Reaction of 1,2-<u>0</u>-Alkylidenehexofuranurono-6,3-Lactones with Diethylaminosulfur Trifluoride (DAST)

Albert, Richard K.; Dax, K.; Katzenbeisser, U.; Sterk, H.; Stütz, Arnold

doi:10.1080/07328308508082674

Cited by 14 publications

(6 citation statements)

References 10 publications

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“…Attempts to hydrolyze 9demethoxy-9-tosylisocolchicine with 5% NaOH in water/ ethanol also resulted in ring contraction product as well as colchiceine. We have found that when the alkoxymagnesium compound is the nucleophile rather than the 7.9 13.2 (±1.7) 53.7 (±2.5) CH3 (10) 4.1 56.6 (±1.5) 96.7 (±9.9) CH2CH3 (11) 4.2 54.9 (±6.8) 96.5 (±9.4) CH2CH2CH3 (12) 3.5 41.7 (±1.5) 89.2 (±5.9) CH(CH3)2 (13) 4.2 44.9 (±5.4) 90.0 (±1.9) (CH2)3CH3 ( 14) 26 13.9 (±7.0) 24.7 (±5.8) CH2CH(CH3)2 (15) 8.5 13.4 (±1.9) 36.7 (±4.6) CH(CH2CH3)(CH3) (16) 10 19.6 (±5.7)…”

Section: Chemistrymentioning

confidence: 94%

“…Table I. Synthesis of C-10 Analogues of Colchicine substrate, X = product, R = yield (%) OH (4) OTos ( 5) 89 (22) °O Tos Cl (6) 86 OTos Br (7) 73 Br K8) 70 OH F (9) 88 (66) F CH3 (10) 52 OH CH3 (10) 52 (39) F CH2CH3 (11) 48 OH CH2CH3 (11) 60 (45) F (CH2)2CH3 (12) 69 F CH(CH3)2 (13) 72 F (CH2)3CH3 (14) 49 F CH2CH(CH3)2 (15) 55 F CH(CH2CH3)(CH3) (16)…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis and tubulin binding of novel C-10 analogs of colchicine

Staretz¹,

Bane²

1993

J. Med. Chem.

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A series of novel C-10 derivatives of colchicine have been prepared and evaluated for inhibition of in vitro microtubule assembly and of [3H]colchicine binding to tubulin. The C-10 substituent of colchicine was replaced by halogens, alkyl and alkoxy groups, and hydrogen. Many of these compounds are available by nucleophilic substitution of 10-fluoro-10-demethoxycolchicine (9) without concomitant formation of ring contraction products. Compound 9 is prepared by reaction of (diethylamino)sulfur trifluoride with colchiceine. Unlike most reactions of colchiceine, the colchicine rather than the isocolchicine regiosiomer is the predominant product of this reaction. It was found that modification of the C-10 substituent of colchicine had a relatively minor effect on the potency of the colchicinoids. The electronic nature of the substituent had no significant effect on the efficacy of the compound, indicating that hydrogen bonding or polar interactions between the C-10 substituent of colchicinoids and an amino acid in the colchicine binding site on tubulin are not present in the colchicine-tubulin complex. A decrease in activity was observed with increasing length of the alkyl chain bonded to the C-10 position, but potency was less affected when the alkyl groups were positioned in close proximity to the C-10 carbon of the tropone ring. It is concluded that the steric rather than the electronic properties of the C-10 substituent are the predominant determinants of activity in this series.

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Section: Chemistrymentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Synthesis and tubulin binding of novel C-10 analogs of colchicine

Staretz¹,

Bane²

1993

J. Med. Chem.

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“…It was not possible either to displace the triflates in 10 by any of an umber of nucleophilicsourcesoffluoride (including TASF, TBAF andC sF) or to introduce fluorine directly by reaction of the alcohol 9 with DAST [35] or Xtalfluor. [36] Accordingly,t reatment of diacetylrhamnal 15 with Select-Fluor in aqueous acetonitrile [37] followed by acetylation with acetic anhydridei np yridine during the workup caused electrophilic fluorination to give am ixture of the four sugar triacetates 46 a/b and 47 (Scheme 6) with little stereoselectivity.O ne Scheme4.i) (CF 3 SO 2 ) 2 O, pyridine,T HF, À20 8C, 95 %, ii)NaN 3 ,DMF, À40 8C, 75 %, iii)DIBALH, CH 2 Cl 2 , À78 8C, 3h,8 4%,i v) see text;85% 36 from 10, v) (CF 3 SO 2 ) 2 O, pyridine, THF, À20 8C, vi)NaN 3 ,DMF, À40 8C, 70 % 36 and 24 % 34 (over two steps), vii)DIBALH, CH 2 Cl 2 , À78 8C, 3h,87%.…”

Section: -Deoxy-2-fluoro-l-rhamnose 16 And2-deoxy-2-fluoro-lquinovosmentioning

confidence: 99%

6‐Deoxyhexoses from l‐Rhamnose in the Search for Inducers of the Rhamnose Operon: Synergy of Chemistry and Biotechnology

Liu

Yoshihara

Kelly

et al. 2016

Chemistry A European J

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In the search for alternative non-metabolizable inducers in the L-rhamnose promoter system, the synthesis of fifteen 6-deoxyhexoses from L-rhamnose demonstrates the value of synergy between biotechnology and chemistry. The readily available 2,3-acetonide of rhamnonolactone allows inversion of configuration at C4 and/or C5 of rhamnose to give 6-deoxy-D-allose, 6-deoxy-D-gulose and 6-deoxy-L-talose. Highly crystalline 3,5-benzylidene rhamnonolactone gives easy access to Lquinovose [6-deoxy-L-glucose], L-olivose and rhamnose analogue with C2 azido, amino and acetamido substituents. Electrophilic fluorination of rhamnal gives a mixture of 2-deoxy-2-fluoro-Lrhamnose and 2-deoxy-2-fluoro-L-quinovose. Biotechnology provides access to 6-deoxy-L-altrose and 1-deoxy-L-fructose.

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“…However, α-hydroxy lactones undergo normal fluorodehydroxylation along with geminal difluorination at the lactone carbonyl. 28 Glycosyl fluorides can be obtained in high yield, and in a stereospecific manner, either by reacting DAST with hemithioacetals in the presence of N-Bromosuccinimide or, more simply, hemiacetals. 29b An interesting fluorination of a phenyl ring of Nbenzylphenylhydroxylamine has been reported (eq 19).…”

Section: Miscellaneous Reactionsmentioning

confidence: 99%