) started from 6-acetyl-O 4 -isopropyl-7-methylpterin (20) which was obtained either by condensation from 6-isopropoxypyrimidine-2,4,5triamine (19) and pentane-2,3,4-trione (6) or from 6-isopropoxy-5-nitrosopyrimidine-2,4-diamine (21) and pentane-2,4-dione (¼ acetylacetone; 22) (Scheme 2). NaBH 4 reduction of 20 led to 6-(1hydroxyethyl)-O 4 -isopropyl-7-methylpterin (23) which was converted into the corresponding 6-(1chloroethyl) and 6-(1-bromoethyl) derivatives 24 and 25. A series of nucleophilic displacement reactions in the side chain and at position 4 were performed as model reactions to give 26 -29, 32 -35, and 39 -41. Hydrolysis of the substituents at C(4) led to the corresponding pterin derivatives 30, 31, 36 -38, and 42. Analogously, 25 reacted with 1-(4-aminophenyl)-1-deoxy-2,3: 4,5-di-O-isopropylidene-d-ribitol (43), prepared from N-(4-bromophenyl)benzamide (47) via 49 and 50 to give 1-{4-{{1-[2-amino-7-methyl-4-(1methylethoxy)pteridin-6-yl]ethyl}amino}phenyl}-1-deoxy-d-ribitol (44) in 62% yield (Scheme 3). Acid cleavage of the isopropylidene groups at room temperature led to 45 and on boiling to 1-{4-{[1-(2-amino-3,4-dihydro-7-methyl-4-oxopteridin-6-yl)ethyl]amino}phenyl}-1-deoxy-d-ribitol (46). The next step, however, attachment of the ribofuranosyl moiety with 55 or 56 to the terminal 1-deoxy-d-ribitol OH group could not been achieved. The second component, bis(4-nitrobenzyl) 2-{[(2-cyanoethoxy)(diisopropylamino)phosphino]oxy}pentanedioate (61), to built-up methanopterin (1) was synthesized from 2hydroxypentanedioic acid (59) and worked well in another model reaction on phosphitylation with N 6benzoyl-2',3'-O-isopropylideneadenosine and oxidation to give 62 (Scheme 6).

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“…At -1 1 O", 2~ CpNa in THF (4.4m1,g.E mmol) was added over 5 min to a stirred soh. of 30 [71] (1.30 g, 5.6 mmol) in dry THF (19 ml). The soh.…”

Section: ( I S/imentioning

confidence: 99%

Synthesis of Enantiomerically Pure Ferrocenes from Glycofuranosyl‐cyclopentadienes, synthetic equivalents of (alkoxyalkyl)fulvenes

Vedø¹,

Chauvin²,

Li³

et al. 1994

Helvetica Chimica Acta

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Cyclopentadienyl C-glycosides ( = glycosyl-cyclopentadienes) have been prepared as latent fulvenes. Their reaction with nucleophiles leads to cyclopentadienes substituted with (protected) alditol moieties and, hence, to enantiomerically pure metallocenes. Treatment of 1 with cyclopentadienyl anion gave the epimeric glycosyl-cyclopentadienes 6/7 (Scheme 1). Each epimer consisted of a ca. 1:l mixture of the 1,3-and 1,4-cyclopentadienes a and b, respectively, which were separated by prep. HPLC. Slow regioisomerisation occurred at room temperature. Diels-Alder addition of N-phenylmaleimide to 6a/b cu. 3 :7 at room temperature yielded three 'endo'-adducts, i.e., a disubstituted alkene (8 or 9,25%) and the trisubstituted alkenes 10 (45%) and 11 (13 %). The structure of 10 was established by X-ray analysis. Reduction of 6/7 (after isolation or in situ) with LiA1H4 gave the cyclopentadienylmannitols 12a/b (80%) which were converted to the silyl ethers 13a/b (Scheme 2). Lithiation of 13a/b and reaction with FeC1, or TiCI, led to the symmetric ferrocene 14 (76%) and the titanocene 15 (34%), respectively. The mixed ferrocene 16 (63 %) was prepared from 13a/b and pentamethylcyclopentadiene. Treatment of 6/7 with PhLi at -78" was assigned on the basis of a conformational analysis. The reaction of the ribofuranose 24 with cyclopentadienylsodium led to the epimeric C-glycosides 27a/b and 28a/b (57%, ca. 1 :I, Scheme 3 ) . The in-situ reduction of 27/28 with LiAIH, followed by isopropylidenation gave 25a/b (65%) which were transformed into the ferrocene 26 (79 %) using the standard method. Phenylation of 27/28, desilylation, and isopropylidenation gave a 20: 1 mixture of 33a/b and 34a/b (86%) which was separated by prep. HPLC. The same mixture was obtained upon phenylation of the fulvene 32 which was obtained in 36% yield from the reaction of the aldehyde-ribose 30 with cyclopentadienylsodium at -100". Lithiation of 33/34 and reaction with FeCI, gave the symmetric ferrocene 35 (88%). Similarly, the aldehyde-arabinose 36 was transformed via the fulvene 37 (32%) into a 18 :1 mixture of 38a/b and 39a/b (78 YO) and, hence, into the ferrocene 40 (83 %). Conformational analysis allowed to assign the configuration of 3S35, whereas an X-ray analysis of 40 established the (lS)-configuration of 38a/b and 40. The opposite configuration at C(1) of 38a/b and 33a/b was established by chemical degradation (Scheme 4 ) . Hydrogenation (+ 41 and 44, resp.), deprotection (+ 42 and 45, resp.), NaIO, oxidation, and NaBH, reduction yielded ( Monocyclopentadienyl titanium [ 191, zirconium [20], and hafnium [20] complexes possessing carbohydrate-derived alkoxy ligands have been used in stoichiometric amounts for the highly enantioselective addition of alkyl [20] [21] and ally1 groups [20-231 and of ester enolates [20-221 [24] to aldehydes. Zirconocenes have been used for the ring

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The isopropylidenation of d-ribose diethyl dithioacetal and ribitol. A new synthesis of α- and β-d-ribofuranosylethyne via 2,3:4,5-di-O-isopropylidene-aldehydo-d-ribose

Cited by 36 publications

References 25 publications

A robust synthesis of 7,8-didemethyl-8-hydroxy-5-deazariboflavin

A robust synthesis of 7,8-didemethyl-8-hydroxy-5-deazariboflavin

Pteridines. Part CXVIII

Synthesis of Enantiomerically Pure Ferrocenes from Glycofuranosyl‐cyclopentadienes, synthetic equivalents of (alkoxyalkyl)fulvenes

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