Discovery of a dihydropyrimidine series of molecules that selectively mimic the biological actions of calcitonin
摘要:
The use of a multiplex mimetic assay led us to identify 1,4-dihydropyrimidines with potent and selective calcitonin receptor mimetic activity. Subsequent modification of the clihydropyrimidine scaffold led to a series of molecules that were efficacious in a neonatal mouse calvaria in vitro model. Dihydropyrimidine 5h, in particular, was identified as a calcitonin mimetic (EC50 = 6 muM), active in-vivo in the Weanling rat model when administered subcutaneously. (C) 2003 Elsevier Ltd. All rights reserved.
Oxone-promoted hydration of electron-deficient allenic esters and ketones into 1,3-dicarbonyl compounds
摘要:
A novel and mild protocol for the hydration of electron-deficient allenic esters and ketones into various 1,3-dicarbonyl compounds is described. The hydration of allenes promoted by oxone in DMF afforded the corresponding products in moderate to good yields. This work features the employment of only a catalytic amount of inexpensive and nontoxic solid reagent oxone (2KHSO(5)center dot KHSO4 center dot K2SO4), avoiding the utility of toxic metals or traditional Bronsted acids, in a green version of viewpoint. A possible reaction mechanism for this transformation is also primarily proposed. (C) 2015 Elsevier Ltd. All rights reserved.
A simple base-mediated synthesis of diverse substituted ring-fluorinated 4H-pyrans (monofluorinated 4H-pyrans) from trifluoromethylated alkenes and 1,3-dicarbonyl compounds was developed.
THE SYNTHESIS OF PORPHYRINS DERIVED FROM CHLOROBIUM CHLOROPHYLLS
作者:J. L. Archibald、D. M. Walker、K. B. Shaw、A. Markovac、S. F. MacDonald
DOI:10.1139/v66-047
日期:1966.2.1
The proofs of the structures proposed for the Chlorobium pheophorbides 650, fractions 1–5, and for the Chlorobium pheophorbides 660, fractions 5 and 6, are completed and the degradational evidence, where parallel, confirmed through the synthesis of derived porphyrins.
High Stereocontrol in the Preparation of Silyl-Protected γ-Substituted Enoldiazoacetates
作者:Kuiyong Dong、Kostiantyn O. Marichev、Xingfang Xu、Michael P. Doyle
DOI:10.1055/s-0037-1611865
日期:2019.7
A robust and efficient synthesis of triisopropylsilyl (TIPS)-protected γ-substituted enoldiazoacetates with excellent Z stereocontrol by using lithium bis(trimethylsilyl)azanide (LiHMDS) as a base and TIPSOTf as a silyl transfer reagent is reported. Despite their increased size compared to previously tert-butyldimethylsilyl (TBS)-protected γ-unsubstituted enoldiazoacetates, a high product yield with
Palladium-Catalyzed Elimination/Isomerization of Enol Triflates into 1,3-Dienes
作者:Ian T. Crouch、Timothy Dreier、Doug E. Frantz
DOI:10.1002/anie.201101820
日期:2011.6.27
were synthesized by the title reaction (see scheme; Tf=trifluoromethanesulfonyl). Preliminary studies support a mechanistically distinct pathway that involves an initial β‐hydride elimination from a cationic vinyl palladium(II) intermediate, a subsequent regiospecific hydropalladation of the corresponding allene intermediate, and a final β‐hydride elimination.
Enantioselective Synthesis of 4<i>H</i>-Pyrans Through Organocatalytic Asymmetric Formal [3+3] Cycloadditions of 2-(1-Alkynyl)-2-alken-1-ones with β-Keto Esters
4H‐Pyran units are frequently present in molecules with significant biological and pharmaceutical activities. Herein, we present the first enantioselective formal [3+3] cycloaddition between 2‐(1‐alkynyl)‐2‐alken‐1‐ones and β‐keto esters catalyzed by a cyclohexyldiamine‐based thiourea‐tertiary amine bifunctional catalyst. Under the mild and eco‐friendly conditions, a wide range of polysubstituted 4H‐pyrans