1. Synthesis and mass spectra of 4-O-acetyl-1,5-anhydro-2,3,6-tri-O-ethyl-D-glucitol and the positional isomers of 4-O-acetyl-1,5-anhydro-di-O-ethyl-O- methyl-D-glucitol and 4-O-acetyl-1,5-anhydro-O-ethyl-di-O-methyl-D-glucitol
S G Zeller, A J D'Ambra, M J Rice, G R Gray Carbohydr Res. 1988 Oct 15;182(1):53-62. doi: 10.1016/0008-6215(88)84091-6.
Reductive cleavage of fully methylated, partially O-ethylated cellulose or fully ethylated, partially O-methylated cellulose and subsequent acetylation had previously been shown to produce 4-O-acetyl-1,5-anhydro-2,3,6-tri-O-methyl-, -6- O-ethyl-2,3-di-O-methyl-, -3-O-ethyl-2,6-di-O-methyl-, -2-O-ethyl-3,6-di-O- methyl-, -2,3-di-O-ethyl-6-O-methyl-, -2,6-di-O-ethyl-3-O-methyl-, -3,6-di-O- ethyl-2-O-methyl-, and -2,3,6-tri-O-ethyl-D-glucitol. Described herein is the independent synthesis of these derivatives, except for the first (which had been reported); and their 1H-n.m.r. spectra, chemical-ionization (NH3) mass spectra, and electron-impact mass spectra are tabulated.
2. EMS Mutagenesis of Arabidopsis Seeds
C Stewart Gillmor, Wolfgang Lukowitz Methods Mol Biol. 2020;2122:15-23. doi: 10.1007/978-1-0716-0342-0_2.
The ethylating agent ethyl methanesulfonate (EMS) is widely used for inducing random point mutations. In Arabidopsis, treatment with EMS causes GC-to-AT transitions with great efficiency: it has been estimated that a population of 50,000 well-mutagenized plants harbors one or more transitions in almost every GC pair of the genome. These properties, combined with ease of use, make EMS a mutagen of choice for genetic screens. Here, we describe a protocol for mutagenizing Arabidopsis seed with EMS. In addition, we briefly consider the germ line sectors typically induced by this treatment, and approaches for estimating the rate of induced mutations.
3. Synthesis and structure/property relationships of regioselective 2-O-, 3-O- and 6-O-ethyl celluloses
Hiroshi Kamitakahara, Toshihiro Funakoshi, Shinji Nakai, Toshiyuki Takano, Fumiaki Nakatsubo Macromol Biosci. 2010 Jun 11;10(6):638-47. doi: 10.1002/mabi.200900392.
Regioselectively ethylated celluloses, 2-O- (1), 3-O- (2), and 6-O-ethyl- (3) celluloses were synthesized via ring-opening polymerization of glucopyranose orthopivalate derivatives. The number-average degrees of polymerization (DP(n)s) of compounds 1 and 2 were calculated to be 10.6 and 49.4, respectively. Three kinds of compound 3 with different DP(n)s were prepared: DP(n)s = 12.9 (3-1), 60.3 (3-2), and 36.1 (3-3). The 2-O-, 3-O-, and 6-O-ethylcelluloses were soluble in water, confirmed by NMR analysis. Furthermore, the 3-O- (2), and 6-O-ethyl- (3-2) celluloses showed thermo-responsive aggregation behavior and had a lower critical solution temperature (LCST) at about 40 degrees C and 70 degrees C, respectively, based on the results from turbidity tests and DSC measurements. The 6-O-ethyl-cellulose (3-3) with DP(n) = 36.1 and DP(w) = 54.6 showed gelation behavior over approx 70 degrees C, whereas the 6-O-ethyl-celluloses 3-1 and 3-2 with lower and higher molecular weight, such as DP(n)s 12.9 and 60.3, did not show gelation behavior at this temperature. It was revealed that the position of ethyl group affected the phase transition temperature. According to our experiments, the 3-O-ethyl and 6-O-ethyl groups along the cellulose chains caused the thermo-responsive property of their aqueous solutions. The appropriate DP of the regioselective 6-O-ethyl-cellulose existed for gelation of the aqueous solution.
