ChemInform Abstract: Mechanisms for the Removal of Benzyl Protecting Groups in Synthetic Peptides by Trifluoromethanesulfonic Acid - Trifluoroacetic Acid - Dimethyl Sulfide.

New approach to the synthesis of steroid oximes bearing O-substituents with terminal amino groups was described. The easily accessible steroid O-(carboxymethyl)oximes were reacted with single-protected Boc-α,ω-diaminoalkanes to give corresponding amide intermediates. From them the Boc protecting groups were cleaved with trifluoroacetic acid to afford the desired steroid derivatives with terminal amino groups. The procedure was succesfully tested on steroids with O-(carboxymethyl)oxime group in positions 7 and 17. The decomposition of target products was observed during deprotection of substituted 19-oximes.

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ChemInform Abstract: Trialkylsilanes as Scavengers for the Trifluoroacetic Acid Deblocking of Protecting Groups in Peptide Synthesis.

ChemInform ◽

10.1002/chin.199001310 ◽

1990 ◽

Vol 21 (1) ◽

Author(s):

D. A. PEARSON ◽

M. BLANCHETTE ◽

M. L. BAKER ◽

C. A. GUINDON

Keyword(s):

Peptide Synthesis ◽

Trifluoroacetic Acid ◽

Protecting Groups

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Selective acid hydrolysis of 2,4,6-trimethylbenzyl esters and its application in peptide synthesis

Australian Journal of Chemistry ◽

10.1071/ch9661511 ◽

1966 ◽

Vol 19 (8) ◽

pp. 1511 ◽

Cited By ~ 3

Author(s):

FHC Stewart

Keyword(s):

Acid Hydrolysis ◽

Peptide Synthesis ◽

Trifluoroacetic Acid ◽

Ester Group ◽

Protecting Groups ◽

Alkaline Conditions ◽

Hydrolysis Of

Experiments with various N-acylamino acid 2,4,6-trimethylbenzyl esters have shown that the ester group is cleaved selectively by cold trifluoroacetic acid without affecting benzyloxycarbonyl, formyl, or phthaloyl amino-protecting groups present. The possible value of this selective behaviour in peptide syntheses where the use of alkaline conditions would be detrimental is illustrated by the synthesis of certain dipeptide derivatives.

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Synthesis of oxytocin, arginine-vasopressin and its deamino-analogue using 2,4,6-trimethylbenzyl group for protection of the cysteine sulfur

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19810286 ◽

1981 ◽

Vol 46 (1) ◽

pp. 286-299 ◽

Cited By ~ 6

Author(s):

František Brtník ◽

Milan Krojidlo ◽

Tomislav Barth ◽

Karel Jošt

Keyword(s):

Peptide Synthesis ◽

Hydrogen Fluoride ◽

Sulfur Atom ◽

Arginine Vasopressin ◽

Liquid Hydrogen ◽

Trifluoromethanesulfonic Acid ◽

Protecting Groups ◽

Mild Conditions

Preparation of oxytocin, arginine-vasopressin and its deamino-analogue serves as an example of use of 2,4,6-trimethylbenzyl group for protection of the cysteine sulfur atom in the peptide synthesis. This modified benzyl group is sufficiently stable under conditions of solvolytic removal of common amino-protecting groups and it can be cleaved off under mild conditions with liquid hydrogen fluoride or trifluoromethanesulfonic acid.

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Synthesis of O-Phosphotyrosine-Containing Peptides. II. Solution-Phase Synthesis of Asn-Glu-PTyr-Thr-Ala Through Methyl Phosphate Protection

Australian Journal of Chemistry ◽

10.1071/ch9891519 ◽

1989 ◽

Vol 42 (9) ◽

pp. 1519 ◽

Cited By ~ 21

Author(s):

RM Valerio ◽

JW Perich ◽

EA Kitas ◽

PF Alewood ◽

RB Johns

Keyword(s):

Trifluoroacetic Acid ◽

Dimethyl Sulfide ◽

Solution Phase ◽

High Yield ◽

Phase Synthesis ◽

Rous Sarcoma ◽

Naturally Occurring ◽

Solution Phase Synthesis ◽

Sarcoma Virus ◽

Methyl Phosphate

The PTyr (O-phosphotyrosine) pentapeptide H-Asn-Glu-Tyr(PO3H2)-Thr-Ala-OH.HO2CCF3, which is a naturally occurring sequence from the autophosphorylated Rous sarcoma virus pp60V-SrC, was prepared in high yield by the use of Boc-Tyr(PO3Me2)-OH in the Boc mode of solution-phase peptide synthesis. The protected pentapeptide, Z-Asn-Glu(OBzl)-Tyr(PO3Me2)-Thr(Bzl)-Ala-OBzl, was deprotected by a two-stage procedure which involved initial palladium-catalysed hydrogenolysis followed by the removal of the phosphate methyl groups by the use of one of the following treatments: (A) 10% bromotrimethylsilane/acetonitrile, (B) 1 M bromotrimethylsilane/thioanisole in trifluoroacetic acid, or (C) trifluoromethanesulfonic acid/trifluoroacetic acid/dimethyl sulfide/m-cresol.

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Synthesis of Novel Isoquinolino[5,4-ab]phenanthridine Derivatives via Pictet–Spengler Reaction

Synthesis ◽

10.1055/s-0037-1610670 ◽

2018 ◽

Vol 51 (06) ◽

pp. 1377-1382

Author(s):

Tzenge-Lien Shih ◽

Min-Chen Tsai ◽

Pei Huang ◽

Liang Syu

Keyword(s):

Phosphoric Acid ◽

Trifluoroacetic Acid ◽

Trifluoromethanesulfonic Acid ◽

Acidic Media

The reaction of 5-amino-2-[2-(dimethylamino)ethyl]-6-phenyl-1H-benzo[de]isoquinoline-1,3(2H)-dione with a series of aldehydes in acidic media (phosphoric acid, trifluoromethanesulfonic acid, and trifluoroacetic acid) is described. This key step is based on the Pictet–Spengler reaction to synthesize ten novel isoquinolino[5,4-ab]phenanthridine derivatives. The most effective acid is phosphoric acid and optimized yields were obtained. The frameworks of target compounds are unique and have never been reported.

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