Demethylation and tannin-like properties of guaiacyl/syringyl-type and syringyl-type dehydrogenation polymers using iodocyclohexane

Journal of Wood Science

Official Journal of the Japan Wood Research Society

Table 1 Demethylation of G/S- and S-DHPs and characterization of deMeG/S- and S-DHPs

Entry	Reaction time (min)	Product	Yield (wt.%)	NMR signal intensity ratio		Phenolic-OH (mmol/g)	Nitroso assay	GPC data^c
Entry	Reaction time (min)	Product	Yield (wt.%)	Ph-OAc/Aliph-OAc^a	Ph-OMe/Total-OAc^b	Phenolic-OH (mmol/g)	Nitroso assay	M_w(× 10³)	M_w/M_n
1	–	G/S-DHP	–	0.07	1.6	1.8	−	6.3	1.8
2	5	deMeG/S-DHP-5	68	0.58	2	5.6	+	2.2	1.6
3	60	deMeG/S-DHP-60	48	93	0.77	11	+	2	1.5
4	720	deMeG/S-DHP-720	53	N.C.^d	0.08	13	+	2.3	1.5
5	–	S-DHP	–	0.13	1.9	3	−	5.9	1.9
6	5	deMeS-DHP-5	48	9.5	1.5	11	+	1.7	1.2
7	60	deMeS-DHP-60	39	63	0.63	13	+	1.8	1.3
8	720	deMeS-DHP-720	26	72	0.13	17	+	2.4	1.4

^aPh-OAc: methyl signals attached to phenolic acetoxy groups, Aliph-OAc: methyl signals attached to aliphatic acetoxy groups
^bPh-OMe, methyl signals attached to phenolic methoxy groups. Total-OAc = Ph-OAc + Aliph-OAc
^cThe data were obtained by acetylated products
^dNot calculated because of no detection of Aliph-OAc