https://chemistry.mdma.ch/hiveboard/rhodium/pdf/indole.synth.review.1994-99.pdf

Recent developments in indole ring synthesis—methodology and applications

Heterogeneous Catalysts for the One-Pot Synthesis of Chemicals and Fine Chemicals

Recent progress in the synthesis of 1,2,3,4,-tetrahydroquinolines

Synthetic methods for azaheterocyclic phosphonates and their biological activity.

Enveloped viruses enter cells by protein-mediated membrane fusion For influenza virus, membrane fusion is regulated by the conformational state of the hemagglutinin (HA) protein, which switches from a native (nonfusogenic) structure to a fusion-active (fusogenic) conformation when exposed to the acidic environment of the cellular endosome Here we demonstrate that destabilization of HA at neutral pH, with either heat or the denaturant urea, triggers a conformational change that is biochemically indistinguishable from the change triggered by low pH In each case, the conformational change is coincident with induction of membrane-fusion activity, providing strong evidence that the fusogenic structure is formed These results indicate that the native structure of HA is trapped in a metastable state and that the fusogenic conformation is released by destabilization of native structure This strategy may be shared by other enveloped viruses, including those that enter the cell at neutral pH, and could have implications for understanding the membrane-fusion step of HIV infection

https://www.pnas.org/content/pnas/94/26/14306.full.pdf

Influenza hemagglutinin is spring-loaded by a metastable native conformation.

Monoclonal antibodies, induced with a phosphonate diester hapten, catalyzed the coupling of p-nitrophenyl esters of N-acetyl valine, leucine, and phenylalanine with tryptophan amide to form the corresponding dipeptides. All possible stereoisomeric combinations of the ester and amide substrates were coupled at comparable rates. The antibodies did not catalyze the hydrolysis of the dipeptide product nor hydrolysis or racemization of the activated esters. The yields of the dipeptides ranged from 44 to 94 percent. The antibodies were capable of multiple turnovers at rates that exceeded the rate of spontaneous ester hydrolysis. This achievement suggests routes toward creating a small number of antibody catalysts for polypeptide syntheses.

http://science.sciencemag.org/content/sci/265/5169/234.full.pdf

Peptide synthesis catalyzed by an antibody containing a binding site for variable amino acids

Enantioselective Synthesis of Diverse .alpha.-Amino Phosphonate Diesters

Asymmetric Synthesis of .alpha.-Aminophosphonates via Diastereoselective Addition of Lithium Diethyl Phosphite to Chelating Imines

A new synthesis of the pyrrolo[4,3,2-de]quinoline system characteristic of a class of marine alkaloids which includes the prianosins, discorhabdins, and other antineoplastic agents has been developed. The approach is exemplified in a total synthesis of makluvamine D, a topoisomcrase II inhibitor isolated from the sponge Zyxxya cf. marsailis. The route begins with a Fischer indole synthesis employing (2,3-dimethoxyphenyl)hydrazine (29) and dihydrofuran, and the resulting tryptophol 32 is protected as its ditosylate 34. Nitration at C4 of the indole, followed by reduction and cyclization, affords the tricycle 41, which is oxidized to the iminoquinone 42 with ceric ammonium nitrate. Replacement of the C7 methoxy substituent of the pyrroloquinoline by tryptamine could only be effected via the salt 42 and, after cleavage of the N-tosyl group followed by treatment with trifluoroacetic acid, gives makaluvamine D (3), which was isolated as its trifluoroacetate 48. Exposure of iminoquinone 42 to sodium azide unexpectedly produced the fully unsaturated pyrroloquinoline 44

Synthetic Studies of the Pyrroloquinoline Nucleus of the Makaluvamine Alkaloids. Synthesis of the Topoisomerase II Inhibitor Makaluvamine D

A series of phosphonochloridates was prepared from the corresponding phosphonate monoesters, and their reactions with alcohols, amines, and the bisnucleophile 4-aminobutan-1-ol have been investigated using 31P NMR spectroscopy. In the conversion of phosphonate monoesters to phosphonochloridates via the addition of thionyl chloride or oxalyl chloride, pyrophosphonate anhydrides were found to be formed readily as byproducts. The anhydrides reacted readily with alcohols, but more slowly than the corresponding phosphonochloridates, and only sluggishly, if at all, with amines. Therefore, when phosphonamides are prepared, anhydride formation must be suppressed. This is accomplished when the monoester is added to the chloridating agent. Unhindered phosphonochloridates reacted predominantly with the amino function of 4-aminobutan-1-ol to furnish the phosphonamidates, whereas a sterically hindered phosphonochloridate demonstrated a preference for O-coupling. This result indictes that the energy gained during P−O b...

Phosphonate Diester and Phosphonamide Synthesis. Reaction Coordinate Analysis by 31P NMR Spectroscopy: Identification of Pyrophosphonate Anhydrides and Highly Reactive Phosphonylammonium Salts1

Kraig M. Yager

Papers

Peptide synthesis catalyzed by an antibody containing a binding site for variable amino acids

Enantioselective Synthesis of Diverse .alpha.-Amino Phosphonate Diesters

Asymmetric Synthesis of .alpha.-Aminophosphonates via Diastereoselective Addition of Lithium Diethyl Phosphite to Chelating Imines

Synthetic Studies of the Pyrroloquinoline Nucleus of the Makaluvamine Alkaloids. Synthesis of the Topoisomerase II Inhibitor Makaluvamine D

Phosphonate Diester and Phosphonamide Synthesis. Reaction Coordinate Analysis by 31P NMR Spectroscopy: Identification of Pyrophosphonate Anhydrides and Highly Reactive Phosphonylammonium Salts1