J 2007

2,5-Dimethylphenacyl carbamate: A photoremovable protecting group for amines and amino acids

KAMMARI, Laxminarayana, Lukáš PLÍŠTIL, Jakob WIRZ and Petr KLÁN

Basic information

Original name

2,5-Dimethylphenacyl carbamate: A photoremovable protecting group for amines and amino acids

Name in Czech

2,5-Dimethylfenacylkarbamát jako fotoodštěpitelná chránicí skupina pro aminy a aminokyseliny

Authors

KAMMARI, Laxminarayana (356 India), Lukáš PLÍŠTIL (203 Czech Republic), Jakob WIRZ (756 Switzerland) and Petr KLÁN (203 Czech Republic, guarantor)

Edition

Photochemical and Photobiological Sciences, Cambridge, United Kingdom, Royal Society of Chemistry, 2007, 1474-905X

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10401 Organic chemistry

Country of publisher

United Kingdom of Great Britain and Northern Ireland

Confidentiality degree

není předmětem státního či obchodního tajemství

Impact factor

Impact factor: 2.208

RIV identification code

RIV/00216224:14310/07:00020037

Organization unit

Faculty of Science

UT WoS

000243204700005

Keywords in English

Photochemistry; photoremovable protecting groups; amines; amino acids

Tags

International impact, Reviewed
Změněno: 23/6/2009 15:13, prof. RNDr. Petr Klán, Ph.D.

Abstract

V originále

2,5-Dimethylphenacyl (DMP) carbamates (1a-c) released the corresponding free amines or amino acid in high chemical yields, albeit with quantum yields of only 0.04-0.09, upon irradiation in either aprotic or protic solvents. The photoreaction proceeded principally from the triplet excited state via the E-photoenol. The lifetimes of the triplet enol and of the E- and Z-enols in the ground state were determined by laser flash photolysis. The primary photoinitiated transformation liberated a carbamic acid derivative, which subsequently decarboxylated to the amino group containing compound. Exhaustive irradiation of a DMP-protected aniline (1a) in acetonitrile did not provide aniline in quantitative chemical yields, because it was involved in reductive cleavage of the starting material as an electron donor, thereby decreasing the overall deprotection yield (86%). Phenylalanine methyl ester, liberated from 1c, was, however, obtained in excellent chemical yields (97%). It was also found that the carbamates, while thermally stable, released amines with higher quantum yields in acidic methanol solutions. The DMP chromophore is proposed as an excellent photoremovable protecting group for amino acids and, under specific conditions, also for amines in organic synthesis and biochemistry.

In Czech

2,5-Dimethylphenacyl (DMP) carbamates (1a-c) released the corresponding free amines or amino acid in high chemical yields, albeit with quantum yields of only 0.04-0.09, upon irradiation in either aprotic or protic solvents. The photoreaction proceeded principally from the triplet excited state via the E-photoenol. The lifetimes of the triplet enol and of the E- and Z-enols in the ground state were determined by laser flash photolysis. The primary photoinitiated transformation liberated a carbamic acid derivative, which subsequently decarboxylated to the amino group containing compound. Exhaustive irradiation of a DMP-protected aniline (1a) in acetonitrile did not provide aniline in quantitative chemical yields, because it was involved in reductive cleavage of the starting material as an electron donor, thereby decreasing the overall deprotection yield (86%). Phenylalanine methyl ester, liberated from 1c, was, however, obtained in excellent chemical yields (97%). It was also found that the carbamates, while thermally stable, released amines with higher quantum yields in acidic methanol solutions. The DMP chromophore is proposed as an excellent photoremovable protecting group for amino acids and, under specific conditions, also for amines in organic synthesis and biochemistry.

Links

GA203/05/0641, research and development project
Name: Vývoj a aplikace fotolabilních chránících skupin
Investor: Czech Science Foundation, Design and Applications of Photoremovable Protecting Groups
MSM0021622413, plan (intention)
Name: Proteiny v metabolismu a při interakci organismů s prostředím
Investor: Ministry of Education, Youth and Sports of the CR, Proteins in metabolism and interaction of organisms with the environment