REDUCTIVE ALKYLATION OF PROTEINS WITH AROMATIC ALDEHYDES AND 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.

Download Full-text

Tetraalkylhydrazine preparation by reductive alkylation with sodium cyanoborohydride

Tetrahedron Letters ◽

10.1016/s0040-4039(01)96208-2 ◽

1973 ◽

Vol 14 (26) ◽

pp. 2321-2324 ◽

Cited By ~ 13

Author(s):

S.F. Nelsen ◽

G.R. Weisman

Keyword(s):

Reductive Alkylation ◽

Sodium Cyanoborohydride

Download Full-text

Synthesis of fluorescent probe – carbohydrate conjugates

Canadian Journal of Chemistry ◽

10.1139/v81-425 ◽

1981 ◽

Vol 59 (20) ◽

pp. 2934-2939 ◽

Cited By ~ 17

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.

Download Full-text

ChemInform Abstract: TETRAALKYLHYDRAZINE PREPARATION BY REDUCTIVE ALKYLATION WITH SODIUM CYANOBOROHYDRIDE

Chemischer Informationsdienst ◽

10.1002/chin.197337170 ◽

1973 ◽

Vol 4 (37) ◽

pp. no-no

Author(s):

S. F. NELSEN ◽

G. R. WEISMAN

Keyword(s):

Reductive Alkylation ◽

Sodium Cyanoborohydride

Download Full-text

Aldehyde gold clusters for molecular labeling

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014066x ◽

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.

Download Full-text