Structural characterisation of the terminating groups of some polyprenyl phosphates and of rubber from the Lactarius mushroom

Sakdapipanich J. T., . and Mekkriengkrai D., . and Gou L. B., . and Tanaka Y., . Structural characterisation of the terminating groups of some polyprenyl phosphates and of rubber from the Lactarius mushroom. pp. 118-130.

A series of trans- and cis-allylic diphosphates were synthesized as model compounds of natural rubber and were analysed by NMR techniques. The H-NMR spectra of terminal methylene protons of polyprenols linked to mono- and di-phosphates showed a triplet signal centering around d 4.41-4.44 and d 4.46-4.49 respectively. The coupling constants of 5.0 Hz - 6.0 Hz and 6.0 Hz - 7.0 Hz were observed for trans- and cis-allylic diphosphate groups respectively. In the a-terminal isoprene unit of polyprenols the cis- and trans-allylic C-4 methylene protons resonate at d 4.081 and d 4.150 respectively. The a C-4 methylene carbon of mono- and di-phosphate groups showed a doublet signal around d 61-63 in the I3C-NMR spectrum the chemical shift value of which decreased with increase the chain-length of polyprenols. The 3IP-NMR spectra of mono- and di-phosphate groups showed a signal around d1.5 and d -7 to d -8 respectively independent of chain-length and configuration of the allylic compounds. A long-chain polyprenol from Lactarius volemus composed of about 300 isoprene units was phosphorylated to analyse the effect of chain length.

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Abstract

A series of trans- and cis-allylic diphosphates were synthesized as model compounds of natural rubber and were analysed by NMR techniques. The H-NMR spectra of terminal methylene protons of polyprenols linked to mono- and di-phosphates showed a triplet signal centering around d 4.41-4.44 and d 4.46-4.49 respectively. The coupling constants of 5.0 Hz - 6.0 Hz and 6.0 Hz - 7.0 Hz were observed for trans- and cis-allylic diphosphate groups respectively. In the a-terminal isoprene unit of polyprenols the cis- and trans-allylic C-4 methylene protons resonate at d 4.081 and d 4.150 respectively. The a C-4 methylene carbon of mono- and di-phosphate groups showed a doublet signal around d 61-63 in the I3C-NMR spectrum the chemical shift value of which decreased with increase the chain-length of polyprenols. The 3IP-NMR spectra of mono- and di-phosphate groups showed a signal around d1.5 and d -7 to d -8 respectively independent of chain-length and configuration of the allylic compounds. A long-chain polyprenol from Lactarius volemus composed of about 300 isoprene units was phosphorylated to analyse the effect of chain length.

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Item Type:	Article
AGROVOC Term:	Lactarius
AGROVOC Term:	Mushrooms
AGROVOC Term:	Rubber
AGROVOC Term:	Natural rubber
AGROVOC Term:	Isoprene
AGROVOC Term:	Biosynthesis
AGROVOC Term:	Sporophores
AGROVOC Term:	Solidago
AGROVOC Term:	Hevea brasiliensis
AGROVOC Term:	Hevea rubber
Depositing User:	Ms. Suzila Mohamad Kasim
Last Modified:	24 Apr 2025 06:28
URI:	http://webagris.upm.edu.my/id/eprint/23193

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