Sains Malaysiana 44(1)(2015): 127–137

Mass Spectrometry (LC-MS-MS) as a Tool in the Maillard Reaction Optimisation and Characterisation of New 6-methoxy-tetrahydro-β-carboline Derivatives

(Spektometri Jisim (LC-MS-MS) Sebagai Alat dalam Pengoptimuman Tindak Balas Maillard

dan Pencirian Terbitan Baru 6-metoksi-tetrahidro-β-karbolina)

T.B. GOH*, M.N. MORDI & S.M. MANSOR

Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia

Received: 18 January 2014/Accepted: 6 June 2014

ABSTRACT

Four new 6-methoxy-tetrahydro-β-carboline derivatives (1-6- methoxy-1-phenyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole,2-6-methoxy-1-(4-methoxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole, 3-6-methoxy-1-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole and 4-2-methoxy-4-(6-methoxy-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol )were prepared via the Maillard reaction using 5-methoxytryptamine and various aldehydes in water. The synthesis reaction conditions were optimised in catalyst loading, temperature and time using LC-MS for optimum yields. Surface response methodology and contour plot was selected as an approach for optimisation. The optimum yield could be achieved below 50^oC within 5 h at 7 mole % catalyst loading at yields > 70%. The β-carboline compounds produced were characterised using electrospray ionization mass spectrometry (ESI-MS) and electrospray tandem mass (ESI-MS/MS). The mass fragmentation patterns of this group of heterocyclic tetrahydro-ß-carboline compounds are described herein.

Keywords: Catalyst loading; heterocyclic; optimization; 5-methoxytryptamine; 6-methoxy-tetrahydro-β-carboline

ABSTRAK

Empat terbitan baru 6-metoksi-tetrahidro-β-karbolina (1-6- methoksi-1-fenil-2,3,4,9-tetrahidro-1H-pirido[3,4-b]indol, 2-6-metoksi-1-(4-metoksifenil)-2,3,4,9-tetrahidro-1H-pirido[3,4-b]indol, 3-6-metoksi-1-metil-2,3,4,9-tetrahidro-1H-pirido[3,4-b]indol dan 4-2-metoksi-4-(6-metoksi-2,3,4,9-tetrahidro-1H-pirido[3,4-b]indol-1-yl)fenol ) telah disediakan melalui tindak balas Maillard dengan menggunakan 5-metoksitriptamin dan pelbagai aldehid dalam air. Keadaan tindak balas sintesis telah dioptimumkan daripada segi muatan mangkin, suhu dan masa dengan menggunakan LC-MS untuk hasil yang optimum. Kaedah gerak balas permukaan dengan plot kontur telah dipilih sebagai satu pendekatan untuk pengoptimuman. Hasil yang optimum telah dicapai pada suhu bawah 50ºC dalam masa 5 jam pada muatan mangkin 7% mol dengan hasil pemerolehan > 70%. Sebatian β-karbolina yang dihasilkan telah dicirikan dengan menggunakan spektrometri jisim pengionan semburan elektron (ESI-MS) dan jisim seiring semburan elektron (ESI-MS/MS). Corak fragmentasi kumpulan sebatian heterosiklik tetrahidro-β-karbolina telah diterangkan di sini.

Kata kunci: Heterosiklik; muatan mangkin; pengoptimuman; 5-metoksitriptamin; 6-metoksi-tetrahidro-β-karbolina

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*Corresponding author; email: gohteikbeng@yahoo.com