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Purification of Organic Chemicals
Dodecyltrimethylammonium chloride [I 12-00-51 M 263.9. Dissolved in MeOH, treated with active charcoal, filtered and dried in vucuo [WaldenburgJPC 88 1655 19841, or recrystd several times from 10% EtOH in acetone. Also repeatedly crystd from EtOWether or MeOH.
Dulcin see p-phenethylurea. Dulcitol [608-66-21 M 182.2, m 188-189O, b 276-280°/1.1mm. Crystd from water by addition of EtOH. Durene (1,2,4,5-tetramethylbenzene) [95-93-21 M 134.2, m 79.5-80.5O. Chromatographed on alumina, and recrystd from aqueous EtOH or benzene. Zone-refining removes duroaldehydes. Dried under vacuum. [Yamauchi et al. J P C 89 4804 19851. It has also been sublimed in vucuo [Johnston et al. JACS 109 1291 19871. Duroquinone (tetramethylbenzoquinone) EtOH. Dried under vacuum.
[527-17-31 M 164.2, m 110-11lo. Crystd from 95%
a-Ecdyson
[3604-87-31 M 464.7, m 239-242O, 2420, [a]ko+72O (C 1, EtOH). Recrystd from tetrahydrofuran-pet ether, and from H20 as a hydrate. It has been purified by chromatogaphy on A12 O3 and elution with EtOAc-MeOH. It has hmax at 242nm (E 12.400). Its acetate has m 214-216O from EtOAcpet ether, and the 2,4-dinitrophenylhydrazonehas m 170-175O (dec) from EtOAc. [Karlson and Hoffmeister A 662 1 1963; Karlson PAC 14 75 19671. P-Ecdyson (P-echdysterone) [5289-74-71 M 480.7, m 245-247O, [a];' Crystd from water or tetrahydrofuradpet ether.
+66O (c 1, MeOH).
zm
Echinenone [432-68-81 M 550.8, m 178-179O, E 2160 (458nm) in pet ether. Purified by chromatography on partially deactivated alumina or magnesia, or by using a thin layer of silica gel G with 4:l cyclohexane/ethylether as the developing solvent. Stored in the dark at -2OO. Eicosane [112-95-81 M 282.6, m 36-37O, b 205°/15mm, d 36-70.7779, n40 1.43453. from EtOH.
Crystd
Elaidic acid [112-79-8] M 282.5, m US0.Crystd from acetic acid, then EtOH. Ellagic acid (2H20) [476-66-41 M 302.2, m >360°. Crystd from pyridine. Elymoclavine [548-43-61 M 254.3. Crystd from MeOH. Embonic acid (Pamoic acid, 4,4'-methylene bis[3-hydroxy-2-naphthalenecarboxylic acid]) [130-85-81 M 388.4, m >30O0. Forms crystals from dilute pyridine which decomposition above 280° without melting. It is almost insoluble in H20, EtOH, Et20, C6H6, CH3C02H, sparingly soluble in CHC13 but soluble in nitrobenzene, pyridine and alkalis [Barber and Gaimster J Appl Chem 2 565 19521. Emetidine hydrochloride hydrate [316-42- 71 M 553.6 + aq, m 235-240°, 235-250°, 240250°, 248-250O (depending on HzO content), [a]
