Efficient syntheses of 1-bromodeoxy-, 1-azidodeoxy- and 1-aminodeoxypentitols from unprotected d-pentono-1,4-lactones
摘要:
The reduction of unprotected 5-bromo-5-deoxy-D-ribono, D-arabinono and D-xylono-1,4-lactones was achieved with NaBH4 in water-EtOH. The corresponding 1-bromo-1-deoxypentitols were isolated after acetylation in good overall yields (60-90%). 1-Azido-1-deoxypentitols were obtained quantitatively either by nucleophilic substitution by azide ion and deacetylation of the corresponding monobromopentitols or by reduction of the corresponding 5-azido-5-deoxy-D-pentono-1,4-lactones. The reduction of the monoazidopentitols by catalytic hydrogen transfer gave the monoaminopentitol analogues in quantitative yield.
Regioselective halogenation of pentono-1,4-lactones. Efficient synthesis of 5-chloro- and 5-bromo-5-deoxy derivatives
摘要:
Treatment of unprotected D-ribono, D-arabinono and D-xylono-1,4-lactones with either thionyl chloride or thionyl bromide in dimethylformamide led to 5-chloro- or 5-bromo-5-deoxy derivatives in 70%-95% yields. Under the same conditions, D-lyxono-1,4-lactone resulted in the 2-halogeno compounds. (C) 1997 Elsevier Science Ltd.
(d-ribono, d-arabinono and d-xylono) and corresponding alditolderivatives with the general formula Su-SR (R=CnH2n+1; n=5-12) are studied. It was shown that the thermotropic and lyotropic phase transition temperatures are influenced by the following structural parameters: alkyl chain length, cyclic or acyclic Su structure and alditolconformation. Besides, it seems that n parity affects thermotropic
研究了S-烷硫基戊内酯(d-核糖基,d-阿拉伯糖基和d-木糖基)和相应的通式为Su-SR(R = CnH2n + 1; n = 5-12)的糖醇衍生物的介晶性质。结果表明,热致相变温度受以下结构参数的影响:烷基链长,环状或无环Su结构和糖醇构象。此外,似乎n平价会影响热致相变温度。
An efficient and facile three-step synthesis of 5-amino-5-deoxy-D-pentonolactams from unprotected D-pentono-1,4-lactones.
Regioselective bromination of D-pentono-1,4-lactones with SOBr2 in DMF led to 5-bromo-5-deoxy derivatives. These intermediates were treated with LiN3 and hydrogenated to give 5-amino-5-deoxy-D-pentonolactams in 60-83% overall yield. (C) 1997 Elsevier Science Ltd.
Efficient syntheses of 1-S-alkyl-1-thio-l-ribitols, d-lyxitols and l-xylitols from d-pentono-1,4-lactones
The thioalkylation of unprotected 5-bromo-5-deoxy-D-ribono, D-arabinono, and D-xylono-1,4-lactone was performed with the alkylthiol-sodium hydride reagent. The corresponding 5-S-alkyl-5-thio-D-pentono-1,4-lactones were isolated in good yields (82-95%). Reduction with NaBH4 of these derivatives gave the 1-S-alkyl-1-thio-L-ribitols, D-lyxitols and L-xylitols in 85-96% yields. (C) 2001 Elsevier Science Ltd. All rights reserved.
Regioselective halogenation of pentono-1,4-lactones. Efficient synthesis of 5-chloro- and 5-bromo-5-deoxy derivatives
Treatment of unprotected D-ribono, D-arabinono and D-xylono-1,4-lactones with either thionyl chloride or thionyl bromide in dimethylformamide led to 5-chloro- or 5-bromo-5-deoxy derivatives in 70%-95% yields. Under the same conditions, D-lyxono-1,4-lactone resulted in the 2-halogeno compounds. (C) 1997 Elsevier Science Ltd.
Efficient syntheses of 1-bromodeoxy-, 1-azidodeoxy- and 1-aminodeoxypentitols from unprotected d-pentono-1,4-lactones
作者:Véronique Bouchez、Imane Stasik、Daniel Beaupère
DOI:10.1016/s0008-6215(99)00261-x
日期:1999.1
The reduction of unprotected 5-bromo-5-deoxy-D-ribono, D-arabinono and D-xylono-1,4-lactones was achieved with NaBH4 in water-EtOH. The corresponding 1-bromo-1-deoxypentitols were isolated after acetylation in good overall yields (60-90%). 1-Azido-1-deoxypentitols were obtained quantitatively either by nucleophilic substitution by azide ion and deacetylation of the corresponding monobromopentitols or by reduction of the corresponding 5-azido-5-deoxy-D-pentono-1,4-lactones. The reduction of the monoazidopentitols by catalytic hydrogen transfer gave the monoaminopentitol analogues in quantitative yield.