Acid Degradation of Lignin. II. Separation and Identification of Low Molecular Weight Phenols.

Lignins: A Twenty‐First Century Challenge

“…While generating some of the substructures found in native lignins, there is, of course, little opportunity for control over primary chain interunit linkage (sequence) designation with in vitro preparations. Thus, numerous important differences between synthetic DHPs [which, for example, release dimeric pinoresinol-derived substructures (see Figure 7.2D, substructure IIIb) upon cleavage] and native lignin polymers [which do not (193)] have long been known, and which diminish greatly their utility (29). While it is possible to synthesize 8-O-4 linked oligomers (194), and also to modulate the amounts of 8-O-4 interunit linkages through varying peroxidase activity in vitro (195), such preparations are not lignins proper.…”

Preparation and microbial decomposition of synthetic [14C]ligins.

“…Degradative acid hydrolysis ("acidolysis") was performed by the method of Lundquist (16,17), and the procedures for oxidative degradation (KMnO4, H202) of methylated samples were those developed by Larsson and Miksche (17,18).…”

“…Number average molecular weight (Ml,) was determined by vapor pressure osmometry at 370 with dimethylformamide as solvent (19) Aqueous lignin suspensions (10-100 gl) containing [10][11][12][13][14][15][16][17][18][19][20] mg/ml were added to 10 ml of scintillation fluid consisting of 10 These wood-destroying fungi were incubated with the labeled lignins in closed 125 ml erlenmeyer flasks that contained 2 g of a 1:1 mixture of ground aspen and spruce wood (20 mesh = 7.9 openings/cm), 2 ml of a filter-sterilized basal medium (below), and 3 ml of lignin suspension (640 Ig, 5 X 104 dpm). Lignins in dimethylformamide solution (20-30 mg/ml) were added aseptically to sterile distilled water to give a fine suspension; no contamination problem was encountered.…”

Structures of New Dimeric Phenylpropanoids fromMyristica fragransHoutt.

“…Acidolysis 7 ) of IVa with dil. hydrochloric acid afforded a small amount of 2,6-dimethoxy-4-propylphenol.…”

“…327 (1) 222 (4) 221 (9) 207 (2) 196 (3) 195 (18) 194 (100) 193 (9) 192 (3) 179 (7) 167 (9) 165 (12) 163 (9) 390 (2) 372 (I) 329 (l) 224 (5) 223 (8) 209 (1) 208 (I) 197 (10) 196 (100) 195 (8) 194 (5) 181 (2) 180 (I) 168 (I) 167 (45) 165 (10) - (8) 178 (10) 177 (11) 167 (7) 165 (27) 163 (8) 418 (2) 400 (1) 225 (4) 224 (20) 222 (3) 221 (9) 196 (5) 195 (33) 194 (100) 193 (8) 192 (4) 179 (5) 169 (5) 168 (3) 167 (4) 165 (2) 163 (4) 402 (9) 221 (2) 209 (100) 208 (18) 194 …”