Reductions of activated carbonyl compounds with chiral-bridged 1,4-dihydropyridines. An investigation of scope and structural effects
作者:Auke G. Talma、Patrick Jouin、Johannes G. De Vries、C. B. Troostwijk、Gerard H. Werumeus Buning、Jan K. Waninge、Johnny Visscher、Richard M. Kellogg
DOI:10.1021/ja00299a038
日期:1985.6
bridged macrocyclic 1,4-dihydropyridines (7) have been synthesized by starting from valine, alanine, phenylglycine, phenylalanine, and proline. Various bridges of different compositions, lengths, and shapes have been incorporated. All these bridged compounds in a nonprotic solvent like CH3CN in the presence of a stoichiometric amount of Mg(ClO4)2·1.5H2O reduce activatedcarbonylcompounds to the corresponding
Proline, 4-hydroxyproline, azetidine-2-carboxylic acid, pipecolic acid and proline containing dipeptides were converted to N-t-butyloxycarbonyl, O-phenacyl derivatives in a one pot synthesis. 1H - and 13C -NMR spectroscopy of certain derivatives (Boc-Pro-PE, Boc-4Hyp-PE, Boc-Pro-4BrPE and Boc-Pip-PE) in CDC13 solution reveal the presence of cis-trans isomers in almost equal quantities. On the contrary
在一锅合成中,将脯氨酸,4-羟基脯氨酸,氮杂环丁烷-2-羧酸,胡椒酸和含脯氨酸的二肽转化为Nt-丁氧基羰基,O-苯甲酰基衍生物。CDC1 3溶液中某些衍生物(Boc-Pro-PE,Boc-4Hyp-PE,Boc-Pro-4BrPE和Boc-Pip-PE)的1 H-和13 C -NMR光谱揭示了顺式-反式异构体的存在几乎相等的数量。相反,1 H和13氮杂环丁烷-2-羧酸的Nt-丁氧基羰基苯甲酸酯的13 C-NMR谱表明仅存在一种异构体。类似地,在溶液中仅观察到一种氨基甲酸酯异构体,用于保护的C端血管紧张素II二肽,Nt-Boc-Pro-Phe-PE和Nt-Boc-Pro-Ile-PE。所有的苯甲酰基衍生物均表现出归因于空间因素的磁不对称性。
Total Synthesis of Microcystin-LF and Derivatives Thereof
作者:Ivan Zemskov、Stefan Altaner、Daniel R. Dietrich、Valentin Wittmann
DOI:10.1021/acs.joc.7b00175
日期:2017.4.7
by cyanobacteria. They can be released to the water during harmful algal blooms and are a serious threat to animals and humans. Described is the totalsynthesis of the cyanotoxin microcystin-LF (MC-LF, 1a) and two derivatives thereof. Deuterated derivative 1b is of interest as an internal standard during MC quantification in biological samples by mass spectrometry and alkyne-labeled 1c can be employed
The present invention provides a process comprising substitution of an acceptor molecule comprising a group —XC(O)— wherein X is O, S or NR
8
, where R
8
is C
1-6
alkyl, C
6-12
aryl or hydrogen, with a nucleophile, wherein the acceptor molecule is cyclised such that said nucleophilic substitution at —XC(O)— occurs without racemisation. This process has particular application for the production of a peptide by extension from the activated carboxy-terminus of an acyl amino acid residue without epimerisation.
Phenylimidazoles as Potent and Selective Inhibitors of Coagulation Factor XIa with in Vivo Antithrombotic Activity
作者:Jon J. Hangeland、Todd J. Friends、Karen A. Rossi、Joanne M. Smallheer、Cailan Wang、Zhong Sun、James R. Corte、Tianan Fang、Pancras C. Wong、Alan R. Rendina、Frank A. Barbera、Jeffrey M. Bozarth、Joseph M. Luettgen、Carol A. Watson、Ge Zhang、Anzhi Wei、Vidhyashankar Ramamurthy、Paul E. Morin、Gregory S. Bisacchi、Srinath Subramaniam、Piramanayagam Arunachalam、Arvind Mathur、Dietmar A. Seiffert、Ruth R. Wexler、Mimi L. Quan
DOI:10.1021/jm5010607
日期:2014.12.11
Novel inhibitors of FXIa containing an (S)-2-phenyl-1-(4-phenyl-1H-imidazol-2-yl)ethanamine core have been optimized to provide compound 16b, a potent, reversible inhibitor of FXIa (K-i = 0.3 nM) having in vivo antithrombotic efficacy in the rabbit AV-shunt thrombosis model (ID50 = 0.6 mg/kg + 1 mg kg(-1) h(-1)). Initial analog selection was informed by molecular modeling using compounds 11a and 11h overlaid onto the X-ray crystal structure of tetrahydroquinoline 3 complexed to FXIa. Further optimization was achieved by specific modifications derived from careful analysis of the X-ray crystal structure of the FXIa/11h complex. Compound 16b was well tolerated and enabled extensive pharmacologic evaluation of the FXIa mechanism up to the ID90 for thrombus inhibition.