60684-36-8Relevant academic research and scientific papers
Synthesis of 24 bacteriochlorin isotopologues, each containing a symmetrical pair of 13C or 15N atoms in the inner core of the macrocycle
Chen, Chih-Yuan,Bocian, David F.,Lindsey, Jonathan S.
, p. 1001 - 1016 (2014/03/21)
Synthetic bacteriochlorins containing site-specific isotopic substitution enable spectroscopic interrogation to delineate physicochemical features relevant to bacteriochlorophylls in photosynthesis but have been little explored. A de novo synthesis has been employed to prepare bacteriochlorins wherein each macrocycle contains a pair of 13C or 15N atoms yet lacks substituents other than a geminal dimethyl group in each pyrroline ring. Preparation of a dihydrodipyrrin-acetal with single-isotopic substitution gives rise to a bacteriochlorin that contains two isotopic substitutions symmetrically disposed by a 180 rotation about the normal to the plane of the macrocycle. Eight such isotopically substituted bacteriochlorins were prepared from commercially available reactants (bacteriochlorin sites): (13C)paraformaldehyde (1, 11); (13C)formamide (4, 14); triethyl (13C)orthoformate (5, 15); K13CN (6, 16); 13CH3NO2 (9, 19); N,N-dimethyl( 13C)formamide (10, 20); (15N)pyrrole (21, 23); CH 315NO2 (22, 24). Some loss of 15N upon TiCl3-mediated McMurry-type ring closure of a nitro( 15N)hexanone is attributed to a parallel sequence of three reactions (Nef, exchange with natural-abundance NH4OAc buffer, and Paal-Knorr ring closure) leading to the dihydrodipyrrin-acetal. Zinc and copper chelates of each bacteriochlorin also were prepared. Together, the 24 bacteriochlorin isotopologues should provide valuable benchmarks for understanding ground- and excited-state molecular physics of the macrocycles related to photosynthetic function of bacteriochlorophylls.
Synthesis of L-histidine specifically labelled with stable isotopes
Cappon, J. J.,Witters, K. D.,Baart, J.,Verdegem, P. J. E.,Hoek, A. C.,et al.
, p. 318 - 328 (2007/10/02)
(2'-13C)-, (1'-15N)- and (3'-15N)-L-Histidine were prepared according to a synthetic scheme that allows the 13C or 15N labelling of all carbon and nitrogen positions or any combination of positions.A 1,5-disubstituted imidazole ring was constructed via condensation of tosylmethyl isocyanide with 3-phenylpropenal and subsequent cycloaddition of benzylamine.The imidazole intermediate was converted into 1-benzyl-5-(chloromethyl)-imidazolium chloride which was coupled to a glycine moiety via an enantioselective coupling with the bislactim ether of cyclo-D-valylglycine.Deprotection of the coupling product afforded L-histidine in high optical purity.Syntheses for the isotopically labelled synthons were developed starting from simple, comercially available, highly enriched compounds.The labelled L-histidines were characterized by mass spectrometry and 1H-, 13C- and 15N-NMR spectroscopy.
