One-Pot Stepwise Synthesis of γ-Lactams through Cycloadditions with Ketenes

The stepwise synthesis of monodisperse polyethylene glycols (PEGs) and their derivatives usually involves using an acid-labile protecting group such as DMTr and coupling the two PEG moieties together under basic Williamson ether formation conditions. Using this approach, each elongation of PEG is achieved in three steps – deprotection, deprotonation and coupling – in two pots. Here, we report a more convenient approach for PEG synthesis featuring the use of a base-labile protecting group such as the phenethyl group. Using this approach, each elongation of PEG can be achieved in two steps – deprotection and coupling – in only one pot. The deprotonation step, and the isolation and purification of the intermediate product after deprotection using existing approaches are no longer needed when the one-pot approach is used. Because the stepwise PEG synthesis usually requires multiple PEG elongation cycles, the new PEG synthesis method is expected to significantly lower PEG synthesis cost.

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Stepwise synthesis of chitooligosaccharides through a transition-state analogue substrate catalyzed by mutants of chitinase A1 from Bacillus circulans WL-12

Holzforschung ◽

10.1515/hf.2006.080 ◽

2006 ◽

Vol 60 (5) ◽

pp. 485-491 ◽

Cited By ~ 11

Author(s):

Michinari Kohri ◽

Atsushi Kobayashi ◽

Masato Noguchi ◽

Shin-ichi Kawaida ◽

Takeshi Watanabe ◽

...

Keyword(s):

Hydrolytic Activity ◽

Site Directed Mutagenesis ◽

Bacillus Circulans ◽

High Yield ◽

Wild Type ◽

Reaction Conditions ◽

One Pot ◽

Stepwise Synthesis ◽

Transition State Analogue ◽

Combined Use

Abstract Several mutants of chitinase A1 from Bacillus circulans WL-12 have been prepared by site-directed mutagenesis of tryptophan 433. The hydrolytic activity of these mutants toward p-nitrophenyl chitobioside was lower than that of wild-type chitinase A1. The mutants were found to catalyze the transglycosylation reaction of the 1,2-oxazoline derivative of N-acetyllactosamine (Gal-GlcNAc-oxa) to N,N′′-diacetylchitobiose (GlcNAc-GlcNAc), giving rise to a transglycosylated tetrasaccharide product (Gal-GlcNAc-GlcNAc-GlcNAc) in high yield. Based on these results, a one-pot synthesis of chitooligosaccharides by combined use of mutant W433Y and β-galactosidase has been demonstrated. By controlling the reaction conditions, chitotriose and chitotetraose were obtained in 74% and 40% yield (determined by HPLC), respectively, without isolating any intermediate products.

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From superphanes to beltenes

Pure and Applied Chemistry ◽

10.1351/pac200678040699 ◽

2006 ◽

Vol 78 (4) ◽

pp. 699-706 ◽

Cited By ~ 30

Author(s):

Rolf Gleiter ◽

Björn Hellbach ◽

Silke Gath ◽

Rolf J. Schaller

Keyword(s):

Short Review ◽

One Pot ◽

Stepwise Synthesis ◽

New Class ◽

Large Rings

This short review describes paths to superphanes with metal-stabilized cyclobutadiene and cyclopentadienone rings in a one-pot and stepwise fashion. The stepwise synthesis also led to a new class of belt-like systems with large rings composed of CpCo-stabilized cyclobutadiene rings connected with propane chains. Finally, our research yielded the first beltenes composed of alternating four- and eight-membered conjugated rings.

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Synthesis of unsymmetrical 3,6-branched Man5 oligosaccharide: a comparison between one-pot sequential glycosylation and stepwise synthesis

Carbohydrate Research ◽

10.1016/j.carres.2014.09.010 ◽

2015 ◽

Vol 401 ◽

pp. 109-114 ◽

Cited By ~ 9

Author(s):

Yan Zhang ◽

Congcong Chen ◽

Lan Jin ◽

Haining Tan ◽

Fengshan Wang ◽

...

Keyword(s):

One Pot ◽

Stepwise Synthesis

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Pd-Catalyzed One-Pot Stepwise Synthesis of Benzo[b][1,6]naphthyridines from 2-Chloroquinoline-3-carbonitriles Using Sulfur and Amines As Nucleophiles

The Journal of Organic Chemistry ◽

10.1021/acs.joc.7b02147 ◽

2017 ◽

Vol 82 (21) ◽

pp. 11531-11542 ◽

Cited By ~ 6

Author(s):

Ritush Kumar ◽

Mrityunjaya Asthana ◽

Radhey M. Singh

Keyword(s):

One Pot ◽

Stepwise Synthesis

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Controlled Stepwise Synthesis and Characterization of a Ternary Multicomponent Crystal with 2-Methylresorcinol

Chemistry ◽

10.3390/chemistry2010009 ◽

2020 ◽

Vol 2 (1) ◽

pp. 93-100

Author(s):

Daniel Komisarek ◽

Carsten Schauerte ◽

Klaus Merz

Keyword(s):

Multicomponent System ◽

Synthesis And Characterization ◽

One Pot ◽

Stepwise Synthesis ◽

X Ray ◽

Target Molecule ◽

Retrosynthetic Analysis ◽

Crystal Design ◽

System 1

A typical approach of a multicomponent crystal design starts with a retrosynthetic analysis of the target molecule followed by a one-pot reaction of all components. To develop protocols for multicomponent crystal syntheses, controlled stepwise syntheses of a selected crystalline ternary multicomponent system 1 involving 2-methylresorcinol (MRS), tetramethyl-pyrazine (TMP), and 1,2-bis(4-pyridyl)ethane (BPE) are presented. The obtained binary cocrystals 2 (involving MRS and TMP) and 3 (involving MRS and BPE) as well as the final resulting ternary multicomponent system 1 were characterized by X-ray analysis.

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