ChemInform Abstract: An Improved Method for Reductive Alkylation of Amines Using Titanium(IV) Isopropoxide and Sodium Cyanoborohydride.

ChemInform ◽  
1990 ◽  
Vol 21 (41) ◽  
Author(s):  
R. J. MATTSON ◽  
K. M. PHAM ◽  
D. J. LEUCK ◽  
K. A. COWEN
Keyword(s):  
Improved Method ◽  
Reductive Alkylation ◽  
Sodium Cyanoborohydride

An improved method for reductive alkylation of amines using titanium(IV) isopropoxide and sodium cyanoborohydride

1990 ◽  
Vol 55 (8) ◽  
pp. 2552-2554 ◽  
Author(s):  
Ronald J. Mattson ◽  
Kahnie M. Pham ◽  
David J. Leuck ◽  
Kenneth A. Cowen
Keyword(s):  
Improved Method ◽  
Reductive Alkylation ◽  
Sodium Cyanoborohydride

scholarly journals A General Stereoselective Approach to 1,2,4-Triazepane-3-thiones/ones via Reduction or Reductive Alkylation of 2,4,5,6-Tetrahydro-3H-1,2,4-triazepine-3-thiones/ones

Proceedings ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Anastasia A. Fesenko ◽  
Anatoly D. Shutalev
Keyword(s):  
Carboxylic Acid ◽  
Sodium Borohydride ◽  
Reductive Alkylation ◽  
Sodium Cyanoborohydride

A general stereoselective approach to previously unknown 1,2,4-triazepane-3-thiones/ones based on reduction or reductive alkylation of readily available 2,4,5,6-tetrahydro-3H-1,2,4-triazepine- 3-thiones/ones has been developed. The approach involved treatment of tetrahydrotriazepines with sodium cyanoborohydride in MeOH at pH 3 or with sodium borohydride and excess of carboxylic acid in tetrahydrofuran to give 1-unsubstituted or 1-alkyl-substituted 1,2,4-triazepane-3- thiones/ones, respectively. The latter were also prepared by reaction of 1-unsubstituted 1,2,4- triazepane-3-thiones/ones with sodium cyanoborohydride and aldehyde in MeOH in the presence of AcOH.

Synthesis of fluorescent probe – carbohydrate conjugates

1981 ◽  
Vol 59 (20) ◽  
pp. 2934-2939 ◽  
Author(s):  
Mansur Yalpani ◽  
Laurance D. Hall
Keyword(s):  
Nmr Spectroscopy ◽  
Fluorescent Probe ◽  
Fluorescent Probes ◽  
Reductive Amination ◽  
Reductive Alkylation ◽  
Sodium Cyanoborohydride ◽  
New Type ◽  
Direct Derivatization ◽  
Base Formation ◽  
C Nmr

A new type of luminescent label has been synthesized and a range of carbohydrates has been derivatized with various fluorescent probes. Amine-containing labels were readily transformed with chloroacetylchloride into the corresponding fluorescent chloroacetamide reagents 1–4. Suitably blocked monosaccharides containing either a free thio 9, hydroxyl 11, or carboxyl 17 functionality have been conjugated with (a) 4-chloroacetamido labels 1 and 2, (b) with 4-aminobenzophenone 5, and (c) with 1-dimethyl-1-aminonaphthalene-5-sulfonylchloride 21, to form the fluorescent carbohydrate conjugates 10, 16, 18, and 20. Direct derivatization of the unblocked disaccharides 22 and 23 was achieved by reductive amination with amines 5 and 7 and sodium cyanoborohydride affording the 1-deoxyglycit-1-yl derivatives 24–26, which were characterized by 13C nmr spectroscopy. The synthesis of fluorescent polysaccharides is exemplified by the condensation of 9-anthraldehyde with chitosan either via Schiff 's base formation to afford 32, or via reductive alkylation to form 33.

Aldehyde gold clusters for molecular labeling

1995 ◽  
Vol 53 ◽  
pp. 858-859
Author(s):  
James F. Hainfeld ◽  
Frederic R. Furuya
Keyword(s):  
Covalent Bond ◽  
Aldehyde Group ◽  
Gold Clusters ◽  
Side Reactions ◽  
Amino Groups ◽  
Sodium Cyanoborohydride ◽  
Schiff’S Base ◽  
Protein Molecules ◽  
Hydroxysuccinimide Esters ◽  
Primary Amino

Glutaraldehyde is a useful tissue and molecular fixing reagents. The aldehyde moiety reacts mainly with primary amino groups to form a Schiff's base, which is reversible but reasonably stable at pH 7; a stable covalent bond may be formed by reduction with, e.g., sodium cyanoborohydride (Fig. 1). The bifunctional glutaraldehyde, (CHO-(CH2)3-CHO), successfully stabilizes protein molecules due to generally plentiful amines on their surface; bovine serum albumin has 60; 59 lysines + 1 α-amino. With some enzymes, catalytic activity after fixing is preserved; with respect to antigens, glutaraldehyde treatment can compromise their recognition by antibodies in some cases. Complicating the chemistry somewhat are the reported side reactions, where glutaraldehyde reacts with other amino acid side chains, cysteine, histidine, and tyrosine. It has also been reported that glutaraldehyde can polymerize in aqueous solution. Newer crosslinkers have been found that are more specific for the amino group, such as the N-hydroxysuccinimide esters, and are commonly preferred for forming conjugates. However, most of these linkers hydrolyze in solution, so that the activity is lost over several hours, whereas the aldehyde group is stable in solution, and may have an advantage of overall efficiency.

An Improved Method for the Preparation and TEM Examination of Sharp Pointed Tips used in APFIM and STM

1990 ◽  
Vol 48 (2) ◽  
pp. 102-103
Author(s):  
E.A. Fischione ◽  
P.E. Fischione ◽  
J.J. Haugh ◽  
M.G. Burke
Keyword(s):  
Atom Probe ◽  
Preparation Process ◽  
Improved Method ◽  
Ion Milling ◽  
Polishing Process ◽  
Probe Field ◽  
Scanning Tunnelling ◽  
Stm Tips ◽  
Tunnelling Microscopy ◽  
Ion Microscopy

A common requirement for both Atom Probe Field-Ion Microscopy (APFIM) and Scanning Tunnelling Microscopy (STM) is a sharp pointed tip for use as either the specimen (APFIM) or the probe (STM). Traditionally, tips have been prepared by either chemical or electropolishing techniques. Recently, ion-milling has been successfully employed in the production of APFIM tips [1]. Conventional electropolishing techniques are applicable to a wide variety of metals, but generally require careful manual adjustments during the polishing process and may also be time-consuming. In order to reduce the time and effort involved in the preparation process, a compact, self-contained polishing unit has been developed. This system is based upon the conventional two-stage electropolishing technique in which the specimen/tip blank is first locally thinned or “necked”, and subsequently electropolished until separation occurs.[2,3] The result of this process is the production of two APFIM or STM tips. A mechanized polishing unit that provides these functions while automatically maintaining alignment has been designed and developed.

Immunoelectron microscopic localization of elastic tissue in archival material using an improved method

1990 ◽  
Vol 48 (3) ◽  
pp. 794-795
Author(s):  
J. C. Fanning ◽  
J. F. White ◽  
R. Polewski ◽  
E. G. Cleary
Keyword(s):  
Normal Animal ◽  
Animal Tissue ◽  
Elastic Tissue ◽  
Human Tissues ◽  
Improved Method ◽  
Tissue Samples ◽  
Archival Material ◽  
Immuno Electron Microscopy ◽  
Arteries And Veins ◽  
Biochemical Examination

Elastic tissue is an important component of the walls of arteries and veins, of skin, of the lungs and in lesser amounts, of many other tissues. It is responsible for the rubber-like properties of the arteries and for the normal texture of young skin. It undergoes changes in a number of important diseases such as atherosclerosis and emphysema and on exposure of skin to sunlight.We have recently described methods for the localizationof elastic tissue components in normal animal and human tissues. In the study of developing and diseased tissues it is often not possible to obtain samples which have been optimally prepared for immuno-electron microscopy. Sometimes there is also a need to examine retrospectively samples collected some years previously. We have therefore developed modifications to our published methods to allow examination of human and animal tissue samples obtained at surgery or during post mortem which have subsequently been: 1. stored frozen at -35° or -70°C for biochemical examination; 2.

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