Reaction of Aryl Isocyanates with Cotton Cellulose

1969 ◽  
Vol 39 (4) ◽  
pp. 317-323 ◽  
Author(s):  
Stanley R. Hobart ◽  
Charles H. Mack
Keyword(s):  
Thermal Reaction ◽  
Cross Linking ◽  
Dmso Solution ◽  
Reaction Conditions ◽  
Soil Burial ◽  
Cross Links ◽  
Aryl Isocyanates ◽  
In Situ Generation ◽  
Rapid Reaction

Nine cellulose N,N′-arylenedicarbamates have been formed by thermal reaction of the respective diphenyl arylenedicarbamates with cotton. Cotton print cloth was padded with a dimethylformamide (DMF) or dimethylsulfoxide (DMSO) solution of the diphenyl arylenedicarbamate and the reaction effected by in situ generation of the arylene diisocyanate in the curing step. Add-ons ranging from 3.8 to 12.0% were obtained; under comparable reaction conditions, more rapid reaction occurred with DMSO solvent rather than DMF. High degrees of cross-linking were indicated by high conditioned and high wet wrinkle recoveries. Decreases in breaking strengths, tearing strengths, and flex abrasion resistance were approximately of the same extent as normally encountered in other cross-linking treatments. Resistance to microbiological degradation for more than 89 days was shown by soil burial tests on the treated samples. Ease and extent of introduction and removal of creases by ironing were used to measure breaking and re-forming of carbamate cross links (reversibility). Ring methoxyl group activation of the N-phenyl carbamates appeared to be slightly more effective in achieving reversibility.

scholarly journals Mass spectrometry reveals the chemistry of formaldehyde cross-linking in structured proteins

2019 ◽  
Author(s):  
Tamar Tayri-Wilk ◽  
Moriya Slavin ◽  
Joanna Zamel ◽  
Ayelet Blass ◽  
Shon Cohen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Carbon Atom ◽  
Mass Spectrometry Data ◽  
Cross Linking ◽  
Atomic Structures ◽  
Cross Links ◽  
Structured Proteins ◽  
Structural Insights ◽  
Current Mechanism

AbstractFormaldehyde is a widely used fixative in biology and medicine. The current mechanism of formaldehyde cross-linking of proteins is the formation of a methylene bridge that incorporates one carbon atom into the link. Here, we present mass spectrometry data that largely refute this mechanism. Instead, the data reveal that cross-linking of structured proteins mainly involves a reaction that incorporates two carbon atoms into the link. Under MS/MS fragmentation, the link cleaves symmetrically to yield previously unrecognized fragments carrying a modification of one carbon atom. If these characteristics are considered, then formaldehyde cross-linking is readily applicable to the structural approach of cross-linking coupled to mass spectrometry. Using a cross-linked mixture of purified proteins, a suitable analysis identifies tens of cross-links that fit well with their atomic structures. A more elaborate in situ cross-linking of human cells in culture identified 469 intra-protein and 90 inter-protein cross-links, which also agreed with available atomic structures. Interestingly, many of these cross-links could not be mapped onto a known structure and thus provide new structural insights. For example, two cross-links involving the protein βNAC localize its binding site on the ribosome. Also of note are cross-links of actin with several auxiliary proteins for which the structure is unknown. Based on these findings we suggest a revised chemical reaction, which has relevance to the reactivity and toxicity of formaldehyde.

In situ Generation and Utilization of CO: An Efficient Route towards N-Substituted Saccharin via Carbonylative Cyclization of 2-Iodosulfonamides

Synlett ◽  
2017 ◽  
Vol 28 (15) ◽  
pp. 2000-2003 ◽  
Author(s):  
Bhalchandra Bhanage ◽  
Sujit Chavan ◽  
Adithyaraj K.
Keyword(s):  
Catalyst System ◽  
Reaction Conditions ◽  
Efficient Route ◽  
In Situ Generation

The present protocol demonstrates the synthesis of N-substituted saccharines via carbonylative cyclization of 2-iodosulfonamides using a Pd(OAc)2/Xantphos catalyst system and phenyl formate as a CO source. A variety of saccharin derivatives is synthesized under milder reaction conditions.

scholarly journals Targeted in situ cross-linking mass spectrometry and integrative modeling reveal the architectures of Nsp1, Nsp2, and Nucleocapsid proteins from SARS-CoV-2

2021 ◽  
Author(s):  
Moriya Slavin ◽  
Joanna Zamel ◽  
Keren Zohar ◽  
Siona Eliyahu ◽  
Merav Braitbard ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Full Length ◽  
Integrative Model ◽  
Cross Linking ◽  
Cross Link ◽  
Integrative Modeling ◽  
Cellular Context ◽  
Cross Links ◽  
The Cross

AbstractAtomic structures of several proteins from the coronavirus family are still partial or unavailable. A possible reason for this gap is the instability of these proteins outside of the cellular context, thereby prompting the use of in-cell approaches. In situ cross-linking and mass spectrometry (in situ CLMS) can provide information on the structures of such proteins as they occur in the intact cell. Here, we applied targeted in situ CLMS to structurally probe Nsp1, Nsp2, and Nucleocapsid (N) proteins from SARS-CoV-2, and obtained cross-link sets with an average density of one cross-link per twenty residues. We then employed integrative modeling that computationally combined the cross-linking data with domain structures to determine full-length atomic models. For the Nsp2, the cross-links report on a complex topology with long-range interactions. Integrative modeling with structural prediction of individual domains by the AlphaFold2 system allowed us to generate a single consistent all-atom model of the full-length Nsp2. The model reveals three putative metal binding sites, and suggests a role for Nsp2 in zinc regulation within the replication-transcription complex. For the N protein, we identified multiple intra- and inter-domain cross-links. Our integrative model of the N dimer demonstrates that it can accommodate three single RNA strands simultaneously, both stereochemically and electrostatically. For the Nsp1, cross-links with the 40S ribosome were highly consistent with recent cryo-EM structures. These results highlight the importance of cellular context for the structural probing of recalcitrant proteins and demonstrate the effectiveness of targeted in situ CLMS and integrative modeling.

scholarly journals Unprecedented nucleophile-promoted 1,7-S or Se shift reactions under Pummerer reaction conditions of 4-alkenyl-3-sulfinylmethylpyrroles

2018 ◽  
Vol 14 ◽  
pp. 2722-2729 ◽  
Author(s):  
Takashi Go ◽  
Akane Morimatsu ◽  
Hiroaki Wasada ◽  
Genzoh Tanabe ◽  
Osamu Muraoka ◽  
...  
Keyword(s):  
Successive Reaction ◽  
Reaction Conditions ◽  
Tetrabutylammonium Hydroxide ◽  
Pummerer Reaction ◽  
In Situ Generation ◽  
Shift Reaction

A unique 1,7-S- and Se-shift reaction under Pummerer reaction conditions of 4-alkenyl-3-sulfinyl- and seleninylpyrroles was described. The usual Pummerer reaction of 4-(alkenylaminomethyl)-3-phenylsulfinylpyrroles and a successive reaction with tetrabutylammonium hydroxide (TBAH) yielded either pyrrolo[3,2-c]azepines or N-pyrrol-3-ylmethyl-N-(4-hydroxy-3-sulfanylpropyl)-p-toluenesulfonamides (diols). Seleno-Pummerer reactions of 3-selanylmethylpyrroles also proceeded via in situ generation of selenoxides, followed by a treatment with TBAH.

scholarly journals Mild synthesis of isoxazoline derivatives via an efficient [4 + 1] annulation reaction of transient nitrosoalkenes and sulfur ylides

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ting-Bi Hua ◽  
Cheng-Xiong Liu ◽  
Wei-Min Hu ◽  
Long Wang ◽  
Qing-Qing Yang
Keyword(s):  
Reaction Conditions ◽  
Sulfur Ylides ◽  
Basic Reaction ◽  
In Situ Generation

AbstractAn efficient [4 + 1] annulation between α-bromooximes and sulfur ylides via in situ generation of nitrosoalkenes under mild basic reaction conditions has been developed, providing an expeditious and scalable approach to synthesize biologically interesting isoxazoline derivatives with good to excellent yields.

scholarly journals Damage to actin filaments by glutaraldehyde: protection by tropomyosin.

1981 ◽  
Vol 90 (2) ◽  
pp. 459-466 ◽  
Author(s):  
S S Lehrer
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Gel Electrophoresis ◽  
Actin Filaments ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Cross Linking ◽  
Cross Link ◽  
Reaction Conditions ◽  
Cross Links ◽  
Link Formation

Reaction of F-actin and the F-actin-tropomyosin complex with 20 mM glutaraldehyde for 19-22 h at 0 degrees C and 25 degrees C results in extensively cross-linked filaments, as judged by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Electron micrographs show shorter, more irregular filaments for glutaraldehyde-treated F-actin in the absence of tropomyosin as compared to the presence of tropomyosin or untreated controls. There was a 40% drop in viscosity of glutaraldehyde-treated F-actin solutions but a 90% increase in viscosity for the glutaraldehyde-treated F-actin-tropomyosin complex in solution, as compared to the untreated controls, indicating different effects of cross-linking. SDS gels indicate that intrasubunit cross-links are introduced into F-actin and that when tropomyosin is present, intramolecular cross-link formation is inhibited. Inhibition of the salt-induced G leads to F polymerization results when intramolecular cross-links are introduced into G-actin under similar or milder reaction conditions. These data indicate that, under conditions for which extensive F-actin filament cross-linking (fixing) occurs, the filaments become damaged due to the concurrent formation of intrasubunit cross-links that cause local depolymerization and distortion and that tropomyosin protects against this damage.

scholarly journals Targeted in situ cross-linking mass spectrometry and integrative modeling reveal the architectures of three proteins from SARS-CoV-2

2021 ◽  
Vol 118 (34) ◽  
pp. e2103554118
Author(s):  
Moriya Slavin ◽  
Joanna Zamel ◽  
Keren Zohar ◽  
Tsiona Eliyahu ◽  
Merav Braitbard ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Full Length ◽  
Integrative Model ◽  
Cross Linking ◽  
Cross Link ◽  
Integrative Modeling ◽  
Cellular Context ◽  
Cross Links ◽  
The Cross

Atomic structures of several proteins from the coronavirus family are still partial or unavailable. A possible reason for this gap is the instability of these proteins outside of the cellular context, thereby prompting the use of in-cell approaches. In situ cross-linking and mass spectrometry (in situ CLMS) can provide information on the structures of such proteins as they occur in the intact cell. Here, we applied targeted in situ CLMS to structurally probe Nsp1, Nsp2, and nucleocapsid (N) proteins from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and obtained cross-link sets with an average density of one cross-link per 20 residues. We then employed integrative modeling that computationally combined the cross-linking data with domain structures to determine full-length atomic models. For the Nsp2, the cross-links report on a complex topology with long-range interactions. Integrative modeling with structural prediction of individual domains by the AlphaFold2 system allowed us to generate a single consistent all-atom model of the full-length Nsp2. The model reveals three putative metal binding sites and suggests a role for Nsp2 in zinc regulation within the replication–transcription complex. For the N protein, we identified multiple intra- and interdomain cross-links. Our integrative model of the N dimer demonstrates that it can accommodate three single RNA strands simultaneously, both stereochemically and electrostatically. For the Nsp1, cross-links with the 40S ribosome were highly consistent with recent cryogenic electron microscopy structures. These results highlight the importance of cellular context for the structural probing of recalcitrant proteins and demonstrate the effectiveness of targeted in situ CLMS and integrative modeling.

In situ generation of functionality in a reactive binicotinic-acid-based ligand for the design of multi-functional copper(ii) complexes: syntheses, structures and properties

CrystEngComm ◽  
2015 ◽  
Vol 17 (8) ◽  
pp. 1871-1880 ◽  
Author(s):  
Dongsheng Deng ◽  
Hui Guo ◽  
Guohui Kang ◽  
Lufang Ma ◽  
Xu He ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Conditions ◽  
Strecker Reaction ◽  
Structures And Properties ◽  
In Situ Generation

Five copper binicotinic complexes have been synthesized depending on the reaction conditions. Complexes 1 and 2 display excellent catalytic activity for Strecker reaction of imines.

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